IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII Mas lllllllllllllllll‘lllllllllllllllllllllllll’lllllllillllllllllfl ‘ 3 1293 00627 2391 r ’ THE ELECTROPLATING 0F CONTINUOUS STEEL STRIP BY ROGER CLARK nwwEs A THESIS Submitted to the Graduate School of Michigan State College of Agriculture and Applied Science in partial fulfilment of the requirements for the degree of CHEMICAL ENGINEER Department of Chemical Engineering 1940 THESIS THE ELECTROPLATING OF CONTINUOUS STEEL STRIP ACKNOWLEDGEMENT \ To the following men for their ready and tai thful service in_this development work:- Harvey E. Hunt, William 0. Long, Jay B. Robinson, 1.. Bayard Spaulding, Alfred Bahm, Douglas R. Icintyre, Lester Saltsman and Eugene L. Combs. 1 Also tolir. LS. Hachtman and Mr. 34!. Hopper for their helpful suggestions. THE ELECTROPLATING OF CONTINUOUS STEEL STRIP INTRODUCTION Host electroplating prior to the deveIOpment of the plating of continuous steel strip was done on small parts or sections. The initial electroplating of steel was done on narrow strips and from.this successful oper- ation it seemed but a simple step to electroplate wider strips of steel. Hewever many difficulties arose from.the use of wider material. These difficulties were mostly of a mechanical nature. At the time this project was started no coils of tin-plate were manufactured. One could only make or obtain tin-plate in sheets of specified dimensions. It can read- ily be seen that the coils would make it possible to speed up the process of fabrication into containers and other articles so often made from.tin-plate, as well as to make the handling of the steel much.easier. This process of the manufacture of a super quality tin-plate by means of the electrodeposition of tin is a pro- cess of a secret type and thus it is impossible to discuss it in this paper. Hewever I can discuss the development of an iron electroplating bath, many steps of which closely follow the procedure and problems encountered in the tin plating lines. TEE ELECTROPLATING 0F CONTINUOUS STEEL STRIP I LABORATORY RESEARCH AND DEVELOPMENT OF AN ELECTROPLATING BATH The research steps taken in the laboratory are the most important steps in the development of a new bath for the Operation of electrodeposition. The purpose of this paper is to follow through the development of a bath from the laboratory to the final plating line in the mill. By previous research it had been found that in order to obtain a satisfactory tin-plate an undercoat of some metal was needed upon the steel, before the tin is deposited thereon. The problem is to produce an electrodeposit which will most nearly satisfy the following requirements: (1) The deposit must be relatively thin, (2) The deposit must not be brittle, (3) The deposit must be smooth, (4) The deposit must be free from too many pits, (5) The deposit must be produced cheaply, (6) The deposit must be such that a tin-plate free from pores can be obtained upon it by electrodeposition, (7) The deposit must be such that the tin-plate can be used for food cans; i.e. non-toxic in nature, (8) The deposit must be obtained at a high current density. Because of requirement, number seven (7) iron was one of the first metals chosen for investigation. By suit- able working and heat-treatment after deposition iron could be made to satisfy all eight (8) requirements. My number of iron baths may be found in the literature, but most of them have to be operated at very low current density. Thus the literature furnishes a start- ing point but fails to provide a satisfactory answer to requirement eight (8). The first requirement to obtain satisfactory results at high current densities is a satur- ated or strong solution. Better than one hundred baths were tried and the following have been chosen as the ex- amples in this report. (NOTE:- Considerable care has been taken to pick out most of the baths used by the author.) BATH 1 Fe804-(NH4)2804°6320 -------------- 350 grams/liter 118401 ----------------------------- lO grams/liter 1m ooca or (NaOOCH) --------------- 10 grams/liter 4 301.04 (neutralized with N33) ------ 20 grams/liter pH adjusted to -------------------- 4.7 Plating for three (3) minutes at forty (40) amperes per square foot gave plates which were gray in color. A slight improvement was noted when the pH was raised to 4.8 . The addition of ten (10) grams per liter of sodium format gave a brighter plate. Further tests were not made on this bath at this time. BATH 2 Fe804'(NH4)2804°6320 ----------- 350 grams/liter H401 --------------------------- 10 grams/liter NaOOCH -------------------------- 10 grams/liter pH - -------- - -------- - ----- ------ 5.0 The tin melt made from the iron plate from this bath was poor and had considerable "orange peel". (NOTE:- After the tin was electroplated upon' the undercoat it was melted in hot oil to give a bright, non-porous tin-plate. By ”orange peel" we mean the characteristic orange peel appearance that occurs on strip steel rather frequently.) is: additional ten (10) grams per liter of'sodium formats made no difference in either the iron depoeit or the tin melt. then the pH was lowered to 4.5 the plate boom bright and smooth, but the melt was still poor. An addi- tion of between twenty (20) and eighty (80) grams per liter of Cresol Sulphonic Acid did not help the plate or melt and in fact blisters were formed on the surface at pH 5.0 md 4.8 . An addition of one (1) cubic centimeter of Harshaw's Won-pitting Addition Agent' did no good, while two (2) cubic centimeters caused too great a lowering of the pH. The best plate was obtained from a bath contain- ing twenty (29) grams per liter of Sodium Formats with a pH of 4.7 . BATH 3 Fe804'(NH4)2SO4°6320 ---- -------- 350 grams/liter 313401 - -------------------------- 10 grams/liter NaOOCH - ------- - ------------- ---- 10 grams/liter pH use- nnnnnnnnnnnnnnnnnnnnnnnnn -- 4.9 This bath gave a very good plate but there was considerable I'orange pesl". Another addition of ten (10) grams per liter of Sodium‘Formate gave a very hard and brittle plate. The addition of ten (10) grams per liter of Amm0nium Perchlorate softened the plate a little, but increasing this addition to twenty (20) grams per liter completely ruined the deposit. BATH 4 Peso4-(sn4)zso4oenzo ------------ 350 grams/liter Baal ------------------ --------- - 10 grams/liter pH - .......... nun-counnonaoncn-O- 3.8 The plate from this bath was very poor. Two and one-half(2i) grams of Ferrous Lactate were added per liter, and the pH raised to 6.5 by the addition of a few drops of Ammonium Hydroxide. The result was a considerable precipi- tats of Ferric Hydroxide. Ten (10) drops of Sulfuric Acid was added to return the pH to a lower value of 4.5 . The deposit still was not good. A further addition of Ferrous Lactate was made, bringing the total to five (5) grams per liter. The plate was still very poor and in addition was very rough. After several more trials five (5) more grams per liter of Ferrous Lactate were added (ten (10) grams per liter total) and the pH adjusted to 5.3 . The plate from this bath was dark and rough but it was soft. Upon the addition of ten (10) grams per liter of Ammonium Formats the plate remained dark and also became pitted. Six (6) drops per liter of Sulfuric Acid were added to reduce the pH to 5.0 and a ten (10) minute plate was soft and smooth, although it contained several sharply defined dark areas. After filtration the above bath gave a badly peeled plate with fifteen (15) minutes of plating time. BATH 5 Fs804°(NH4)2804'6820 ------------ 350 grams/liter llaCl ----- ------- ---------------- 10 grams/liter NaOOCH -------- --------- -~------- 10 grams/liter M40104 - ----------------------- - 20 grams/liter The above plate was dark and was also pitted. For this reason this bath was discarded. BATH 6 Peso4-(m4)zso4°enzo ------------ 350 grams/liter 1111401 ------------ ----------- um 10 grams/liter NaOOCH ----- -------------------- - 10 grams/liter Fs(033503)2°3320 ---------------- 2.5 grams/liter The plate resulting from the above bath at forty (40) amperes per square foot was bright and smooth.but a little too brittle. A ten (10) mdnute plate gave a badly blistered melt. By increasing the wuantity of Ferrous Lactate to five (5) grams per liter the plate appeared a little softer. By trying to soften the plate still more with the addition to a total of ten (10) grams per liter of Ferrous Lactate, a melt with very bad I'orange peel“ resulted. Then the pH of the bath.was adjusted to 4.9 . A twenty (20) minute plate was soft and a three (5) minute plate gave a better melt but there was still ”orange peel", although it was of a finer grain. When a five (5) minute plate was made it was rather rough so five (5) grams per liter of Sodium.Formate (total 15g) were added. This gave a smoother two (2) minute plate and a better melt, but a fifteen (15) minute plate was brittle. An addition of five (5) grams per liter of Sodium Formats (total 20g) was made and a four (4) minute plate was soft and smooth and gave a better melt. This was the best yet obtained. By the use of a stronger Sulfuric Acid - Sodium Nitrate pickel a better melt was obtained on a four (4) minute plate, but there was a fine "orange peel“ present. After filtering, this bath gave the brightest plate so far obtained, but the plate was brittle and peeled after long plating periods. A.two (2) minute plate at 10 seventybfive (75) amperes per square foot gave a smooth and bright melt still blemished with a fine "orange peel”. Ban: 7 Fe804°(HH4)280406320 ----- ----- -- 350 grams/liter NH401 -------------- ----------- -- 10 grams/liter NaOOCH - ----- - -------------- ----- 5 grams/liter A different procedure was used in the case of this bath. It was made up in a twenty (20) gallon crock and one (1) liter samples were taken out for tests. The first plate obtained from this bath was dull, hard and had oxide streaks running over its entire surface. A five (5) gram per liter addition of Ammonium‘Formate did not remove the black streaks. Therefor five (5) more grams per liter of AmmoniumiFormate were added and the pH adjusted to 5.5 with the result that the plate had fewer black streaks. The next step was to take a fresh sample of the bath and add five (5) grams per liter of Bodium.Formate which gave a plate that still had black streaks, but these streaks were fewer in number. A five (5) cubic centimeter addition of Benzene Disulphonic Acid gave a bright, smooth, and hard plate. The pH was adjusted to 4.5 . Another new sample of the bath was taken from.the crock and tested for pH and plating characteristics. The pH was 4.6 and the plate had many black streaks upon it. 11 Five (5) cubic centimeters per liter of Benzene Disulphonic Acid were added and the resulting plate was the brightest iron plate yet obtained. Also the melt turned put to be the best, but the iron deposit was too hard and brittle. Upon standing over night the pH dropped to a point below5.8 and a few black streaks appeared upon the plate. In order to raise the pHTa few drops of Ammonium.Hydroxide were added. A few black streaks still remained on the edges of the plate. A number of streaks still remained after the addition of five (5) grams per liter of Sodium Para-phenol Sulphonato. An addition of five (5) cubic centimeters per liter of Benzene Disulphonic Acid gave a very low pH but at the same time the plate was bright. The pH"was raised to 4.5 with the addition of a few drops of Ammonium.Hydroxide, giving a plate with black streaks. These streakstere reduced in density by the addition of Sodium Formats in the quantity of five (5) grams per liter and an additional five (5) gram addition had no effect upon the plate. These black streaks were nearly eliminated by long electrolysis at high current density. Another sample taken from the crock had a pH of 5.2 . Again a plate deposited from this solution was very brittle and streaked with black. This sample was electro- lysed at seventy (70) amperes per square foot for fifteen (15).minutes. A two (2) minute, fifty (50) amperes per square foot plate was bright as also were three (5) and four (4) minute plates made at the same current density. A five (5) minute plate was slightly grayish, smooth and even but brittle. An addition of five (5) grams per liter of Ammonium.Perchlorate gave a plate that was still brittle. Further additions of Ammonium Perchlorate to a total of ten (10) grams per liter resulted in no observable change in the plate; to a total of fifteen (15) grams per liter gave a plate slightly less brittle; to a total of twenty (20) grams per liter gave a soft plate. Five minute plates with all of the above additions yielded a dull plate at fifty (50) amperes per square foot. The addition of Ferrous Lactate to the above bath was the next trial. A one (1) gram.psr liter addition gave a bright, smooth.plate and the melt was good only on one side. Several four (4) minute plates at forty-five (45) amperes per square foot were checked. When two (2) grams per liter of Ferrous Lactate were added the bath.became quite turbid and the plate was gray, necessitating the filtration of the solution. Before this bath.was discarded five (5) grams per liter of Sodium Formats were added but it did not brighten the plate. One (1) gram of 2-Naphthol-6-Sulphonic Acid added per liter yielded a bright, smooth and soft plate. The addition of two (2) grams per liter made no difference although five (5) grams per liter gave a bright five (5) minute plate. 13 Streaks began to show at the end of a ten (10) minute plat- ing interval although the plate remained soft. when the concentration of a 2-Haphthol-6-Sulphonic Acid was increased to ten (10) grams the same sort of plate resulted. Some of this addition agent was removed by the addition of six (6) drops per liter of Sulfuric Acid to lower the pB to 4.7 . Several plates made at sixty (60) amperes per square foot gave good melts. Another liter sample was taken from the creek and an addition of five (5) grams per liter of 2-Naphthol- 6-Sulphonic Acid made lowering the pH to 4.1 . This plate was fine but the tin contained more “orange peel" than in the above case and was not quite as good quality. When this solution was filtered a large amount of the 2- Naphthol-S-Sulphonic Acid remained on the filter. One (1) gram.per liter of Diphenyl Sulphonic Acid was added to the above bath and the result was a fair plate and a fair melt. After three (5) minutes of plating at sixty (60) amperes per square foot the streaks all vanished but the plate tended to have a grayish color. Diphenyl Sulphonic Acid was added, bringing the total to two (2) grams per liter, and the resulting plate was even and soft but still gray. This plate was a fifteen (15) minute plate made at the same current density of sixty (60) amperes per square foot. An increase to five (5) grams per liter of this addition agent resulted in a brighter five (5) minute plate 14 but the soft plate turned gray color after a ten (10) minute plate. ‘lith and increase of the Diphenyl Sulphonic Acid to ten (10) grams per liter rough streaks appeared after five (5) minutes of plating, but the plate was bright and soft. At the same time the solution became cloudy and then cleared up. A check of the pH showed a value less than 3.8 and enough Ammonium.Hydroxide was added to bring the pH value to 4.2, giving a dark,smooth and soft plate. A new sample of the crock solution was plated at sixty (60) amperes per square foot for ten (10) minutes. The pH increased to 6.4 and Ferric Hydroxide was precipi- tated. The deposit was bright on the edges and dark in the center. The center was fairly bright, unless contrasted.with the edge, and was soft. The bright edge was very brittle. Three (3) drops per liter of Sulphuric Acid gave a pH of 6.3 and the deposit remained about the same. Six (6) drOps per liter of Sulfuric Acid lowered the prto 5.6, from which a poor, streaked, brittle, and black centered plate was obtained. Three (3) more draps per liter of Sulfuric Acid gave a pH of 5.3 and a very poor deposit. Filtering of the solution did reduce slightly the area of darkness upon the plate. An additional three (3) drops per liter of Sulfuric Acid gave a pH of 5.0 which improved the appearance of the plate a slight amount, but the plate was still brittle. Another acid addit- ion of three (3) drops per liter gave a pH of 4.8 and the same brittle plate. Three (3) more drops per liter of acid 15 and the resulting pH of 4.7 gave the same type of deposit. Six (6) drops per liter of acid reduced the pH to 4.5 and there was no change in the plate. The bath was then run at a current density of sixty (60) amperes per square foot for an hour, after which the anodes had to be cleaned. This long run increased the pH and the addition of twelve (12) drops per liter of Sulfuric Acid lowered the pH to 4.1, giving a poorer deposit as well as raising the voltage from two (2) to two and eight tenths (2.8). At a pH of 3.6 the anodes went into solution very rapidly and the plates were streaked and very brittle. From this series of tests it appears that the best range of pH is 4.5 to 5.0 . The next variable to be taken into consideration was the current density. The pH chosen for a study of this variable was 4.7 . At thirty (30) amperes per square foot a brittle gray area appeared around the edge of the plate after twenty (20) minutes time. A plate of similar appearance but softer resulted from fifteen (15) minutes of plating at a current density of forty-five (45) amperes per square foot. Sixty (60) amperes per square foot was used as a check once more and the results agreed with previous tests. Sodium Formats in five (5), ten (10), fifteen (15) and twenty (20) gram.additions per liter progressively brightened the plate but caused it to become brittle. 16 The efficiency of the iron bath in the crock was determined at several different pH values. At a pH of 5.0 the efficiency at the cathode was nintyhsix and four tenths percent (96.4%) while at a pH of 3.6 the cathode efficiency dropped to a value of eighty-five and one tenth percent (85.1%). Other values of efficiency were : pH 6.0 gave nine- ty-three and seven tenths percent (93.7%), pH 4.6 gave nine- ty-two and six tenths percent (92.6%), and a pH of 5.4 gave ninety-five and nine tenths percent (95.9%) at the cathode. This again places the best pH values in the range of 4.5 to 5.6 e Sodiumpueta-benzene Disulphonate in a one (1) gram per liter addition did not seem.to make much.difference in the deposit. After increasing this addition agent to two (2) grams per liter the plate became very bright and smooth after a ten (10) minute run, and the plate still remained firm and bright even after thirty (30) minutes. After forty (40) minutes the plate began to pull away from the steel but it still seemed to be soft. An increase to five (5) grams per liter of Sodiumpketa-benzene Disulphonate did not change the plate or melt unless there was a slight increase in the amount of "orange peel”. A ten (10) grams per liter addition gave a bright plate which.pulled away from the steel. “\\\s\_‘\\ _ . H M . l H . _ 5 sunset?” ‘ m _ I . .30. an. em. mm“. ea. in. an. cu. n...» ma. use use owe a». can u— 3 _ .-——1 . _ . ,, ‘ a m . . A . hunt. ices _ a A _ , Eek _ , i , . £330 \oaSuQKNR tax . as sees no I I6 , _ {owe/1.1.7 2: | . . i . _ c H A _ _ . i __ A u w. i H i w p a . a i i e e . (I 1 ix 1,1 l I l I , -1 m _ m _ _ no , e , a . , _ i , i . w I 1 a . .. a x i , M a. 18 BATH 8 FeSO4'(NH4)ZSO4°6320 ------------ 350 grams/liter NH4CI - ------------------------ -- 10 grams/liter The plates from this bath were dull gray, pitted around the edge, and soft. The melt was dull and there was considerable "orange peel". An addition of two (2) grams per liter of SodiumpMeta-benzene Disulphonate did not make any apparent change in the plate. Another addition agent tried on this bath.was Beta-Naphthol, which would not go into solution and did not make any apparent change in the plate. The cathode efficiency of this bath was ninety- seven percent (97%). We can at this time arrive at several conclusions regarding the iron baths investigated. SodiumpMeta-benzene Disulphonate was a very good brightener, but did not effect the melt or soften the iron deposit. An increase in concentration above two (2) grams per liter did not improve the brightening characteristics. This addition agent can be used to clear up dark areas in the deposit but has no further use in this bath. Its use is not recommended as very good results can be obtained by the proper control of the plating conditions. 19 Beta-Haphthol had no effect either as a brightener or softener. Sodium Bromate acted as a buffer in the bath, and for this reason had an indirect effect upon the quality of the deposit. Sodium-Meta-benzene Disulphonate without Sodium Formats or Ammonium Perchlorate was no good and it was nearly impossible to control the pH of the bath in this case. Ammonium Perchlorate softens the plate but it is not needed in the case of the thin deposits in this type of work. BATH 9 FeSO4o(NH4)ZSO4°6H20 ---------—-- 350 grams/liter m4c1 --- ---------------------- -- 10 hrams/liter NaOOCH ------------------- ----- -- 10 grams/liter NH40104 ------------------------- 20 grams/liter This formula seems to give the best results in the tests so far conducted. At this time a sample of Bath seven (7) was taken from the crock and the efficiency was determined at vartous current densities and various temperatures. 20 pH held constant at 4.9 Current Density Efficiency Amps./Sq, Ft Percent so ------- ----- - ---------- - 95.5 45 - ------- - ----------- ---- 95.7 60 ------------------------ 95.0 75 ----- --------- - -------- - 94.4 There was a tendency for the deposit to pit at seventy-five (75) amperes per square foot, due to the greater liberation of hydrogen as shown by the lower value of the efficiency for this current density value. Current density held at forty (40) amperes per square foot and pH at 4.9, with a variation in the temp perature gave the following data: Temperature Efficiency °C (Percent 34 -- ----------------------- 96.9 47 ----------------- -------- 97.0 21 IIIIIII IIII .. . Egan-ere _-_- ..... Tl: . .._. TT.- - I II I — I I I C _ . — e I I 'lIs I - I I I III III I IIII IIIII II I I I ' I e In I —- 'I—I_--II—.I _I_- I—. 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Two (2) minutes of plating at sixty (60) amperes per square foot gave the best melts in the case of this bath. The use of higher current densities caused pitting. T By using agitation there was less tendency for the plate to pull away from the edges and also the plate appeared brighter. After plating at forty-five (45) amperes per square foot for eight (8) minutes, cracks began to show over the surface of the deposit. A plate made from two (2) minutes at forty-five (45) amperes per square foot gave a good melt while a very good melt was obtained by increasing the time to three (5) minutes at the same current density. At higher temperatures the plate darkened and became coarse in appearance, also Ferric Hydroxide was formed quite read- ily. However the plate was softer at the higher temperatures and the roughness or coarseness seems to be due to pitting. The following results were obtained by the addi- tion of Harshaw's 'Non-pitter': Five (5) cubic centimeters per liter - plate smoother and possibly a bit softer; ten(10) cubic centimeters - no further improvement; twenty (20) cubic centimeters - bright on one side and gray on the other; fifty (50) cubic centimeters - same appearing plate but just 23 a little softer; one hundred (100) cubic centimeters gave no apparent improvement. Another sample of Bath seven (7) was changed by the addition of twenty (20) grams per liter of Ammonium.Per- chlorate. After six (6) minutes of electrolysis the plate began to crack at the edges. In creasing the quantity of this addition agent to thirty (30) and then to forty (40) grams per liter seemed to make no improvement in the plate. when the concentration of Ammonium.Perchlorate was raised to fifty (50) grams per liter the plate pulled away from the edges at the end of ten (10) minutes. The addition of five (5) grams per liter of Sodium Perborate to Bath seven (7) oxidised all of the iron to the Ferric state. The resulting deposit was very soft with burned edges. Also there was copious gassing at the anodes. A current density of forty-five (45) amperes per square foot after adding five (5) grams per liter of Boric Acid to Bath seven (7) gave a gray plate. An increase of this agent to ten (10) grams per liter and an increase in current density to sixty (60) amperes per square foot gave a deposit containing many black areas. A liter sample of Bath seven (7) plus five (5) cubic centimeters of 65% - Technical Benzene Sulphonic Acid, without the use of agitation, gave a plate which‘was very 24 brittle on one side only. Increasing the amount of the addition agent to ten (10) cubic centimeters gave a very bright and soft plate. The addition agent was slightly removed from this solution when filtered, but it was later concluded that the clearing of the solution was due large- ly to the removal of Ferric iron. Still another sample of Bath seven (7) was taken in order to make some further checks tn current density. The following periods of time are needed in order to get a deposit of iron seven one hundredths (0.07) of an ounce per square foot: Current Density Tums Amps./Sq.Ft. Minutes so -- ------------------ 4.5 45 ---- ---------------- 3.0 60 ~------------------- 2.25 Thirty (30) amperes per square foot gave a soft plate with no cracking at the edges. Forty-five (45) amperes per square foot gave a soft plate with a very slight amount of cracking at the edges. Sixty (60) amperes per square foot gave a brittle plate which cracked upon using the bend test for softness determination. However at the higher current density the plate was a bit brighter. Still more tests were made using the different current densities with the following results: Using thirty 25 (30) amperes per square foot the first sign of cracks at the corners of the plate showed up after five (5) minutes of plating time. The edges started to crack after eight (8) minutes of plating time. With forty-five (45) amperes per square foot cracks appeared at the corners within two minutes time and the edges started cracking after four minutes. The same length of plating time, two (2) minutes, at a current density of sixty (60) amperes per square foot gave cracks at the corners. Hewever the time necessary for the cracks to appear at the edges shortened to three (3) minutes. At this stage of the tests a twenty (20) grams per liter addition of Ammonium Perchlorate was made to the bath, this made the total forty (40) grams per liter, with no noticeable improvement in the deposit. Ten (10) cubic centimeters of 65%-Technical Benzene Sulphonic Acid added to one (1) liter of Bath seven (7) gave a pH of 4.7 . 'Iithout agitation a soft plate with dark areas was obtained. When agitation was used the plate was soft and quite bright. A ten (10) minute plate showed very little tendency to peel at the edges and was the softest plate yet obtained from an iron bath. Filtration of the bath at this point did not change the characteristics of the deposit. Hewever after electrolysis for twenty (20) minutes the plate peeled at the edges but still remained soft as far as the bend tests were concerned. Then a three (3) minute plate 26 made right after this test peeled very badly at the edges, which would indicate that the addition agent had run out, probably in part because of the filtration operation. There- for ten (10) cubic centimeters of a.filtration solution, made up of twenty five (25) cubic centimeters of 65%-Technical Sulphonic Acid and seventy-five (75) cubic ventimeters of water were added. A one and one-half (1%) hour plate did not peel as much as the previous one, or as much as the plate from the solution containing forty (40) grams per liter of Ammonium Perchlorate plated over the same period of time. Three (3) minutes at forty-five (45) amperes per square foot gave a plate that was both soft and bright. The pH of the bath at this time was determined to be 4.5 . Ammonium Formats did not seem to have much effect as a brightening agent. Sodium Formats was better as an addition agent but it caused the deposit to be hard. From many tests a concentration of ten (10) grams per liter was determdned as the optimum. It was found, much to our amazement, that a deposit of six one hundredths (0.06) of an ounce per square foot of tin did not give as fine an appearing tin plate on the iron undercoat as did a deposit of only three one hun- dredths (0.03) of an ounce per square foot. Harshaw's 'Non-pitter' did not improve the iron deposit when used within the ecconomical concentrations of one (I) or two (2) cubic centimeters per liter. 27 Ammonium Perchlorate softened the plate but a concentration of twenty (20) grams per liter was needed to accomplish it. Ferrous Lactate in a quantity of ten (10) grams per liter gave a soft plate but it was rough. Benzene Disulphonic Acid gave a bright, smooth, and hard plate while SodiumrPara-phenol Sulphonate, even in concentrations as high as five (5) grams per liter, did not eliminate the dark streaks in the deposit. BATH 10 FeSO4-(NH4)ZSO4°6H20 -4----------- 350 grams/liter NH4C1 --------------------------- 10 grams/liter NaOOCH - --------- -------- ------- - 5 grams/liter A plate from this bath, after it had been thorough- ly worked in, had many dark streaks. Below are tabulated the results of different quantities of Ammonium Perchlorate ‘upon the properties of the plate: Total gramm/Iiter Results Ammonium Perchlorate 5, ---------------- - ------ Gave a brittle plate 10 - -------------- ------- Gave a brittle plate 15 ----------- - ---------- Slightly softened plate 20 -— ------------------- - Still softer plate 30 - --------------------- Still softer plate 40 --------------------- - Still softer plate 50 - ---------- - -------- -- No improvement in plate, higher efficiency. 28 Using this same bath the effect of the pH again was tested with the results tabulated below: fiH 6.4 6.3 5.6 5.3 5.0 4.8 4.7 4.5 4.1 3.6 Results Ferric Hydroxide precipitate in solution; areas of dark color on edge of deposit The same results as with the above pH Plate has black areas - specks - brittle Plate has black areas - specks - brittle Some improvement in plate - brittle No Ferric Hydroxide - brittle plate No Ferric Hydroxide - brittle plate No Ferric Hydroxide - brittle plate No Ferric Hydroxide - more brittle plate Black streaks - very brittle - anode efficiency too high The best pH range seems to fall aroind 4.5 to 5.0 . For a number of months the work digressed from the simple Iron baths to baths of Iron and Nickel salts. This type bath gave very excellent plates of Iron-Nickel alloy. It was, however, hard to obtain uniform results and the plate was rather expensive, because of the need of replacing the salts of Nickel very often due to poor anode corrosion. For this reason Chloride baths were tried for the deposition of the alloys, which finally led to Chloride Iron baths. 29 BATH 11 F0012.4H20 ------------ HCl ‘ """"""""""""""""" - 10 cc/liter 400 grams/liter These Chloride baths had to be run at 190°F. or higher, but the current densities could be run up to as high.as three hundred (300) amperes per square foot. Bath eleven (11) oxidized very rapidly but gave a good deposit and there was more than enough anode cor- rosion. At this time the current density trials were made both with and without the use of agitation. The results of these trials follow: N0 AGITATTON Current Density Results Amps./Sq.Ft. 30 -- -------------- Uniform.gray and soft 45 ---------------- Not as uniform in color and not as soft 60 --------------- - Plate very rough and quite hard 75 ---------------- Plate full of pits 100 - --------------- Plate full of pits AGITATION Current Density Results Amps./Sq.rt. 3O ----------------- Excellent plate 45 - ------------- --- Excellent plate 60 ----------------- Very good plate 75 - ------------- --- Poor, pitted plate 100 - ----------- ----- Poorer plate 300 - ------------ ---- Poorer plate lhile engaged in the research upon the Iron- Nickel baths, it was determined that the addition of a small quantity of Sodium.Tartrate to the hot Chloride baths seemed to aid in the deposition. However the greatest help of the Tartrate was the prevention of ex- cessive oxidation in the heated baths. The second Chloride bath was made up from.this experience as Bath twelve (12). BATH 12 Fe012'4H20 - ----- --------------— 200 grams/liter H01 - --------------------------- 10 cc/liter (0.204n) NaZC4H4O6 --------------------- - 1 gram/liter This bath gave excellent plates and was very easily controlled. The above solution really marked the end of the investigation for a suitable Iron bath for use in depositing and undercoat preparatory to tin plating. 31 Also heat treatment of the deposit fulfilled all the re- quirements stated at the beginning of this paper. The addition of four (4) cubic centimeters per liter of Hydrochloric Acid when the bath.became cloudy gave a clear bath. The high acid concentration gave gasses at the cathode while lower acid concentrations did not yield gassing. The cloudiness was due to the slight precipitation of Ferric Iron at lower acid con- centrations. The concentration range should be between fifteen hundredths (0.15) normal and thirty hundredths (0.30) normal in Hydrochloric Acid. The following pages contain data obtained from this bath and also some other rather interesting data obtained in the laboratory. 32 Data Obtained From.Bath 12 No Agitation Temperature 19009 0.15 N in H01 Current Density Efficiency Remarks Amperes/Sq. Ft. Percentage Concerning plate 5 -- ----------- --- 95.0 - ----- --- Dull and dark 10 ---------------- 99.1 - -------- Bright, gray and smooth 20 - ------- -------- 99.0 --------- Bright, gray and smooth 40 - -------------- - 99.5 - ------- - Uniform gray and soft 80 -------------- -- 98.9 - ------- - Streaked 160 - ------------- -- 94.0 - ------- - Streaked and pitted 320 - -------------- - 81.3 - -------- Peeled edges and pits Agitation Temperature 190°F. 0.15 N in HCl Current Density Efficiency Remarks Amperes/Sq.Ft. ' Percentage Concerning Plate 5 ---------- ----- -90.6 --------- Light gray 10 ------ -------- -- 95.5 --‘------- Light gray 2O -—---- --------- - 94.8 --------- Light gray 40 ---------------- 97.6 - -------- Light gray and soft 80 - -------------- - 94.0 --------- Streaked and pitted 160 ---------------- 83.2 - -------- Edge peeled and pits 320 ---------------- 80.0 - ------- - Edge peeled and pits 500 - --------------- 75.5 --------- Edge and center peeled III-I '1IIIIa _-- : Us. \-\.\._.W\I.W._ I henna. a I _ OI IO I 9 I Cult. 0 loll. I l _-- - {Axe-Se. Khfimaau {SENT-xi m .N\ ski . I I l i "I I .v 34 No Agitation Temperature 190°F Current Density ' Efficiency Amperes/Sq.Ft. Percentage 5 - ----- -------—-e 96.0 ---------- 10 - -------- -------- 96.1 ---------- 20 ---------------r- 95.8 --- ------- 40 ----------------- 97.9 --------- - 80 --------------r-- 98.1 ---------- 150 ----------------- 97.0 - -------- - 320 - ---------------- 80.0 - --------- Agitation Temperature 190°? Current Density ' Efficiency Amperes/Sq.Ft. Percentage 5 ----+ ------------ 90.2 .--4 ------ 10 --- ------------ -- 95.5 .L-e4----- 20 --------------- -- 99.0 --e ----- -- 40 - ------------- --- 99.6 - ------ --- 80 ------------ ----- 99.5 --- ----- ~- 160 -- -------- - ----- - 98.7 ---------- 320 - ----- - -------- -- 97.1 ---------- 0.204 N in HCl Remarks Concerning Plate Uniform, gray and Uniform, gray and Uniform, gray and Uniform, gray and- Uniform, gray and soft soft soft soft soft Streaked and brittle Streaked and pitted 0.204 N in HCl Remarks Concerning Plate Uniform-gray Uniform.gray Uniform gray Uniform gray Uniform gray Uniform gray Uniform.gray 500 - ---------------- 91.0 ---------- Uniform-gray .< .I .3 8. III! : ex. IE 3.. «32:2. 2 Ouivthn .92 I 56 No Agitation Temperature 190°F 0.30 N in H01 Current Density Efficiency Remarks Amperes/Sq.Ft. Percentage Concerning Plate 5 --- ----------- -- 87.3 -- ----- Light gray and non-uniform 10 -- ------- ------- 89.0 ----- - Light gray and non-uniform 20 ~------ -------- - 90.3 ------ Light gray and non-uniform 40 -- ----- --------- 95.5 ------ Light gray and brittle 80 - ----------- ---- 92.1 ----- - Light gray and brittle 160 ---------------- 82.0 ------ Streaked and britt1e 320 ----- - --------- - 77.0 ------ Pitted and peeled 500 ---- ------------ 8.0 - ----- Plate did not adhere Agitation Temperature 190°r 0.50 n in H01 Current Density Efficiency Remarks Amperes/Sq.Ft. Percentage Concerning Plate 5 - -------------- - 85.0 — ----------- Streaked 10 - --------------- 85.1 -- ---------- Streaked 20 ---------------- 86.0 -- ---------- Streaked 4O - ------- -------- 93.6 - -------- --- Good gray and brittle 80 - -------------- - 85.0 - ---------- - Streaked and pits 160 - ------------ -- 75.0 - ---------- - A mass of pits 320 - ------ - ------ - 18.7 - ----------- All pitted 500 ------------- -- 1.4 --- -------- - Not visible Optimum conditions seemed to be: agitation, 190°F., 0.204 N in Hydrochloric Acid and sixty (60) amperes per square foot of current density. 3'7 '1 I .3 Z- .91! :51. “lb. Oh II¢<=OV :— ofllnvafia .92 I 38 Because there was such.a great loss of Hydro- chloric Acid during the tests it was supposed that a con- siderable quantity must be going off in vapor form. The following table taken from the International Critical Tables shows this assumption to be wrong. Evidently the acid was lost by Attack upon the anodes and dragout loss. Partial Vapor Pressure of Hydrochloric Acid in Hillimetsrs of Mercury at Various Temperatures 01?. °c. 6% 12% 24% 36% % Commercial Acid 16.6% 55.5% 66.6% 100% 68 ---- 20 -- 0.00076 - 0.0088 -- 1.00 ---- 105.5 77 ---- 25 -- 0.00131 - 0.0145 -- 1.49 ---- 142 86 ---- 30 -- 0.00225 - 0.0234 -- 2.17 ---- 188 95 ---- 35 -- 0.0038 - 0.037 -- 3.14 ---- 246 104 ---- 40 -- 0.0062 - 0.058 -- 4.5 ---- 322 113 ---- 45 -- 0.0102 - 0.0102 -- 6.4 ---- 416 122 ---- 50 -- 0.0163 - 0.136 -- 8.9 ---- 535 140 ---- 60 -- 0.040 - 0.305 -- 16.9 ---- 860 158 ---- 70 -- 0.094 - 0.66 -- 31.0 -------- 176 -“’- 80 -" 0.206 - 1.34 -.. 54.5 o ....... 194 -'-" 90 -" 0044 - 2e65 ‘"' 94.0 --"'--- 212 -"'"’100 -" 0.92 '- 50]. -- 157 I nnnnnnn 250 --- 110 -- 1.78 - 9.3 -- 253 -------- 59 The next factor that should be taken into con- sideration is the relative time of immersion in the vari- ous baths or units. Bath or Unit Time of Immersion Cleaner (Dri-sil) - --------------------- 45 seconds ‘Wash Tanks (Hot Water) - ---------------- 30 Seconds Scrubbers (Brush and Water) ~----------- 5 Seconds Pickle (Sulfuric Acid-Sodium.Nitrate) -- 30 Seconds Plating Tank (Iron) --- ----------- ------ 2.25 minutes Drier (H0t Air) ------------------------ 10 Seconds Another set of data needed by the designer is a set of corrosion tests. These tests were made in flasks connected to reflux condensers and the temperature of the solutions was held as near 190°F. as was possible. This data, which will be found on the following pages, includes a little data on Hydrochloric Acid alone as a comparison. 40 Tests on Corrosion Resistant Alloys 2N'HCI at 190 - 2009?. Sample Hours Loss in Inches of Percent Order of Run Grams Penetration/Yr. Loss Resistance Hastaloy A - l7 - 0.1960 -- ----------------- 0.46 -—---- 3 Hastaloy B - 17 - 0.0701 - ----------------- - 0.105 ----- l Hastaloy c - 17 - 0.4904 ------------------- 0.82 ----—- 5 Hastaloy D - 17 - 0.7279 -------- - ---------- 1.2 ------- 8 MOnel ------ l7 - 1.4033 ----- ------------- - 6.0 ------ - 14 Stainless -- 17 -23.2619 - ------------------ 100.0 ------ 17 Resistol 3 - 17 -28.3665 --------- -------- --80.0 ------- 16 Stellite 1 - l7 -1l.5707 ------------------ 18.7 ---—--- 15 Durichlor -- 17 - 0.4581 - ------------- -—-- 0.52 ------ 4 Duriron ---- 17 - 0.5847 -------- ------- --- 1.05 ------ 7 Alloy 24 --- 24 - 0.1220 ------ 0.086 ----- 0.84 ------ 6 Alloy 1010 - 24 - 0.2239 ------ 0.138 ----- 2.0 ------ 9 Alloy 701 -- 24 - 0.5180 ------ 0.274 ----- 2.7 ------ 11 Alloy 1 --- 22% - 3.5745 ------ 1.4945 ---- 2.09 ------ 10 Alloy 45 -- 22% - 0.4038 ------ 0.1883 ---- 0.24 - ----- 2 Alloy 103P ~22§ - 1.8640 ------ 2.0057 ~--- 2.75 ------ 12 Alloy 111 - 22% - 7.0303 ------ 3.2309 ---- 4.56 ------ 13 41 Tests on Corrosion Resistant Alloys Iron (Ferrous) Chloride Sample Hours Loss in Inches of Percent Order Run Grams Penetration/Yr. Loss Resist. Hastaloy A - 11% -- 0.1075 -------------------- 0.25 - ........ Hastaloy A - 55} -- 0.2126 -------- 0.09 ------ 0.49 ---- 5 Hastaloy B - 11% -- 0.0928 -------------------- 0.14 --------- Hastaloy B - 33% -- 0.2008 -------- 0.05 ------ 0.3 ---- 4 Hastaloy C - 11 -- 0.0795 -------------------- 0.15 --------- Hastaloy C - 33% -- 0.1723 ~------- 0.05 ------ 0.3 ---- 3 Hastaloy D - ll§‘-- 0.1915 -- ------------------ 0.5 ---- ..... - Hastaloy D - 33% -- 0.3766 -------- 0.106 ----- 0.6 ----- 6 Resistol 5 - 9 --- 6.7602 ------------------ --19.4 - ........ Resistol 3 - 16 --- 8.1398 - ------------------ 22.1 - ------ --- Resistol 3 - 32 --10.2614 - ------------------ 27.9 ----- 18 Stellite 1 - 9 ---- 4.5570 - ------------------ 9.0 - ...... --- Stellite 1 - 16 ---- 6.7611 - ------------------ 11.6 ------ ---- Stellite 1 - 52 ----10.6870 - ------------------ 19.5 ------ 17 Durichlor - 2% --g- 0.3343 - ------------------ 0.5 --—------- Durichlor - 10% --- 0.557a:------- ------- ----- 0.95 - ..... --- Durichlor - 32 ---- 0.7495 -- ------ 2.5 ------ 1.2 ----- -9 Haveg ------ 2 ---- 0.3990 gain -------------- 4.0 gain ----- Haveg ------ 10 ---- 0.4042 gain - ------------ - 4.2 gain or--- Beveg ------ 32 ---- 0.4086 gain - ------------ - 4.4 gain ----— 42; Tests on Corrosion Resistant Alloys Iron (Ferrous) Chloride Sample Hours Loss in Inches of Percent Order Run Grams Penetration/Yr. Loss Resist. Duriron ---- 8 ---- 0.3850 - ---------------- 0.3 ---------- Duriron ---- 24 --- 0.8400 ------ 1.5 ------ 0.7 ------ 7 Monel ------ 24 --- 1.2662 ------ 7.0 - ----- 4.9 ------ 15 Copper ----- 24 --- 0.5545 ------ 0.97 ----- 1.21 ----- 10 Alloy 24 --- 24 --- 0.3133 ------ 0.226 ---- 2.24 ----- 12 Alloy 1010 - 24 --- 0.6822 ------ 0.414 ---- 5.9 ----- 16 Alloy 701 -- 24 --- 0.4536 - ----- 0.244 ---- 2.4 ----- 13 Alloy 1 ---- 18% -- 0.3634 ------ 0.1834 --- 0.21 ----- 2 Alloy 45 --- 194 -- 0.1401 ------ 0.0794 --- 0.092 ---- 1 Alloy 103P - 18% -- 0.9235 ------ 1.1923 --- 1.35 ----- 11 Alloy 111 -- 18% -- 1.4445 - ----- 0.7999 --- 0.93 ----- 8 The Alloy 24; 1010; 701; l; 45; 103P; and 111 a special composition of brass. is 43 Although it may seem a little out of place in the report the data given below shows the distribution of the Iron deposit upon a twenty (20) inch steel strip from the plating line as used in a mill. uniformity of Deposit Metal Plus Metal‘Wt. It. of Ounces per Pounds per Iron Grams Grams Deposit Sq. Ft. Base Box 3.1269 --- 3.0933 ---- 0.0336 ---- 0.0853 ----- - 1.16 3.2720 --- 3.2535 ---- 0.0185 ---- 0.0470 ------- 0.639 3.2515 --- 3.2332 ---- 0.0183 ---- 0.0465 ------ - 0.632 3.2026 --- 3.1866 ---- 0.0160 ---- 0.0406 -- ----- 0.552 3.2539 --- 3.2374 ---- 0.0165 ---- 0.0419 ------- 0.570 3.2195 --- 3.2045 ---- 0.0150 ---- 0.0381 ------ - 0.518 3.2300 --- 3.2136 ---- 0.0164 ---- 0.0416 ------- 0.566 3.2779 --- 3.2617 ---- 0.0162 ---- 0.0411 ----- -- 0.559 3.1629 --- 3.1456 ---- 0.0173 ---- 0.0439 - ----- - 0.597 3.3083 --- 3.2924 ---- 0.0159 ---- 0.0404 ------- 0.549 3.2727 --- 3.2567 ---- 0.0160 ---- 0.0406 ------- 0.552 3.2167 --- 3.2023 ---- 0.0144 ---- 0.0365 ------- 0.496 3.1649 --- 3.1494 ---- 0.0145 ---- 0.0367 - ------ 0.499 3.2900 --~ 3.2751 ---- 0.0149 ---- 0.0379 ------- 0.515 3.2164 --- 3.2012 ---- 0.0152 ---- 0.0385 ------ - 0.525 3.2364 --- 3.2215 ---- 0.0149 ---- 0.0379 ------- 0.515 3.1750 --- 3.1600 ---- 0.0156 ---- 0.0381 ------- 0.518 3.1447 --- 3.1292 ---- 0.0155 ---- 0.0393 ------- 0.535 44 natal Plus Metal'lt. Wt. of Ounces Per Pounds Per Iron Grams Grams Deposit Sq. Ft. Base Box 3.1862 ---- 3.1697 --- 0.0165 ---- 0.0419 ----- 0.570 3.2509 ---- 3.2218 --- 0.0291 ---- 0.0739 ----- 1.01 Total Area -------- --- 0.2497 ---- 0.0634 ----- 0.862 By the elimination of many false leads the follow- ing analytical procedures were worked out for the control of the solutions used in the Iron Plating Line. Dri-sil Cleaner Pipette a twenty-five (25) mdlliliter sample of the cleaner into a two hundred and fifty (250) milliliter volumetric flask and dilute to the graduation mark with freshly boiled distilled water. A ten (10) milliliter portion of this diluted cleaner is used for the analysis. Pipette this ten (10) milliliter sample into a two hun- dred and fifty (250) milliliter flask, add fifty (50) milli- liters of distilled water, three (3) dr0ps of phenolphtha- lein indicator solution and titrate with standard hydro- chloric Acid. ‘Iith this cleaner methyl orange gives nearly the same end-point. Calculations m1. of HCl 3 N of H01 ' Normality of the cleaner Normality of cleaner x 5.92“ Oz. per gallon of cleaner or gen. of 301) (N of HCl)j5.92) I Oz.per gallon of cleaner (ha; of sample 45 Pickle Analysis Total Acidity Pipette a twenty-five (25) milliliter sample of the pickle into a two hundred and fifty (250) milliliter volumetric flask and dilute to the mark with freshly boil- ed distilled water. Pipette a ten (10) milliliter sample of this diluted pickle into a two hundred and fifty (250) milliliter flask and titrate with standard sodium hydroxide using phenolphthalein as the indicator. Calculations ml. of NaOH x N of NaOH 3 Normality of acids N of acids 1 (49 x 0.135} - 02. per gallon of Sul- . furic Acid N of acids 1: 2.79 - {by vol. of 100% Sulfuric Acid (m1. of Na0H1(N of NaOH)(2.67) I fi'by volume of Tech- (ml. of sampIS) nical Sulfuric Acid Sodium.Nitrate Sodium Nitrate is determined by the use of a special reagent; FeSO4'7H20 - 278 grams per liter and 32804 - 450 grams per liter. Results are very poor unless the following procedure is followed exactly: Using a graduated cylinder, measure twenty (20) milliliters of concentrated Sulfuric Acid into a five hun- dred (500) milliliter flask. Then carefully add a five (5) mdlliliter sample of the pickle (Not Diluted) keeping the 46 pipette tip under the surface of the concentrated acid and rotating the flask to prevent local overheating. Keeping the temperature below 60°C., by means of a water bath, titrate to a red coloration using the above mentioned special reagent. Calculations m1.FeSO4 used x 0.9755 I Oz. per gallon NaNOs Iron Bath Hydrochloric Acid Pipette a ten (10) milliliter sample of the bath into a two hundred and fifty (250) milliliter flask. Add ten (10) milliliters of glycerine and a dr0pper full of brom0phenol blue indicator. Titrate with standard sodiwm hydroxide to an aquamarine blue. Express the acidity in terms of normality. Ferrous Iron Pipette a five (5) milliliter sample of the bath into a five hundred (500) milliliter flask. 'Add twentyb five (25) milliliters of concentrated hydrochloric acid and fifteen (15) milliliters of phosphate reagent (150 g/l H2804 and 150 g/l 33PO4). Dilute to two hundred fifty (250) milliliters with freshly‘boiled distilled water and then add ten (10) drops of diphenylamine indicator. Titrate to a deep violet color with standard cerric sulfatesolution. 47 m1. «(904)2 x N of 06(804)2 x 27.92 = 3/1 Ferrous Iron (E3. of sample ml. Ce(SO4)2 x N of Ce(SOI)2 x 63.375 I g/l Ferrous Chloride (m1. of sample) ml. 00(504)2 x n of 00(504)2 x 99.41 n 3/1 F001204H20 (m1. of sample) g/l x 0.134 I 03. per gallon. Total Iron Pipette a five (5) milliliter sample of the bath into a five hundred (500) milliliter flask and add twenty- five (25) milliliters of concentrated hydrochloric acid. Dilute to one hundred and fifty (150) milliliters with distilled water. Add one twelfth (1/12) of one square foot of lead foil torn into small bits. Stopper the flask with a stepper containing a glass tube leading into a ten (10) 'percent sodium bicarbonate solution. ‘Qgil for one half (i) hour or until colorless. Cool for ten (10) minutes at room temperature and then in a cold water bath. Decant from lead using fine hundred and fifty (150 milliliters of water for washing purposes. Add fifteen (15) milliliters of phosphate reagent and ten (10) drops of diphenylamine indicator. Titrate to a deep violet with cerric sulfate. Be sure to keep all air out of the flask. This can be dens by the use of a few chips of calcium carbonate or marble. 48 Calculations The calculations in this case will be exactly the same as the above Ferrous Iron calculations. Ferric Iron This is calculated on the basis of the metal ion rather than the compound ferric chloride. (3/1 total F0012 - 3/1 of FeClz) 1.29 a 3/1 F0013 g/l F0013 x 0.345 I g/l of Iron in Ferric state The above equations are applicable only to weights in anhydrous salts. This concludes the portion of this report devoted to laboratory investigations prior to the designer's work. The balance of the report will be made up of calculations and design of the plating line as well as a brief portion upon the need of heat-treatment in the case of using this Iron plate as an undercoat for tin-plate manufactured by the electrolytic method. 49 II DEVELOPMENT OF PLATING LINE The following statement covers the specifications for the plating line: Three thousand (3000) pounds per hour of ten (10) gauge, twenty (20) inch low carbon steel is to be plated with seven one hundredths (0.07) of an ounce per square foot of Iron at a current density of sixty (60) amperes per square foot. Density of steel - 7.83 g/cc Then: 7.83 x 20 x 0.010 x 12 a lbs./ linear foot 28.3495 x 16 x 0.0610 0.690 1bs./linear foot of strip 3000 s 4415 feet of strip per hour 0.680 Introduce a safety factor of 10% - 4,857 feet per hour 4857 s 81 feet per minute speed of line “30' 81 x 45 a 60.7 feet of strip in cleaner tank 81 x 5 . 60 81 xlgg I 40.5 feet of strip in wash tanks 30 I 6.75 feet of strip in scrubber 81 x ‘30 81 x 135 I 182 feet of strip in plating tank 60" 81 x‘ég 8 13.5 feet of strip in drier I 40.5 feet of strip in pickle tank 50 & a % c$\.e\\§ 9.56 x x . . um .. N30.» ngk . O 90 \Q RVKQDKK§0 \ h. a s h. n . EN X§Vk NNVKh RV>§¥NNNN§§ \‘Sxk 3353‘.» V\.fiu\§ \ 7 kayak \anK ck 99%... N . «no? :4. fl. \l‘ h Vaamxkoengfiu . ex .. uh N35... Qakauktahsckrc M9 __ l|| Qwsatfihw 5.9... 353‘ 3.0. $24». Nashua... N \ 7E5 «use. . ex .. .. an Newman Samoan» .. Tantra _ 4 «643333 0h 9. m e. .w. a. N -kaaaem. m. a 39% Pack... 3% 05.5, 51 511638.465 0xxxwav-rmnxa .xJMJRSQn V VQAV Kb‘KxQQb \\.N\.&XW A» \\ meawmqssao nfiQfiSQ.hRS&&RXw N i N L hU lllll !hu 1- -uhr nnnnnn uni- Alum“ H. H H ....Illl|ll ._. “WIN: ; if‘ “' 82 Calculations for Volume of Cleaner Tank Tank dimensions are 75' x 3' x 3' if filled to overflowing. However if the tank is filled within 4" of the top it gives: 75 x 12 x 36 x 32 I 2405 gallons 431 Displacement of the four rubber rolls: 30 x'II x 10 x 10 x 4 a 21.85 gallons 4 x 431 Displacement of the anodes: 8 --- 2' x i" x 30' 95 --- 2" x 4" x 50" 8x2 x569 ,1 93x2x30 .6.69/6.47.15.1sga1s. 2 x 431 2 x 431 Corrected Velume 0f Dri-sil Solution 2405 - (21.95 ,1 15.15) .-. 2 5 70 gallons The usual concentration of Dri-sil cleaner when used to clean steel is eight (8) ounces per gallon. Therefor: 2 370 x‘§_ - 1185 pounds. of Dri-sil needed. 16 Space needed for cleaning tank seventy-five (75) feet. 53 Calculations for the Volume of Pickle Tank The dimensions of the pickle tank when filled to over- flowing are : 45' x 3' x 3' . When pickle tank is filled within 4" of top it gives: 45 x 12 x 36 x 32 a 1445 gallons. 431 The volume of two (2) submerged rolls is found by: 30 x 11.x 10 x 10 x 2 g 10.93 ga llons 4 x 431 This makes the corrected volume of the tank: 1445 - 10.93 a 1434 gallons In making up the pickle the usual concentrations used are eight (8) ounces per gallon of Sodiumeitrate and ten (10) percent by volume of Technical Sulfuric Acid. Thus: 1434 x 0.10 3 143.4 gals. Tech. H2804 and 14 34 x 8 I 717 pounds of NaN03 '16— Calculations for Volumes of'wash Tanks These tanks are the same size as the above pickle tank and the strip runs through.them in the same manner. Thus the above calculations for the tank volume holds for these tanks, giving: 143 4 gallons as volume of wash tank. 54 sr\\e.\\\ .. CR .6 . \ an“. -4330.» 999‘ 5.1.300 .. cu \n 3...... x. be ..\.Q .mxxk \ackthxkxhae‘n kibe‘K (VV\\V\A\ §\_\\ \3‘.\\\3 IE m - $9 § \ a; m _ .e §\ 4.. RM. XV. flak NVINNH RV§§M Q§§N 55 Scrubber This equipment consisted of a motor driven set of oscillating brushes, the purpose of these brushes being to remove scale and grease. Presure sprays of water were forced on to the steel in these scrubbers. (The author lacks details of construction for this equipment). Plating Tank The plating tank was designed to be like the Cleaner Thnk with the following changes: Five (5) instead of three (3) contact rolls. Four (4) anode sections each 45' 6' long (Total 182') Spaces for adjustment of rubber rolls 3' (Total 18') Two (2) four (4) foot spaces at ends (Total 8') Total length of tank 192 7% 19 {'9 a 209 feet. Dimensions of tank 208' x 3' x 3' Dimensions of Anodes 3' x 4' x 1" Number of anodes per set I 7 x 15 x 2 I 210 Number of anodes in tank I 210 x 4 I 840 Volume of Plating Thnk Calculate volume when filled to within 4" of top: 209 x 12 x 56 x 52 g 6690 gallons ' 451 Displacement of rubber rolls: 30 1'11 x 10 x 10 x 10 8 54.7 gallons 4 x 431 56 Displace ment of anodes: 36 x 4 x l x 840 I 280.3 gallons 431 Volume of tank: 6680 - (54.7 / 280.3) a 6345 gallons Chemicals Needed 5.0121320 --- ----- -- 200 3/1 ---- 0r ---- 26.9 oz/gal. HCl (Tech.) -------- - lOcc/l ---- or —--- lfl'by Vol. Na204H406 - -------- -- 1 g/l ---- 0s ---- 0.134 oa/gal. 6345 x‘ggzg I 10,600 lbs. or 5.3 Tons FeC12°4320 16 6345 x 0.01 a 63.45 gallons of HCl (Tech). 6345 x 0.134 I 53.0 lbs. of N8204H406 16 Drier This equipment should be temper coils over which fans blow air and in turn force the heated air over the strip. Thirteen and one-half (13.5) feet is sufficient fpr drying purposes. Length of Plating Line Coil support to hold the feeding coils - ---------- 10' 'Welding table for welding together coils - ------- - 10' Slack producer to make welding possible -- ----- --- 5' scrubber ------ nnnnnnnn -n uuuuuuu noun-oco—ccaoan-nn '7' Heat 57 Pickle Tank - --------------------------- 45! Two'Wash Tanks - ------------------------ 90: Scrubber ------------------------------- 7: Plating Tank --- ....................... 2031 Two wash Tanks ......................... gov Drier -------------------- - .......... -‘13.5. Wind-up - --------------------------- ---- 10: Space taken between tanks -------------- 22' Total length of plating line - ------- 592.5' Heat Requirements Volume of cleaner solution - 2370 gallons Assume specific heat @ 212°F. as - 0.75 Loss from Tank: Rubber lining %" and steel &“ k G 212°F. for steel - 25.9 k @ 212°F. for rubber (Assume) - 0.11 q I Act I 62 1.1 ,l 52 0.0417 ,1 0.0417 klAl k2A2 25.9(75x3x3 {'5x5x2) 0.11(75x9 {'9x2) q s 62 : fig 0.00000252 / 0.000547 0.00054952 (1 . 115,000 9.t.u./‘hr. 16. s through tank Assume specific gravity - 1.15 Assume a vapor loss of 1.6%7hr. Assume a dragout loss of 0.5%[hr. 58 2570 x 0.016 x 1.15 x 451 x 972 : 660,000 B.t.u./hr Vapor loss 28.3495 x 16 x 0.0610 2370 x 0.005 x 1.15 x 431 x 0.75 x (212 - 60) 3 24,250 B.t.u./hr. 28.3495 x 16 x 0.0610 dragout loss Total B.t.u. loss from cleaner: 115,000 {’660,000‘{ 24,250 : 797,250 B.t.u./hr. In order to heat tank from 60° to 212°F. in one (1) hour: 2570 x 1.15 x 451 x 0-75(212-691,{'797.250 = 28.3495 x 16 x 0.0610 4,950,000 {'797,250 . 5,647,250 B.t.u. The heat loss from the pipes would be: Assume 90°F. as surface temperature: 300' of 2" pipe; Legged with 2" magnesia - k a 0.04 (300)(II)(6.375 - 2.57511 12 3 517.5 sq.ft. 2.5 loglo ( 6.375) ( 2.575) q : (0.04)(517.5)(212-90) : 9290 B.t.u./hr. 2/12 Total B.t.u. for Cleaner: start: 4,950,000 {'797,250,/'9290 : 5,656,540 B.t.u./hr. Run : 797,250 /’9290 3 806,540 B.t.u./hr. From.McAdams "Heat Transmission“ Steam 30¢/1068.t.u. Start: 5,656,540 cost $1.695 Run: 806,540 cost $0.242 59 Duriron Heat Exchanger No. 12-140 400,000 B.t.u./hr. 75# steam 5,656,540 4 400,000 . 14 / or 15 in parallel Velume of Pickle Tank - 1434 gallons. Assume specific heat - 0.75 @ 212°F. k @ 212°F for 2" Cypress Wood a 0.1 9.1mm. 0.1x (45x3x3j3x3x2jx62 =15,750 1. . 2/12 B.t.u./hr. Assume same vapor and dragout loss as for cleaner Assume specific gravity - 1.18 Vapor: 1454 x 0.016 x 1.19 x 451 x 972 a 410,000 B.t.u./hr. 28.3495 x 16 x 0.0610 Dragout: 1434 x 0.005 x 1.18 x 431 x 0.75(212-60) : 15,050 29.5495 x 16 x 0.0610 Bot-uo/hr. Total heat loss from tank: 15,750 / 410,000 / 15,050 3 440,900 B.t.u./hr. In order to heat tank from 60° to 212°F. in one (1) hour: 1454 x 1.19 x 451 x 0.75(212-60) ,1 440,900 . 28.3495 x 16 x 0.0610 5,050,000 ,1 440,900 . 5,490,900 B.t.u. start. A steam.Jet was used for heating. Cost: Start: $1.047 Run: $0.132 60 Volume of‘Wash Tanks ------------ - 1434 gallons k same as for pickle. Specific heat 1.0 i a 0,1(423)(62) a 15,750 B.t.u. per hour. ' 2/12 Assume same vapor and dragout losses as above Specicic gravity 1.0 Vapor: 1454 x 0.016 x 1.0 x 451 x 972 .-_- 547,500 B.t.u./hr. 28.3495 x 16 x 0.0610 Dragout: 1434 x 0.005 x 1.0(212 - 60) x 431 a 16,900 B.t.u. 28.3495 x 16 x 0.0610 hr. Total heat loss from wash tank: 15,750 / 547,500 / 16,900 3 590,150 B.t.u./hr. In order to heat tank from.60° to 212°F. in one (1) hour: 1454 x 1.0 x 451 x 1.09.12 - 60) ,1 590,150 : 28.3495 x 16 x 0.0610 5,400,000 / 590,150 . 5,790,150 B.t.u. Heat obtained by the use of a.steam.Jet: Cost: Start: $1.132 'Run: $0.114 Velume of the Iron Plating Tank: 6345 gallons Specific heat assumed to be 0.75 @ 212°F. k for steel and k for rubber as for cleaner. substitution made in same equation: a . 62 3 507,500 B.t.u./hr. 0.000201955 61 Assume specific gravity of 1.15 Assume same vapor and dragout loss as before. vapor: 6545 x 0.016 x 1.15 x 451 x 972 3 1,765,000 B.t.u./hr. 29.5495 1 16 x 0.0610 Dragout: 6345 x 0.005 x 1.15 x 451 x 0.75(212 - 60) : 64,900 29.5495 x 16 x 0.0610 B.t.u./hr. Total B.t.u. Loss: 507,500 {'1,765,000 / 64,900 . 2,157,400 B.t.u./hr. In order to heat the tank from.60° to 212°F. in one (1) hour: 6545 x 1.15 x 451 x 0.753212 - 60) ,4 2,157,400 . 29.5495 x 16 x 0.0610 19,100,000 / 2,157,400 . 20,257,400 B.t.u. The heat loss from circulating pipes would be calculated in the same manner as for the pipes on the cleaner tank but their length would be 566' instead of 300'. Heat loss from pipes : 17,550 B.t.u./hr. Total B.t.u. would be: Start: 20,257,400 {'17,550 3 20,254,950 B.t.u./hr. Run: 2,157,400 / 17,550 4 2,154,950 B.t.u./hr. Cost: Start: $6.08 Run: $0.64 Heat supplied by Duriron heat exchanger 12-140: 20,254,950 2 400,000 a 50.6 or 51 exchangers. Arrange these in 17 parallel rows with 3 in series in each row. 62 Heat needed in the Drier: Assume specific heat as 0.1175 q : 0.690 x 91 x 60 x 0.1175 x (366 - 212) = 600,000 B.t.u./hr. To heat steel to temperature of 150 # gauge steam. Assume density of water on strip to be 0.3667 Assume 1194.9 B.t.u./1b. to heat water from 212 to 366°F. (366 - 212) x 1434 x 0.005 x 431 x 0.3667 x 1194.9 3 121,000 1728 B.t.u./hr. Total q in drier: 600,000 {'121,000 2 721,000 B.t.u./hr. Total Steam for Plating Line. B.t.u. Start B.t.u. Run Cleaner - --------- 5,656,540 ----- ------ --- 806,540 Scrubber - ------- - None - ----------- -- None Nash Tank (1) ---- 3,780,150 ------------- - 380,150 Pickle ----------- 3,490,800 - ------------ - 440,800 Scrubber --------- None - ------------- None ‘Wash Tank (2) ---- 3,780,150 ----------- --- 380,150 Plating Tank -----20,254,950 ------- ------2,154,950 wash Tank (3) ---- 3,780,150 -------------- ~380,150 lash Tank (4) ---- 3,780,150 - -------------- 380,150 Drier - ------- ---- 721,000 ----------- --- 721,000 Total Steam.- ----- 45,243,890 ------------- 5,643,890 At 50¢71069.t.u. -$ 15.57 ------- -------- - $1.59 63 Pumping Requirements From the Chemical Engineering Catalog (1938) and the pages of the Duriron Company therin: Diagram with centrifugal pumps gives a Pump 2E. From this curve five (5) horse-power is needed to drive the pump at a flow of 120 gallons per mdnute. The cleaner tank needs one (1) such pump while the plating tank needs two (2) such pumps running in parallel. This gives a total of 15 H.P. The above specifications give sufficient cir- culation for the solutions in the tanks as well as through the heat exchangers. Total Power As an interesting calculation we will convert the B.t.u. requirements into K.l. hrs. Start: 45,245,990 x 2.95 x 10" . 15,270 NJ. hrs. Run: 5,645,990 x 2.95 x 10"4 g 1,650 Km. hrs. Pumps need: 15 x 0.746 g 11.2 H.l.hrs. Power to pull strip: 15 x 0.746 : 11.2 K.I.hrs. Power for fan in drier: 5 x 0.746 g 3.7 K.W.hrs. Power forcleaner: 7 x 12,140 g 84.98 K.W.hrs. 1000 Power for Plating: 3.4 x 36,500 124.0 wa.hrs. 1000 15,155.08 K.W.hrs. Bath not run first hour would give the above total. 64 Assume $0.002/H.W.hr. a s cost of electricity. Power equivalent cost then: 15,155.08 x 0.002 a $30.31 Figured on B.t.u. and Km. with 50¢/106B.t.u. $15.57 ,4 $1.59 / 3(255 x 0.002) a $15.65 Hewever the above is heating baths to temperature plus the first hour of running. Now then if we eliminate this first hour the figures become: $1.59‘/ $0.47 : $2.06/hr. for steam and power. let us consider the first heating of the bath has to be done once in 144 hours or six days: 13.57 g 144 s $0.094 or approx. 10¢'per hour. Then power and steam costs corrected : $2 .16 /hr. Help Needed 1 - Foreman e $1.00/hr. - ------- ' -------- $1.00/hr. 1 .. Head Tankman e 50.90/hr. - --------- - .80/hr. 2 - Tank helpers o 80.625/hr. --------- - 1.25/hr. 1 - Chemist e $0.70/hr. - ------------ -- .70/hr. Total - ----------------------------- $3.75/hr. The total Operating costs, using Just this simple calculating and without going into depreciation, amortisa- tion, etc., are: $2.16 ,1 65.75 . $5.91/hr. or 55.91 x 2000 . $3.94/Ton of strip. 5000 65 Filtration and storage facilities were separated from the system.by means of values. The filtration was not carried out continuously but only once a week. Filtering was done through a one hundred (100) plate press with plates 36" x 36". The solution was forced through the press by gravity from the overhead, rubberlined storage tanks. These were of eight thousand (8000) gallon capacity and lined with hard rubber. 66 III Heat Treating of the Finished Product The steel and the deposit of iron were both too brittle to be used directly as an undercoat and base for tin-plate. Therefor it became necessary to heat-treat this material so that it would be soft. For maximum softness annealing would be the first choice. The annealing operation was carried out in the following manner: Several of the three thousand (3000) pound coils were tipped on their sides and stacked on a steel platform. By means of a crane a refractory lined steel shell was lowered over the stack of coils. This shell was provided with gas connections so that the temperature of the coils could be raised to the annealing temperature and also an atmosphere of natural gas surrounded the coils to prevent their oxidation. Twelve hours was taken to heat the steel. It was held at temperature for twenty-four (24) hours and then the cooling rate was such as to take forty-eight (48) hours to cool to room temperature. From the above explanation it can be seen that four days was taken for this operation. Also, excepting for customers desiring a "dead-soft anneal", the strip was too soft for most uses. 6'7 gnaw $55.14 Awkxa . \ "Hum 534$. VESVQL nkhakh\\c\ themskhxna Ram... .0586an I NkwaoxaQak‘ .06 weather Mohahbk 9.5.4 9549‘ N§T§K.ha\_ . sxmeh:0M t0 unaware. Rwanda humans: \a E m_ \ NYC. . x . am 13.55: 3.380%.0 \§\u§a\k.utd. 9.500 5390.56 «$363.60.. 1 .1- 9 30535? k¥5§8 68 From.the above considerations normalizing seemed to fit the needs much more closely. The normalizing Job .could be done on continuously moving strip as shown by the sketch on the preceding page. The tall section heated the strip to 1800°F. and the long horizontal section cooled it to room.temperature. This represents four (4) minutes for heating and the same period of time for cooling the strip. After the normalizing treatment the steel and iron deposited thereon were sufficiently soft. They even had to be subjected to a light pinch in a two-high mill to give a slight temper or enough springiness to make a round tin can instead of a fluted structure. Another purpose of the two-high mill and pinch after normalizing, was to produce a smooth, dense, and bright surface for the deposition of tin. The smoother the base the higher the quality of the tin plated thereon. 69 Summary The purpose of this paper has been to point out a few of the more important steps of developing an elec- troplating line. The composition of assatisfactory bath was first worked out in the laboratory. The chemdcal engineer with the laboratory findings at his disposal was enabled to design equipment of sufficient capacity to handle the desired production of this electro- plate. In no way has the writer attempted to give a complete cost accounting. He has only tried to show the power, steam and labor costs, directly connected with the plating line. After the deposit was obtained it was necessary to dev010p a satisfactory heat-treatment to prepare the material for tin-plate. Any omissions were present because of the secret nature of the development problem. A a. 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