cs cae ee 4 s m ot co 3 sy ts ee a3 [IMNMNIININI a ae Se ee alll aT Tt i THESIS. THE PROPERTIES OF SEMI-STEEL. o WY Se oe vv Re eT CLS Ca A A oe NA A MoS ee ee | | BS Ae RD EN Wut AAA AA A SS f 2 en ee . Ta ee see ee ge ae Ow Tr vy SHESIS Sa - on <= - S a wa 0g bao < oa 3 =} ei G cane ee a3 IMMIMIININNNIN D a oe eee eX pes a eae F " ow YY yy ey et YS aw ee ee hm As THESIS THE PROPERTIES OF SEMI-STEEL. 3. BH. Steele, 1896. Oo A A Oe ae “ “* i 3 J a ; 7 5 ‘ s 4 “ 4 te K Hera JHESIS wee TEES TIS on THE PROPGRTIAOS CF SEVI-STiix Michigan fgricultural coiiege, August lai, 2&ve, THESIS THE PROPERTI“5 OF SHWI-STAEL, The object of this thesis was an investization of the proverties of Semi-Steel., Aili that was kiown of semi-steel at the beginning of the work was that it was a mixture of cast iron and steel and that in some instatces a certain alloy nad been mixed to give the resulting product certain desired “qualities. It was desired to procure test bars of semi-steel and test them and compare the results with the results ob- tained from ordinary cast iron, I* was also desired to have a chemicel analysis of the alloy whigh is used to make the semi-stcel, and to manufacture in the College foundry, accord- ing to the analysis, some semi-steel and compare it with the test vars of semi-steel procured outside, In the first rlace some srecimens of the alloy were fpro- cured and were analyzed by the Chemical Department. The srpcee- imens pvrovured were gmall pieces that had evidently been melt- ed. The results of the analysis are as follows: Mice ecw ccc ccc ee tO Gk | 00,47 CLL eee eee eee CL 7S Cece cee ewe O4 CG TO ee ee Oe AY ee Ue en The results of the erslyeis shored that the alloy was nothing more or less than spiegeleisen, Chemistry "Spiezeleisen is a variety of wnite cast iron contain- says: ing 3.5 to 3 7 of cervon and from 5 to 20 “ of manganese," 105872 (2) The specimen analyzed is scen to contain 15.6 % of man- mranese, 4 _ of carbon ani the remainier iron with traces of silicon and phosrpnorus, Following this clue, the ijechanical De:-artment sent for e quentity of spiegeleisen with ea view to casting some test bars of semi-steel, Meanwhile I leerned,thet the iicDowell Steel Co. of Chi- cago were the originators of the semi-steel process ana that all the material used in the process by the various foundries of the country ceme from them, I also found that they claimo: 4 for their proiutt a tensile strength of 34000 to 38000 ¥ per sq. in. I wrote to the Chicago company and asked them for some test bars, promising to pay all expenses, In reply they seid that "they hei no test bars at present iut perhaps Robt, Thint *« Co, migtit ssare me some," Not Knowing the relation between the iiecDowell Steel Co. and Robt. Hunt and Co., I wrote to the latter firm and asked for some test bars, Here, to my disercointment, I was met by a polite refusal and I. founi that the Robt. Hunt Co. vere consulting engineers to the KeDowell Steel Co. However, rrom other sources, a number of test bars of geni-steel vere obtained and these were tested on the Olsen testing machine belonging to the Mechanical Depar*ment. Test bar 2 1 of semi-steel was put in the machine and extensometer readings taken up to 11000 % or 17000 # per sq.in. (=) At 138£00 x= £0000 = per sq. in. the piece broke in the upoer jaw of the machine. An examination of the piece showed that it hai been ernushed in the jays instead of milling apart. The grain was that of fine grained, fray cast iron, These pieces heve a slizhi bulb cast on eaer end to hold in the jaws of the machine, I+ wes in this bulb that the piece erusned. The next piece crushed just as did the first at c* 140CO ;= 238750 =; per sq. in. Modulus of elacticity _ EF for this piece - 12750000 #. Rar = 3 broke in exeectly the same way at 14000 # = 21000; per sq. in. E for this piece = 124b800C0 =. These three Lars having e11 ernshed in the jaw of the machine we began to study to find some wav to nuli them apart, An attempt was mace to find the crushing strength of the ma- terial. A compression piece was turned down from the end of one of the test bars. It had a length of .8¢y" and a diam eter of .411" and stood 40000 + without crushing, The erush- ing in the jays must have been due to the wedge action there, The material was ut very easilv iv the lathe tool and the drill, behaving like cast iron, A viece was preparei with the bulbs turned off to give the jays a better grip. This piece pulled apart at 1B0CO zx. - 29700 # per sq. in. Another piece broke at 13600 # = 21104,’ per sq. in. Pinaily a piece was put in ‘he machine which was turned (4) the whole length. ‘This broke at 1470° # = FFoO5o 7 per sq. in, Elastic limit 16000 # per sq. in. For the sake of comparison with the above results I tested some tars of ordinerv cast iron which I bought at the foundries at Lansing. Bar =" 1 f¥om te Lansing Iron Works broke st 18400 or -80C0 # per sq, in, E = 16420000 #. Bar # 2 broke at 20000 # = 25400 # per sq. in. EF - 12975000 ;. From the Olds Engine Works I re- ceived & var wnixh broke at 13060 ¢ — 26000; per sq. in. E= v31lSUCC, Elastic limit reached at 9005 + = 19566 4“ per sq. dn, and had E = 14732000 #, One from the Bement fourdrv broke at 8865 7 = REYEC 3 per sq. in, From these results I think it is clearly shown that the svecimens of semi-steel which I tested possessed a tensile strength equal to but not above gook cast iron, 9 Jowili here quote from one from whor I learmed the reci- pe for making sémi-steel: The cupola is charged with 30 cf -¢ pig iron, 30 “ east iron scray and 40, scrar steel. ter 4 this is all melted it is drawn off in ladles and for every 100 # of molten metal in the ladle 1 + of alloy is added. The * of alloy is only guess work as they pick up a handful 7 4 ani throw it into the ladle as it is being carried away. There is nothing peculiar in the casting of semi-steel, the only difference from the heats taken at the College is the addition of the serap steel in the cupola and the addition of the alloy in the ladle. (6) Prom the chemical analysis given before, it is seer that 78 5° of the alloy is iron and only 20 “ of it is manganese ana caroon. From this it seemed to me that the aidition of 1° of alloy would not have a perceptible influen-e because £9 of 1 co seemed too smali a proportion to exert much influ- ence, It seemed to me that if anv extra strength were found in the compound the greater part would come from the 40 7” scrap stecl. Tis matter we proceeded to test in the College foundry using the proportions given, We used 30 “ of Lake Superior pif, 30 a cast serarp and 20 a boiler scrap, a low grade of steel. As has been shown above, the alloy showed by analysis that it was merely sriegeleisen, We, therefore, used spiegel instead of the alloy. After waiting until the iron was quite hot, sone test bars were pourdd, first without any spiegel in them, and then 4 some with 1 < ,: of spiegel in them. We desired to have some bars with larger ver cents of spiegel, but we found that over 1“ of spiegel cooled the iron so rapidly that it could not be poured. The spiegel was erushed into small pieces about the size of bullets and in this form it was thrown into the ladles whigh had been freviously warmed. We did not guess at the per cent of spiegel but I filled one of the ladles with water, putting as mich water as the ladle usually contained (68) tron, and multiplied the weight of the water put in by the specific gravity of iron, I thus found that the ledle held un “. an " a Ss 4 43 7 of iron, ani I weicned .437 -1 > of splegel, A bar with no spiegel in it broke at 12000 7 _ 22787 ¢ per sq. in. This piece had a flaw in it. Another piece broke at 107000 5 = 19000 % per sq. in. A bar with 1 i spic- gel in it broke at 10000 ; = 168000 % per sq. in. ‘This piece had E = 109Rn6000 =. Another piece broke at 10505 ; = 18650 ; per sq. in. It mav, perhaps, be argued that in the limited opportu- nities of this term's work I have not given semi-stcel a trial surficiently extensive to do it justice; but I think the results noted above roint, at least, to these conclusions: 1. The alloy which companies are buying by the pound and paving (;395.6% a year for the right to use is nothing more or less than spiegeleisen., Sm. Semi-stcel has the same tensile strength as good cast iron ani is similar to it in its various properties, 3. The addition of the sriereleisen to the mixture of pig, cast scrap and scray steel does not seem to affect the result. In @onelusion I wish to thauk the professor in charge and also the foreman of the foundry for the interest they have taken in mv thesis and the assistance thev have given me, fee ++S' fo6éeoe |? 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