844 TURNER THE IKFLUESCE OF SILICON LXX.-The Injluencs of Silicon o n the Properties of Iron and Steel. Part 11. .By THOMAS TURKER Assoc. R.S.M. P.T.C. Lecturer on Metallurgy, Mason College Birmingham. l x the first part of this paper (Trans. 1887 51 129) a brief re'sume' was given of previous experiments on this subject and observations were described connected with the influence of silicon on the purest form of iron which can be obtained commercially in considerable quantities and in the fluid condition viz. the metal produced in the basic process at the end of the blow and before any addition of carbon o r manganese has been made. From this material ingots were prepared containing gradually increasing proportions of silicon, 2nd by combined chemical and mechanical testing the following con-clusions were arrived at.The metal being as above stated very low in manganese was originally rather red short and this red shortness was increased by the presence of silicon so much so that all ingots containing over 0.13 per cent. of silicon crumbled to pieces in the rolls. Silicon increased the tensile strength and limit of elasticity ; i t also rendered the metal quiet in the mould; the elongation and contraction of area were both considerably diminished however and the fracture changed in character from finely silky to crystalline. On khe other hand silicon had no apparent influence on the welding pro-perty of the iron. At the same time it was pointed out that these iysults were only true under the circumstances of the experiments, and that in the presence of larger quantities of other elements the influence of silicon would doubtless be considerably modified.The results of the above experiments differ in one or two important par-ticulars from what is observed commercially with ingot iron con-taining about half a per cent. of manganese which is one of the purest forms of metal produced by steel works. The results differ in the same way from those of the experiments now to be described. The present series of experiments was undertaken i n order to deter-mine the effect produced by silicon 0x1 ingot iron that is the " mild steel " now so largely used and which differs from the mctal employed in the previous experiments chiefly i n containing about one-tenth pe ON THE PROPERTIES OF IRON -4SD STEEL.845 cent. more carbon and a half per cent. moremanganese. The experi-ments were conducted as before at the works of the South Stafford-shire Steel and Ingot Iron Company Bilston and the general method of procedure was very similar to that described in Part I though a few alterations in detail were necessary. A weighed quantity of the same siliceous iron (10.3 per cent. silicon) as had been previously used was placed in a covered clay crucible which was heated in a small rever-beratory furnace t o the melting point of cast iron ; at the same time a second and exscbly similar crucible was heated in the same way and to the same temperature. The crucibles were capable of holding about 4Olbs. of metal. .At the conclusion of the blow after the addition of ferromanganese had been made and the metal teemed into the ladle the crucibles were rapidly brought from the furnace and the one contain-ing the siliceous iron was filled up with ingot iron from about the middle of the cast.After standing for about a minute and while the contents of the crucible were st'ill thoroughly fluid the metal was poured into the other red-hot crucible so as to ensure as nearly as possible perfect mixture. I n the second crucible the metal was allowed to solidify and the ingots so obtained were examined as in the previous experiments. I have again gratefully to acknowledge the important assistance received in conducting these experiments. The rolling of the specimens and the works tests were superintended by Nr. F. W. Harbord of Rilston ; the mechanical testing was per-formed by Professor A.B. W. Kennedy with the University College testing machine ; whilst the whole of the chemical analyses were cou-ducted by Mr. J. P. Walton of Wishaw. The author's part lias been merely the preparation of the ingots and the general arrangement of the experiments and of the results. Works Tests. (See Table A.) The ingots were reheated and rolled by workmen accustomed to the macipidation of mild steel ; no special care was given so as t o humour the metal the desire being to give all the ingots as fair a test as possible. In each case the ingots rolled satisfactorily and the required round bar of l+ inch diameter was obtained. I n each case also the hot test was satisfactory. These results are quite different from what was noticed when manganese was absent but they accord with obser-vations of experienced steel makers.It may be mentioned that the hot test employed was that commonly used at the works the bar being plated out hot doubled flat upon itself across the middle of the platcd portion and the doubled part bent again at right angles to the first bend. In the cold or bending test all thesamples behaved well with the single exception of No. 11 which contained not only 0.504 per VOL. LIII. 3 -No I 1 2 3 4 5 6 7 8 9 10 11 -Chemical Analyses. (By J. P. Wnlton.) Xi. 0 *010 0 *061 0.070 0.092 0 *lo2 0,121 0.135 0 *247 0 *320 0.382 0.504 C. -0 -16 0 -16 0 -15 0 -21 0 '18 0.19 0 *13 0 -19 0 -15 0.16 0 *18 8.-. 0.050 0,028 0 '084 0 *084 0 *028 0 -064 0 -028 0 *028 0 -040 0 -042 0 *094 P. -0.060 0 *058 0.051 0.064 0 -066 0 * 068 0.057 0.07'4 0,081 0 *087 0 9121 Mn. -0 -550 0 *619 0 *500 0 *634 0 '662 0 '576 0.480 0 ,642 0 -490 0 -533 0.455 -Worlis Tests. (By 3'. W. IIarbord.) Rolling. -Rolled well. >> 7 ) 7) > ) 7) > ) > 9 9) 7 7 >> 7 7 7) 7 ) 77 7 7 97 7 7 )) 7 ) 7) Hot. Good. ) ) 7 7 > > 7 ) Good but rather red-shori st weld-ing heat. Good. 7 ) 7 7 ) J 7) Cold. --Perfect . 9 ) Good. Perfect. Good. 9 ) Y7 7 9 9 9 Perfect. Broke short off at 50". flelding. --Perfect,.J ) 7) 7 ) J) 7 ) > > >> )7 )) 9 9 -Limit of elas-ticity. tons. 22 * 22 -21 21 * 22 -43 21 '26 22 -70 21 '29 22.23 22 '32 24.72 26 - 3 ON THE PROPERTIES OF IRON AND STEEL. 847 cent. of silicon bnt also 0.121 of phosphorus. It is not at all certain that the sample would ha-ve proved quite so brittle in the absence of phosphorus. It is to be regretted that the comparatively small scale on which tlie experiments were performed precluded accurate tests as to resistance to shock but so far as these experiments have gone they appear t o show that there is certaiiily no appreciable brittleness in ingot iron until the proportion of silicon reaches 0.25 per cent. Beyond that proportion the character of the other tests would lead us t o expect more or less brittleness.The welding tests as in the previous experiments were all perfect and silicon appears t o be without influence in this respect. C'hemicnZ Composition.-An examination of the results of chemical analysis (given in Table A) shows that the silicon gradually increases throughout the series. It should be explained that Sample No. 1, which is given for comparison represents ingot iron to which no silicon has been added. The composition shown is about what may be expected in good quality ingot iron of this kind whilst the niechanical values are derived from four separate tests made by Professor Kennedy on metal which had been produced on two separate occasions by treating ingot iron in precisely the same way as in the other cases when silicon was added.I n experiments of this kind it is of course extremely difficult to keep all the other con-stituents quite constant while silicon varies and in the deductions which are drawn from these experiments I have endeavoured as f a r as possible to make allowance for the known effect of the variations observed before drawing any cpnclusion as to the influence of silicon. The mxxinizcrn variations observed are as follows :-Carbon 0.08 per cent. ; sulphur 0.056 per cent.; phosphorus 0.036 per cent. (in a single instance previously mentioned this is exceeded) ; and man-ganese 0.207 per cent. JIechanlcaZ Tests.-These were performed in duplicate the actual results being given in Table B ; the mean values deduced from these experimental data being given in Table A.It ail1 be seen from Table A that the two experiments with each sample generally gave values which agreed very fairly well with each other. The greatest variations are noticed in the elongation and contraction of area where, in a few cases very considerable differences are noticed. Some allowance must of course be made on account of the small scale on which the experiments were conducted; but it may be pointed out that in the previous series of experiments as in the present case the samples low in silicon are distinctly more regular than those contain-ing a larger proportion of this element ; hence the results support the views of M. Pourcel that silicon renders tlie contraction of area and the elongation irregular.(Compare Trans. 1887 51 141.) 3 ~ TABLE B.-iVechanical Tests. Pyofessor A. B. IV. Ii'fmaecly's -NO, -1 2 3 4 5 6 7 8 0 10 11 II University College No. -Original metal, mean of 4 12,296 12,297 12,284 12,285 12,280 12,281 12,292 12,293 12,278 12,279 12,288 12,289 12,294 12,295 12,290 12,291 12,282 12,283 12,286 12,287 -3ilicon per cent. -. 0.01 0 -061 0 *07 0.092 0 *lo3 0.121 0 *135 0 -247 0 '320 0'382 0 -504 Limit of elasticity per sq. inch. Pounds. 49,280 49,400 50,100 45,480 48,800 48,860 Ei 1,600 45,550 49,750 51,570 50,100 47,330 48,060 46,490 53,110 51,280 48,720 54,300 56,420 59,120 58,930 -Tons. 22.00 22 -06 22 *37 20 '31 21 -79 21 *82 23.04 20 -33 22 '21 23 *02 22 '37 21 -13 21 *46 20 -75 23 * 71 22 -89 21.75 2-4-25 25 -19 26 -40 26-31 7 Breaking load ?er square inch.Pounds -66,385 70,040 71,580 65,000 66,270 76,000 74,020 76,160 71,640 74,769 71,100 67,120 64,630 79,700 75,470 73,380 79,800 80,000 81,300 83,180 75,780 -Tons. -29 '64 31.26 31 *96 29 '43 29 '59 33.38 33.94 33'04 34 *01 31 *98 31 9 5 29 *96 28 *88 33 -83 35 *58 33 -70 32 *76 35 *63 35 9 2 36 '30 37 -14 --Ratio of limit to break. 0 *743 0 906 0 -700 0 *690 0 -736 0.654 0 -679 0 ,615 0 -653 0 '720 0 a 705 0 '705 0 '743 0 .G13 0 *666 0 -679 0 *664 0.681 0.705 0.727 0 * 70s --Exten-sion per cent.on 10 inches. 23 *1 23.0 17 -8 22 *1 23 ' 8 20 '1 18 a 8 22 -7 18 *6 21 *2 22 *6 24 - 3 25 '3 20'3 15 ' 0 17 .O 16.5 12.7 23 * 4 18 *5 20 *3 --Reduc-tion of area a t fracture per cent 43 -8 48 -4 33 *1 49 *3 53 -7 42 *2 46 -1 52.0 60.9 42 *7 44 -8 57 a2 56 -0 45 -4 50 *0 28 *8 43.8 10 *7 50.8 34 '0 35 -6 --Work done in fracture ,er cubic inch. hi. tons. -6 -25 6-43 5.12 5 '83 6.42 5 -94 5.70 6 *54 5 *59 6 *15 6 -47 6 -56 6 *6S 5 *98 4 *74 5 *12 4 '80 4 -04 7.54 6 -10 6 -81 OX THE PROPERTIES OF IRON AND STEEL. 849 Limit of Elasticity.-This is rather high (22 tons) in the original metal and in the mean results (Table A) varies over a maximurn range of 1.65 tons in the six following samples (Nos.2 to 7). These small differences are precisely of the kind which can be accounted for by the observed variations in the other constituents present and the addition of 0.135 per cent. of silicon does not appear to have produced any important alteration in the limit of elasticity. The limit is however distinctly raised with more silicon, Breaking Load.-This varies in a manner almost exactly like that of the elastic limit. It is high in the original metpal (29.64 tons), and in the six following samples shows a maximum range of 4.1 tons, due apparently to circumstances other than the proportion of silicon. With more silicon however the breaking load is distinctly raised.Extet~sion.-The extension is rather below the average for such metal in the original sample and in the first six specimens but is about what would be anticipated from the other mechanical properties of the metal. The average of the values for the extension of these six samples is rather lower than that of the original metal so that the influence of silicon though slight is probably not beneficial. The irregular and lower results are more marked with larger proportions of silicon. Beduction of Area.-This as would be expected follows closely in the order of extension and is distinctly low and irregular with the larger percentages of silicon. Appearance cf Fracture.-In the first specimen the fracture is almost entirelg silky in appearance the intermediate specimens show greater tendency to granular or crystalline structure while the specimens with most silicon were most crystalline 01' granular and the fracture in several instances showed considerable irregularity.These results tend to show that the influence of several tenths per cent. of silicon is not beneficial. Ingct iron containing silicon in all proportions up to 0.5 per cent. (and with about 0.5 per cent. of manganese) rolls well and does not show any signs of red shortness ; i t welds perfectly wit.h a11 pro-portions of silicon and with the somewhat doubtful exception of the 0.5 per cent. specimen is not brittle when cold. With less than about 0.15 per cent. of silicon the limit of elasticity the breaking load the extension and the reduction of area are but little if at all, affected by the proportion of silicon present. The fracture though not much altered shows rather greater tendency to a crystalline or granular appearance. With upwards of 0.15 per cent. of silicon th 850 RUHEMANN AND ELLIOTT THE limit of elasticity and breaking load are increasd though the effect of silicon in this respect is not nearly so marked as that of carbon. The reduction of area and extension (that is the ductilit'j) are dis-tiiictly reduced and rendered more irregular by the presence of much silicon. The fracture is also rendered more granular or crystallinc, 2nd is less regular in character