Oil the Microstruchii'e of Hypo-eutectoid StecL 267 



inclined sheet of plate-glass to enable the excess solution to drain 

 off. The sample is then brought into contact with the paper, when 

 the H2S evolved produces dark stains of various densities. 



The results from Xo. 1 section gave very definite evidence of 

 the presence of sulphur, and also located the areas in which segre- 

 gations existed. As will be noted in the illustration (fig. 2), there 

 is a sharply-defined segregation in that part of the section which 

 was originally the centre of the head, and, also, there are fine 

 " sulphur-lines " commencing in the region of the segregate and 

 continuing down into the web, which terminate, curiously enough, 

 in a " curved " formation a little to the left of the centre of the foot, 

 which curve is apparently the most sulphur-free part of this lower 

 area. 



On examination of the print from section No. 2 (fig. 3), it will 

 be observed that sulphur is also markedly present — a little better 

 diffused perhaps, although still occupying relatively the same 

 positions as in section Xo. 1 ; indeed, each feature is again 

 reproduced, even to the small comparatively sulphur-free " curve," 

 although a reference to the first print will show a rather well- 

 marked area on each side of the foot of considerable density, which 

 at a point 8 in. away — viz. in the section No. 2 — is very greatly 

 reduced, though still in evidence, from which it could be assumed 

 that the sulphur was present through the whole length of steel. 



The pieces No. 3 and No. 4 were then cut and prepared for 

 tensile-testing, one of the physical tests regularly used. For this 

 the steel is turned perfectly cylindrical for a given distance in the 

 lathe, and suitable " collars " are allowed for in the turning to 

 enable the test-piece to be firmly secured in the machine. The 

 tensile tests were conducted on a 100-ton tensile machine made by 

 Messrs. Buckton and Co., Ltd., Leeds. 



InsufiBcient material remained to enable the test from No. 3 

 to be made the usual size of 0*798 in. diam. (equal to J sq. in. 

 sectional area), so this had perforce to be made 0'565 in. diam. 

 (equal to \ sq. in. sectional area). Knowing that No. 3 contained 

 a sulphur segregation, experience does not lead us to expect normal 

 tensile results, as, generally speaking, segregated material is apt to 

 be more or less hard and brittle according to the character of the 

 segregation ; consequently I expected that a higher tonnage would be 

 required to break the test No. 3 than No. 4, whilst at the same time 

 the reduction in area would not be so great, and also less elonga- 

 tion would be recorded. To facilitate comparisons, the following 

 results are given on the square inch in both cases : — 



Breaking stress .... 

 Reduction in area at point of fracture 

 Elongation . 



