pouring into the moulds, an accident occurred to the tapping-hole of the ladle, and the metal was allowed to get cold in it, instead of being poured out. Here was the ordinary condition of a common casting in a gun mould, with, however, this important difference, that in this case it was very shallow, as compared with the gun mould, and there was, therefore, no condensation of the material from fluid pressure. A cylinder of 2 in. diameter was taken out of this mass, and gave a tenacity of 42,908 lb. on the square- inch, and a specific gravity of 7.626. A similar cylinder was drawn out under an ordinary smith's hammer to twice its length, and then gave a tenacity of 64,426 lb., and a specific gravity of 7.841. This portion of metal was examined by the Chemist to the War Department, and was found to contain
Silicon . . 0.00 Graphite . . 0.00 Combined Carbon . minute quantity Sulphur . . 0.02 Phosphorus . . trace Manganese . . traceThis appeared to him to approach more nearly to true iron than any he had seen. The ordinary iron of the market was, in that sense, not iron, but a compound of iron and certain other ingredients. The ordinary re-melting would remove, or combine, the graphite only; the Bessemer process would remove the silicon, and when applied to an iron having but little phosphorus and sulphur, would do all that was required. If an additional process was discovered for removing these, all the iron ores of England, instead of only a very large portion of them, could be converted into pure iron.
As regarded the steel, he had been using it for turning the outside of iron guns, cutting off large shavings several inches in length, and he had found none superior to it, although much more costly. It was only necessary to witness the operation of the manufacture by the Bessemer process to be satisfied that the expense of converting the pig-iron into any of the products involved scarcely any cost beyond the labour, and that for a very short period of time. And as far as the price went, Mr. Bessemer had offered to supply such sizes as it was worth his while to make at the prices stated.
The above quotation serves to corroborate what I have previously said as to the deep interest taken by the Superintendent of the Royal Gun Factories on this subject, and I much regret that the numerous analyses made from time to time at the Arsenal have not been preserved. But I find that I gave in my Paper, which I read in May, 1859, at the Institution of Civil Engineers, when Colonel Wilmot was present, a number of official tests of the tensile strength of soft Bessemer malleable iron in its cast unhammered state, and also when hammered. There were also several tests of highly-carburised Bessemer steel, in hammered and unhammered condition.
The extreme limits of tensile strength of the converted metal are shown in the following Tables, which give the results of many trials made at different times at the Royal Arsenal at Woolwich, under the superintendence of Colonel Wilmot :-
TESTS MADE AT WOOLWICH OF BESSEMER STEEL. Tensile Strength per Square Inch. . . Bessemer Steel. . Various Trials. . Mean Tensile Strength. ..................................................................... . lb . . 42,780 . . 48,892 . In the cast . 57,295 . 63,023 lb.= 28.13 tons unhammered state. . 61,667 . per square inch. . 64,015 . . 72,503 . . 77,808 . . 79,223 . ..................................................................... . . . 136,490 . After hammering . 145,512 . 152,912 lb.= 68.26 tons or rolling. . 146,676 . per square inch. . 156,862 . . 158,899 . . 162,970 . . 162,974 . ..................................................................... COLONEL WILMOT'S EXPERIMENTS TESTS MADE AT WOOLWICH OF BESSEMER IRON. Tensile Strength per Square Inch. . . Bessemer Iron. . Various Trials. . Mean Tensile Strength. .......................................................................... . lb . . 38,197 . In the cast . 40,234 . 41,243 lb.= 18.41 tons unhammered state. . 41,584 . per square inch. . 42,908 . . 43,290 . ........................................................................... . . . 64,059 . After hammering . 65,253 . 72,643 lb. = 32.43 tons or rolling. . 75,598 . per square inch. . 76,195 . . 82,110 . ........................................................................... . . . 63,591 . Flat Ingot rolled . 63,668 . 68,319 lb. = 30.50 tons into Boiler Plate . 72,896 . per square inch. without piling. . 73,103 . ...........................................................................
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