Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

446 MOLESWORTH’S POCKET-BOOK Steel Manufacture—continued. or steel scrap is added as fast as it dissolves, until a sample taken out in a small ladle indicates by its toughness and fracture that it is of the desired quality; then from 6 to 8 per cent, of spiegeleisen or ferro-manganese in a solid state in added, and the result is a bath of metal, the precise chemical condition of which is known; the charge is then run into ingots. This process is much used for the conversion of scrap steel and old ends Into steel Ingots. The use of ferro-manganese instead of spiegeleisen allows the use of manganese with so little carbon, as to neutralize the objectionable effect of phosphorus so long as the latter does not exceed 0 • 25 per cent. Mushet’s tungsten steel consists of iron combined with tungsten, and cannot be forged, but if cast and ground sharp it produces cutting tools of great endurance. Chromium has also been used to produce strength and endurance in steel. Manganese added in the proportion of 0-5 per cent, to ingot metal containing from 0’15 to 0-20 per cent, of carbon, has the effect of removing “red-shortness," and making the metal extremely malleable both when hot aud cold. The furnace is heated by gas formed from small coal on Siemens’ regenerative principle. The bed is 10 feet long, 8 feet broad, and 12 or 15 inches deep in front, being more shallow behind. The bed of the furnace is of quartzose sand sufficiently fusible to set into a hard mass at a full steel melting heat. The sand is thoroughly dried or calcined before use, and, in repairing the bottom, it Is simply poured on the place to be made up, after scraping away the slag. The parts exposed to the full intensity of heat are of refractory Dinas brick, the regenerators of Stourbridge fire-brick, and the reversing flues and chimney of ordinary brick. The proportion of scrap varies from 3 to 10 times the weight of pig. The time required to work a 5 or ö ton charge is from 9 to 11 hours, 60 or 70 tons of steel being a fair week’s work. The loss in converting Bessemer scrap with hematite pig is 4 or 5 per cent., and the consumption of coal 13 or 14 cwt. per ton of steel. Iron may be produced by this process from Cleveland ore with only 01 per cent, of sulphur aud «06 of phosphorus. The roof of the furnace will with proper care last ivr 150 or 200 charges.