A PROCESS FOR PRODUCING COPPER-BEARING, AGE-HARDENED STEEL OF INCREASED YIELD STRENGTH, BENDABILITY AND WELDABILITY

摘要

(a) making steel in Electric Arc Furnace/LD furnace by charging scraf containing cuttings of mild steel plates, bars and sheets, which is reasonably free from residual elements like Arsenic, Tin and Lead, lime, petroleum coke, sponge iron, iron ore and/or hot metal in required quantities in the furnace and melting the said raw materials by electric arc or oxygen lancing with addition of 0.5-3.0% by weight quantity of Fe-Mn-Nickel sinter and Fe-Mo in the BOF(LD) furnace and 3 to 4 times slag off; (b) adding Cu, Fe-Mo, Fe-Mn (high carbon), Fe-Min (low carbon), Fe-V to molten steel in ladle; (c) further adding FeMn, FeNb in VAD-I by arc degassing (below 5 torr) for 10 minutes and adjusting the composition of steel in VAD-II at 1625-1630°C; (d) injecting CaSi wire into molten steel in ladle; (e) casting the molten steel into slabs in a continuous casting machine; (f) cross-rolling the slabs into plates, as herein described; and (g) ageing the plates, as herein described; characterised in that (i) the chemical composition of the steel produced is (by weight %)