Controlled hot rolling procedure - for killed steels

摘要

killed steels of general compsn. 0.04-0.08% C; 0.3-1.8% Mn; 0.0-0.5% Si; 0.05-0.15% Ti; 0.015-0.080% Al, =0.025% S + P, can be given a carefully controlled hot rolling treatment to produce material with high yield strength, very good cold formability and weld ability as well as high resistance to brittle fracture and creep. Further addns. of =1% Cr, Mo, Ni or Cu, is not 0.2% Nb, Ta, V, Ir, Hf and not 0.1% B, can be made to further improve properties and corrosion resistance. The hot rolling procedure consists of heating the ingots to 1100 degrees C and giving a =50% reduction between 950 and 800 degrees C, with a final rolling temp. above the gamma-alpha transition temp. The hot rolled sheet is then cooled at =5 degrees C/sec to a coiling temp. of 680-570 degrees C. No further heat treatment is necessary before use.