| 摘要 |
1384263 Steel USS ENG and CONSULTANTS Inc 3 Feb 1972 [3 Feb 1971] 5181/72 Heading C7A Steel, for making thin sheet with enhanced ageing resistance, comprises:- C 0À01-0À08% Mn 0À2 -0À6% Si 0À03-0À08% acid soluble Al up to 0À015% normal impurity amounts of O and N, together with sufficient B up to 0À01% to give a B/N ratio of 1À4-2À5 for oxygen contents of over 150 p.p.m. and of 1-1À2 for oxygen contents less than 150 p.p.m, the balance being Fe. The cast alloy may be hot rolled (e.g. at 2100‹-2300‹F and with a finishing temperature above 1500‹F), coiling above 1100‹F (e.g. 1150‹-1250‹F) pickling, cold rolling and then annealing (e.g. at 1250‹-1275‹F). |
