| 摘要 |
PURPOSE: A door hinge manufacturing steel sheet and a manufacturing method thereof are provided to have a micro-structure including austenite and a composition wherein the phase transformation from austenite to martensite easily occurs during a cold processing stage or in a slow cooling stage after the cold processing stage. CONSTITUTION: A manufacturing method of a door hinge steel sheet comprises the following steps. A slab plate is reheated, wherein the slab is composed of, in wt%: C 0.2-0.5; Cr 8.0-12.0; Cu 5.0-15.0; the remainder Fe; and other inevitable impurities. The reheated plate is hot-rolled at Ar3 temperature or greater(S120). The hot-rolled plate is cooled to Ms to the Ms+200>=(S130). [Reference numerals] (AA) Start; (BB) End; (S110) Reheating slab(SRT: 1100 to 1300°C); (S120) Hot rolling(FDT: 700 to 900°C); (S130) Cooling(Ms to Ms+200°C);
|
