PRODUCT METHOD OF FERRITIC STAINLESS STEEL EXCELLENT IN THERMO-MECHANICAL FATIGUE PROPERTY

摘要

carbon (C): 0.03 wt% or less (excluding 0%), silicon (Si): 1.0 wt% or less (excluding 0 wt%), manganese (Mn): less than 1.0% (excluding 0%), the (P): 0.04 wt% or less (excluding 0 wt%), sulfur (S) less than 0.03 wt% (excluding 0%), chromium (Cr): 21 weight%, more than 23% by weight, nickel (Ni): 2.5 ~ 3.5% by weight, titanium (Ti): 0.6 ~ 0.8% by weight, and cobalt (Co): 0.7 and 1.0 wt.%, nitrogen (N): (excluding 0%), 0.01 wt% or less, the balance iron (Fe), and other steps for producing a sheet, including unavoidable impurities, the grain size of the steel sheet after the hot rolling was 6.0 or less so that the hot-rolled and annealed steel sheet subjected to hot rolling step and the annealing heat treatment was conducted after the heat treatment cold rolling a grain size including the step of heat conducted to the heat treatment the cold-rolled annealed 7.0 or higher and mechanical fatigue property is excellent ferritic . improved mechanical fatigue properties, yield strength and tensile strength - Stainless steel manufacturing methods are introduced ; Heat with these compositions - excellent mechanical fatigue properties of ferritic stainless steel fabrication method of heat at high temperatures can be applied to improve the durability of the components, r-value can be improved is to increase formability, does not include an expensive and rare metals is possible to achieve a reduction in material costs. ; stainless steels, ferritic, exhaust manifolds, thermal-mechanical fatigue