论文部分内容阅读
A ferrite-martensite dual-phase stainless steel(0.07%C-2%Ni-16.3%Cr alloy)having good formability has been developed.However,when this steel is bent toward transverse direction,its bending workability is inferior to when bent toward longitudinal direction,because this steel has anisotropy of bending workability and ferrite-martensite lamellar structure formed by rolling one way.It was confirmed that the anisotropy of bending workability was improved by aging treatment in this investigation.This study was carried out to examine the effect of the aging treatment at various temperatures ranging from 250℃ to 450 ℃ for 1~24h.As a result,bend tests showed that the bending workability had been improved by the aging treatment at temperatures between 300℃ for 9h and 400℃ for 9h while maintaining strength.In the case of an aging treatment at temperature between 300℃ for 9h and 400℃ for 9h,the Cottrell atmosphere is formed by carbon in ferrite phase,therefore the hardness of ferrite phase increases.On the other hand,the hardness of martensitic phase decreases by tempering.This fact shows that an appropriate aging treatment decreases the strength difference between ferrite phase and martensitic phase.The decreasing of the strength difference reduces concentration of deformation in ferrite phase.The improvement of bending workability is attributed mainly to the decreasing of the strength difference between ferrite and martensite.