Fe-Cr-Ni系ステンレス鋼の機械的性質に対する加工温度の影響

Abstract

In order to investigate the influence of working temperature on the mechanical properties of Fe-Cr-Ni stainless steel, the specimens were rolled at several temperatures between room temperature and 200°C. These specimens had such chemical compositions as to make the austenite structures stable or unstable at room temperature. Then, the amount of martensite formed in specimens were estimated by means of saturation flux density measurement, and the Federbiegegrenze, Young’s modulus, tensile strength, and elongation were also measured. The results obtained are as follows:(1) The variation in the mechanical properties with working temperature was considerably large in the specimens with chemical compositions in which the austenite structures were unstable at room temperature: Namely, the strength became greatly lowered according to a sharp decrease in the amount of strain-induced martensite with the rising working temperature.(2) A good elongation and a relatively high strength were obtained by warm working of specimens with a chemical compositions in which the austenite structures were very unstable at room temperature.(3) There was a little influence of working temperature on mechanical properties of the specimens with chemical compositions in which the austenite structures were stable at room temperature.(4) The relationships were shown between the mechanical properties and the modified Ni equivalent, which is a universal quantity deduced thermodynamically from the chemical composition and the working temperature.