Study on Creep Rupture Strength and Microstructure of 10Cr-2Mo-V-Nb Steel

Abstract

In order to develop a new ferritic heat-resisting steel that have high creep rupture strength, good weldability and oxidation resistance at the temperature of 600°C, we performed creep rupture tests, mechanical tests, microstructure observation by transmission electron microscope and X-ray diffraction analysis of electrolytic extraction residue of tested steel.
Main resuhs are as follows:
(1) It was found that the creep rupture strength of 0.05C-10Cr-2Mo-0.1V-0.05Nb steel was superior to that of SUS 304 steel at the temperature of 600°C.
(2) This steel comprises two structure of delta ferrite and tempered martensite. Main precipitation at longer term are M₂₃C₆ and Fe₂Mo at 600°C-700°C. The precitation of Fe₂Mo type in delta ferrite would increse favorably the high temperature strength as well as the M₂₃C₆ and M₆C carbides.