The soften mechanisms of martensitic heat resistant steels during hot deformation

2017 3rd International Conference on Applied Materials and Manufacturing Technology

Zhang, Wenfeng^1 ; Liu, Yunqiang^1 ; Ye, Dong^1 ; Liu, Xiaogang^1 ; Yan, Wei^2

Guangxi Colleges, Universities Key Laboratory of Robot and Welding, Guilin University of Aerospace Technology, Guilin

541004, China^1

Institute of Metal Research, CAS, Shenyang

110016, China^2

关键词: Critical condition;    Different slopes;    Dynamic recrystallization (DRX);    Dynamic strain induced transformations;    Linear relationships;    Martensitic heat resistant steel;    Softening effect;    Temperature range;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/242/1/012012/pdf
DOI  :  10.1088/1757-899X/242/1/012012

来源: IOP

【 摘 要 】

Hot deformations for the experimental steels were carried out in the temperature range of 900-1200 °C and the strain rate range 10-3-100 s-1. In this study, the critical condition for dynamic recrystallization (DRX) was determined by a cooperation of the minimum value of -(∂θ/∂σ) and the deviation point of the linear slope of θ-σ curve. From the analysis, it was found that only one slope ratio of critical strain, cversus critical stress, σcappeared in the 9Cr and 10Cr steels, whilst two different slopes in P92 and NS steels due to the augmentation of auxiliary softening effect of the dynamic strain-induced transformation (DSIT). The results also exhibited that ln(Z) kept an approximate positive linear relationship with ln(c) below the value of 40, but barely changed beyond it. However, the ln(σc) value increased continuously with the rise of the ln(Z) value at a smaller growth rate after the value of ln(Z) reached 40 than that of the initial part.