XIA Zhi-xin
,
ZHANG Chi
,
HUANG Qun-ying
,
LIU Shao-jun
,
LI Zhao-dong
,
YANG Zhi-gang
钢铁研究学报(英文版)
The effect of TaC on grains and packets coarsening in the reduced activation ferritic/martensitic (RAFM) steels was investigated. It was found that the combined effect of the austenitizing temperature and heating rate resulted in the heterogeneous austenite grain growth. When the austenitizing temperature was raised above 1423 K, the TaC particles disappeared, and the homogenous grains abruptly increased. The thermodynamic model for dissolution of TaC particles during austenitizing was applied to interpret the results.
关键词:
reduced activation steel
,
TaC precipitation
,
diffusion
,
thermodynamic model
TAO Peng
,
ZHANG Chi
,
YANG Zhi-gang
,
et al
钢铁研究学报(英文版)
Transformation and coarsening of carbides in 2.25Cr-1Mo steel weld metal during tempering at 700 oC for different time intervals ranging from 1 to 150 h has been examined by transmission electron microscopy and scanning electron microscopy. M3C carbides were observed in the as-welded specimens and when tempered the precipitates were mainly composed of M3C, M7C3 and M23C6 carbides. A sequence for corresponding carbide transformation during tempering with initial precipitation of M3C and followed by M7C3 and M23C6 has been proposed. The precipitation of M7C3 with higher Cr content is the main factor contributing to the decrease of coarsening rate of precipitates after prolonged tempering. The decrease of hardness in the tempered specimens agreed well with the prediction of the weakening of precipitation strengthening due to the coarsening of carbides.
关键词:
weld metal;carbide;tempering;coarsening
