Effect of PWHT Conditions on Toughness and Creep Rupture Strength in Modified 9Cr-1Mo Steel Welds

High Temperature Materials and Processes

Nishikawa Satoru¹  Hasegawa Tadayuki²  Takahashi Makoto³ 

[1] Department of Physical Science and Materials Engineering, Iwate University, Morioka, Japan;Japan Power Engineering and Inspection Corporation, Tokyo, Japan;Joining and Welding Research Institute, Osaka University, Osaka, Japan;

关键词: modified 9cr–1mo steel welds;    fine grain haz;    creep rupture strength;    pwht;    vn;    chromium carbide;   

DOI  :  10.1515/htmp-2019-0031

来源: DOAJ

【 摘 要 】

We clarified the effect of post weld heat treatment (PWHT) conditions on the toughness and creep rupture strength of modified 9Cr–1Mo steel weldments used for high temperature components of ultra-supercritical power plants. Fracture appearance transition temperature (FATT) decreased as PWHT temperature increased, and for all of the weld metals of tungsten inert gas welding, submerged arc welding and shielded metal arc welding, FATTs were lower than 293 K when the PWHT temperature was higher than 1,008 K. In contrast, in the uniaxial creep test with a loaded stress of 108 MPa, the creep rupture strength of the specimen on which PWHT was carried out for a holding time of 7.2 ks was significantly decreased when the PWHT temperature was more than 1,033 K. Therefore, the appropriate PWHT temperature range to maintain the toughness and creep fracture strength was 1,008 K ≤ T ≤ 1,033 K.

【 授权许可】

Unknown