Cr-Mo鋼のクリープ脆化におよぼす溶接後熱処理の影響
1981 年 67 巻 6 号 p. 774-783
詳細
1981 年 67 巻 6 号 p. 774-783
The effects of PWHT ( Postweld heat treatment ) on creep embrittlement in weldment of Cr-Mo steels for use of boiler and chemical reactor vessels were investigated.
The correlation among rupture ductility, density and damping capacity was also investigated
The following results were obtained.
(1) The rupture ductility of HAZ (heat affected zone) increased with increasing PWHT temperature.
(2) Intergranular cracking which reduced the ductility was observed under an optical microscope in the earlier period of the secondary creep stage when PWHT had been carried out at lower temperature.
(3) The creep embrittlement of HAZ generally corresponded with decreasing density and increasing damping capacity.
(4) The creep embrittlement of HAZ of 1Cr-1/2Mo steel was severer than that for 2 1/4Cr-1Mo steel.
(5) The service temperature where the severest embrittlement occurred was between 500 and 550 °C for the HAZ of 1Cr-1/2Mo steel and between 550 and 600°C for that of 2 1/4Cr-1Mo steel.
