1/2 Mo鋼溶接部の水素アタック限界温度におよぼす溶接後熱処理の影響
1987 年 73 巻 1 号 p. 175-182
詳細
1987 年 73 巻 1 号 p. 175-182
Relationship between a critical temperature in hydrogen attack and postweld heat treatment conditions was shown by a metallurgical investigation that was conducted to make clear a preventive measure of failures occurring in 1/2 Mo steel welds of heat exchangers and pipe lines which had been used in oil refineries and petrochemical plants.
The authors examined degradation of tensile properties, susceptibility to intergranular cracking and bubble formation behavior in both actual welds and a simulated-heat-affected zone material (simulated HAZ) after a hydrogen exposure in the temperature range from 320 to 500°C under a pressure of 100 or 150 kgf cm2 (9.81 or 14.71 MPa).
Postweld heat treatment at a temperature range from 550 to 650°C produced a significant improvement in hydrogen attack resistivity of the actual weld. In addition, an examination result of the simulated HAZ exhibited to produce a maximum critical temperature in hydrogen attack by excuting a heat treatment at around a temperature of 650°C. It was concluded that the highest resistivity to hydrogen attack was able to maintain provided a postweld heat treatment would be performed in the temperature range between 625 and 650°C.
