加氢装置碳钢管道焊后热处理分析

The Analysis of PWHT for Carbon Steel Piping in Hydrotreating

加氢装置中,为防止焊接冷裂纹的产生和应力腐蚀开裂,需对碳钢管道进行焊后热处理以消除焊接残余应力。其中,应力腐蚀开裂仅在特定的腐蚀环境发生,焊后热处理是避免应力腐蚀开裂的主要措施之一。本文介绍了国内现行石化行业标准、国家标准和国外ASME标准等标准规范对碳钢管道进行焊后热处理的要求。加氢装置中应力腐蚀开裂主要表现为湿硫化氢应力腐蚀开裂,对于存在湿硫化氢应力腐蚀开裂的管道,应全部进行焊后热处理。同时,文中明确指出了加氢装置中应进行焊后热处理的碳钢管道。

In order to prevent the cold welding crack and stress corrosion cracking in hydrotreating,the post welded heat treatment（PWHT） for carbon steel piping is needed to eliminate the welding residual stress.Stress corrosion cracking arise in specific corrosive environment,PWHT is one of the main measures to avoid stress corrosion cracking.The article describes the requirements of PWHT for carbon steel piping in the current standards,such as petrochemical industry standard（SH）,the national standard（GB） and ASME standards.Wet H2 S stress corrosion cracking is main stress corrosion cracking in hydrotreating,PWHT is needed for all carbon steel piping in hydrotreating to avoid wet H2 S stress corrosion cracking.At the same time,the article clearly states that the carbon steel piping which the PWHT should be carried out in hydrotreating unit.