一、前言在火电站锅炉施工安装中,有大量的高温高压蒸汽、给水管路接头的焊接。由于管路材料一般为耐热合金钢,成分比较复杂,可焊性比较差,所以必须采取焊前预热,焊后热处理等措施,以防止冷裂。改善焊缝及热影响区的组织和性能。热处理效果的好坏,直接关系到电站能否安全运行。焊缝硬度在一定程度上反映焊接接 I. Preface In the construction and installation of thermal power plant boilers, there are a large number of high-temperature and high-pressure steam and water pipeline joints. As the pipe material is generally heat-resistant alloy steel, the composition is more complex, poor solderability, it is necessary to take pre-welding, welding and other heat treatment measures to prevent cold cracking. Improve the organization and properties of welds and heat affected zones. Heat treatment is good or bad, is directly related to the safe operation of power plants. Weld hardness to some extent reflect the welding connection