实验表明,预热之后施焊由于熔池表面积相对增大,焊接过程中熔池从电弧气氛中吸收的总氢量增加,因而焊缝中的初始氢含量提高;残余氢含量的大小取决于预热对初始氢含量及氢逸出速度的综合影响,后热对粗晶区组织韧性的影响与材料成分有关,对于18MnMoNb钢,后热过程中由于粗晶区马氏体板条间过冷奥氏体分解析出渗碳体,因此经过后热的粗晶区的韧性有所下降。 Experiments show that, after preheating, the surface area of ​​the weld pool increases relatively and the total hydrogen absorbed by the weld pool from the arc atmosphere increases during the welding process, so the initial hydrogen content in the weld increases; the residual hydrogen content depends on the size of the pre-weld Heat on the initial hydrogen content and hydrogen escape velocity of the combined effect of post-heat on the toughness of the coarse grain region and the composition of the material toughness of the 18MnMoNb steel, after the heat due to the coarse grain martensite lath Austrian cold Decomposition of cementite cementite, so after the heat of the coarse grain toughness decreased.