不同厚度DH36船用板FAB埋弧焊缝微观组织及力学性能研究

Study on Microstructure and Mechanical Properties of FAB Submerged Arc Weld for DH36 Ship Plate with Different Thicknesses

对不同厚度DH36船用低合金高强钢进行FAB(挠性石棉衬垫)埋弧焊接的焊接性研究。采用光学显微镜对焊缝微观组织进行分析,用拉伸试验、低温冲击试验、弯曲试验对不同板厚FAB焊缝的力学性能进行了测试。结果表明:随着DH36钢板厚度的增加,FAB焊缝中晶内针状铁素体比例降低,先共析铁素体和侧板条铁素体比例增加;焊缝伸长率和-20℃低温冲击韧性降低,屈服强度增加,焊缝抗拉强度值相差不大。8 mm厚DH36钢板的FAB埋弧焊缝力学性能最佳。20 mm厚DH36钢板FAB埋弧焊缝力学性能不能满足使用要求。

The weldability of FAB submerged arc welding for DH36 high strength low alloy steel with different thicknesses was studied. The microstructure of the weld was observed by optical microscope, and the mechanical properties of the weld with different plate thicknesses were tested by means of tensile test, charpy V-notch impact test and bending test. The results show that with the increase of DH36 steel plate thickness, the proportion ofintragranular acicular ferrite in FAB-SAW weld decreases, while the proportion of grain boundary ferrite and ferrite side plate increase. Meanwhile, the elongation and impact energy at -20℃ decrease significantly, the yield strength increases slightly, and the tensile strength is almost the same. The mechanical properties of FAB submerged arc weld of DH36 steel plate with thickneSs of 8 mm are the best. However, the mechanical properties of FAB submerged arc weld of DH36 Steel plate with thickness of 20 mm cannot satisfy the requirements.