核电站钢衬里壁板安装脉冲TIG自动焊试验

Automatic pulsed TIG welding test for construction of steel lining panel of nuclear power station

采用脉冲TIG自动焊对6 mm厚核电站钢衬里壁板用钢P265GH进行横焊、立焊试验,并分析焊接接头的组织和力学性能。结果表明:钢衬里壁板对接焊采用I形坡口和适当的焊接工艺,能够得到成形良好且无缺陷的焊接接头;横焊和立焊焊接接头的焊缝组织均主要为侧板条铁素体(FSP)+针状铁素体(AF)+晶界铁素体(GBF)+粒状贝氏体(GB),粗晶热影响区(CGHAZ)组织均主要为侧板条铁素体(FSP)+上贝氏体(UB)+晶界铁素体(GBF)。横焊和立焊焊接接头的力学性能试验结果表明,其横向抗拉强度均≥470 MPa,断裂位置均位于母材;焊缝的0℃冲击功吸收均≥130 J,热影响区的0℃冲击吸收功均≥140 J;焊接接头硬度均≤HV10350,未出现硬化倾向;焊接接头弯曲试样均未出现裂纹,焊接接头的力学性能符合RCC-M标准要求。

The horizontal and vertical welding tests had been done on the steel of P265 GH which used for assembling steel lining panel of nuclear power station with a thickness of 6 mm by automatic pulsed TIG welding, and the microstructure and mechanical properties of the welded joints had been analyzed. The results showed that welded joints with good shaping and zero defects could be obtained by square groove and appropriate welding procedure for the butt welding of steel lining plate. The main microstructure of weld metal for the horizontal and vertical welded joints was ferrite side-plate(FSP) + acicular ferrite(AF) + grain boundary ferrite(GBF) + granular ferrite(GF),and the microstructure of the coarse grain heat affected zone(CGHAZ) was ferrite side-plate(FSP) + upper bainite(UB) + grain boundary ferrite(GBF). The results of mechanical property tests of the horizontal and vertical welded joints suggested that the transverse tensile strength was above 470 MPa, and the failure locations were all at the base metal. The impact absorbed energy ≥130 J at 0 ℃ for weld metal and ≥140 J at 0 ℃ for heat affected zone(HAZ).There was no hardening tendency for the welded joints and the hardness(HV10) was ≤350. The bending test results showed that there were no cracks on the testing samples. The above results showed that the mechanical properties of the welded joints met the standard of RCC-M.