Structure and properties of the double tungsten argon arc hybrid welding joint of stainless steel used in nuclear power plant

For 304L stainless steel plate with the thickness of 6 mm used in the welding of stainless steel pool of nuclear power plant, the comprehensive evaluation of the double tungsten argon arc hybrid welding joint is carried out. The tensile properties, impact properties, bending properties, hardness, structure, ferrite content, intergranular corrosion resistance and coarse-grained grain size rating are tested and comprehensively analyzed. The results show that the comprehensive properties of the welded joint are good when the nuclear grade 304L stainless steel is welded with the double tungsten argon arc hybrid welding. Although the dual heat source process increases the heat, the structure is made of austenite and a small amount of ferrite, and the ferrite content is in the range of 5%−12%. At the same time, no obvious coarsening phenomenon is found in the coarse-grained zone of the welded joint, and the joint has certain hot cracking resistance and good plasticity toughness. No sensitization is found in the intergranular corrosion test, and this welded joint has excellent corrosion resistance. To sum up, the comprehensive performance of the double tungsten argon arc hybrid welding joint of the stainless steel pool used in the nuclear power plant is reliable.