Repair welding wire for flaws of cast two-phase stainless steel 6A

Abstract

The invention discloses a repair welding wire for flaws of cast two-phase stainless steel 6A. The two-phase stainless steel 6A refers to 25Cr-7Ni-Mo-N(6A), and the repair welding wire basically comprises: carbon: not larger than 0.03%, silicon: not larger than 0.7%, manganese: not larger than 0.7%, chrome: 25.0-26.0%, molybdenum: 3.0-3.2%, copper:0.5-0.7%, tungsten: 0.5-1.0%, nickel: larger than 8.5-9.0%, nitrogen: 0.30-0.40%, other unavoidable impurities and elements: smaller than 0.06%, and the balance of iron. The repair welding wire with phi 2mm is finally formed by carrying the steps of refining, hot forging, multiple cold pulling and annealing on the basic constituents, satisfies the requirements of the two-phase stainless steel 6A on erosion corrosion resistance and cavitation corrosion resistance, and guarantees that a flawed repair welded position of the cast two-phase stainless steel 6A has favorable erosion corrosion resistance and cavitation corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of welding materials, in particular a welding wire specially used for repairing defects after casting of duplex stainless steel 6A. The duplex stainless steel 6A is specifically referred to as 25Cr-7Ni-Mo-N (6A) in the invention. Background technique [0002] 25Cr-7Ni-Mo-N (6A) is only one of the types of duplex stainless steel. In the structure of this material, the ferrite phase and the austenite phase account for almost half, so 25Cr-7Ni-Mo -N(6A) has both the characteristics of austenitic stainless steel and ferritic stainless steel. Compared with ferritic stainless steel, 25Cr-7Ni-Mo-N(6A) has higher plasticity and toughness, and has no room temperature brittleness. , Intergranular corrosion resistance and welding performance are significantly improved, while maintaining the 475 ° C brittleness of ferritic stainless steel, high thermal conductivity, and superplasticity. Compared with austenitic stainle...

AI Technical Summary

Problems solved by technology

[0010] 25Cr-7Ni-Mo-N (6A) is generally made of castings by casting. For this reason, casting defects are usually unavoidable. Repairing welding for casting defects is a very important part of the production of pump body castings. In addition to a reasonable welding process for repair welding repair, it is very important to choose the repair welding material. Wrong or unqualified repair welding materials will directly lead to the scrapping of the original parts.

Due to the mismatch between other welding materials and the base metal composition of 25Cr-7Ni-Mo-N (6A), the performance of casting defect parts deteriorates after repair welding, which reduces the resistance of 25Cr-7Ni-Mo-N (6A) Erosion corrosion performance and cavitation corrosion resistance, high reject rate, greatly limit the application of 25Cr-7Ni-Mo-N (6A) in pump and valve castings, resulting in great waste

Images