Flux-cored wire for gas shielded welding of super duplex stainless steel and preparation method thereof

Abstract

The invention discloses a flux-cored wire used for super duplex stainless steel gas shielded welding and a preparation method thereof. The flux-cored wire is composed of an external use steel belt andflux powder, wherein the external use steel belt is made of an austenitic stainless steel belt with 17.0%-18.0% of chromium and 11.0%-12.5% of nickel; and the flux powder comprises the following components of, in percentage by weight, 36.0%-38.0% of chromium powder, 9.0%-13.0% of high-nitrogen chromium iron, 2.5%-3.0% of electrolytic manganese metal, 4.0%-5.0% of molybdenum powder, 0.5%-1.0% of ferrosilicon, 1.0%-1.5% of ferrotitanium, 0.5%-1.0% of aluminum-magnesium alloy, 18.0%-20.0% of rutile, 1.0%-2.0% of quartz, 5.0%-6.0% of zircon sand, 1.0%-1.5% of potassium feldspar, 3.0%-3.5% of albite, 1.0%-1.5% of fluorite, 0.5%-1.0% of sodium cryolite, 1.0%-1.5% of potassium titanate, 0.1%-0.3% of bismuth oxide and the balance iron powder. According to the flux-cored wire used for super duplexstainless steel gas shielded welding and the preparation method thereof, the components and the two-phase proportion of deposited metal can be balanced, thus obtaining a duplex stainless steel welding joint which is good in forming quality and excellent in corrosion resistance.

Description

technical field [0001] The invention relates to a flux-cored welding wire for super duplex stainless steel gas shielded welding and a preparation method thereof, belonging to the welding field of material processing engineering. Background technique [0002] Duplex stainless steel is the "key special steel variety" for the development of my country's iron and steel industry. The ferrite phase and austenite phase in the microstructure each account for about 50%, so that it has both the excellent toughness of austenitic stainless steel and the ferrite phase. The high strength and chloride ion corrosion resistance of solid stainless steel have been more and more widely used in marine structures, petrochemicals, fresh water purification and other fields. [0003] The development of duplex stainless steel has gone through three generations. The first generation of duplex stainless steel is represented by 3RE60 steel developed in Sweden in the mid-1960s, which can be used in chlor...

AI Technical Summary

Problems solved by technology

The technical bottleneck in the popularization and application of super duplex stainless steel is that the corrosion resistance of the welded joint does not match the base metal. The welded joint is the weak link of the stainless steel welded structure. In a corrosive environment, the joint will be corroded first, causing the overall failure of the structure. As a result, the corrosion resistance of super duplex stainless steel cannot be fully utilized, resulting in a large amount of waste of steel

[0006] Literature research shows that no welding material is added during welding, and the molten or molten super duplex stainless steel parent metal solidifies and cools to form a welded joint under the action of a welding heat source, but the austenite content of the weld is only about 30%. Its corrosion resistance is significantly reduced; the austenite content of the weld metal can be increased by feeding nitrogen gas during the welding process, but since the nitrogen comes from the shielding gas, its transition coefficient depends on the degree of ionization of the nitrogen gas during the welding process and the nitrogen element in the welding process. The solubility in the molten pool is greatly affected by the welding process parameters, and the chemical composition of the weld metal and the ratio of the two phases are not easy to accurately control

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