TIG (tungsten inert gas) welding method for high-nitrogen steel under double-layer gas flow shielding

Abstract

The invention belongs to the technical field of welding, and particularly relates to a TIG (tungsten inert gas) welding method for high-nitrogen steel under double-layer gas flow shielding. The TIG welding method is applicable to a welding process of high-nitrogen austenitic stainless steel (the high-nitrogen steel), and solves problems that a weld pool is shallow and nitrogen elements in weld joints leak when tungsten inert gas welding is carried out for high-nitrogen steel in the prior art. The TIG welding method includes that double layers of protective gas channels including an inner-layer gas channel and an outer-layer gas channel are arranged on the outer side of a tungsten electrode, pure inert gas is filled in the inner-layer gas channel, mixed gas containing inert gas and active gas is filled in the outer-layer gas channel, electric arcs are generated via the electrode, and tungsten inert gas welding is carried out for high-nitrogen steel parent metal. Active components are transited to a weld pool, so that a convection mode for heat transfer of the weld pool is changed, and the depth of the weld pool is increased; and the width of the surface of the weld pool is reduced, so that overflow of nitrogen elements in weld joints is reduced. Besides, the depth of the weld pool for welding the high-nitrogen steel is increased by 2-3 times of that of a common arc weld pool while overflow of the nitrogen elements at the weld joints is further effectively reduced.

Description

technical field [0001] The invention belongs to the field of welding technology, in particular to a double-layer gas flow protection TIG welding method for high nitrogen steel, which is suitable for the welding process of high nitrogen austenitic stainless steel (high nitrogen steel). Background technique [0002] High-nitrogen austenitic stainless steel (high-nitrogen steel) is an engineering material that has received widespread attention in recent years. Its nitrogen content generally exceeds 0.4%. Nitrogen is mainly used to partially or completely replace alloying element nickel to obtain a full austenite structure. High nitrogen steel has high strength and toughness, as well as good corrosion resistance, because: 1) Nitrogen is an effective element for grain boundary strengthening and solid solution strengthening of the matrix, and can also refine grains; 2) Nitrogen It is a strong austenitizing element, which reduces the formation ability of ferrite and martensite and ...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a double-layer gas flow shielded TIG welding method for high-nitrogen steel to solve the problems that the depth of the molten pool is relatively shallow and t

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