Method for improving mechanical property of advanced high-strength steel spot welding joint

Abstract

The invention relates to a method for improving the mechanical property of an advanced high-strength steel spot welding joint, which belongs to the field of metal materials and aims at thinning nugget metal grains, improving the texture of the joint and improving the mechanical property of the advanced high-strength steel spot welding joint. The method includes the processing steps: firstly, preparing inoculant with 10-30% of Nb (niobium), 30-70% of Ni (nickel) and 20-40% of Ti (titanium) in the particle size of 20-60 micrometers and with the purity of 99.99% according to mass percent Wt / %; secondly, evenly mixing 90% of inoculant powder alloys and 10% of adhesives according to the mass percent, wherein the adhesives are transparent plastics made of polystyrene serving as solute and trichloroethylene serving as solvent and are heated at the temperature ranging from 150 DEG C to 370 DEG C to completely volatilize without any remaining residues; and thirdly, evenly coating inoculant alloy paste at the spot welding position of advanced high-strength steel to perform spot welding.

Description

technical field [0001] The invention relates to a method for improving the mechanical properties of advanced high-strength steel spot welding joints, belonging to the field of metal materials. Background technique [0002] An important means to reduce the weight of automobiles, reduce fuel consumption and emissions, and improve collision safety is the use of advanced high-strength steels. Advanced high-strength steel (AHSS) has comprehensive advantages such as good formability, high strength, high energy absorption rate and initial work hardening rate, and good anti-crash performance. It has rapidly developed into one of the most promising lightweight materials in automobile manufacturing. Among them, safety regulations are an important driving force to promote the application of advanced high-strength steel. Many safety parts in automobile manufacturing, such as A, B, C pillars, bumper anti-collision beams, door anti-collision bars and bumper anti-impact columns, etc., are...

AI Technical Summary

Problems solved by technology

The growth characteristics of the columnar grain structure will form the weak surface of the nugget, and the weak surface coincides with the plate seam in the high stress area of ​​the spot welded lap joint, which will significantly reduce the mechanical properties of the spot welded joint

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