Welding wire for laser welding of low-cost ultrahigh-strength steel

Abstract

The invention belongs to the technical field of welding wires, and particularly relates to a welding wire for laser welding of low-cost ultrahigh-strength steel. The composite material comprises the following components in percentage by weight: 0.15%-0.20% of C; 0.20% to 0.40% of Si; mn: 1.20% to 1.70%; 0.20% to 0.40% of Cr; 0.40% to 0.60% of Mo; less than or equal to 0.020% of P; the sum of C, Cr / 5 and Mo / 5 is greater than or equal to 0.30, and the sum of C, Cr / 5 and Mo / 5 is greater than or equal to 0.30. The alloy also possibly comprises the following components in percentage by weight: 0 to 0.15 percent of V, 0 to 0.15 percent of Ti, 0.002 to 0.005 percent of B and 0 to 0.15 percent of Nb. According to the hot-forming cold-rolled plate, the strength of a joint after the hot-forming cold-rolled plate is welded is 800 MPa or above, after the hot-forming cold-rolled plate is heated to 900-950 DEG C, subjected to heat preservation for 3-6 min and cooled at the speed of 50 DEG C / s or above, 95% or above of a weld joint structure is converted into a martensite structure, the strength of the welded joint is 1500 MPa or above, and the production cost is low.

Description

technical field [0001] The invention belongs to the technical field of welding wires, and particularly relates to a welding wire for laser welding of low-cost ultra-high-strength steels. Background technique [0002] In the automobile body, in order to meet the requirements of the forming, strength and weight reduction of the parts, laser tailor welding is usually used to weld steel plates of the same thickness or different thicknesses together. Hot-formed steel laser tailored blanks are currently the most popular steel plates for laser tailored blanks. Thermoforming laser tailored blanks are two or more thermoformed cold-rolled sheets for laser tailoring, and then put into a heating furnace to be heated to austenitizing, and then the steel sheets are quickly put into a thermoforming mold for stamping forming. And the steel plate is quenched in the mold. [0003] The steel plate has low strength and good formability at high temperature. After quenching, the structure of th...

AI Technical Summary

Problems solved by technology

Therefore, the cost of welding wire is high, the production cost of mass application is high, and the cost performance is low

After being applied to laser tailor welding of thermoformed steel, it often occurs that the weld cannot obtain martensitic structure during the quenching process, resulting in low weld strength, which cannot meet the production requirements of laser tailor welding of thermoformed steel

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