Low-carbon high-copper high-strength welding wire for gas protection welding

Abstract

The invention discloses a low-carbon high-copper high-strength welding wire for gas protection welding, wherein the components of the welding wire are as follows: 0.04 to 0.07 wt% of C, 0.35 to 0.6 wt% of Si, 0.7 to 1.0 wt% of Mn, 0.45 to 0.7 wt% of Cr, 2.0 to 2.4 wt% of Ni, 0.40 to 0.60 wt% of Mo, 0.50 to 0.8 wt% of Cu, 0.01 to 0.05 wt% of Ti, the balance of Fe and inevitable impurities. With the adoption of the welding wire for the gas protection welding provided by the invention, when the MIG (Metal Inert-gas Welding) welding is adopted, the welding arc is concentrated and stable; a weld microstructure is a mixed microstructure of low-carbon equivalent acicular ferrite and bainite; a little dispersive retained austenite exists in the microstructure, thus being beneficial to the improvement of cold cracking resistance performance of weld metal; and in addition, the yield strength of deposited metal is more than 735MPa and the ballistic work is more than 60J at the temperature of -50 DEG C.

Description

technical field [0001] The invention relates to a welding material, in particular to a low-carbon, high-copper, high-strength gas-shielded welding wire. Background technique [0002] The MIG welding method is the first choice for welding high-strength steels with a yield strength greater than 700MPa. Usually, MnNiCrMo welding wires with (2-3) wt% Ni content are used together. The typical representatives are MIL120S and MIL130S welding wires in the US military standard MIL-E-23765-2E . The advantages of this type of welding wire are: its alloy system has been widely used and verified, its weld structure is a medium temperature transformation structure, contains more acicular ferrite, and the weld metal has excellent strength, plasticity and toughness; but there are also the following Disadvantages: (1) Alloying elements such as Si, Mn, Ni, Cr, and Mo must be added to the welding wire to meet the requirements of high strength. It can be seen from the CEN carbon equivalent for...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a low-carbon, high-copper, high-strength gas-shielded welding wire, which belongs to the low-carbon, high-copper gas-shielded welding wire, and solves the problem of poor crack resistance of the weld metal of high-strength steel; In case of change, less than 0.075 wt% C and 0.5-0.8 wt% Cu are used to replace some alloying elements such as Si, Mn, Ni, Cr, Mo, etc., to reduce the carbon equivalent of the weld metal, so that the weld metal structure is acicular iron The mixed structure of ferrite and bainite is mainly used to reduce the susceptibility to hydrogen-induced cracks, and at the same time make the strength and toughness of the weld metal in a reasonable coordination state

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