Economical CO2 gas protection welding wire suitable for ultra-low heat input automatic welding and manufacturing method of economical CO2 gas protection welding wire

Abstract

The invention discloses an economical CO2 gas protection welding wire suitable for ultra-low heat input automatic welding. The welding wire comprises the following chemical elements of, in percentageby mass, 0.06%-0.13% of C, 0.4%-1.1% of Si, 0.5%-1.3% of Mn, 0.05%-0.1% of Al, 0.2%-0.8% of Cu, and the balance Fe and other inevitable impurity elements. The invention further discloses a manufacturing method of the economical CO2 gas protection welding wire. The method comprises the following steps of performing vacuum electric furnace smelting on raw materials, and performing rolling, drawing and layer winding on a solidified steel ingot. According to the economical CO2 gas protection welding wire, the chemical composition design is reasonable and simple, the effective interaction of the chemical elements in the molten pool environment is fully utilized under the condition that precious metals are not added, the self-advantages of the chemical elements are exerted, the requirements of ultra-low heat input welding are met, and the welding quality during final welding is good.

Description

technical field [0001] The invention relates to a welding wire and a manufacturing method thereof, in particular to a gas shielded welding wire and a manufacturing method thereof. Background technique [0002] MMA automatic welding has the advantages of high welding efficiency, stable welding quality and good operability, and has been widely used in the industry. Especially in the construction of long-distance oil and gas pipelines, the advantages of gas metal shielded welding are more obvious, making it the mainstream welding method for circumferential seam welding of line pipe on-site construction. Since the weld metal belongs to the typical non-equilibrium rapid solidification columnar grain structure, the performance can only be guaranteed by adjusting the chemical composition. Therefore, the welding wire composition system used largely determines the quality and performance of the welded joint. In MIG welding, inert gases (such as Ar and He), active gases (such as CO ...

AI Technical Summary

Problems solved by technology

[0006] like figure 1 As shown, for API 5LX70M pipeline steel pipes, low-alloy steel commonly used AWS A 5.18ER70S-G gas-shielded solid wire is used for automatic welding with ultra-low heat input of 0.25kJ / mm (shielding gas is 80%Ar+20%CO 2 ), due to the rapid cooling after welding, unevenly distributed strip martensite and a large number of clustered M-A components appear in the weld metal, which leads to a serious decline in its toughness, and the single value of impact energy at -10°C is even lower than 35J, the CTOD fracture toughness value is generally lower than 0.1mm, and some are lower than 0.05mm

[0007] In addition, 80%Ar+20%CO 2 The mixed gas has the characteristics of argon arc. Although the welding process is stable and the spatter is small, due to the characteristics of the argon arc plasma energy distribution center is high and the periphery is low, the fusion ability of the edge of the groove is poor during rapid welding under the requirement of ultra-low heat input. The probability of non-fusion defects is high, and the welding process adjustment window is very narrow

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