Welding seam-strengthening MAG welding wire

Abstract

The invention discloses a welding seam-strengthening MAG (Metal Active Gas) welding wire for steel GR.65 (Grade 65). The composition of the welding seam-strengthening MAG welding wire comprises the following components by mass: C accounts for 0.07 to 0.12 percent; Si accounts for 0.075 to 0.095 percent; Mn accounts for 0.50 to 1.00 percent; P is less than or equals to 0.01 percent; S is less thanor equals to 0.01 percent; Ni acounts for 1.50 to 1.90 percent; Cr accounts for 0.03 to 0.04 percent; Mo accounts for 0.20 to 0.45 percent; Al accounts for 0.10 to 0.15 percent; and the others are ferrum. By adopting MAG to weld steel GR.65, the welding seam-strengthening MAG welding wire can achieve the effects as follows: crystal grains in a welding seam area can be thinned, the volume fractionof a spicule body in the welding seam area can be increased, the volume fraction of proeutectoid ferrite can be reduced, and the carbide segregation of a welding seam can be reduced. Therefore, the tensile strength and the Charpy impact ductility of the welding seam area can be improved obviously, and the welding crack tendency can be reduced; in addition, the ductile-to-brittle transformation temperature of a welding joint can be reduced, and the temperature adaptability of a welding component can be improved. The welding seam-strengthening MAG welding wire can be dedicated for steel GR.65.

Description

technical field [0001] The invention relates to the field of low-alloy high-strength steel welding materials, in particular to a weld-strengthening MAG welding wire for GR.65 steel. Background technique [0002] In view of the fact that GR.65 steel (see Table 1 for its chemical element composition) is usually used for gas shielded welding with ER55-G welding wire when using the existing welding wire to manufacture UHV iron towers, but the weld shows poor toughness and crack tendency. It is a big practical application problem. The actual production requires a method that can greatly improve the toughness of the weld without significantly deteriorating the strength and stiffness of the welded joint. Weld alloying is an effective method that can improve the toughness of the weld , Reduce the crack tendency. Through experimental research, it is found that Ni element has a good performance in improving the properties of steel welds. Add an appropriate amount of Ni element to th...

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Problems solved by technology

[0002] In view of GR.65 steel (see Table 1 for its chemical element composition), when using existing welding wire to manufacture UHV towers, ER55-G welding wire is usually used for gas shielding Welding, but it shows the practical application problems of poor weld toughness and large crack tendency. The actual production requires a method that does not significantly deteriorate the strength and stiffness of the welded joint and can greatly improve the toughness of the weld. The weld alloy Melting is an effective method to improve weld toughness and reduce crack tendency

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