Flux cored wire for gas shielded arc welding

Abstract

The flux-cored welding wire in which the steel sheath is filled with flux has a composition containing 0.01 to 0.12% by mass of C, 0.05% by mass to less than 0.30% by mass of Si, and 1.0 to 3.5% by mass of Mn in the total mass of the wire. %, Ni is 0.1 mass % or more and less than 1.0 mass %, Mo is 0.10 to 0.30 mass %, Cr is 0.1 to 0.9 mass %, TiO2 is 4.5 to 8.5 mass %, SiO2 is 0.10 to 0.40 mass %, Al2O3 is 0.03 ~0.23% by mass, Fe is 80% by mass or more.

Description

Technical field [0001] The invention relates to a flux cored wire for gas shielded arc welding. More specifically, it relates to a flux cored wire for gas shielded arc welding used for welding steel materials with a tensile strength of 490 to 670 MPa class. Background technique [0002] Historically, various researches have been conducted for the purpose of improving the welding workability and the mechanical properties of the weld metal in the flux-cored welding wire used for gas shielded arc welding of steel materials with a tensile strength of 490 to 670 MPa. (For example, refer to Patent Documents 1 and 2.). [0003] In Patent Document 1, a flux-cored wire for gas shielded arc welding is proposed, which has good welding operability in all positions and obtains a weld metal with excellent strength and low temperature toughness in the welded state (AW) and heat treatment (PWHT) , While limiting the wire composition. The flux-cored welding wire described in Patent Document 1 ha...

AI Technical Summary

Problems solved by technology

[0010] However, in the flux-cored welding wire of the above-mentioned Patent Document 1, in order to ensure excellent low-temperature toughness, 0.1 to 3.0 mass % of Ni is added, and the Ni content of the weld metal may exceed 1 mass %, which cannot sufficiently cope with NACE. Require

In addition, the flux-cored welding wire described in Patent Document 1 lacks research on heat treatment conditions, and it is not clear whether a weld metal that is still excellent in yield strength, strength, and low-temperature toughness can be obtained when heat treatment is performed under more severe conditions.

[0011] In addition, the flux-cored wire described in Citation 2 also contains Ni at 1.0 to 3.0% by mass, so it cannot meet the requirements of NACE.

In addition, in this flux-cored welding wire, the performance of the weld metal after heat treatment has not been studied, and similar to the flux-cored welding wire described in Citation 1 above, if heat treatment is performed under stricter conditions, whether the strength and Weld metals that are still excellent in low temperature toughness are not clear

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