A flux-cored wire for gas-shielded welding

Abstract

The invention discloses a flux-cored wire for gas shielded welding. The flux-cored wire comprises the following components by weight percentage: 80%-90% of carbon steel sheath and 10%-20% of flux core, wherein, the carbon content of the flux-cored wire is 0.06%-0.15%. The flux-cored wire is characterized in that the flux core comprises the following components by weight percentage: 2%-8% of TiO2, 1%-4% of SiO2, 0.1%-0.3% of Al2O3, 0.1%-0.8% of fluoride, 0.8%-3.2% of Mn, 0.4%-1.8% of ferrotitanium powder, 0.4%-2.4% of Fe2O3 and the balance of iron powder and unavoidable impurities. In the invention, by adding the ferrotitanium powder and the Fe2O3 to the flux core, fine and dispersedly distributed titanium-containing oxides or titanium-containing composite oxides are formed in welding seams, and the oxides induce generation of acicular ferrite; and due to faster welding cooling speed and greater mixing power, the inclusions are dispersedly distributed in the welding seams owing to no enough time for growth so that metal structures of the welding seams are refined.

Description

technical field [0001] The invention belongs to the field of welding and relates to a flux-cored welding wire for gas shielded welding. Background technique [0002] The welding process is a unique metallurgical process. Under the conditions of fusion welding, the welded joint is composed of two interconnected parts with very different organizational properties, namely the weld seam and the heat-affected zone. The weld is the weak link of the weldment, the quality of the weld directly affects the quality of the weldment, and the quantity, size and distribution of the inclusions in the weld will directly affect the structure and performance of the weld. [0003] As the demand for energy grows and the supply of crude oil and natural gas expands even to areas with severe environments such as the icy arctic regions, the requirements for weld performance become more stringent. In order to meet this requirement, a series of measures have been taken such as reducing the content of...

AI Technical Summary

Problems solved by technology

In terms of reducing the size and quantity of inclusions in the weld, traditional welding processes generally control the purity of welding raw materials and reasonable welding processes. The patent "A Carbon Steel Flux-Cored Wire for Gas Shielded Welding" (application No.: 200510019874.2, Publication No.: CN 1775452A) and the patent "Titanium Gas Shielded Flux-Cored Welding Wire" (Application No.: 94109138.4, Publication No.: CN 1117902A) use a strong deoxidizer to reduce the oxygen content in the weld and reduce the number of inclusions , but due to the fast cooling rate of welding, there will still be some inclusions left in the weld, these inclusions are mostly silicon-manganese inclusions or aluminum inclusions, which cannot induce the formation of acicular ferrite, resulting in coarse structure and performance degradation