Self-protecting flux-cored wire containing polyvinylidene resin

Abstract

The invention relates to a self-shielded flux-cored wire containing polyvinylidene fluoride resin, which comprises a shuck manufactured by adopting the home-made SPCC common mild-carbon steel strip. The invention is characterized in that flux core of the common mild-carbon steel strip consists of villaumite, carbonate, oxide, Manganese (Mn), Silicon (Si), Aluminum (Al), Magnesium (Mg), Nickel (Ni) and ferrous powder jointly; wherein, the components of the flux core include 20 percent to 45 percent of the villaumite, 4 percent to 13 percent of the carbonate, 4 percent to 15 percent of the oxide, 1 percent to 5 percent of Mn, 1 percent to 3 percent of Si, 3 percent to 8 percent of Al, 3 percent to 7 percent of Mg, 0 percent to 5 percent of Ni and ferrous powder serving as the rest. The invention has the advantages that the defects that the pore sensitivity of the self-shielded flux-cored wire is high and the impact toughness of the deposited metal is not excellent; when the multi-layer welding is carried out, the surface blowhole is not generated, the complete slag coverage is achieved, the slag can be easily detached, the weld can be formed well and the impact toughness of the deposited metal is high and stable; the concentration of the hazardous substances in the welding fume is lowered and the invention is beneficial to the health of the welder.

Description

(1) Technical field: [0001] The invention relates to a self-protecting flux-cored welding wire, in particular to a self-protecting flux-cored welding wire containing polyvinylidene fluoride resin. (two) background technology: [0002] Since the self-shielded flux-cored wire is directly exposed to the air for welding by the arc, oxygen and nitrogen in the air will invade the welding zone, causing adverse reactions such as high porosity sensitivity and insufficient toughness of the deposited metal during the welding metallurgical process. In order to obtain a good welding process and mechanical properties, a certain amount of deoxidizer and denitrification agent (such as aluminum, magnesium, manganese, titanium, etc.) is usually added to the core, which can form stable oxides and nitrogen with oxygen and nitrogen. However, too little addition of these substances will not have the desired effect. Too much addition will cause the columnar crystals of the weld to become thicker, ...

AI Technical Summary

Problems solved by technology

[0002] Since the self-shielding flux cored wire is directly exposed to the air for welding, the oxygen and nitrogen in the air will invade the welding zone, causing adverse reactions such as high porosity sensitivity and insufficient toughness of the deposited metal during the welding metallurgy process.

In order to obtain a good welding process and mechanical properties, a certain amount of deoxidizer and denitrification agent (such as aluminum, magnesium, manganese, titanium, etc.) is usually added to the core, which can form stable oxides and nitrogen with oxygen and nitrogen. However, too little addition of these substances will not have the desired effect. Too much addition will cause the columnar crystals of the weld to become thicker, pro-eutectoid ferrite will increase, acicular ferrite will decrease, and a large amount of ferrite will be formed at the same time. Non-metallic inclusions such as aluminum nitride (AlN), which can split the metal matrix, greatly reduce the impact toughness; another method is to increase gas-generating agents (such as various fluorides, carbonates, magnesium, etc.) lower the partial pressure of oxygen and nitrogen in the welding area, so that the fluoride content is often high. Due to its small specific gravity, it will cause difficulty in rolling the welding wire and uneven performance. At the same time, it will increase the harmful substances in the welding fume. Bad health for welders