Flux-cored welding rod for stainless steel welding

Abstract

The invention belongs to the field of welding materials, and particularly relates to a flux-cored welding rod for stainless steel welding. The flux-cored welding rod comprises a flux-cored welding core, a nano graphene coating and a coating from inside to outside, the flux-cored welding core is of a structure similar to a cable, a nickel strip is sequentially bent into three e-shaped circles whichare externally tangent pairwise and are equal in diameter, then is wound into a circular ring which is internally tangent to the e-shaped circles, and is closed to form the flux-cored welding core, gaps in the closed circular ring are filled with flux core, and modified potassium titanate is adopted in the flux core to serve as an arc stabilizer. According to the welding rod, during welding, thecenter of the welding core is high in electrical conductivity and stable in electric arc, resistance heat generated by the flux-cored welding core is small, the heat conduction performance of the welding core is high, the volume expansion of the welding core is small, and the reddening and cracking resistance of the coating is good. The use length of the welding rod is 88% or above of the length of the coating, the utilization rate of the welding rod is increased, deposited metal is uniform in chemical component, the comprehensive mechanical property is good, and the welding rod is an innovation in the aspect of flux-cored welding rods for stainless steel welding.

Description

technical field [0001] The invention belongs to the technical field of welding materials, in particular to a flux-cored electrode for stainless steel welding. Background technique [0002] At present, there are generally disadvantages of poor workmanship in the process of using stainless steel electrodes. The key problem is that the coating is prone to redness and cracking when the electrode is welded to the second half. At the same time, the beneficial elements transitioning through the coating will also burn out in advance, which will have an adverse effect on the properties of the weld metal. In more serious cases, the coating will crack or fall off and the welding will have to be terminated, resulting in Huge waste of welding rods; in addition, the melting speed increases, the welding process deteriorates, and the spatter increases, resulting in deterioration of weld formation and difficulty in slag removal. In short, the redness of the coating means that the gas-genera...

AI Technical Summary

Problems solved by technology

The disadvantages of this technical solution are: ①A large number of chromium particles and nickel particles exist in the coating, and the arc is moving. In order to avoid melting defects, the moving speed of the arc should be moderate and not too slow, which will cause chromium Particles and nickel particles cannot all melt into the weld, but part of them melt into the molten pool, and some exist in the form of particles in the welding slag, and the proportion of particles melted in the molten pool and remaining in the slag cannot be predicted and controlled. Therefore, its design and manufacture are extremely difficult. On the other hand, due to the rapid drop in the temperature of the molten pool, part of the particles dissolved in the molten pool have no time to melt, but exist in the deposited metal in the form of solid particles, resulting in a decrease in the mechanical properties of the weld. The desired effect cannot be achieved; ② a large amount of alloying elements chromium and nickel need to be added to the coating, which will inevitably lead to thickening of the coating of the electrode, and a series of problems: such as reduced adhesion of the coating and insufficient melting of the coating of the electrode etc.; ③During welding, the welding core melts first, and the coating melts later, and elements such as chromium and nickel in the coating are easily distributed unevenly after entering the molten pool, resulting in a decrease in the mechanical properties of the welded joint

The disadvantages of this technical solution are: ①The welding core is formed by filling the center of the seamless tube with powder, and the center part is composed of powder particles. No matter how dense the particles are stacked, there will be gaps, resulting in poor conductivity of the welding core, and the arc is very weak during welding. It is easy to rotate along the surrounding tube walls, the arc is unstable, and the weldability is poor; ②The drug core is a round whole. Due to gravity, due to vibration and other reasons during storage or transportation, the drug powder will be different according to the density. As a result, the displacement becomes unevenly distributed, and the phenomenon of penetration or impermeability often occurs during welding; ③Because the arc is constantly moving during welding, the cooling rate of the molten pool is fast, and after the welding core is melted, the surface composition of the circumference and the middle Due to the positional relationship, it is difficult to mix the core components of the flux core evenly, resulting in uneven chemical composition of the weld deposit metal, which affects the mechanical properties of the welded joint; ④Although seamless steel pipes are used, it is inevitable to In contact with water vapor, moisture will enter the flux core from both ends of the flux cored wire, and it will gradually infiltrate. From both ends to the middle, potassium titanate is very easy to absorb moisture, which will affect the welding process. The absorption resistance described in this technical plan tide effect is not significant

[0007] The Chinese patent application number 94118437.4 (application date: November 20, 1994) discloses a redness-resistant austenitic stainless steel electrode and its preparation method. Metal materials achieve the purpose of faster heat dissipation, but the effect is not significant, and the effect of improving the crack resistance of the electrode is not obvious, and it cannot prevent the expansion and deformation of the stainless steel core from increasing, resulting in cracking of the coating

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