A flux-cored electrode for stainless steel welding

Abstract

The invention belongs to the field of welding materials, in particular to a flux-cored electrode for stainless steel welding, which includes a flux-cored core from the inside to the outside, a nano-graphene coating and a coating. The tape is first bent into three E-shaped circles of equal diameter that are circumscribed in pairs, and then wound into a ring that is inscribed with the three E-shaped circles, and then closed to form. The drug core fills the inner gap of the closed ring. Modified potassium titanate is used as an arc stabilizing agent in the drug core. During welding, the invention has strong conductivity at the center of the welding core, stable arc, small resistance heat generated by the flux cored welding core, high thermal conductivity of the welding core, small volume expansion of the welding core, and good anti-redness and cracking performance of the coating. The use length of the electrode of the invention is more than 88% of the length of the coating, the utilization rate of the electrode is improved, the chemical composition of the deposited metal is uniform, and the comprehensive mechanical performance is good, which is an innovation in the aspect of the flux-cored electrode 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, the process of using stainless steel electrodes generally has the disadvantage of poor manufacturability. 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 passing through the coating will be burnt out in advance, which will have an adverse effect on the properties of the weld metal. It is a huge waste of welding rod; in addition, the melting speed increases, the welding process becomes poor, and the spatter increases, which leads to the deterioration of the weld formation and the difficulty of slag removal. In short, the redness of the coating means that the gas generating agent in the composition of the coating will decompose prematurely, and a series of metallurgica...

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

Images