Formula of iron-based shape memory alloy electrode and manufacturing method of iron-based shape memory alloy electrode

Abstract

The invention discloses a formula of an iron-based shape memory alloy electrode and a manufacturing method of the iron-based shape memory alloy electrode. The formula of the electrode comprises the formula of an electrode welding core and the formula of an electrode coating. The electrode welding core comprises chemical components as follows: C, Mn, Si, N, Cr, V, Nb, Ti, Zr, N and Fe; and the formula of the electrode coating is the formula of an acidic electrode coating, a basic low-hydrogen electrode coating or a stainless electrode coating. The manufacturing method comprises the following steps of manufacturing the iron-based shape memory alloy welding core, preparing the electrode coating and extruding and coating the electrode. The weld microstructure of the electrode after the welding is the iron-based shape memory alloy, the residual tensile stress of a welded seam can enable the alloy to induce gamma-to-epsilon martensite phase transformation, and the phase transformation deformation loosens the residual tensile stress of the weld seam to decrease the residual tensile stress to be lower than the yield strength (because the driving force inducing the phase transformation is lower than the yield strength) and reduce the welding deformation. Therefore, the fatigue strength of the weld seam is high, and the comprehensive mechanical property of a welded joint is guaranteed.

Description

technical field [0001] The invention relates to a design and manufacture technology of a low residual stress and high fatigue strength welding rod, in particular to a formula of an iron-based memory alloy welding rod and a manufacturing method thereof. Background technique [0002] Due to thermal shrinkage, the welding material will produce residual tensile stress after welding, which makes it difficult to guarantee the size and shape of the welded structure, and leads to a decrease in the fatigue strength of the weld. According to the mechanism of eliminating residual stress, we should try to eliminate and reduce the inherent strain source that produces residual stress. According to this theory, the existing methods for eliminating residual stress require complex processes, and even need to add additional processes, which greatly increases the welding cost. In order to solve this problem, Ota Akihiko et al. used a welding material that completed the martensitic transformat...

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Problems solved by technology

According to this theory, the existing method for eliminating residual stress requires complex processes, and even requires additional processes, which greatly increases the welding cost

In order to solve this problem, Ota Akihiko et al. used a welding material that completed the martensitic transformation and expansion at room temperature or close to room temperature at the end of welding and a shielding gas containing carbon dioxide to perform arc welding on the weld metal, and proposed a low-phase The new "welding method" of variable temperature welding material (Japanese Patent No. 3010211), the advantage of using this welding material and method is that it can improve the welding fatigue strength without preheating before welding and without heat treatment after welding, but in use There is also the problem that the impact strength is not high enough and the application range is limited

To this end, Ota Akihiko and others applied for the Chinese patent "Welding method using low phase transition temperature welding material" (patent number: 03821352), which provides gas protection measures and Strict process path. The advantage of this method is high welding fatigue strength and high impact strength. The disadvantage is that the welding process is complex and requires high shielding gas.

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