Welding technique of Invar alloy and hard alloy welding piece

Abstract

The invention discloses a welding technique of a welding part of invar alloy and hard alloy; the technique adopts a laser-argon arc complex welding method to realize the welding of a thick board of the invar alloy and hard alloy; an invar alloy welding layer with the single-side thickness of 6 to 12mm can be formed by only one-time welding; beveled edges are not opened when in welding, filling materials are not added, nitriding processing is not needed after welding and the interface of a sample does not have air holes and cracks after welding, and the Eta phase of the hardness of the interface can be controlled. Therefore, the technique not only overcomes the defects of the prior art, provides a shortcut for solving the difficulty that the invar alloy can not meet the requirements of strength of special occasions and high-temperature red hardness, but also provides a welding technique which has simple operation, low cost and excellent performance and is applicable to industrialized implementation.

Description

technical field [0001] The invention relates to a welding process of an Invar alloy and a hard alloy welding part, and belongs to the technical field of alloy welding. Background technique [0002] Invar alloy has the characteristics of low expansion coefficient, and is widely used in the production of instruments and equipment such as aerospace precision key parts, military weapons and oil transportation containers. However, due to the low strength, poor wear resistance and high temperature performance of Invar alloys, in special applications, the advantages of Invar properties are often not fully utilized. Many studies have been carried out in the field of Invar alloy strengthening at home and abroad, including the strengthening of the Invar alloy system, the use of B to improve the high-temperature red hardness of the Invar alloy, and the surface modification of the Invar alloy, etc., but the strength of the Invar alloy still cannot meet the strength of special occasions....

AI Technical Summary

Problems solved by technology

The inventor has disclosed a cemented carbide connector in Chinese patent 200810035711.7, which is welded by a high-binder phase cemented carbide and Invar alloy through an argon tungsten arc automatic welding process. Alloy connectors not only have the high strength, high wear resistance and good red hardness of cemented carbide, but also have the constant thermal expansion performance of Invar alloy in a certain temperature range. The problem of strength requirements and high-temperature red hardness requirements provides a new way, but the argon tungsten arc welding method used in the above invention is only suitable for welding medium and thin plate Invar alloys and hard alloys, and requires multiple flip welding to form. Unable to realize the welding of thick plate Invar alloy and cemented carbide

[0004] At present, laser welding and other high-energy beam welding methods are used to realize the welding of thick plate alloys, but laser welding has the following specific problems: (1) The laser forms reflection on the surface of the base metal, resulting in a large energy loss, and blackening treatment is required; (2) ) The performance of laser bridging is poor. Under the conditions of no groove opening and no filling material, the processing accuracy and clearance of the butt joint surface of the welded materials are strictly required; (3) The cemented carbide side of the formed weld interface has brittle hard The formation of η phase reduces the performance of joints; (4) need to introduce post-weld treatment processes such as post-weld nitriding