Cu/INVAR/Ni composite brazing filler metal for heterogeneous connection of hard alloy and steel and laser welding and brazing process thereof

Abstract

The invention discloses Cu / INVAR / Ni composite brazing filler metal for heterogeneous connection of hard alloy and steel and a laser welding and brazing process thereof, and belongs to the technical field of laser brazing. The Cu / INVAR / Ni composite brazing filler metal is of a sandwich sheet structure composed of a Cu foil, an INVAR sheet and an Ni foil, the Cu foil is arranged on one side of steel in advance, the Ni foil is arranged on one side of hard alloy in advance, the INVAR sheet is located between the Cu foil and the Ni foil, the thickness of the Cu foil is consistent with that of the Ni foil, the thickness of the INVAR sheet is larger than that of the Cu foil and that of the Ni foil, and laser welding and brazing is conducted through an automatic platform based on a laser, a robot and an outer shaft positioner. According to the Cu / INVAR / Ni composite brazing filler metal and the laser welding and brazing process thereof, the stress between the hard alloy and the steel with overlarge difference of physical properties such as thermal expansion coefficients is buffered, the welding heat input is reduced, and the problem of cracks caused by overlarge heat input in laser welding of the hard alloy and the steel is solved.

Description

technical field [0001] The invention belongs to the technical field of laser brazing, and in particular relates to a Cu / INVAR / Ni composite solder used for heterogeneous connection of cemented carbide and steel and a laser melting and brazing process thereof. Background technique [0002] Cemented carbide has the characteristics of high hardness, excellent wear resistance, and stable chemical properties. It is an ideal material for making knives. However, due to the high brittleness of cemented carbide, it is easy to break, and the tool with the cemented carbide tip embedded in the steel matrix can reduce the disadvantages of poor toughness and brittleness. The connection between cemented carbide and steel is usually brazed. However, due to the large difference in thermal physical properties such as linear expansion coefficient, thermal conductivity, and melting point between cemented carbide and steel, eutectic structures are prone to appear during welding, and brittle phase...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a kind of Cu / INVAR / Ni composite brazing filler metal that is used for cemented carbide and steel heterogeneous connection, and it is the sandwich sheet structure, solves the laser welding of cemented carbide and steel with excessive difference in physical properties The problem of cracks caused by excessive heat input

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