KR20010096370A - Joining method for tungsten carbide to high speed steel dissimilar joint - Google Patents

Abstract

PURPOSE: A method for bonding a cemented carbide material with high speed steel is provided to increase strength and durability of a bonding part by using nickel based foil or powder, or varieties of nickel based molten metals as an inserting material, constructing the bonding part in an irregular shape, and brazing or diffusion bonding the bonding part. CONSTITUTION: In bonding a cemented carbide material with high speed steel, the method for bonding a cemented carbide material with high speed steel comprises the steps of forming irregular surfaces on a bonding surface of both materials(10,20), wherein each of the irregular surfaces are corresponding to each other; inserting the inserting material into the bonding surface of both materials using nickel based foil or powder, varieties of nickel based molten metals or a material containing a high content of nickel as an inserting material of the bonding surface; and bonding both materials passing through the above steps, wherein the bonding surface is constructed in a one stage concave and convex parts(30,40) or two or more stage concave and convex parts(50,60), a thickness of the inserting material used on the bonding surface of both materials(10,20) as a bonding medium is 500 microns or less, and a content of nickel is 36 wt.% or more, and wherein both materials are bonded by diffusion welding process using diffusion phenomena under the vacuum environment, or brazing process.

Description

Joining method for tungsten carbide to high speed steel dissimilar joint}

The present invention relates to a method of joining a cemented carbide material and a high speed steel by joining a cemented carbide material and a high speed steel to form a concave-convex portion on the joint surface where the cemented carbide material and the high speed steel are joined and by diffusion bonding or brazing.

As a method of joining dissimilar materials, a melt bonding method (fusion welding), a liquid-solid reaction bonding method, a solid state bonding method or a gas phase-solid bonding method is disclosed, and silver is a main element for joining a ceramic-based carbide material and a metal-based high-speed steel. A method of brazing using silver wax to be widely used.

However, in the case of joining by brazing using the above silver wax, ceramic cemented carbide material has a very small coefficient of thermal expansion while metal-based high-speed steel has a large coefficient of thermal expansion, so it is cracked at the joint due to thermal stress during the bonding process. There is a problem that this tends to occur, so the strength of the joint is low and the durability is not sufficient.

In the present invention, thermal stress is generated during the joining process when the thermal expansion coefficients of the dissimilar materials are different in joining dissimilar materials using silver wax as an insert, so that cracks occur in the joint, the strength of the joint is low, and the durability is poor. In order to solve the problem, nickel (Ni) -based thin film (foil), powder or various types of Ni-based solder are used, and the shape of the joint is formed to have an uneven portion and brazing or diffusion bonding to improve the strength and durability of the joint. There is a technical challenge in raising it.

Fig. 1A is a perspective view of the concave-convex surface formed in one step in both materials according to the present invention.

1B is a cross-sectional view of FIG. 1A.

It is a perspective view which shows that the uneven surface was formed in two steps in both materials by this invention.

2B is a sectional view of FIG. 2A;

※ Explanation of code about main part of drawing ※

10: upper material 20: lower material

30: main part 40: iron part

50: two-stage main part 60: two-stage iron part

70: insert

In the method of joining the cemented carbide material and the high speed steel of the present invention for realizing the above technical problem, in order to increase the interfacial area of the joining surfaces of both materials to be joined and to alleviate thermal stress, Forming an uneven surface;

Inserting the joining surfaces of both materials using Ni-based thin plates or powders having higher strength and durability than silver wax or various brazing solders of Ni-based materials or using Ni-containing materials as inserting materials for the joining surfaces;

Characterized by consisting of the step of bonding both materials through the above step.

Hereinafter, with reference to the accompanying drawings will be described in detail the bonding method of the present invention.

Fig. 1A is a perspective view showing a concave-convex surface formed in both materials according to the present invention in one step, Fig. 1B is a cross-sectional view of Fig. 1A, and Fig. 2A is a concave-convex surface formed in two steps in both materials according to the present invention. 2B is a cross-sectional view of FIG. 2A.

In order to form concave and convex portions on the joint surfaces of both materials, but to form one step portion 30 and convex portions 40 in the upper material 10 and the lower material 20, or to increase the interface area of the joint surface. The step of forming the two-stage recessed part 50 and the two-stage convex part 60 in the one-stage uneven part 30 and 40 is performed again.

FIG. 2 is a cross-sectional view showing the insertion material being inserted into the joint surface of both materials in which the uneven portion of the first stage is formed;

After forming the concave and convex portions, various types of Ni foil, Ni powder, and Ni-based brazing brazing materials having a thickness of 500 μm or less on the joint surface of the upper material 10 and the lower material 20 Or inserting a thin plate having a Ni content of 36% or more as the insert material 70;

After the above steps, the diffusion bonding is carried out using a diffusion phenomenon under a vacuum atmosphere or brazing by melting of the brazing filler material. The upper and lower materials are thermally stressed through the insert. Bonding with improved strength and durability is achieved.

As described above, in joining dissimilar materials, a very thin Ni plate, Ni powder, various Ni-based lead materials, or a high Ni content material is used as an inserting material, and the joining method is diffusion bonding or brazing. By using the method and forming convex and concave portions on the joint surface of dissimilar materials, the interface area of the joint increases, so that the thermal stress generated at the joint is alleviated, and cracks do not occur at the joint. Therefore, the reliability of the joint is increased and the strength of the joint is increased. Increasing durability has the effect of improving.

Claims (4)

Forming a concave-convex surface corresponding to each other on the joint surface of both materials in joining the cemented carbide material and the high speed steel; Inserting the joining surfaces of both materials using nickel (Ni) -based thin plates, powders, various Ni-based solders or using nickel (Ni) -containing materials as the inserting surfaces of the joining surfaces; Bonding method of cemented carbide material and high-speed steel, characterized in that consisting of the step of bonding both materials passed through the above step. 2. The method of joining cemented carbide materials and high-speed steel according to claim 1, wherein the shape of the joining surface is formed of recesses and convexities of one stage or of recesses and convexities of two or more stages. The method of joining cemented carbide materials and high-speed steel according to claim 1, wherein the thickness of the insert used as the bonding medium on the joining surfaces of the two materials is 500 µm or less and the nickel (Ni) content is 36% or more. 2. The method of joining cemented carbide materials and high-speed steel according to claim 1, wherein the joining of both materials is performed by diffusion welding or brazing using a diffusion phenomenon in a vacuum atmosphere.