JPS59147774A - Joining method of sintered hard alloy and steel - Google Patents

Abstract

PURPOSE:To obtain a composite tool having high joint strength without cracking by interposing a thin metallic sheet or plating layer on the joint surface between a sintered hard alloy and a steel, pressing the same, an irradiating a high energy beam to the sintered hard side to diffuse heat energy on the steel side. CONSTITUTION:A thin metallic sheet of <=0.5mm. is sandwiched between the joint surfaces of a sintered hard alloy and a steel or a plating layer is provided on both or either of the sintered hard alloy and the steel. The assembly is set in the state of pressing the above-mentioned joint surfaces into a vacuum vessel. The above-mentioned intermediate layer is constituted of Fe, Co, Ni, Cu or the alloy thereof. Such a high energy beams as an electron beam or laser beam is irradiated to the sintered hard side in proximity to the joint surfaces to increase the temp. of the sintered hard alloy and to diffuse the heat energy thereof to the steel side, thereby diffusion-joining the sintered hard alloy and the steel. The joint part of different materials having high strength is thus obtd. and the generation of a crack in the sintered hard alloy side arising from the joining is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a method for manufacturing a composite tool member made of a cemented carbide and a steel member. In particular, it relates to the manufacture of punches, end mills, and drills in which a carbide material is bonded to the tip of a vise, or ice spikes, golf spikes, seal rings, etc. in which a small piece of carbide is bonded to a steel component material.

(b) Background of the technology Generally, cemented carbide and steel are joined by brazing, shrink fitting, etc., but in brazing, heating the steel member to a temperature lowers the hardness of the steel, making it difficult to use as a tool. does not satisfy the required characteristics. Additionally, the difference in thermal expansion between cemented carbide and steel causes tensile stress to act on the cemented carbide, often causing cracks. Therefore, in brazing, a low melting point brazing material such as Ag solder is used. Low-melting brazing materials have weak bonding strength (and are unsuitable for tools that require high bonding strength. Therefore, solid alloys made entirely of cemented carbide are used in such tools.

According to this method, expensive ~V, which is the main raw material of cemented carbide, is often used, and the tool inevitably becomes expensive, so there was an urgent need to develop a strong joining technique.

(C) Disclosure of the Invention The present invention involves the welding of cemented carbide and steel by inserting a metal thin plate of 0.5 to Alternatively, after providing a plating layer on either side, pressurize the contact surface between the cemented carbide and steel and irradiate a high-energy beam to the cemented carbide side near the contact surface to reduce the temperature of the cemented carbide. This is a joining method in which cemented carbide and steel are diffusion bonded by elevating -L and diffusing the energy to the mesh side. Here, the thin metal plate or plating layer inserted into the contact surface between the cemented carbide and the steel is made of Fe or Ni.

Go, Cu, and alloys containing these are desirable. Further, it is preferable that the high-energy beam be an electron beam or a laser beam, which can locally heat the beam, for the reasons described below.

The effects of the present invention will be explained in detail below.

When welding cemented carbide and steel, when the steel melts and solidifies, large tensile stress moves near the fusion weld of the cemented carbide, causing cracks in the cemented carbide. - When bonding cemented carbide and steel by heating them to welding temperature in order to prevent cracks in the force welding part, the hardness of the steel decreases and - the performance as a tool is not satisfied. .

In the present invention, the beam diameter of the electron beam or laser beam is expanded over a wide area without narrowing the beam focus, and the cemented carbide side near the contact surface between the cemented carbide and the steel is heated. Due to heating, thermal energy flows to the mesh side, resulting in diffusion bonding between the cemented carbide and steel on the contact surface. The feature of this method is that a high-energy beam with a relatively wide beam diameter is applied to the contact surface of the cemented carbide side, which has a smaller coefficient of thermal expansion than steel. A temperature difference occurs between the two, and this state is maintained until welding is completed. Furthermore, cemented carbide is a material with high thermal conductivity, so even if a high-energy beam is applied to a local part of the cemented carbide, the entire part of the material will be heated. Therefore, the residual stress generated due to the difference in thermal expansion coefficient after welding is completed is
Since the temperature gradient described above can be made smaller, cracking can be prevented.

Furthermore, another reason for heating the cemented carbide side is that if a high-energy beam is applied to the net side, the temperature of the steel will rise, and the hardness and strength of the steel will decrease or change in quality.

The metal thin plate or plating layer inserted between the contact surfaces of the cemented carbide and the steel preferably has a thickness of 0.5 mm or less. If it is 0.5112 or more, it is necessary to increase the irradiation beam energy, and at the same time, the temperature on the mesh side increases, which is undesirable for the reasons mentioned above.The metal to be inserted has a high tensile strength and a temperature equivalent to that of steel. Fe+ Go, N which has the following melting point
i, Cu, or an alloy containing it is desirable. When these metals are inserted, the hardness of the welding surface decreases by 1.
It can prevent corrosion and embrittlement.

Further, no problem occurs even if the plated layer and the thin metal plate are used in combination at ℃.

Example In manufacturing a composite punch in which a carbide part with a diameter of 6 mm and a length of 10 mm is welded to the tip of a SK, l-19 punch with an outer diameter of 8 mm and a length of 60 mm, a cemented carbide and 5KL (9
6φXO on the contact surface of the seed? A Ni plate II was inserted and set in a vacuum container under pressure. With the electron beam out of focus, the beam was irradiated for about 30 seconds at a position 2 mm from the end face on the carbide side of the contact surface.

Beam conditions are voltage 150KV, current Q, 5mA
Met.

The cemented carbide was red-hot by the beam irradiation, and the heat spread to the net side.The shear strength was 40 kl//-, which was about twice the joining strength of conventional brazing. We also checked the hardness of the steel part, but H
It was located north of RC62, and no decrease in hardness was observed.

When this bonded product was ground and made into a ↑J punch, a punching test was conducted on a 2006 silicon steel plate, and the life was more than twice that of high speed steel. It was also found that it has a lower breakage rate than carbide and can be used stably.

Claims (2)

[Claims] (1) When welding cemented carbide and steel, insert a thin metal plate of 0.5 mm or less between the contact surfaces of the cemented carbide and steel, or After this plating layer is provided, the contact surface between the cemented carbide and the steel is pressurized, and the temperature of the cemented carbide is raised by 1 by irradiating a high-energy beam to the cemented carbide side near the contact surface. , by diffusing the thermal energy to the mesh side, the cemented carbide and steel 4 bonding method is used. (2) The metal thin plate or plating layer to be inserted is Fe+(
6) A patent claim characterized in that the high-energy beam is an electron beam or a laser beam.