JPS63104790A - Method for joining steel to aluminum - Google Patents

Abstract

PURPOSE:To improve the joining strength of materials by forming the inside diameter of Al material smaller than the outside diameter of steel and fixing the Al material and then, rotating the steel and pressurizing and inserting it into the Al material and again, pressurizing it after the rotation is stopped. CONSTITUTION:The inside diameter of the Al material 2 made of an Al cast alloy or an Al die-cast alloy is formed smaller than the outside diameter of a steel pipe 1 by about 0.5mm and clamped on a fixed part 3a. On the other hand, the Al material 2 is softened and the steel pipe 1 is inserted thereinto by applying the initial pressure P1 to the pipe 1 while rotating it on the rotational fixed part 3a. Next, after the rotation of the steel pipe 1 is stopped, the steel pipe 1 is pressed in the Al material 2 by the still larger pressure P2 than the pressure P1. Since the joining utilizing the generation of heat by friction is performed, the joining strength is improved. Furthermore, since the influence of an oxide film is prevented, a fragile intermetallic compound is prevented from being formed and further, the joining strength is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to joining steel and aluminum casting alloy or aluminum die-casting alloy, such as joining the shaft of a continuously variable transmission for automobiles, etc. It is used for.

(Prior art) As a prior art related to the present invention, Japanese Patent Application Laid-Open No. 59-3048
There is one shown in Publication No. 9.

This is a method of bonding aluminum or aluminum alloy with iron or iron alloy using an electron beam heat source.It is a diffusion bonding method in which nickel is inserted and the electron beam is irradiated only on the aluminum side to partially diffuse the nickel. .

(Problems to be Solved by the Invention) However, in the above-mentioned electron beam joining, instead of pure aluminum and aluminum alloy wrought materials, in the case of aluminum casting alloys and aluminum die-casting alloys, blowing is required due to the gas contained in them. Holes and opening defects are likely to occur, and bonding methods using diffusion welding tend to produce brittle intermetallic compounds at the joint, and are affected by the aluminum oxide film, making it difficult to obtain high strength.

The technical object of the present invention is to provide a joining method that can provide high joining strength in joining aluminum casting alloys or aluminum die-casting alloys and steel materials.

[Structure of the invention]

(Means for solving the problem) The technical means for solving the above technical problem is to make the inner diameter of the aluminum pipe made of aluminum die-casting or aluminum casting smaller than the outer diameter of the steel pipe round bar, This is a method in which the aluminum pipe material is fixed, the joining tip of the steel material is tapered, the steel material is rotated, the joining surfaces are brought into contact, the inner wall of the aluminum material is partially softened, and after the rotation of the steel material has stopped, pressure is applied to join. be.

(effect) The technical means works as follows.

The inner diameter of the aluminum material is about 0.5 mm smaller than the outer diameter of the steel material, and the tip of the steel material is tapered, so by inserting the steel material into the inner diameter of the aluminum material under pressure P1 while rotating the steel material, the aluminum material will be frictionless. It can be inserted by expanding the opening due to the heat, and after the rotation of the steel material stops, the pressure P2
A strong joint can be achieved by press-fitting.

(Example) Examples will be described below.

FIG. 1 shows the point where a rotating steel pipe 1 and a fixed aluminum material 2 come into contact, where la is a part of the tapered tip of the steel material, and 3a and 3b are clamping jigs.

The outer diameter of steel pipes is 0.5 times smaller than that of aluminum pipe materials.
When the initial pressure P1 is applied in this state, the contact surface between the aluminum material 1 and the steel material 2 generates heat due to frictional heat, and the aluminum begins to soften.

After that, after the rotation of the steel material is stopped, the pressure P is even higher than Pl.
2, the joint is press-fitted into the aluminum pipe material, and the joining is completed as shown in FIG.

(Example-1) In the case of joining AC2B pipe material (inner thickness 2 m1) with a diameter of 151 m and 5Cr20 (inner thickness 2 mm) with a diameter of 11.5 tit, the rotation speed of the 5Cr20 was 240 Orpm.

If the initial pressure PI is 4 kg/wJ and the upset pressure P2 after rotation is stopped is 10 kg/-, then AC2B (F material)
Almost the same strength was obtained.

Figure 3 shows another embodiment of a belt-type continuously variable transmission in which part A of the pulley is made of aluminum die-casting in order to release heat generated from the belt, and the cylinder shaft B made of steel is made by the above method. C is a belt.

〔Effect of the invention〕

The present invention has the following effects.

In other words, it is possible to join difficult-to-join steel, aluminum casting alloys, and aluminum die-cast alloys, and it is a joining method that utilizes frictional heat generation rather than mere press-fitting, resulting in extremely good joints.

Further, since the steel material is joined to the partially shaved surface of the aluminum material, pressure welding can be performed regardless of the influence of the aluminum oxide film. Furthermore, since the upset pressure is applied after the rotation has stopped, the temperature during pressure welding is low, and brittle intermetallic compounds are not formed, resulting in strong welding.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of this embodiment before bonding, FIG. 2 is a cross-sectional view after bonding is completed, and FIG. 3 is a cross-sectional view of another embodiment.

Claims (1)

[Claims] In the method of joining aluminum and steel, the inner diameter of the aluminum material made of aluminum die-casting or aluminum casting is made smaller than the outer diameter of the steel pipe round bar, and the aluminum material is fixed to form the steel pipe round bar. A method of joining aluminum and steel, in which the steel material is rotated to bring the joining surfaces into contact and pressure is applied to insert the material, then the rotation of the steel material is stopped and further pressure is applied to join the material.