JP2833198B2 - Cast iron joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for joining cast iron materials or between a cast iron material and another metal material.

<Prior art and problems> Welding of cast iron materials is mostly used only for repairing partial casting defects such as burrowing and overlaying, and no joint welding for assembling structures or the like is performed.

The reason for this is that the weldability is extremely poor. Usually, the welded part is hardened, cracks occur, and blowholes occur, resulting in low reliability.

CO ₂ arc welding is used for welding of cast iron materials.However, since welding is performed by melting the workpiece, welding distortion occurs due to shrinkage deformation of the molten metal, heat input imbalance, etc. . The distortion is corrected, but it has its limitations. In addition, there is a heat-affected zone near the joint, and the quality is not uniform. In addition, there is a margin and accuracy is poor.

On the other hand, productivity can be improved if the cast iron material can be joined not by mechanical joining or the like but by highly reliable welding or a technique corresponding thereto.

<Means for Solving the Problems> In order to solve the above-mentioned problems, in the present invention, cast iron materials or a cast iron material and another metal material are butted with a low melting point Cu-based amorphous alloy thin film interposed therebetween, and the two materials are joined together. By applying pressure and heating the butted portion of the two materials below the melting point of the cast iron material, the low-melting amorphous alloy is diffused into the two materials to join the two materials.

<Operation> In the above method, the cast iron material is not heated to a high temperature higher than its melting point, so that the hardening and cracking of the cast iron material are prevented. Further, since the amorphous alloy thin film is used, the diffusion time can be shortened.

<Embodiment> Next, as one embodiment of the present invention, joining of cast iron materials is performed.

As shown in FIG. 2, the end faces of the cast iron materials 1 and 2 to be joined are butted with a low melting point amorphous alloy thin film 3 interposed therebetween. As the amorphous alloy thin film 3 having a low melting point, for example, a Cu-based amorphous alloy or the like is used.
Further, a thickness of about 20 μm to 40 μm is employed.

The butted cast iron materials 1 and 2 are set in a high-frequency heating coil 4 to heat the butted portion by high-frequency induction heating and pressurized means (not shown) through the amorphous alloy thin film 3 through the amorphous alloy thin film 3. Press. The heating is performed at a temperature equal to or lower than the melting point of the cast iron materials 1 and 2 as the base material.

By heating the butted portion, as shown in FIGS. 1A and 1B, the amorphous alloy thin film 3 is melted. The molten metal 3a is thinly and uniformly filled between the end faces by the application of the pressing force.

Thereafter, when the temperature is maintained at an isothermal temperature, mutual diffusion occurs between the molten metal 3a and the cast iron materials 1 and 2 as shown in FIG. Spreads in 1,2. Therefore, although the melting point of the molten metal 3a gradually increases, the molten metal solidifies because the butted portion is kept at the same temperature.

Thereafter, the diffusion of the elements further proceeds, and finally the joint becomes a homogeneous structure without leaving a solidified structure as shown in FIG. 1 (d).

Although the present embodiment relates to joining between cast iron materials, according to the present invention, joining between cast iron and cast steel, steel, non-ferrous metal materials and the like is also possible.

<Effect of the Invention> According to the method for joining a cast iron material according to the present invention, joining can be performed without heating the cast iron material to a high temperature higher than its melting point, so that defects such as cracks and strains do not occur and there is no excess. For this reason, a joint having good appearance accuracy can be obtained, so that the time for diffusion joining can be shortened.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a diffusion bonding process of a cast iron material, and FIG. 2 is a schematic view of a diffusion bonding operation state. In the drawing, 1 and 2 are cast iron materials, and 3 is an amorphous alloy thin film.

Claims (1)

(57) [Claims] 1. A cast iron material or a cast iron material and another metal material are butted together with a low melting point Cu-based amorphous alloy thin film interposed therebetween. And joining the two materials by heating and diffusing the low melting point amorphous alloy into the two materials.