JPS60171275A - Formation of ceramic ring-form layer around metal axis - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an annular layer of ceramic around a metal shaft.

Ceramic is a material with extremely high wear resistance, but
On the other hand, it is an extremely fragile material. In order for this material to be widely used in various fields in the future, it will be necessary to use it in rough combinations with different materials, such as metal materials, but it is weak and has no elongation. This is getting in the way. This is particularly troublesome when fitting and joining a ceramic ring around the shaft. During the process of joining at high temperatures and cooling, the differences in expansion coefficients and the transformation characteristics of the shaft material almost always result in peeling or cracking at the joint surface. The present invention has been made in view of the above-mentioned circumstances, and provides a novel method capable of forming an annular layer of ceramic (including cermet, etc.) around a metal shaft, which solves the above-mentioned problems. That is.

The present invention takes the following measures to solve the above problems.

(1) High 1 (100'0
Brazing and diffusion bonding at temperatures around ℃ are required, but
During this heating and temperature rise, the outer ceramic layer is placed in the circumferential direction so that the shaft material is restrained by the outer layer material and plastic deformation does not occur.
Split into multiple parts in the axial direction. - In the conventional method, the outer layer material is fitted onto the core material in advance and then heated and the temperature is increased. For this reason, if the core material expands more than the outer layer material, plastic deformation occurs in the core material when heated. When this happens,
The dimensional balance of the outer layer and core material that was initially applied was destroyed, and the stress balance of the joint during the cooling process was destroyed.
Peeling or cracking may occur. In the present invention, since the outer layer material is divided, the core material can freely expand.

(When members with different linear expansion coefficients are bonded together based on 2>-m, the larger the member, the greater the strain and the easier it is to peel off. Conversely, if this is made infinitely small, the linear expansion Even things with significantly different coefficients can be balanced.

The present invention is basically based on this idea, and the number of divisions and dimensions of the outer ceramic layer are determined by taking into account conditions such as the linear expansion coefficient, transformation characteristics, and bonding temperature of the core material. In other words, the larger the difference in expansion and contraction between the outer layer and the core material, the more the outer layer is divided into infinitely small pieces.

The present invention has the above-mentioned characteristics, and the gist thereof is that when joining a ceramic annular layer around a metal shaft, the ceramic layer is divided into a plurality of parts in advance and the ceramic layer is discontinuously divided into a plurality of parts. superimpose the divided pieces on the circumference of the shaft as a body,
This is a method of joining a ceramic annular layer around a metal shaft, which is characterized by metallurgical joining.

Next, the present invention will be specifically explained by referring to examples.

Example 1: Cemented carbide (WC-α) is used for the outer layer material, and mild steel is used for the core material.Outer diameter and length of the mild steel core material: 100u+φx20Q Number of divisions of the outer layer material: 15 divisions in the circumferential direction (however, The curvature should match the curvature of the outer diameter of the core material.) Total length of the inner circumferential surface of the outer layer material: 313.9 mm + with brazing:
NI-P amorphous foil brazing temperature: Approximately 1000°C Brazing atmosphere: Steam The brazing material is sandwiched between the carbide split ring and the core material and brought into close contact with a suitable jig, and heated to raise the temperature.

A melt of NI-P appears between the outer layer and the core material at a temperature of around 900°C. After brazing, it is slowly cooled in a furnace.

Joint status: No peeling or cracking was observed at the joint, confirming that the joint was metallurgical. In addition, the gaps between the split rings were substantially continuous.

Example 2゜ Ceramic is used for the outer layer material and mild steel is used for the core material.

The inner surface of the ceramic is metallized with NI-
10μ electroless plating of P amorphous.

Outer diameter and length of mild steel core material: 1001mφx Number of divisions of 100Q outer layer material 2 circumferential direction 30 divisions Length direction 10 divisions Total length of inner circumferential surface of outer layer material: 314.1mm Brazing: Silver solder (fine powder paste) Raw Brazing temperature: Approximately 800°C Brazing atmosphere: Hydrogen atmosphere A thin layer of silver brazing paste is applied to the surface of the core material, overlapped with the outer layer material, brought into close contact, heated, heated, and after brazing, slowly cooled in a furnace.

Joint status: No peeling or cracking was observed at the joint, confirming that the joint was metallurgical.

Through the process described above, cemented carbide or ceramic can be stably bonded around the core material, and the gaps between the outer layer materials can be reduced to a point where it is almost unusable, forming a nearly continuous layer. be done.

The present invention is accomplished by the method detailed above,
It has the following effects.

(1) It is also possible to have a relatively large diameter.

(2) Various metals can be used for the core material.

(3) The ceramic material for the outer layer can be selected from a wide range of materials, from cermets such as cemented carbide to materials such as alumina.

(4) It is relatively inexpensive.

Claims (1)

[Claims] When joining an annular layer of ceramic to the periphery of a metal shaft, the ceramic is divided into a plurality of parts in advance, made into discontinuous pieces, and the divided pieces are superimposed on the periphery of the shaft and metallurgically joined. A method of forming an annular layer of ceramic around a metal shaft.