JPS58141376A - Plasma cementation - Google Patents

Abstract

PURPOSE:To carry out plasma cementation with high energy efficiency in a short time by diffusing a metal or a nonmetal in a metallic surface using plasma. CONSTITUTION:A gas such as B2H6, PH3, SiH4, G2H6, SbH3, CrCl2 or an analogue thereof, a mixture of >=2 kinds of said gases or a mixture of said gas with steam, ammonia, hydrogen or the like is used. Plasma is generated by arc or glow discharge using DC high frequency power. The service temp. is about 150-700 deg.C, the high frequency power is about 30W-3kW, and the pressure of the gas is regulated to 0.05-50Torr. The gas contg. a metallic or nonmetallic element is decomposed with the plasma, and the element is diffused in a metallic surface to obtain a hardened surface layer having about 0.1mm. thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma cementation system that performs surface treatment using Goodsma.

Conventional surface hardening methods include fire hardening, induction hardening, syrup beaning, carburizing, immersion foot hardening, nitriding, cement, Teishing carbon method, and bonding method of hard surface Iia. However, these O methods, for example,
In induction hardening, it is difficult to obtain a homogeneous hardening layer), which causes the transformation of the inner weave,
After these treatments, tempering must be carried out and
However, there are disadvantages such as low compensation, large capital investment, and difficulty in processing small products. In addition, in the sheet beaning method, when the temperature exceeds 250°C, the fatigue limit of the round material disappears, it has no heat resistance, and when a small ball is hit, it causes noise from the hammer, and the processing of grade 11 products is poor. However, there are drawbacks such as the inability to process large products.

Surface hardening methods by carburizing, carbonitriding, and nitriding are: 1
il11 In order to prevent honey-shaped cracks, additional heat treatment is required, resulting in high costs; the use of a furnace requires a large investment in equipment; the high-temperature treatment is energy-efficient; surface treatment requires precision; It has disadvantages such as difficulty.

The cementation method, a method for bonding hard surface layers, is
Limited applicable materials, lack of versatility, high temperature I
Since it is a ring, it has the disadvantage that the material must be able to withstand high temperatures, for example, 1000°C.

The present invention eliminates such drawbacks, and its purpose is to:
Economical, increasing energy efficiency, non-polluting,
This process is based on the discovery that it is a low-temperature treatment, that the processing time can be shortened, and that unique properties can be imparted to the surface.

In the present invention, the gases used are B, H,, Pli, ,
8 (H4e G#H4e GIH@t 81
．． H4t 86HS, HB de, 8SCj
4.

CrCJ, etc., or similar gases), use one of these gases, or a mixture of two or more of these gases, or use water vapor, ammonia, hydrogen, oxygen, ha! It can be used in combination with any one of natural gas, organic gas, and inert gas.

In the present invention, plasma is obtained by arc discharge or glow discharge, and direct current or high frequency discharge is used as the discharge type.

Plas i contains a mixture of electrons, ions, neutral particles, and radical particles), which react with the surface of the material and diffuse internally to obtain a hardened surface layer. Plasma is very active, takes less time than conventional methods, allows low-temperature treatment, makes it easy to control the hardened layer, and can harden the surface without causing any change in the internal properties of the material. The present invention utilizes the advantage of plasma to decompose a gas containing a metal or nonmetal element by plasma and diffuse it onto the surface to obtain a hardened surface layer.

Metals or non-metals penetrating into the metal induce lattice distortion in the parent metal or form intermetallic compounds, thereby hardening the surface. The surface hardening layer is 0. 1) Since the goods macerating process does not involve high temperatures of 800°C or higher, unlike the cementing process, there is no quenching cracking after the process and there is no need for tempering.

The shapes to which the present invention can be applied range from small to large.

In the present invention, the temperature is 150°C to 700°C, and the high frequency power is 30W to 3! W, gas pressure is 0.05 to 50 torr
Let it be r. Hereinafter, the remarkable effects of the present invention will be explained according to Examples.

Example 1 Cleaned round bearing steel IINCM25, diameter 55I x length 2
Set 0aI in the glue discharge tank, and set the inside of the tank to lXl01o.
The degree of vacuum in the r de is set to KL, the temperature of the bearing steel O is set to 400°C, and 10 LsBslis diluted with argon is flowed into the lto
Dede. Thereafter, power is applied between the electrodes K24jSOMIig to cause glow discharge, and power of 1KW is input.

The discharge was continued during addition and the dripping was measured with a Vickers hardness needle. The results are shown in j11mlK, where the horizontal axis is the distance from the surface and the vertical axis is the Vickers hardness at a load of 10 F. This is it), Vickers hardness is up to 600-6
Values around 50 were obtained up to 80μ inertia 1 degree from the surface, indicating that the plasma cementation method is extremely effective.

Example 2 Same as Example 1 except that the gases were CH4, C1”CJ
Proverb * Use a, 'fe) Flow rate ratio Fi, CH4/Cr0
4 m 0.2 to 5.0 is appropriate, but in Example 2 it was set to 1, the gas pressure was 1 torr, the other conditions were the same as in Example 1, the material used was A45C], the shape was diameter 2
txm, length 10-c! II. After plasma treatment,
The hardness from the surface was examined using a Vickers hardness needle after maintaining the temperature at 500'CK for 1 minute. The results are shown in FIG. The horizontal axis is the distance from the surface, and the vertical axis is the Vickers hardness. 1 is the hardness of the material without plasma treatment, 2 is the hardness of the material with plasma treatment only, 3Fi, 500'' after plasma treatment
tl: for 30 minutes. Surface hardening is solid solution hardening with Cr and CO, hardening with nickel and K, in which four atoms form carbides, and secondary hardening, which is further hardened when the material is used at high temperatures with only IC or plasma treatment. It has been found that this is effective when wear resistance is required.
During processing, it is not hardened so it is easy to process)
The advantage is that if the surrounding temperature is high during use, self-hardening due to precipitation can be avoided and wear resistance can be obtained.

Example 3 Same as Example 1, but gas is 4e mrt
The flow rate ratio was 8 (Hv whip 0.01 to 1 is appropriate, but in Example 3 it was set to 0.1, and the gas pressure was 0.1f.
Other conditions were the same except that the temperature was 650°C.

The material used is A45C, and the shape is 2tms in diameter.
.

The length was 10m, and the results are shown in FIG. The horizontal axis is the distance from both sides, and the vertical axis is the Vickers hardness. 1 means no plasma treatment, 2 means no plasma treatment, take it! Cementation is very effective. Silicon combines with carbon to form carbide, but does not precipitate and does not cause precipitation strain. Therefore, it is effective when dimensional accuracy is required.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between hardness and surface depth when boron is plasma cemented. The horizontal axis is the distance from the surface, and the vertical axis is the Vickers hardness. FIG. 2 shows the relationship between hardness and surface profilability when chromium is plasma cemented. The horizontal axis is the distance from the surface, and the vertical axis is Vickers hardness. Figure 3 shows the relationship between hardness and surface depth when silicon is plasma cemented. The horizontal axis is ll! The distance from the surface, the vertical axis, is Vickers hardness. Applicant: Suwa Seikosha Co., Ltd. Omotomei 1, Ra no Eiryu Figure 1 Chomencho et al.'s port Diagram 2 f7f et al. 1 page Figure 3

Claims (1)

[Claims] Goods cementation seal characterized by infiltrating metal surface WK, various metals or non-metals using Prazo TT