JPS61186468A - Lubricity-improving method by metal hardening treatment - Google Patents

Abstract

PURPOSE:To improve sliding characteristic on the metallic surface by heating Mo-vapor-deposited metallic parts at high temp. and then hardening them in S compound-containing oil to form an MoS2-containing film. CONSTITUTION:The vapor-deposited films of metallic Mo are formed on the surfaces of metallic parts, which are heated at high temp. in a reducing atmosphere and the like, subjected to carburizing, diffusion, or other treatments, and then thrown into the oil to which S compounds such ZnDDP or the like are incorporated so as to be hardened, so that the MoS2-containing coatings are formed on the metallic parts surfaces. In this way, the metallic parts having superior sliding characteristic on the surface as well as improved hardness and excelling in lubricity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for improving the lubricity of a metal surface by quenching the metal in oil.

(Prior Art) Conventionally, in order to prevent the entire metal from becoming brittle due to welding, carburizing and quenching treatment, which hardens only the surface portion of the metal, has been often used. This carburizing heat treatment is performed, for example, by first preheating the target metal part in a carburizing furnace in a reducing atmosphere of RX gas (butane cracking gas), and then firstly carburizing and diffusing the wire mesh part at about 900 to 950°C. This is done by applying it to the frictional surface of the part, then cooling it to about 850C, and then putting the metal part into oil to harden it. Thus, a carburized layer with a depth of about 0.5 to 1.0- is usually formed on the surface m5 of the gold M component.

In the above method, the carburized metal parts are quenched in oil to prevent quench cracking and the like. Conventionally, the quenching oil used in this process has been mixed with various additives, such as sulfur-containing agents such as zinc dialkyl ditheophosphate (ZnDI) P, to improve the quenching properties or stabilize the oil. is usually used.

(Problem to be solved by the invention) However, conventionally, when metal parts such as carburized steel are quenched using furnace oil containing additives such as znDDP, the nuclear additive is damaged by the high heat of the metal parts. The decomposition produces hydrogen sulfide and the like, which combines with metals such as iron to form iron sulfide and the like on the surfaces of parts, which can significantly deteriorate the sliding properties of the surfaces of metal parts.

An object of the present invention is to provide a method for improving lubricity that improves the sliding properties of a metal surface by quenching the metal in oil.

(Means for Solving the Problems) The method of improving lubricity by metal quenching treatment of the present invention is a method of quenching gold parts on which molybdenum has been vapor-deposited in advance in oil containing the above additives. That is, a metal part having a vapor-deposited film of metal molybdenum on its surface is heated to a high temperature, and then placed in oil containing a sulfur compound to be quenched.

The special feature of this method is that it forms a film containing molybdenum disulfide on the surface of metal parts.

(Function) According to the method of the present invention, in the φ insertion process of metal parts in oil,
Even if additives such as ZnDDP are decomposed at 130 to 250°C to produce hydrogen sulfide, mercaptans, thiohydrocarbons, etc., as described in J.S., 10.85 (1967), etc., the metal molybdenum film on the surface of the part will not be removed. is converted into a film containing molybdenum disulfide (Most) by reacting with hydrogen sulfide and the like. The present inventors have confirmed that this molybdenum disulfide film has high strength, a small coefficient of static friction, and excellent wear resistance. Therefore, the gold f% component obtained according to the present invention has a high lubricity on its surface. .

In addition, as described in Japanese Patent Application No. 58-2087I (publication etc.), the inventors of the present invention have developed a method to apply a molybdenum disulfide coating to the metal parts by leaving the molybdenum vapor-deposited metal parts in a sulfur dioxide gas atmosphere for an appropriate period of time. A method has already been proposed for improving the lubricity by forming it on the surface. 1. When the surface of metal parts (mainly steel parts) that is subjected to carburizing and quenching is improved according to the above method. To achieve this, a contact step with sulfite gas must be separately provided before the quenching step.In contrast, in the method of the present invention, the formation treatment of the molybdenum disulfide-containing film is carried out in oil. This method is performed at the same time as the quenching treatment, and there is no need to add a new step to improve lubricity to the carburizing and quenching process.

In the method of the present invention, the φ hardening treatment of the t1 gold llN41flS product may be carried out in accordance with a commonly used method in which a metal part heated to a high temperature is placed in quenching oil and rapidly cooled. For example, if the Kinzo parts are made of steel, the quenching temperature is about 8 oo.
It is good if it is ~850C. By keeping the heating temperature and quenching speed the same, a product with a uniform hardened structure can be obtained. In addition, the furnace oil is a conventional oil (for example, Cortemper No. 2 manufactured by Nippon Grease Co., Ltd.) containing additives of sulfur compounds or additives that generate sulfur compounds such as hydrogen sulfide through thermal decomposition. You can use the one you made.

Further, in the method of the present invention, metal molybdenum (Mo)
The vapor deposition is performed using a vapor deposition apparatus such as an ion etching apparatus or a vacuum furnace. However, when using a vacuum furnace, molybdenum oxide may be generated on the surface of the deposited film.
In this case, it is preferable to reduce the molybdenum oxide portion to molybdenum. This reduction treatment is performed, for example, by immersing the material in a NaBH4 solution for a certain period of time under heating. When vapor depositing molybdenum, in order to improve the degree of adhesion of molybdenum to the surface of the metal part, the surface of the metal part may be pretreated using a method normally used for vapor deposition. It is also good to keep it in shape. The preferred thickness of the molybdenum deposited film is about 0.1μ to 0.3μ.

(Example) The present invention will be explained in detail below.

Example 1 α-Fe gold m s product and gold snake molybdenum 100-20
01! The IP was placed in an ion etching device (Model 0: PEC-2A manufactured by Takasu Seisakusho Co., Ltd.) and the degree of vacuum was set to 10''.
va Hf or less, voltage 100V.

When a current of 4 A is applied for 8 to 10 minutes, a vapor deposited molybdenum film with a thickness of about 0.1 to 0.3 μm is formed on the surface of the metal part.

Next, the molybdenum-deposited metal parts are placed in a carburizing furnace with an RX gas reducing atmosphere, preheated, then main heated, and then heated to approximately 90°C.
The metal parts are carburized and diffused at 0 to 950°C, then cooled to about 850°C, and then ZnDDP
The carburized metal parts are quenched by putting them into quenching oil (Cortemper No. 2, manufactured by Nippon Grease Co., Ltd.) at about 100°C and containing additives such as the following.

Therefore, we decided to examine the composition of the surface portion of the metal parts after the hardening treatment and after the coin purse treatment, respectively, by X-ray diffraction spectroscopy. The measurement is performed using an X-ray source: CuK a-ray e
The test was carried out under conditions such as tube voltage: 40 KV and tube current: 30 mA. The obtained Xa concentration charts are shown in FIGS. 1 and 2. In these figures, the horizontal axis is the diffraction angle (
20), and the vertical axis represents the intensity of the diffraction line. Also,
times't1rMa, b and C are α-Fe, MO and MO
Each represents a diffraction line at 8°. From these figures, it can be seen that the composition of the surface film of the metal parts changes from molybdenum to molybdenum disulfide through the quenching process.

Example 2 Metal parts and molybdenum plates with a purity of 99.91 or higher
Place it in an empty furnace, then reduce the pressure inside the furnace to 1 degree of vacuum.
At the same time as heating the inside of the furnace to a temperature of about 500 to 600°C, the temperature was maintained for several hours, and then the metal parts were immersed in NaBH solution under heating. Then, a molybdenum vapor deposition film is formed on the surface of the metal part. 'A simulated carburizing and quenching process was carried out in the same manner as in Example 1.

Comparative Example Carburizing and quenching of α-Fe metal parts was carried out in the same manner as in Example 1, without vapor deposition of molybdenum. A surface lubricity test was conducted on each of the metal parts of Example 2 and Comparative Example, and it was found that the metal parts of Examples 1 and 2 had significantly smaller surface vibration coefficients and higher strength than those of Comparative Example. It was large and extremely smooth.

(Effects of the Invention) As explained above, the method for improving lubricity by gold Me injection treatment of the present invention is based on molybdenum vapor-deposited gold J! By quenching Ii parts, a film containing molybdenum disulfide is formed on the surface of the parts. In addition to improving hardness through quenching, the metal parts have extremely good surface sliding properties and excellent lubricity. can get. Moreover, the method of the present invention
By using a method that generates molybdenum disulfide at the same time as the quenching process of metal parts, there is no need to incorporate a new lubricity improvement process into the manufacturing process of the parts, which reduces the complexity of the manufacturing process. I won't wake you up.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams respectively showing X-win charts of the surface composition of the metal parts after and after the quenching treatment in the method of Example 1 of the present invention. Figure 1 Figure 2 2θ(0)

Claims (1)

[Claims] Metal parts with a vapor-deposited film of metallic molybdenum on the surface are heated to high temperatures, and then put into oil containing sulfur compounds for quenching, thereby forming a film containing molybdenum disulfide on the surface of the metal parts. A method for improving lubricity through a characteristic metal quenching process.