JPS586968A - Method of forming antiabrasive coating of titanium carbide or titanium carbonitride on sintered hard alloy products - 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 chemical and heat treatments of metals or alloys useful in the mechanical and metalworking industries to extend the service life of metal products. More specifically, the present invention relates to a method for forming a wear-resistant coating of titanium carbide and titanium carbonitride on a sintered metal product.

The present invention is useful in manufacturing products from hard metals, as well as in mechanical engineering plants that use hard metals in the processing of metals and alloys.

1970) and methods of providing titanium carbide and carbonitride coatings (e.g. Australian Patent 813129).
52.40b12101, 1974) is publicly known. These methods consist of precipitating said compounds at 900-1100° C. from a gas mixture containing titanium tetrachloride, hydrogen, methane or a mixture of methane and nitrogen;
The specified gas is continuously supplied into the heated matsufuru containing the product. At the threshold of one step cycle in these known processes, approximately 4 liters of titanium tetrachloride and 800 to 10
00 liters of methane or nitrogen are consumed. These known processes require complete purification and drying of the hydrogen and other gases, and at the same time extra equipment for neutralizing the reaction products (titanium chloride and hydrochloric acid per 1 bath). is necessary. These known methods can only be carried out using special equipment specifically adapted for these purposes, but require significant capital investment. moreover,
These methods are only suitable for tantalum-containing hard alloys, which are much more expensive than alloys that do not contain any tantalum.

The known methods do not allow the production of titanium carbide or carbonitride coatings with maximum stoichiometry;
It is not possible to produce the coating without contaminating all and hydrogen.

Therefore, these methods do not guarantee that products provided with such coatings will be produced at sufficient production rates.

The present invention is directed to the application of titanium carbide or titanium carbide to products of sintered hard metals by continuously carried out controlled operations, whereby maximum product-specific operational improvements are achieved. Furthermore, the use of dangerous hydrogen gas, its purification and drying equipment, and by-product neutralization equipment can be avoided.

The purpose is to produce wear-resistant coatings of titanium carbide or carbonitride on products of sintered hard metals using titanium chloride, carbon and nitrogen-containing gases. sJ4y, temperature 1100-125
placed in a closed space at 0°C; the product is first treated with a carbon-containing gas and then with titanium tetrachloride resulting from the treatment of titanium metal placed together with the product in said closed space; This is accomplished by treatment with carbon- or nitrogen-containing gases. S゛゛゛It is possible to adjust the amount of carbon in the product prior to film formation, and the amount of carbon in the film itself, and at the same time, it does not use hydrogen gas or titanium tetrachloride, which contains hydrogen and water as impurities. , by the method of the invention,
Wear-resistant coatings of titanium carbide and titanium carbonitride can be produced in stoichiometric amounts and with small amounts of oxygen. The method for producing a wear-resistant coating of titanium carbide or titanium carbonitride according to the present invention is carried out as follows.

The product to be processed (for example, a polyhedral unsharpened chip) is placed in a vacuum haze-conducting electric furnace, and a titanium metal such as a titanium piece or a titanium powder is also placed. In the cooled state, the furnace space is adjusted to a vacuum of LIO-'' to LIO-5 mmHf to minimize the amount of residual 111 as much as possible.

Thereafter, heating is started while the pump is further operated, and aIf: is increased to 1100 to 1250°C depending on the composition of the hard alloy. Too low a temperature makes the process economically inefficient, while too high a temperature is unacceptable because melting of the core phase of the hard alloy occurs. , a carbon-containing gas, e.g. propane, butane, methane, is introduced into the furnace and the product is carburized.The residence time during carburization is selected according to the composition and temperature of the hard metal.After carburization is completed, Evacuate the furnace and 1.10
The pressure is increased again to -2 to 1.10-5 mmHt, and titanium tetrachloride is fed into the furnace. At the selected operating temperature,
Carbon tetrachloride dissociates to form elemental chlorine.

The generated chlorine reacts with titanium metal according to the following formula: Ti + C12 → TICt2 2Ti + 3CL2 → 2TiCA3 Tl+ 2Ct2 → TICt.

Lower titanium chloride reacts with the carbon dissolved in the rut phase of the hard alloy to form a titanium carbide coating according to the following formula: 3T, Cz2+ C-4'r, c + 2T, Ct.

4TICts + C → Tic + 3TICt4 Titanium tetrachloride, which is a higher titanium chloride, reacts with titanium metal,
Lower titanium chloride is again produced and the process is repeated synchronously in a closed system. The thickness of the titanium carbide coating is adjusted by the residence time according to the selected operating temperature.

After forming a coating of the desired thickness on the product, a carbon- or nitrogen-containing gas, such as methane, propane, butane, nitrogen, ammonia, is fed into the furnace and the product is exposed to such atmospheric gas. The operating temperature is maintained for a period of time to promote stoichiometric formation of titanium carbide or stoichiometric conversion of titanium carbide to titanium carbonitride. After retention, heating is stopped, the product is cooled together with the furnace, and then extracted.

The vacuum induction furnace used in the inventive method for forming wear-resistant coatings can at the same time be used as a furnace for sintering products or for other purposes.

By means of the method of the present invention, the wear resistance of mechanically bonded hard metal cutting pieces can be increased by a factor of 2 to 5; the method does not require any special equipment and large capital investments;
Furthermore, not only does it not require a by-product neutralization device, but
Eliminates the need for hazardous hydrogen and its purification and drying equipment. This method is useful for coating any type of hard metal containing a binder capable of melting carbon.

In order to provide a better understanding of the invention, some specific examples are set forth below that illustrate specific aspects of the invention.

Example 1 A titanium carbide coating was coated with 14 parts by weight of TiCl3.
A multifaceted unsharpened tip of a sintered hard metal consisting of 78 wt. Co and 78 wt. WC was produced.

The above product and titanium powder are placed in a vacuum induction electric furnace. The pressure inside the furnace is set to LIOmmHf and heating is started.

Run the pump continuously during heating to create a vacuum. When the temperature differs from 1120 to 1150℃, stop the pump, introduce methane into the furnace, and keep the product for 2 hours.
′(゛.

After the carbonization of the product surface in the furnace is completed, the inside of the furnace is heated to 610-”□sH.
A vacuum of f is applied, then the pump is stopped and carbon tetrachloride is fed into the furnace.

A titanium carbide film with a thickness of 7 to 10 μm is formed on the chip surface by keeping it under a vacuum of 610-"&lO-' mmHt for 2 hours. Next, methane is introduced into the furnace. Within 2 hours. The titanium carbide coating is further carburized and the composition of the titanium carbide approaches the stoichiometric composition. After the carburizing operation is completed, heating is discontinued and the furnace is cooled. What is the titanium carbide coating obtained? 10μm thickness and T
It has a stoichiometric amount of iCα97.

For uncoated chips, HB hardness 212
h/mW? of steel at a speed of 140 m/siH, 1
The time required to cut at a depth of 0.2 mm/rev s at a feed rate of 0.2 mm/rev s is 11.4 minutes, and the rear surface is cut at a depth of 0.2 mm/rev s.
8mm wear 9. For the tip with the coating of the present invention, it is 31.9 minutes and the wear on the rear face is 0.45 m.
It was m. The wear resistance coefficient is 27 or higher, which means substantially less wear.

Example 2 A titanium carbonitride coating was prepared using 10 wt-(TiC+T
BC) was formed into a faceted unsharpened chip of a sintered hard metal consisting of 8 wt.% Co and 82 wt. WC. It was carried out in a manner similar to that described in Example 1.

The furnace was evacuated to LIO-5 mmHt. Carburizing of the chips is carried out at 1140-1160° C. for 1 hour in a propane atmosphere.

Treatment with titanium carbide is carried out for 3 hours.

During this time, a titanium carbide coating with a thickness of 10-12 μm is formed on the surface of the chip. Nitrogen gas is introduced into the furnace and the product is kept in the furnace for 3 hours. During this time, a titanium carbonitride film having a thickness of 10-12 μs and having a composition of T1CN is formed on the chip surface.

The chips with the resulting coatings were tested as described in Example 1. What is the wear resistance coefficient? -8, and the wear value is α
It was 25 mm.

Example 3 A titanium carbonitride coating was prepared using 92 wt. WCl and 8 wt.
A polyhedral unsharpened cutting tip made of a sintered hard metal containing 4% by weight of CO is formed.

This was carried out as described in Example 1 above.

The furnace is evacuated and HIKed to 110 mm. Carburization is carried out in a methane atmosphere at a temperature of 1200 to 1250 DEG C. for 1 hour.

Chip treatment with titanium carbide is 1.10”~LOm
It is carried out for 3 hours under a pressure of mHr.

During this time, a titanium carbide film with a thickness of 5 to 7 μm is formed on the chip surface.

Thereafter, anthonia gas is supplied and maintained for 3 hours. During this period, a titanium carbonitride film having a thickness of 5 to 7 μm and a composition of T1CN is formed on the chip surface.

The tip having such a coating exhibited a wear resistance coefficient of Z5 and a degree of friction of α5 mm during cutting of cast iron.

Continued from page 1 0 Inventor Ella Robertnav Tone Soviet Union Moskovskaya Oblast Lyubertsy Novy Teyupik 5 Kwarchila 18 ■ Applicant Vsesoyuzny Nauchnowitssledovatersky Ibroektny Institute・Tyugoblavkik Metallov i Teverdyk Splavov Soviet Union・Moscow Warsawskoye Chausse 56,), 1

Claims (1)

[Claims] A titanium chloride and carbon-containing gas is a method of applying a wear-resistant coating of titanium carbide and titanium carbonitride to a product made of a sintered hard metal using a nitrogen-containing gas. l H1, temperature 1100-125
placed in a closed space at 0° C.; the product is first treated with a carbon-containing gas and then with titanium chloride obtained by reaction of titanium metal with carbon tetrachloride, which is placed together with the product in the closed space; A method characterized in that the product is then treated with a carbon- or nitrogen-containing gas.