RU2271265C1 - Tool for cutting or plastic working of metals - Google Patents

Abstract

FIELD: tool materials, namely tools for plastic working or cutting metals with strengthening coatings.

SUBSTANCE: tool includes hard alloy steel base with strengthening coating. Copper-nickel diffusion layer is used as strengthening coating; said layer is formed by diffusion saturation in melt of eutectic lead-lithium alloy to which copper and nickel are added. In variants of invention diffusion layer is formed in melt of eutectic lead-lithium alloy containing 5 - 10 mass % of copper and 2 - 3 mass % of nickel at temperature of diffusion saturation 1000 - 1200°C.

EFFECT: enhanced strength of tool, improved efficiency of process for plastic working or cutting metals.

2 cl, 2 ex

Description

The invention relates to instrumental materials, in particular, to a tool for processing metals by cutting and pressure with reinforcing coatings.

Known tool for processing metals by cutting, which is a non-turning plate of various shapes made of carbide materials coated with titanium nitride deposited from the gas phase [Vityaz PA, Dubrovskaya GN, Kirilluk L.M. Gas-phase deposition of titanium nitride coatings. - Minsk: Science and technology, 1983. - 96 p.]. As a carbide base, for example, VK6 alloy can be used. Increasing tool life is achieved due to the high hardness of the coating. The tool has several disadvantages. The titanium nitride layer is brittle and wears out by cracking and chipping. The tool material does not have a sufficiently high thermal conductivity, which leads to a limitation of the cutting speed.

Also known is a tool for metal cutting, made of steel P18, P6M5, with a cyanide surface layer, the thickness of which is for threaded mills and taps 10 ... 15 microns, for countersinks and drills 15 ... 20 microns [Chemical-thermal treatment of metals and alloys: Reference book / Borisenok G.V., Vasiliev L.A., Voroshnin L.G. and others - M .: Metallurgy, 1981. - 427 p.]. The disadvantages of this tool are low thermal conductivity and fragility of the cyanide layer.

The closest to the achieved positive effect is a tool with a coating based on carbide (SiC) and silicon dioxide (Si ₂ O), obtained by ion-plasma spraying [Kamenenva A.L. The structure and properties of coatings obtained under conditions of low-temperature plasma synthesis on high-speed steels and hard alloys: Abstract. dis. for the competition degrees of cand. tech. sciences. - Perm: Perm state. technol. un-t, 2002. - 20 p.]. As a basis, P6M5 steel or VK8 alloy is used. A positive effect is achieved due to the fact that the coating improves the morphology of the hardened surface, reduces heat transfer to the tool matrix, shifts the deformation process to higher temperatures, helping to preserve the strength of the tool material and reduce wear on its cutting part. As a result, the tool life increases by 1.4 ... 3 times. The tool has the following disadvantages. The oxide-carbide coating is brittle and does not have a sufficiently high adhesion to the base, so the wear of the tool material occurs by cracking and peeling the coating. The material does not have a sufficiently high thermal conductivity, which leads to a limitation of the cutting speed. Carbide coatings do not have good solderability, and this makes it difficult to attach the plates to the tool.

The objective of the invention is to increase the tool life and productivity of the metal processing by cutting and pressure.

The problem is solved by the proposed tool for metal cutting and pressure, including carbide or steel base and hardening coating, which, in contrast to the known, as a hardening coating contains a copper-nickel diffusion layer obtained by diffusion saturation in a lead-lithium eutectic melt with copper and nickel additives. The lead-lithium eutectic melt contains 5 ... 10% copper and 2 ... 3% nickel by mass. The temperature of diffusion saturation is 1000 ... 1200 ° C.

The technical result is to reduce the brittleness of the metal of the tool and lower the temperature of its working surfaces in the process of metal cutting.

Copper-nickel coating, which has high thermal conductivity, provides intensive heat removal from the working surfaces of the tool. Due to this, for example, at high cutting speeds, the material does not soften, and the tool maintains wear resistance and cutting properties for a long time. During the cutting process, the coating material is hardened and intensely hardened, which prevents the abrasion of the surface layer. In addition, it has a high viscosity, due to which the tendency of the surface layer to cracking and chipping is reduced.

The presence of transitional diffusion layers ensures the adhesion of the coating to the base, which eliminates the peeling of the coating during operation, which is characteristic of sprayed coatings.

In terms of linear expansion coefficient, copper-nickel coatings are compatible with most tool steels and alloys. This distinguishes the proposed material from known materials with carbide and nitride coatings and allows the tool to work in more severe conditions.

Copper-nickel coating provides good solderability, which allows you to fasten carbide plates by soldering, in contrast to plates with carbide and nitride coatings. Carbide plates with copper-nickel coatings have a good presentation. If the coating is worn, it may be reapplied.

Example 1. A tool for processing metals by cutting in the form of a non-rotatable carbide alloy plate of VK8 alloy with a diffusion copper-nickel coating. The copper-nickel coating is applied by diffusion saturation in a liquid metal bath containing a lead-lithium eutectic melt (by weight 99.25% Pb and 0.75% Li) with the addition of 10% copper and 3% nickel by weight. The saturation temperature is 1150 ° C, the exposure time is 0.5 hours. As a result, a copper-nickel diffusion coating with a thickness of 10 ... 15 μm is obtained on the surface of the carbide base.

The presence of a copper-nickel coating on the surface of the tool ensures a reduction in temperature of the cutting edge by 300 ° C or more, depending on the material being processed. Even in the case of wear of the coating on the front surface, while maintaining it on the rear surface, heat is removed from the cutting edge. When turning aluminum alloys, no setting of the processed material with the tool surface is observed, which is typical for known tool materials.

As a result of applying diffusion copper-nickel coatings, the tool life increases by 2 to 10 times depending on the material being processed.

Example 2. Roller mounted in a hydromechanical borehole perforator, designed to create perforations in the casing of oil wells. A copper-nickel diffusion coating is applied to the surface of a rolling roller made of X12M steel in order to increase its strength, wear resistance and corrosion resistance. Diffusion saturation is carried out in a lead-lithium eutectic melt with an addition by weight of 10% copper and 3% nickel. The saturation temperature is 1100 ° C, the exposure time is 0.5 hours. As a result, a copper-nickel diffusion coating 25 ... 30 μm thick is obtained on the surface of the rolling roller. The presence of a copper-nickel coating contributes to an increase in the resistance of the knurling roller up to 3 times in comparison with an uncoated tool.

Claims (2)

1. A metal processing tool containing a carbide or steel base with a hardening coating, characterized in that it contains a copper-nickel diffusion layer as a hardening coating obtained by diffusion saturation in a molten eutectic lead-lithium alloy with copper and nickel additives. 2. The tool according to claim 1, characterized in that the diffusion layer is obtained in the melt of the eutectic lead-lithium alloy containing 5-10% copper and 2-3% nickel by weight and diffusion saturation temperature of 1000-1200 ° C.