RU115706U1 - TOOL FOR FORMING SURFACE SURFACES WITH NANOCRYSTAL STRUCTURE ON DETAILS - Google Patents

Abstract

A tool for forming tribo-mating surfaces on parts with a nanocrystalline structure, consisting of an indenter body fixed in a holder, the tip of which is made of fine cubic boron nitride, a rubber seal mounted on a nut, a rubber sleeve installed in a body in which a low-boiling liquid is poured.

Description

The utility model relates to the field of mechanical engineering technology, namely to tools used in the manufacture of tribojet parts from hardened steels with surfaces subject to intense wear, the operational properties of which are enhanced by the formation of a nanostructured surface layer of the part and is intended for use mainly on CNC machines and turning and milling centers.

Widely used devices for finishing (grinding, honing), providing the specified accuracy and microgeometry, slightly change the physical and mechanical properties of the surfaces of the parts.

It is known the use of intermittent friction disks for surface hardening of metal alloys with alternating high-speed friction (Evdokimov V.D., Klimenko L.D., Evdokimova A.N. Technology of hardening engineering materials: Textbook-reference book. Odessa Nikolaev: Publishing house of NGSU im. Peter the Grave, 2005, 283 S. Fig. 53).

Known intermittent tool for friction surface hardening, comprising a housing made in the form of fixed on the hub of the main and additional disks of a material with a low coefficient of thermal conductivity and with a working surface on their periphery with grooves on the main disk and with depressions on the additional (patent RU No. 2241590)

These devices are complex in design, have large dimensions, which excludes the possibility of their use on turning and milling centers.

Known smoother consisting of a housing, an indenter, a set of Belleville springs, a rubber seal mounted on a nut, a rubber sleeve mounted in the housing, in which a low-boiling liquid is poured, which cools the indenter, can increase the speed of smoothing, reduce the complexity of the processing process. The rubber sleeve reduces self-oscillations arising at a high speed of smoothing (patent RU No. 62554).

The tool smooths the surface with a sliding indenter without significant heating of the treated surface in the contact zone with achieving sufficiently high parameters of surface roughness and surface hardening, but does not provide the formation of nanocrystals.

Designs of tools designed for surface nanostructuring used in the processing of parts on CNC machine tools in one setup were not found.

To nanostructure the surface layer of parts and reduce roughness, a tool is proposed for forming tribocouple parts with surfaces with a nanocrystalline structure, consisting of a holder, a housing, an indenter, the tip of which is made of finely divided cubic boron nitride, a spring, a rubber seal mounted on a nut, a rubber sleeve, installed in a housing in which low-boiling liquid is poured.

A fundamental improvement in the physicomechanical characteristics of the metal with modern methods of intense plastic deformation of the material is achieved by transferring the structure of the surface layer to the nanocrystalline state, which effectively blocks dislocation motion by nanograin boundaries. For effective nanostructuring and hardening of metal materials, conditions must be ensured for the accumulation of intense plastic deformation in the surface layer, which is achieved by increasing the shear component of the deformation, normal load and the number of passes of the processing tool.

Causal relationship - the impact of the tool indenter made of finely dispersed cubic boron nitride provides a tangential shift, crushing and rotation of the material crystals in the surface layer of the part due to high contact pressure and an increase in tangential force, while the friction coefficient in contact with the workpiece surface is cemented steel 20X is equal to 0.34. Extruded mesosilanes propagating in the surface layers according to the pattern of population waves contribute to the uniform development of microdeformation throughout the entire loading process, provide nanostructural hardening of the surface layer with an increase in ductility. Low-boiling liquid in the housing significantly reduces the heating of the treated surface in the contact zone. Securing the housing in the holder allows you to install the tool on CNC machines and turning and milling centers.

Figure 1 shows a tool for forming high-quality surfaces with a nanocrystalline structure during multipurpose processing of tribojet parts, figure 2 - scanning microscopy of a transverse section of a surface layer of a part before processing, figure 3 - scanning microscopy of a transverse section of a surface layer of a part after processing with the proposed tool .

The tool consists of a holder 1, in which the body 2, indenter 3 is fixed, the tip 4 of which is made of a material with a high coefficient of friction, a spring 5, a rubber seal 6 mounted on the nut 7, a rubber sleeve 8 installed in the body 2, in which low-boiling liquid 9. An indenter 3 with a tip 4 and a rubber sleeve 8 mounted on the indenter is installed in the tool body 2. A spring 5 is installed in the body 2 and a low-boiling liquid is poured 9. A rubber seal 6 is put on the nut 7.

The tool works as follows.

By screwing the nut 7 into the housing 2, the spring 5 is pressed against the required smoothing force. After the indenter 3 touches the workpiece, the tool is inserted into the part until the indenter 3 abuts against the housing 2. As soon as the indenter 3 stops abutting against the housing 2, it begins to fully absorb the force of the pre-pressed spring 5. When the tool moves, the indenter cools 2 low-boiling liquid 9, and the rubber sleeve 8 damps the indenter vibrations. The surface of the part was machined from hardened cemented steel 20X, after turning, by an indenter of finely dispersed boron nitride, with a spherical tip whose radius was 2 mm, speed 10 m / min, feed 0.04 mm / rev, smoothing force 200 N in 2 passes. Formed surface with a nanocrystalline structure of 20-40 nm (figure 3).

To create nanocrystalline structures, the required number of tool passes is set depending on the initial thermal or chemical-thermal treatment of the workpiece material and the required surface quality.

The use of the tool allows you to form a surface with a nanocrystalline structure with a grain size of less than 100 nm.

Claims (1)

A tool for forming surfaces with a nanocrystalline structure on tribojoint parts, consisting of an indenter fixed in the holder, the tip of which is made of finely divided cubic boron nitride, a rubber seal mounted on a nut, and a rubber sleeve installed in the housing in which low-boiling liquid is poured.