RU2276007C1 - Surface plastic deforming method - Google Patents

Abstract

FIELD: processes and equipment for working machine parts by surface plastic deforming.

SUBSTANCE: method comprises steps of imparting to blank rotation around its own axis and imparting lengthwise feed to tool in the form of rolling around roller applying pressure to surface of worked blank. Working portion of tool is in the form of three-step surface that includes leading smoothing cone with predetermined conicity angle, cylindrical strengthening band being tore like at side of said leading smoothing cone and back smoothing cone with inverse conicity angle arranged successively in direction of lengthwise feed. Tool is loaded by lateral effort until leading smoothing cone touches surface of blank. Diameter of cylindrical strengthening band is determined with use given formula.

EFFECT: enhanced quality of surface due to reduced plastic wave in tool feed direction.

4 dwg, 1 ex

Description

The invention relates to the processing of machine parts by surface plastic deformation (PPD), to pressure treatment of internal and external cylindrical and other surfaces of revolution.

A known method of PPD tool, which is a roller with a toroidal belt, which is installed parallel to the surface of the workpiece being rolled, the latter is reported to rotate relative to its own longitudinal axis, and a longitudinal feed is reported to the tool exerting pressure on the surface of the workpiece [1].

A disadvantage of the known tool is the high probability of the appearance of a plastic wave during rolling in the longitudinal direction, which contributes to the formation of cracks and peeling of the surface of the processed layer.

The objective of the invention is to improve the quality of the processed surface by reducing the plastic wave in the feed direction due to the design of the rolling tool, which is a roller, in which there are smoothing cones in front of the cylindrical reinforcing belt and after it.

The problem is solved by the proposed method of surface plastic deformation of bodies of revolution, in which the workpiece is given rotational motion relative to its own longitudinal axis, and a longitudinal feed is reported to the tool, which is a rolling roller and exerts pressure on the surface of the workpiece, the working part of the tool is a three-stage surface consisting of from the front smoothing cone with a taper angle of 2 ... 5 °, a cylindrical reinforcing belt of toro aznogo Side smoothing of the cone and the rear cone smoothing with reverse taper angle 1 ... 3 °, respectively, located sequentially in the direction of longitudinal feed, the tool load to transverse force until its front smoothing cone base diameter d _nk is not touch the surface of the workpiece, in addition, the diameter of the cylindrical reinforcing belt is determined by the formula:

d = d _{mi nk} + 2Δ,

where d _PC - the diameter of the cylindrical reinforcing belt, mm;

d _pc - the largest diameter of the front smoothing cone, mm;

Δ is the value by which the size of the part changes after processing, mm

The essence of the proposed method is illustrated by drawings.

Figure 1 shows the design of the roller that implements the proposed method for rolling in surfaces of revolution, a partial longitudinal section; figure 2 - diagram of the processing of surface plastic deformation of the shaft obkatnym roller according to the proposed method; figure 3 is a second embodiment of the obkatnogo roller, which is a prefabricated tool, a longitudinal section along BB in figure 4; figure 4 is a prefabricated tool, a left view along A in figure 3.

The proposed method is implemented by a tool, which is a three-stage deforming roller, which serves to process surface plastic deformation of parts of bodies of revolution as part of single and multi-roller devices.

The method of surface plastic deformation of bodies of revolution consists in the fact that the workpiece is informed of a rotational movement relative to its own longitudinal axis, and the longitudinal feed is reported to the tool, which is a rolling roller and exerts pressure on the surface of the workpiece to be processed.

The working surface of the roller has three bands arranged in series in the direction of longitudinal feed. The front smoothing cone 1 with a height of b _pc with a maximum diameter of d _pc and a taper angle of 2 ... 5 ° serves to smooth the plastic wave going in front of the main deforming belt in the direction of longitudinal feed, which reduces the likelihood of cracking and peeling of the treated surface layer (Fig. 2). The belt 2 with a width of b _pc and a diameter of d _pc has a cylindrical shape and is the main deforming element. On the side of the smoothing cone 1, the working profile of the cylindrical reinforcing belt 2 has a torus shape with a profile radius R _pr = 0.8 ... 16.0 mm.

Before rolling in, the tool is loaded with shear force until the front smoothing cone 1 with its large base of diameter d _pc touches the surface of the workpiece.

The diameter of the cylindrical reinforcing belt 2 depends on the size by which the size of the workpiece changes after processing and is determined by the formula:

d = d _{mi nk} + 2Δ,

where d _PC - the diameter of the cylindrical reinforcing belt 2, mm;

d _pc - the largest diameter of the front smoothing cone 1, mm;

Δ is the value by which the size of the workpiece changes after processing, mm

The rear cone 3 with a reciprocal taper angle of 1 ... 3 ° serves to smooth the residual plastic wave coming after the contact of the reinforcing belt 2 of the deforming element with the workpiece, which improves the roughness of the processed surface. Its greater base diameter equal to the diameter d 2 _mi of the reinforcing rib, and the height corresponds to the height d _nk smoothing front cone 1.

The principle of operation of the proposed tool for rolling is as follows. The tool roller is traditionally fixed, for example, in the holder 4 or other multi-roller device [1].

The workpiece, for example, the shaft 5 is given a rotational movement with a speed of V _З , and the rolling tool P is informed by the rolling force P due to lateral movement until the front smoothing cone 1 with its large base with a diameter d _pc touches the surface of the workpiece, and then the longitudinal feed S _ave

The front smoothing cone 1, in contact with the untreated workpiece surface immediately near the deformation zone, smoothes out the plastic waves traveling in front of the deformation belt 2 in the longitudinal feed direction, which reduces the likelihood of cracks and peeling of the treated surface layer (see Fig. 2).

The rear smoothing cone 3, in contact with the already processed surface of the workpiece directly near the deformation zone, smoothes the residual plastic waves coming after the passage of the deforming belt 2 in the opposite direction of the longitudinal feed, which also reduces the likelihood of cracking, peeling of the treated surface layer (see figure 2 ) and improves surface roughness.

The performance of the rolling process is determined by the height of the cylindrical reinforcing belt b _PC roller. A roller with a high height b _pc allows processing with a high feed rate (up to 2.5 mm / rev), however, in this case, to obtain a high surface quality, it is necessary to create large working forces P. The roller parameters depend on the value of the allowable working force P. The greater the width b _{pc of the} cylindrical belt, the larger the feed can be. When machining massive parts on large machines, the b _center should be made wider (more than 12 ... 15 mm), since it is rather difficult to process such parts at a high speed, and a large feed can be successfully applied. For processing parts of less rigidity, when the rolling force should not be large, apply rollers with a belt with a width of 2 ... 5 mm. Hardness of a working surface of rollers from HRC 62 ... 65 steels. The parameter of the surface roughness of the working profile R _a = 0.32 μm.

To expand the range of application of this method, and the tool for giving versatility, a prefabricated rolling-roll design is proposed (see Figs. 3-4), which allows one to select the value of Δ by which the size of the part changes after processing.

The prefabricated construction of the tool consists of a hub 6 with a cylindrical hardening working part 2, onto which the interchangeable rings 7 and 8 are pressed. The peripheral outer surface of the interchangeable ring 7 is a smoothing cone 1. The outer surface of the interchangeable ring 8 is made as a reverse smoothing cone 3. To protect against turning the rings 7 and 8 on the hub 6 into the prefabricated structure, a conical or cylindrical pin 9 is pressed in. For dismounting the rings 7 and 8 by screwing in the screws, each of them has two p screw holes 10.

Mechanical runout roller, based on the proposed method, diameters d and d _{pc HRC} regarding Bore IX must comply with the degree of accuracy according to GOST 24643-81. Size R _pr choose for a given range from the range: 0.8; one; 1,2; 1.6; 2; 2.5; 3.0; 4.0; 5.0; 6.0; 8.0; 10.0; 12.0; 16.0. Material of rollers - steel ШХ15, hardness HRC 63 ... 65. The parameter of the surface roughness of the working profile R _a = 0.32 μm.

The advantages of the proposed method PPD three-stage deforming roller of bodies of revolution are:

- the ability to run in at maximum feeds in comparison with the known deforming elements;

- reduction of the error of the previous processing;

- an increase in the contact spot, due to which a higher quality of processing is achieved;

- the formation of certain macro- and microgeometric forms of the treated surface, reduction of roughness parameters - smoothing of the surface, change in the structure of the material - surface hardening and the creation of a certain stress state, favorably affecting wear resistance.

Example. The shaft was machined by rolling, which had the following dimensions: total length - 150 mm, cross-sectional diameter of the shaft - D27 ^-0.05 mm, roughness R _a = 0.4 μm; material - steel 18HGT GOST 4543-74, hardness HB 207 ... 228, weight - 0.8 kg. Preliminary processing by turning and finishing processing by rolling was carried out on a mod screw-cutting lathe. 16K20, the peripheral speed of the workpiece - v _s = 84.78 m / min (1.41 m / s), n _s = 1000 rpm, the longitudinal feed was taken S _pr = 0.4 mm / rev, the outer diameter of the roller was 50 mm, the total height is 19 mm, the height of the front and rear smoothing cones is 6 mm, the height of the reinforcing girdle is 7 mm, the profile radius is R _CR = 3 mm. The diameter of the cylindrical reinforcing belt is greater than the maximum diameter of the front smoothing cone by 0.06 mm. The breaking-in force was about ≈ 1700 N, the depth of the riveted layer was in the range 0.15 ... 0.20 mm; the size by which the size has changed after running-in - 0.03 ... 0.06 mm; Sulfofresol (5% emulsion) served as a lubricant-cooling fluid during the run-in.

The required roughness and surface accuracy was achieved after T _m = 0.8 min (against T _m ^bases = 1.75 min according to the basic version with traditional toroidal rolling in accordance with GOST 16344-70). The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68. In a batch of 50 pcs. marriage not found.

Thanks to the use of a roller with three working surfaces as a deforming element in the proposed method, the magnitude of the plastic wave traveling in front of and after the deforming elements is significantly reduced, the likelihood of cracking and delamination of the processed surface layer is reduced, the cost of processing is reduced, productivity is increased and workmanship is improved.

The proposed method and a deforming tool for blanks of bodies of revolution is simple to implement, uncomplicated in design and reliable in operation. The structural layer obtained on the surface of the workpiece has increased hardness and, accordingly, wear resistance and resistance to fatigue failure.

Information sources

1. Reference technologist-machine builder. In 2 vols. T. 2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Mechanical Engineering, 1985.S. 387-389, Fig. 6. tab. 3 - prototype.

Claims (1)

A method of surface plastic deformation of bodies of revolution, in which the workpiece is given rotational motion relative to its own longitudinal axis, and a longitudinal feed is provided to the tool, which is a rolling roller and exerts pressure on the surface of the workpiece to be machined, characterized in that the working part of the tool is a three-stage surface consisting of front smoothing cone with a taper angle of 2 ... 5 °, a cylindrical reinforcing belt toroidal from the front a tapering cone and a rear smoothing cone with a reciprocal taper angle of 1 ... 3 °, respectively, arranged sequentially in the direction of the longitudinal feed, while the tool is loaded with shear force until the front smoothing cone with its base with a diameter of d _pc touches the workpiece surface, the diameter of the cylindrical reinforcing belt is determined by the formula d = d _{mi nk} + 2Δ, where d _PC - the diameter of the cylindrical reinforcing belt, mm; Δ is the value by which the size of the part changes after processing, mm

Images