SU1563955A1 - Method of mechanical working of parts - Google Patents

Abstract

The invention relates to mechanical engineering and can be used in the treatment of the external surfaces of long parts with a round and non-circular (shaped) cross section, the value of which is constant or variable in length. The purpose of the invention is to improve the quality of processing products due to the simultaneous straightening of small- and large-period curvature, removal of over-reinforced peaks of the protrusions of the relief and oxide film. The method of machining products includes reciprocating movement of the tool relative to the longitudinal axis of the workpiece with the coordination of the parameters of its axial feed and movement of the tool. Plastic deformation of the product is carried out at least twice in mutually perpendicular directions in conditions of friction sliding. The number of tools is chosen at least two, and their planes of symmetry are arranged perpendicular to each other, with the tools moving with movement frequencies, stroke lengths, contact zone lengths, respectively, multiples of each other. The axial feed of the product is periodically changed during processing by 5–20% relative to its initial value at a frequency that is a multiple of the tool movement frequency. This makes it possible to increase the uniformity of processing products along the length and perimeter. 2 hp ff, 2 ill., 1 tab.

Description

The invention relates to mechanical engineering, can be used in the machining of long parts, namely pipes and shafts, methods of surface plastic deformation or impact-cutting effect, abrasive processing.

The purpose of the invention is to improve the quality of processing due to the simultaneous straightening of small- and large-period curvature, removal of over-reinforced peaks of the protrusions of the relief and the oxide film.

FIG. 1 shows a schematic of the machining of non-rigid pipes and shafts; on

FIG. 2 shows a constructive implementation of the method under production conditions.

A pipe (or shaft) 1 of length L and diameter D is moved at a speed Ux, acting on it with an axial tensile force Px, and successive tools 2 and 3 make reciprocating movements with double stroke numbers (frequencies), respectively, n and n%. Plastic deformation is carried out at least twice in mutually perpendicular directions.

Tool 2 consists of two symmetric with respect to the vertical plane J

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These Xz elements or having the same length of contact zones LZ, having a stroke length of L2. Tool 3 also consists of two elements-plates, symmetric about the horizontal plane Hg, having the same length of contact zones / 3 and stroke length From. On the contact surfaces of the instruments, brook cuts are made along their entire length, so that the diameter of the caliber gap (Dk) made by these streams exceeds the diameter of the pipe) t by 10-25%. On the side of both halves of tool 2, the forces of Py act normal with respect to the Xg plane, and the sides of tool 3 act on the forces of Pg, normal to the Hu plane. The forces Рx, Py, Pz, acting in the direction of the axes of the same name (X, Y, Z), also determine the direction of action of the corresponding stresses — tensile a and compressive op and a2.

The pipe 1 is fed through the grooves of tools 2 and 3, and the clamping forces of the RU and Pz plates are then set and adjusted by means of pressure screws on each pair of plates. The front end of the pipe 1 is clamped in the insert 4 of the chuck 5. The tools 2 and 3 are mounted on carriages with sliding or rolling bearings and move along the guides.

Pipe 1 by force PX is moved by means of a carriage 6, on which the chuck 5 is located. The carriage 6 is moved axially with the help of a cable 7, which is gradually wound on a drum 8, rotated from an individual drive with a speed of Uvar. A tension roller 9 is used to adjust the tension of the cable. The diameter of the drum 8 is 1.5-2.2 times smaller than the diameter of the crank disk 10, which moves a pair of tools 2 and 3 relative to the pipe 1 through the connecting rod 11.

To overlap the treatment zones along the perimeter, horizontal 2 and vertical 3 pairs of plates are installed in series with a gap between them along a length of 25- 35 mm, which is chosen from the condition of overlapping the large-period curvature with both pairs of plates.

The speed (Vx) of the axial feed of the pipe 1 is uneven, periodically variable with an amplitude of 2-5% and a frequency multiple of the angular frequency of rotation of the drum 8. This is achieved, for example, by using a drum with a multi-faceted cross section.

The oscillation frequency with the tension Px of the pipe 1 is chosen to be a multiple of the rotation frequency of the crank disk 10, and therefore, the frequencies of reciprocating movements of tools 2 and 3. Tools 2 and 3 contain symmetrical radius grooves along their axes (and the radii can be the same and the depth

each stream is different), so that the diameter of the caliber (Dk) formed by these streams is 1.1 -1.25 of the diameter of the pipe being processed (LT).

Tools 2 and 3 are produced during processing at the same time impact-cutting and removal of the tops of the protrusions of the terrain roughness. Simultaneously with the abrasive-cutting removal of the vertices of the reinforced protrusions, tool 2 and 3 produce surface plastic deformation, creating a compressive stress in the surface layer. And, finally, the fine and large-period curvature of the processed pipe or shaft is corrected due to both normal pressure forces Ru

and Pr of tools, as well as additional tensile force Px, variable along the stroke of the tools, acting between the tools 2 and 3. The variability of this force PX at different points of the length of the course is determined by different values of the speeds of tools 2 and 3, the magnitude of the elastic forces their longitudinal connection. The values of the numbers of the strokes of tools 2 and 3, the clamping forces Pr and Ru, the elastic connection between the tools, the effort of the additional

5 stretching Pk is adjustable depending on the parameters of the pipe (or shaft) to be processed 1. The amount of clamping forces Py and Pr is regulated from 5–12 kg (for particularly thin-walled pipes) to 65–85 kg for

0 pipes (and shafts) of large diameters with a greater wall thickness.

The functions of acting on the surface of the pipe 1 can be divided between successive tools. Tool closest to the front end of the pipe

, - has an abrasive-cutting effect on the surface, and the subsequent - an elastic-plastic SPD. The value of the forces Ru and Pr will be significantly (1.5-2.5 times) different from each other. Pipe 1 can be machined with tools 2 and 3

0 or more passes. In each subsequent passage, the pipe 1 is set in the treatment area with the opposite end. The ratio of the forces of the clamping Ru and P2 in the second (finishing) passage may be different from the first passage.

The method of machining is intended for thin-walled tubes of viscous stainless steels that are difficult to be machined by known methods (1-5) when preparing these pipes for subsequent technological operations: dressing, grinding, cold rolling, finishing or as a finishing (finishing) operation.

The proposed method makes it possible to get rid of the outer solid hardened layer of the oxide film, which is not completely removed during straightening, abrasive treatment (grinding) and other operations. In the process of editing without using the proposed method, racking takes place,

pressing in the surface of a special-thin-walled tube of re-strengthened protruding particles of vertices of protrusions and films having a greater hardness than the base metal.

 During abrasive machining (grinding with circles, tapes or a jet of abrasive slurry) without applying this method, it is impossible to obtain quality pipes due to the elevated (small and coarse-grained materials were chosen both the same and different and were within 5–80 kg, which provided the required machining conditions .

Separate pipes were processed in two passes, asking them to the treatment area in the second passage: the opposite end. After the second pass, the quality improved significantly. The proportion of pipes processed in two passes was 12–22% of the period periodic curvature, which results in 10 batches of batch. As processed

the products were taken from stainless steel constructional and tool steels, as well as mandrels of KPTR mills.

uneven film removal and base metal damage.

To eliminate the film in the valleys (in the case of waviness, due to the method of pipe production on the HPT or KhPTR mill), the longitudinal profile of the stream troughs along their ridges can be made convex or convex-concave, with radii of longitudinal curvature less than or equal to the radii of curvature in the valleys.

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the products were taken from stainless steel constructional and tool steels, as well as mandrels of KPTR mills.

The main technological parameters of the processing modes, tested under production conditions at the pilot plant, are presented in the table.

The effectiveness of the proposed method of machining is determined by its combined effect on machining. Execution of tools 2 and 3 from matte products, which significantly increases various stiffnesses (steel, aluminum, alloys yield and reduces the cost of nium alloys, fluoroplastic, polyurethane, etc. ) also provides additional vertical movement of tools due to elastic forces.

The proposed method of machining provides simultaneous complex combined processing containing the elements of dressing, abrasive machining and PPM. The above combined processing is highly productive and replaces several separate technological operations for the finishing of pipes, which themselves cannot provide the desired result.

New indicators of quality, not achievable in other known operations, as well as high productivity, ensure the technological efficiency of the proposed method.

Example. Thin-walled pipes and with an average wall thickness of 12–95 mm in diameter and 1.5–4.5 m long were moved at speeds of 0.95–1.5 m / min, applying pressure to them, and the indicated displacement forces about 80-450 kg. In- and feed in the axial direction of the consistency of the reciprocating struc- tives among themselves, characterized in that the displacements with a frequency (number of double strokes per minute) of 50-100,

a stroke of 350–750 mm, brought about by a common 45 and large-period curvature, removing a crank mechanism. The length of the hardened vertices of the protrusions of the relief and each instrument were chosen as a dependency of the oxide film, plastic deformability depending on the specified processing conditions, the product is realized twice in adjusting the crank radius and the length of perpendicular directions. tuna The lengths of the machining zones were for this purpose. The number of tools chosen is not different steels and diameters of 70-180 mm. 50 less than two pairs, and the plane of their symmetry. The values of the frequencies of displacements, lengths of moves and RIs are arranged perpendicularly one other lengths of the treatment zones were selected as multiples or goi, and the displacement of the tools of the scrub head compared to the processing by traditional methods.

An important advantage of the method is also the stability of the temperature regime of processing, as well as the possibility of maintaining it within relatively narrow limits. A significant technological advantage of the method is the possibility of controlling the uniform distribution of residual stresses along the perimeter and length due to the favorable distribution of residual stresses.

Claims (3)

1. A method of machining products, in which axial feeding and reciprocating movements of the tool are performed relative to the longitudinal axis of the product with plastic deformation in order to improve the quality of product processing due to simultaneous fine-tuning with moving frequencies, stroke lengths and contact zone lengths, respectively one another equal to each other. Axial feed forces (axial pipe tensile force) periodically changed in the process of processing by 5–20% in 55%, when feeding in the axial direction, the period to the original frequency is changed by a factor of 5–20% in terms of the (equal to) frequency of tool movements. to the initial value with a frequency that is a multiple of the Clamping force of consecutive tools to the frequency of tool movements. the cops were chosen both the same and different and were in the range of 5–80 kg, which provided the required processing conditions. Separate pipes were processed in two passes, asking them to the treatment area in the second passage: the opposite end. After the second pass, the quality improved significantly. The proportion of pipes processed in two passes was 12-22% of the lot size. As processed Party mask. As processed the products were taken from stainless steel constructional and tool steels, as well as mandrels of KPTR mills. The main technological parameters of the processing modes, tested under production conditions at the pilot plant, are presented in the table. The effectiveness of the proposed method of machining is determined by its combined effect on the processed products, which significantly increases the yield and reduces the cost of world, moreover, the indicated movements and feed in the axial direction are consistent with each other, characterized in that pipes compared with traditional processing methods. An important advantage of the method is also the stability of the temperature regime of processing, as well as the possibility of maintaining it within relatively narrow limits. A significant technological advantage of the method is the possibility of controlling the uniform distribution of residual stresses along the perimeter and length due to the favorable distribution of residual stresses. Invention Formula 1. A method of machining products, in which axial feed and reciprocating movements of the tool are carried out relative to the longitudinal axis of the product with plastic deformation, and the movements and feed in the axial direction are consistent with each other, characterized in that and large-period curvature, removal of over-reinforced vertices of the protrusions of the relief and oxide film, plastic deformation of the product is carried out two times in mutually perpendicular directions, the number of tools is chosen at least two pairs, and their planes of symmetry are perpendicularly to one another, and the movement of osus tools with the aim of improving the quality of machining of products due to simultaneous straightening of small particles with movement frequencies, stroke lengths and lengths of contact zones, respectively fighting one another when fed in the axial direction, they are periodically changed by 5–20% in relation to the initial value with a frequency that is a multiple of the tool movement frequency. 2. A method according to claim 1, characterized in that the processing is carried out with the same frequency of tool movements. , nd 1563955 eight 3. The method according to paragraphs. 1 and 2, characterized in that the processing is carried out with the same tool stroke length. Table continuation Pjl FIG. one at