SU1720769A1 - Method of pressing tubes from continuous cylindrical billets - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular to the pressing of precision tubes, for example, for hydraulic cylinder bodies, etc. The purpose of the invention is to increase the yield by reducing the volume of press residue. Solid cylindrical billet set in a smaller cavity of a two-stage container until it stops at the end of the counter-punch. A punch with a pointed double cone is inserted into the container. The workpiece material is squeezed out in the radial direction with the subsequent change of the flow direction to the axial one with simultaneous formation of a double-cone cavity with a broken convex generatrix at the end of the workpiece. At a certain extrusion stage, the process is stopped. Punch return to its original position. In the recess at the end of the workpiece and the space above it is placed transmitting pressure medium. Continue extrusion with the formation of a pipe with a diameter greater than the diameter of the workpiece. To completely press out the preform material, a washer of ductile metal is placed between the punch and the pressure transfer medium. The presence of a recess at the end of the preform, filled with pressure-transmitting medium, makes it possible to carry out the pressing process with a minimum height of the press residue and exclude the possibility of a press weigher. 5 Cpfla, 5 Il. (Ls

Description

The invention relates to the processing of metals by pressure, in particular to the pressing of precision tubes, for example, for hydraulic cylinder bodies, etc.

The purpose of the invention is to increase the yield by reducing the volume of press residue.

FIG. 1 shows the initial blank; in fig. 2 - extrusion in the radial direction (beginning) and the formation of a double cone cavity; in fig. 3 - the moment of approaching the groove to the end face of the counter-punch; in fig. 4 - violation

continuity of the workpiece using the medium transmitting pressure, and the formation of a pipe with an inner collar; in fig. 5 - Suppressing the pipe with a plastic washer.

Positions in the drawings: 1 - blank; 2 — container; 3 — punch; 4 — counterpunch; 5 — medium transmitting pressure; 6 - pressed pipe; 7 - inner collar of the pipe; 8 - press washer; 9- press residue; 10-biconical recess; 11 - pointed two-stage end of the punch.

The method of pressing the tube is carried out as follows.

h | Yu O

s about you

A conventional cylindrical billet 1 is placed in a smaller cavity of a two-stage container 2 up to the stop at the end of the counter-punch 4, a punch 3 with a pointed two-step end 11 is inserted into the container 2 and the billet material is extruded in the radial direction into the gap between the container 2 and the counter-punch 4 with the subsequent change flow direction to axial. At the same time at the end of the workpiece 1 form a double cone 10.

When the tip of the end face 11 of the punch 3 reaches the end of the counter-punch 4 (Fig. 3), the process is stopped, the punch 3 is returned to its original position and pressure transfer medium 5 is placed in the recess 10 and the space above it (mixture of glycerol with ethylene glycol or technological lubricant). In order to eliminate leakage of the medium 5, the core 3 is provided with an appropriate seal (not shown). The container 2 is sealed by the metal of the preform 1, which precipitates during extrusion.

Under the action of the punch 3 and the radial pressure of the medium 5, the volume of which is equal to the volume of the cylinder with a diameter equal to the diameter of the counter-punch 4 and a height equal to the wall thickness of the pipe 6, the metal breaks and the diameter of the resulting hole increases (Fig. 4). The expansion of the hole occurs as long as the metal is between the container 2 and the end face of the counter-punch 4, sealing the gap with itself. As soon as the edges of the hole are compared with the edge of the counter-punch 4, the seal is broken, the pressure in the medium 5 drops and the pressing process is stopped. As a result, a press residue remains in the form of an inner collar 7 on the pipe 6. By increasing the diameter of the counter-punch 4, the collar 7 can be reduced to a minimum.

In order to completely press out the metal and to obtain a waste-free pipe between the punch and medium 5, a press washer 8 of ductile metal is installed. It ensures the complete extrusion of the workpiece 1 into the pipe 6, to compensate for the pressure loss in medium 5, since it takes its place and continues the extrusion process. At the end of the process, the washer 8 is transformed into a press residue 9, which is removed from the die as in conventional pressing.

Example. To manufacture a cylinder of a telescopic hydraulic lift of a dump truck from art. 45 pressed the pipe from a solid cylindrical workpiece 90.5 x x 311 mm.

At the beginning of the extrusion at the end of the cooking, a double cone cavity is formed with the parameters: the maximum diameter of the cavity is equal to the diameter of the workpiece

(90.5 mm), the diameter in cross section passing through the apex of the convex forming cavity is 48.5 mm, the angles of inclination of the forming sides are 120 ° and 90 °. As a result of pressing, a tube of high quality 181 x 159 x 330 mm is obtained. Reducing the amount of compaction makes it possible to increase the utilization rate of the metal to 0.86. In the manufacture of similar products by known methods, the metal utilization factor is 0.715-0.750.

The method provides an increase in yield with high quality extruded products.

Claims (6)

1. The method of pressing tubes from solid cylindrical billets with the formation of a pipe with a diameter greater than the diameter of the workpiece, including the execution of the workpiece, the installation of the workpiece in the smaller cavity of the two-stage container with an end face on the counter spindle and extrusion a punch of the workpiece material in the radial direction with the subsequent change of the flow direction on the axial along the wall of the greater cavity of the container, characterized in that, in order to increase yielding due to a decrease in the volume of press residue, extrusion is carried out in two stages: the first one forms a double cone in the end of the workpiece with a broken convex forming, the second is the finished product, and after the first stage of extrusion is completed place the transmission medium. 2. A method according to claim 1, characterized in that a liquid, such as a mixture of glycerol and ethylene glycol, is used as the pressure transmitting medium. 3. A method according to claim 1, characterized in that a process lubricant is used as the pressure transmitting medium. 4. A method according to claim 1, characterized in that the volume of the pressure transmitting medium is not less than the volume of the cylinder, the diameter of which is equal to the diameter of the counter-punch, and the height is equal to the wall thickness of the finished pipe. 5. A method according to claim 1, characterized in that, in order to obtain a pipe without a bottom part, after forming a recess between the pressure transmitting medium and the punch, a washer is made of plastic metal. 6. The method according to p. 5, about tl and h and y and with the fact that as a washer using a solid cylindrical billet. Mr. Xi / (Puei eleven Fig 3 five