RU2208490C2 - Method for extruding short-length tubes - Google Patents

Abstract

FIELD: plastic metal working, namely production of short-length tubes of hard- to-form metals and alloys. SUBSTANCE: method comprises steps of placing in die holder centering ring whose inner diameter corresponds to that of molding needle at providing sliding fit; feeding heated blank with axial opening to container; extruding tube in gap between pressure pad and wall of container by one or several transitions for forming bottom and for separating bottom through cut-off ring; heating technological washer with axial opening; placing said washer between centering ring and blank in container when diameter of axial opening of heated technological washer corresponds to diameter of molding needle at providing sliding fit; extruding tube until forming bottom in technological washer. Before extrusion process needle is joined to ram with possibility of radial motion; pressure pad may freely move on needle. EFFECT: enhanced factor of metal usage due to lowered wall thickness difference of extruded tubes, due to extruding tube without forming bottom of tube material, reduced crops, normalized properties of extruded metal along the whole length of tube. 3 cl, 4 dwg

Description

 The invention relates to the processing of metals by pressure and can be used in the production of short-length pipes from hardly deformable metals and alloys.

 A known method of pressing pipes, including placing a workpiece in a container, pressing a pipe by extruding it on a punch into an annular gap between the punch and the container, cutting the bottom of the pipe, moving the pipe forward, pushing the pipe out of the container (Zholobov V.V., Zverev G.I., Pressing Metals. - M.: Metallurgy, 1971, p. 27).

 This pressing method allows to obtain pipes whose diameter is equal to or slightly less than the diameter of the container.

 The disadvantages of this method are the large pressing forces when pressing thin-walled pipes, a large difference and significant metal loss due to an increase in the bottom height.

 This method coincides with the claimed method of pressing short pipes according to the following essential features: placement of the workpiece in the container, extruding the pipe by extruding it into the annular gap between the punch and the container, and cutting the bottom.

 A known method of pressing pipes, including placing the plug in the matrix holder, feeding the heated ingot to the container, extruding the ingot with a stamp with a press washer, piercing the hole with a piercing needle to form a cup, removing the plug from the matrix holder, separating the bottom of the workpiece with a needle through a cutting ring and pressing the pipe into the annular gap formed by the matrix and the needle, returning the needle to its original position, pushing the pipe with the press residue from the container, separating the press residue and pushing the pipe (ibid., p. 12).

 The disadvantage of this method is the low accuracy of the pipes due to the incompatibility of the holes of the stitched workpiece and the axis of the workpiece. In addition, this method can only be implemented on presses with a firmware system.

 This method coincides with the claimed method of pressing pipes according to the following essential features: the pressing of the pipe is made from a workpiece with a central hole.

 Closest to the technical nature of the present invention is a method of pressing pipes, including placing a plug in the matrix holder, feeding a heated ingot into a container, pressing an ingot, piercing an axial hole with a piercing needle to form a cup, removing the bottom of the workpiece with a needle through a cutting ring, installing a centering ring, diameter the holes of which correspond to the diameter of the needle, with a sliding fit and pressing the pipe into the gap between the press washer and the container wall, and the ring of the bottom branch (patent RU 2146177, 2000) - The prototype.

 The disadvantage of this method when pressing short tubes of difficult to deform alloys is the great effort at the end of the flashing and pressing operations of the pipe when pressing the metal from the zone of difficult deformation due to the cooling of the metal along the contact surface of the end face of the workpiece with a plug, then with a centering ring.

 This method coincides with the claimed method of pressing pipes according to the following essential features: installing a centering ring, the diameter of the hole of which corresponds to the diameter of the needle, providing a sliding fit for pressing the pipe into the gap between the press washer and the container wall from a heated billet having a central hole, installing a cutting ring and bottom separation.

 The problem to which the claimed invention is directed is to increase the utilization of metal by reducing the difference in extruded pipes, pressing the pipe without forming a bottom from the pipe material, reducing the end trim of the pipes, obtaining the regulated properties of the pressed material along the entire length of the pipe.

 The technical result achieved during the implementation of the invention is the creation of pressing conditions that ensure the centering of the press needle along the axis of pressing, extruding the entire volume of the workpiece material into the pipe, eliminating the cooling of the end face of the workpiece facing the die holder.

 The specified technical result is achieved by the fact that in the proposed method of pressing short pipes, which includes placing a centering ring in the matrix holder, the inner diameter of which corresponds to the diameter of the press needle, providing a sliding fit, feeding the heated billet with an axial hole into the container, pressing the pipe into the gap between the press - the washer and the container wall in one or several transitions with the formation of the bottom and separation of the bottom through the cutting ring, heat the technological washer having an axial opening before reaching a diameter of the size corresponding to the diameter of the press needle, place the technological washer between the centering ring and the workpiece in the container with a sliding fit on the press needle and press the pipe to form the bottom in the technological washer.

 In contrast to the prototype, when a pipe is pressed between a workpiece installed in a container and a centering ring installed in a matrix holder, a technological washer is placed. The washer is made of a material having mechanical properties comparable to the pressed material and, as a rule, much less expensive and more technological.

Using a technological washer in the pressing process allows
- to exclude cooling of the end face of the billet facing the matrix holder, since a technological washer heated to operating temperature is placed between them;
- to provide an optimal pattern for centering the press needle along the axis of pressing, the technological washer is based on the outer surface on the inner surface of the container, and the inner hole of the washer mates with the press needle on a sliding fit;
- to ensure the extrusion of the entire volume of the workpiece material into the pipe, the bottom of the pipe is formed in the material of the technological plug.

 When pressing the pipe before pressing, the press needle is connected to the press stamp movably in the radial direction, and the press washer is freely axially placed on the needle.

 The absence of a rigid connection between the press needle and the stamp allows you to compensate for bending forces when pressing on the press needle due to misalignment of its axis, which coincides with the axis of the container, and the axis of the stamp.

 When pressing the pipe, the press needle is connected to the press washer.

 This allows you to use the workpiece with a height commensurate with the length of the container, with the exception of the height of the technological washer. In this case, the press needle is fixedly connected to the press washer, placed in the axial hole of the workpiece, fed to the pressing axis and then into the container together with the workpiece, and the press stamp is in contact with the press needle along the supporting surface, ensuring the press needle is radially movable relative to stamps.

 The invention is illustrated by drawings, where FIG. 1 shows a diagram of a pressing process, FIG. 2 - separation of the bottom of the glass, figure 3 is a diagram of the pressing process when the press needle before pressing is connected to the press stamp movably in the radial direction, figure 4 is a diagram of the pressing process when the press needle is connected to the press washer.

 The method of pressing pipes is as follows. A centering ring 1 is installed in the matrix holder, an ingot 2 heated to an operating temperature with an axial hole, and the technological washer 3 are placed in the container 4. The press needle mates with the centering ring and the technological washer in a heated state on a sliding fit. The press washer is mounted on the press needle 6, which mates with the press stamp 8 for a loose fit, then the pipe is pressed onto the press washer 5 into the gap between the container and the press washer. Then the centering ring 1 is removed, the cutting ring 9 is installed and the annular bottom 10 is separated. After that, the press needle 5, the press washers 6 and the pipe 12 are pressed out. The number of pressing transitions is determined technologically, while the centering ring 1, the press needle are replaced 6 and the press washer 5. When pressing long workpieces, the press washer 5 and the press needle 6 are rigidly interconnected.

 The industrial applicability of the claimed method for pressing short pipes is confirmed by the following specific example.

 The horizontal press with a force of 3150 tf does not have a piercing system and is intended for pressing pipes from a workpiece with a central hole. In accordance with the proposed method, a centering ring is installed in the matrix holder, and a technological washer made of St3 steel, having dimensions ⌀279x⌀62x90 mm in a heated state, and a blank of titanium alloy VT6, having dimensions ⌀279x962x200 mm in a heated state are placed in a container. Then, by pressing the stamp, a press needle, a press washer are fed, the press needle with its front end is centered in the centering ring, then the pipe is pressed into the gap between the press washer and the container. Pressing is performed in one transition. The Donets is separated by a cutting ring. Then the press tool is removed and the finished product is pushed out. After cooling, the pipe has dimensions ⌀277х⌀217х517 mm.

Claims (3)

 1. A method of pressing short pipes, including placing a centering ring in the matrix holder, the inner diameter of which corresponds to the diameter of the press needle with a sliding fit, feeding the heated billet with an axial hole into the container, pressing the pipe into the gap between the press washer and the wall of the container into one or several transitions with the formation of the bottom and separation of the bottom through a cutting ring, characterized in that they heat the technological washer having an axial hole until its diameter reaches the size corresponding to favoring the diameter of the press-needle placed technological washer between centering ring and the workpiece in a container to ensure a snug fit at the press-molding is carried out and the needle tube to form a bottom in a process washer.  2. The method according to claim 1, characterized in that the press needle before pressing is connected to the press stamp movably in the radial direction, and the press washer in the axial direction is freely placed on the needle.  3. The method according to claim 1, characterized in that the press needle is connected to the press washer.

Images