RU2549787C1 - Punch for broaching at press - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: punch for broaching is made as a body of rotation with two holes. The outer diameter of the punch is alternating. The said diameter at the punch length section from its front end face being equal to the inner diameter of the produced hollow billet is equal to the said inner diameter of the hollow billet. Along the remaining length section, the punch diameter is constant and is by 2 mm less than the inner diameter of the hollow billet. One of the holes is through, has the diameter alternating by the length and the axis matching the punch axis. The diameter of the said hole at the length section from the punch front end face equal to its maximal outer diameter is equal to 2/3 of the said punch diameter. Along the remaining length section, the hole diameter is constant and is by 2 mm greater than the hole diameter at its length from the punch front end face. The second hole is fitted by an axis crossing the punch axis at the right angle. The axis of the second hole is set at the distance from the punch front end face equal to 4/5 of the punch length. The diameter of the second hole is constant along the whole hole length and is equal to 5 mm.

EFFECT: improved quality of broached billets due to the reduction of their wall thickness variation and elimination of faults, reduction of friction at the outer and inner surface of the punch.

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Description

The invention relates to the field of metal forming, namely, punches for flashing on presses in a container with or without a matrix and can be used for flashing blanks, including continuously cast, on horizontal and vertical presses.

The design of hollow firmware is known (Yu.A. Titov, A.Yu. Titov, Free forging. Basic operations and technologies). The firmware is used for blacksmith firmware, i.e. without container. When flashing with firmware of this design, metal flows into the firmware hole and compresses the air inside the firmware. This leads to difficulty in the flow of metal into the firmware hole and to an increase in the firmware force. The presence of compressed air inside the firmware may lead to the destruction of the firmware.

The known firmware design (patent SU 946768, published 07/30/1982, Bulletin No. 28). Due to the use of a conical working surface in the hole, the piercing creates additional resistance to the flow of metal into the cavity of the punch. This increases the effort required to complete the firmware.

Known firmware design (patent SU 1238871 A1, published 06/23/1986, Bulletin No. 23). The firmware is used for blacksmith firmware, i.e. without container. Composite firmware requires the use of extensions and rings, which complicates the operation process.

Known firmware design (SU 1530316 A1, published 12/23/1989, Bulletin No. 47). The tool is used for forging firmware blanks, i.e. firmware without container. Due to the narrowing of the hole, the firmware is half its length, counting from the front end, there is additional resistance to the flow of metal into the firmware cavity, which leads to an increase in the firmware force.

A known design of blacksmith firmware (patent SU 555964, published 04/30/1977, Bulletin No. 6). The cylindrical recess in the piercing base allows a limited volume of metal to flow into it. When this recess is completely filled with metal during firmware, the stress-strain state of the metal of the stitched workpiece changes. This will lead to increased effort and incomplete removal of defects in the axial zone of the stitched ingot or continuously cast billet.

An object of the invention is to improve the quality of the inner surface of the obtained sleeves by removing defects of the continuously cast billet, reducing the force on the punch, reducing the difference in the sleeves, as well as reducing friction on the outer and inner surfaces of the punch.

The technical result is achieved by the fact that in the proposed design of the punch, which has the shape of a body of revolution, there is a through hole (figure 1, 1), the axis of which coincides with the axis of rotation of the punch. The diameter of the hole is variable, over a length equal to the inner diameter of the obtained sleeve, counting from the front end of the punch, equal to 2/3 of the maximum outer diameter of the punch, then increases by 2 mm and remains constant over the remaining length of the punch, which reduces friction on the inner surface of the punch . When flashing a continuously cast billet, the metal of the axial zone flows into this hole, containing defects and discontinuities, which, therefore, do not pass to the inner surface of the sleeve. In this case, the metal flowing into the hole of the punch is compacted, worked through due to deformation, acquiring the shape of a cylinder. The result is: a sleeve - a hollow tube billet, an otter in the form of a bar that can be used, including in subsequent pressure processing processes. Reduced effort compared to using a continuous punch can be achieved by reducing the contact area at the end of the punch with the pierced metal. Reducing the difference in the resulting sleeves is achieved due to the greater stability of the hollow punch in comparison with a continuous punch. When flashing a hollow punch, the metal flows not only along the surface of the punch, but also inside it, thereby creating a guide and increasing the stability of the punch and its resistance to longitudinal bending. To reduce friction on the outer surface of the punch, its outer diameter is made variable: at a length equal to the diameter of the obtained sleeve, counting from the front end of the punch, the outer diameter of the punch is equal to the diameter of the obtained sleeve, then the diameter decreases by 2 mm and remains constant over the entire remaining length of the punch. In the proposed design of the punch made a second hole - through - with a diameter of 5 mm (figure 1, 2), the diameter is the same along the entire length. The axis of rotation of the second hole intersects the axis of rotation of the punch at a right angle and is located at a distance equal to 4/5 of the length of the punch from its front end. The hole is designed so that the air, when the metal flows inside the punch, does not compress, preventing the metal from flowing, but leaves through this hole.

The use of the punch of the proposed design does not require a change in the technology for flashing shells and equipment for the press press.

The use of the invention will reduce the effort on the punch, reducing the difference and the number of defects on the inner surface of the resulting sleeves.

An example of the use of the punch of the proposed design is the firmware on the press of the tube billet. The experiments were conducted on a hydraulic press with a force of 400 kN of the department of TOTP NITU "MISiS". For firmware used a hollow punch with holes for air outlet. The diameter of the working part of the hollow punch was 10 mm, the diameter of the hole was 6 mm, the depth of the hole was 80 mm (FIG. 2). Also used a solid punch with a diameter of the working part of 10 mm (figure 2). Stitched lead blanks with a diameter of 40 mm and a height of 60 mm, part of the blanks were composite (figure 3).

The experiments showed that the process of flashing a hollow punch on the press proceeds stably. The metal flows into the hole of the hollow punch to a depth approximately equal to the initial height of the workpiece (figure 4). Moreover, in addition to the hollow tube billet obtained, an otter was obtained as a waste (Fig. 5), the diameter of which was equal to the diameter of the axial hole of the hollow punch.

When flashing with solid and hollow punches, a change in the firmware force was recorded. It was found that when flashing with a hollow punch, the force is 8-10% lower (Fig. 6) than with flashing with solid.

Claims (1)

A punch for piercing blanks in a container on the press, made in the form of a body of revolution with a variable profile and two holes, characterized in that it is made with a variable outer diameter, which is equal to the said diameter along the length of the punch from its front end, which is equal to the inner diameter of the hollow billet the inner diameter of the hollow billet, and on the remaining length of the punch has a constant value that is 2 mm less than the inner diameter of the hollow billet, one of the holes is through, has a variable length its diameter and axis coinciding with the axis of the punch, and the diameter of the said hole along the length from the front end of the punch equal to its maximum outer diameter is 2/3 of the maximum outer diameter of the punch, and on the remaining length has a constant value 2 mm greater than the diameter holes along the length from the front end of the punch, while the second hole is made with an axis that intersects the axis of the punch at a right angle and is located at a distance from its front end equal to 4/5 of the length of the punch, and with a constant over the entire length Diameter equal to 5 mm.

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