SU988399A1 - Composite blank for extruding bimetallic products - Google Patents

Description

The invention relates to the processing of metals by pressure, and more specifically to the technology of pressing polymetallic products (rods, pipes, profiles). The known preform consists of a core whose length is less than the length of the shell by an amount of 0,, 1b and the external diameter of the shell, with the ends of the shell and the core coinciding at the rear end of the preform. When pressing this type of billet, high quality welding of the layers of the fll billet is provided. However, the end trim remains at a high enough level, which affects the yield. Closest to the proposed technical entity is a composite billet for pressing bimetallic products made of concentrically mounted core, casing and intermediate ring mounted on a part of its length from the rear end of the billet 2. A disadvantage of the known preform is that its use does not allow us to avoid the non-uniform outflow of the shell material from the matrix point in the initial, unsteady process characteristic of bimetal pressing processes. The inner layer of the workpiece (core) in the initial stage of pressing advances the casing, which leads to a significant unevenness of the cladding and defines a significant end cut at the front end of the finished product. The purpose of the invention is to increase the yield by increasing the uniformity of the outflow of materials of parts of the workpiece. The goal is achieved by the fact that in the composite blank for the press3988 994

The vanilla of bimetallic products, the shell, the ring and the core gradually graduated from the end of the fixed core, the shell and the intermediate ring installed on the part of its length from the rear end of the workpiece, the intermediate ring is made of a material with a yield strength greater than the yield strength of the shell material, while The core is made with a length shorter than the shell from the back end by an amount of 0.25 - O, "O from the outer diameter of the shell. Figure 1 shows schematically the proposed preparation, a general view; FIG. 2 is a diagram illustrating the use of the proposed blank. The blank for pressing bimetallic articles consists of core 1, shell 2 and intermediate ring 3 pressed between the core and the shell according to the inner diameter of the shell. The core 1 is made shorter than the shell 2 by a value of 0.25 - 0.4, the outer diameter D of the shell 2. At the front end of the preform, the ends of the shell and core are Bv of the same plane XX. The pressing of the preform is carried out as follows. The blank is placed in the container of the press in such a way that the ring 3 faces in the direction of the presstamp 5. Downwardly, the presstamp 5 proceeds to be pre-pressed until the shell material touches the walls of the container. After that, the end of the press-stamp 5 (ZZ plane) begins to act on the rear end of the shell 2 and the ring 3. As the yield strength of the material of the ring 3 is higher than the yield strength of the material of the shell 2, during the lowering process the press-stamp 5 down the shell 2 material cannot fill the cavity 6 at the rear end of the workpiece, as a result of which the sheath 2 material starts to be squeezed out through the matrix 7. This causes the gradual lowering of the strips 5, the core material is carried into the matrix not due to the backpressure from the side of the pin and from the forces of contact friction with the material of the extruded shell of the workpiece. Therefore, the core material does not advance the shell material, but rather cuts off from it in the initial pressing stage, which is why the rear ends are installed in the same plane (2-Z).

Core sizes are selected from the following considerations. The minimum size of cavity 6 is chosen such that, until the cavity 6 disappears, decompression takes place and the cavity of the material (matrix funnel) is filled. 7- This With real values of the stretch (} 10), the angle of the matrix taper (90-150) and the sizes of blanks (D 0 - 200 mm) corresponds to the initial depth of the cavity 6 С ie The distance between the ends of the shell 2 and core 1 at the rear end of the workpiece is more than 0.25 of the outer diameter of the shell. The maximum depth of cavity 6 is chosen as such. ring 3, the length of which is actually 1.10-1.15 depth of cavity 6 ,. completely remained in the pressure switch. At the indicated parameters of pressing of bimetallic products, taking into account that the length of the pressostat in the container is 0.5-2.0 matrix heights (the height of the ring does not exceed the height of the pressostatka in the container) the distance between the ends of the shell and core (i.e., practically - ring length 3) does not exceed the value of 0.40 outer diameter of the shell. In the final pressing stage, the product is separated from the pressure chamber, in which the ring 3 remains, and is sent for finishing. After removing the pressure gun from the container, all of these operations are repeated. Examples The bale is pressed under a 30 MN press for the production of steel pipes of carbon type steel (shell) stainless steel (core). A batch of pipes from billets of the traditional form (the lengths of the core and the shell are equal) and from the billets of the proposed form are pressed. In the second case, the distance between the shells and the core orts and the length of the ring made of tool steel are varied. Blanks of the proposed form are made by coaxially inserting the core into the shell, followed by pressing from the back end between the shell and the core of the sealing ring along the inner surface of the shell.

The parameters of the experiment are as follows: Billet size, mm130-4. Pipe size, mm60-6 pressing temperature, о Siisotio

External material

layer (Nd 36 mm)

carbon steel

with yield strength

in the initial state MPa 313-315

Material of the inner layer (L.8mm)

alloyed stainless steel

Х18Н10Т with a limit

yield strength in the original

condition. MPa it96-500

Material pressed

from the rear end of the billet rings (wall thickness 5 mm, outer diameter 60 mm) instrumental steel yS with

The distance between the Tetorium envelope of the pileiness of the core of the core, carried from the material to the diameter of the ring, the workpiece MPa (at the rear end)

ABOUT

825

0.05 825

0.15 825

0.25 825 s O, 0 825

0, 825

0.30

315 0.15

core length equal to the length of the shell.

Claims (2)

Invention Formula Composite billet for pressing bimetallic products, made of a concentrically mounted core, shell and intermediate ring, installed on a part of its length from the side of a given end by means of an initial condition, MPa (in one series of experiments carbon steel rings were used). The research results are summarized in the table. As follows from the data in the table, the use of the proposed billet allows a 25 to 30% reduction in the length of the annular cut on pipes due to a decrease in the longitudinal thickness variation of the layers. The economic efficiency from the implementation of the proposed invention on a 30 MN type press plant is about 250 rubles. per ton of finished products. Thus, the proposed technical solution allows for significant metal savings, which gives an economic effect in the people. country of affairs. The length of the end trim on truPAlozhenie bach, mm Prototype Final peak pressures Known stocking The product is characterized in that, in order to increase the yield by increasing the uniformity of the material outflow of parts of the workpiece, the intermediate ring is made of a material with a yield strength greater than the yield strength of the shell material, while the core is made with a length 79883998 shorter shell length from the back- 1. Production of bimetallic it end of the workpiece on the value of co-pipes. Bulletin Chermetinformatsi. put Khtsuyu 0.25 - 0.40 from the outer sever. 8, issue. 5, 1979, p. 2, Fig. 1a shell diameter. . -. Sources, information, 5 2. Patent of Sweden If 393757, taken into account during examination. B 21 C 23/22, 1977 (prototype. Wy /////// A Fig-7 W5-4;