SU1480950A1 - Hot-forming die and method of producing same - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular, to an apparatus and method for producing dies for hot stamping, and can be used in mechanical engineering. The purpose of the invention is to increase tool life. The fibers are placed in the cage on the reference part from their ends. The fibers in the places of curvature of the engraving surfaces are made with a cross-sectional area of 20-50% of the cross-sectional area of the fibers of the remaining sections of the engraving. The fibers are clad on the side surface with a material with a thermal diffusivity factor of 10 to 30 times that coefficient for a fiber material. The cross-sectional area of the cladding material is 1-15% of the cross-sectional area of the fiber material. When an annular charge explodes, a deforming pulse is created, thereby forming the working surface of the tool. Cladding material is placed between the fibers. The thickness of its layer is selected from a predetermined ratio. 2 hp f-ly, 4 ill.

Description

one

The invention relates to the processing of metals by pressure and can be used in engineering enterprises in the manufacture of blanks for parts by the method of hot stamping.

The aim of the invention is to increase tool life.

FIG. 1 shows the lower part of the stamp, a general view; in fig. 2 is a view A of FIG. one; in fig. 3 — node 1 in FIG. 2 (fragment of the working surface of the stamp); in fig. 4 - complete workpiece assembly before the deformation of the explosion.

The stamp (Figs. 1 and 2) consists of body 1, into which is inserted a liner 2 with strands 3 made with outer 4 and inner 5 radii of curvature. The liner is placed in the cage 6. The working surface of the stream is made of connected fibers 7,

which are clad with high temperature conductive material 8 (FIG. 3). In the housing 1, a cavity 9 may be provided for supplying a coolant.

The stamp works as follows.

A deformable hot piece (not shown) is placed in the cavity of the stream, where it is deformed by the second half of the stamp. In the process of deformation, heat transfer is carried out from the billet heated to the forging temperature to the working surface of the stream. From the working surface heated in this way, heat is distributed in the volume of the entire liner due to thermal conductivity, and most of the heat is transferred to the liner heat by the cladding material, since its thermal diffusivity is much higher than the thermal diffusivity of the core

I 00 O CO

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fiber material. The rapid distribution of heat in the bulk of the liner eliminates the local overheating of the metal fibers, thereby increasing its wear resistance, virtually eliminating the appearance of hot cracks. For greater intensity of heat removal, the die body can be equipped with a chamber for a cooler that takes heat from the liner. In case the fiber material is non-corrosion resistant to the cooler, it is advisable to contact the cooler only with the cladding material, selecting it as pre-corrosion resistant. Cooler maybe

ten

Numbering the stamp brook, the stamp is out of order due to wear and the appearance of spark cracks in the outer and inner radii of the brook cavity. When the ratio of coefficients is more than 30, there is no increase in durability of the stamp, however, the use in this case of expensive cladding materials dramatically increases the cost of the stamp and increases the cost of the tool.

The cross-sectional area of the cladding material is 1-15% of the cross-sectional area of the fiber material. Studies in laboratory conditions have shown that when the ratio of areas is circulating (water, air, liquefied%), no uniform gas is provided, etc.). The nose of the stamp, the stamp goes out of operation. razgarnyh cracks on the open volume, i.e. to be non-circulating-dius rounded stream. This is explained by

shim. In this case, the fibers may be due to the fact that, because of its cladding material, they are made hollow with the presence of a small cross section in the cavity.

the cooler that evaporates, picking up heat from the working surface of the stream, from the side of the working fiber end, and

condenses on its opposite side. The fibers made in this way are heat pipes and have

the ability of intensive heat transfer jr of conductive materials from one end to another, but made of a sufficiently strong material also performs the work of deformation.

Fibers located on radii

rounding the cavity of the stream (both external, 30 deforming metals and alloys, both from internal and internal) are made with thermal stamping) fibers arranged cross-section constituting 20 wedges in areas prone to max 50% of the cross-sectional area and internal

the remaining areas of the working surface, the radii of the cavity rounding), are performed outside the radius of the material having a hardness exceeding the rounding. This makes it possible, as it were, to create 35–2–2.0 times the hardness of the matte of the most wearable portions of the strain of the remaining portions of the working surface of the fine-grained metal structure. The bo-nosti. This may be the same material.

More fine fibers prevent, in places of composition, only the past thermal overheating, more evenly transfer the treatment in the fiber stage to higher heat from the working surface. For definiteness, or the material is more expensive for this interval, the ratio of the total is 40 hours, other chemical composition with increased

the resistance of the entire working surface of the stream is reduced, which is associated with relatively low strength properties of heat to obtain uniform wear of the working surface of the streams with a deep cavity, as well as dies operating at elevated temperatures (difficult to heat the working surface of the stream, With a ratio of more than 15% sharply

resistance of the entire working surface of the stream is reduced, which is associated with relatively low strength properties of heat-conducting materials

deforming metals and alloys, isothermal stamping) fibers located in areas prone to maximal wear in order to obtain a uniform wear of the working surface of streams with a deep cavity, as well as dies operating at elevated temperatures (it is difficult

fiber spawn performed special experiments. Experimental data showed that when the area ratio is less than 20% of the durability of the stamp at the indicated hardness.

When the hardness of the fiber material at radii exceeding the hardness of the fiber material of the remaining sections is less than

the working surface (radius is 1.3 times 1.3 times; the uniform

lnia) decreases sharply, which is apparently due to the impossibility of equal strength fiber welding between them. When the area ratio is more than 50%, the working surface of the streams of dies working under severe conditions is not evenly worn, first of all the curvature radii fail due to cracks, wear and size loss. With the hardness of the material of the fibers at the radii, the stamping of the stamp, the areas at the radii more than 2 times rounding up, the hardness of the hollow cavities wear out approximately in the material of the fibers at the remaining sections

working surface, chipping of the working surface occurs on the radii of curvature, the resistance of the dies decreases.

As a cladding material, the thermal diffusivity exceeding 10–55 can be used as a cladding material — 30 times the thermal conductor coefficient with a coefficient of friction of 0.15–0.8 of the coefficient of friction of the fiber material. It may be, for example,

1.5 times faster than areas outside of radii. The lateral surface of the fibers is clad with material with a coefficient of temperate material of the fibers. With a ratio of less than 10, it is not provided with uniformity.

When the hardness of the fiber material at radii exceeding the hardness of the fiber material of the remaining sections is less than

 1.3 times, not uniform

the wear of streams of dies operating under severe conditions, first of all, rounding radii due to cracks, wear and loss of size are out of order. When the hardness of the material of the fibers at radii exceeding more than 2 times the hardness of the material of the fibers in the remaining sections

copper composite with graphite. In this case, the cladding material serves as a source of lubricant, thus providing less wear on the working surface of the die of the stamp. When the coefficient of friction of the cladding material is less than 0.15 of the coefficient of friction of the fiber material, uniform wear of the entire working surface of the die of the stamp is not ensured. With a coefficient of friction greater than 0.8 of the value of the coefficient of friction, cracking is observed on the working surface, which is associated with the loss of the strength properties of the cladding material. In this case, the centers of origin of cracks are observed in the plating material.

The stamp is made by jointly deforming the fiber bundle to obtain a fiber preform. In this case, prior to the deformation of the fiber bundle, the reference part 11 is installed in the cage 10 (FIG. 4). In FIG. Figure 4 shows a variant of the placement of the reference part in the middle part of the holder, with both halves of the stamp being formed at once. The reference part repeats in its configuration a finished forging with a small allowance for finishing machining (grinding). Fibers with cladding material (as fibers can be used, for example, bimetallic steel wiring, clad with copper) are arranged with the ends to the surface of the reference piece., While the fibers are arranged coaxially of the cage. The deformation is carried out by pulsed loading of the cage with the energy of explosion of an external annular charge 12 of an explosive. The ends of the fibers arranged parallel to the longitudinal axis of the cage, form a working cavity between the two liners 13 and 14 (Fig. 4). On the non-working end side, fibers can be pressed by gaskets 15 of bulk material, for example, sand. On the upper end of the cage set the cone generator 16 flat shock waves. An explosive charge 12 with a wall thickness HbB is placed on the outer surface of the cage, which is initiated by an electric detonator 17. The pressure of the casing energy transmitted to the walls of the casing explodes to press the cage to its axis. The fibers are compacted and welded together on the contact surfaces on which the cladding material is preliminarily applied with the required properties.

Depending on the thickness of the charge layer during the welding of fibers, the following cases may occur: the fibers are welded to form channels (capillaries) between them in the entire volume of the liners, through which a coolant can be supplied under pressure; the fibers are welded to form channels in a portion of the volume of the liners; the fibers are welded without

channeling in the entire volume of liners.

The thickness of the explosive layer is not selected from the ratio established experimentally:

H

NoHPoHPpm: (0, o ... 3, o) -TP7xT1 -: -,

0

0

five

0

five

0

five

0

five

where P „, P.

Non - wall thickness of the yoke; in ,, PM is the density according to the material of the cage, the explosive, the cladding material and the fiber material.

To perform welding with the formation of channels in the entire volume of inserts, the coefficient value (in brackets) is chosen equal to 0.5 ... 1.5. At values of this coefficient less than 0.5, part of the fibers in the volume of the liner does not weld over the contact surfaces, which sharply reduces the durability of the working surface of the die of the punch. In order to carry out the welding case specified in claim 2, the coefficient is chosen to be 1.6 ... 2.2. In order to carry out a welding case using a cladding material with a friction coefficient of 0.15 ... 0.8 friction coefficient of the fiber material, the coefficient is chosen to be 2.3 ... 3.5. When the coefficient is equal to 3.5, guaranteed welding of fibers takes place over the entire volume of the liner, therefore, it is impractical to choose a coefficient value of more than 3.5, since this does not increase the positive effect, but leads to an overrun of the explosive.

After crimping (welding), the holder is cut along the plane of the working cavity. The cut width is compensated for by the dimensions of the reference part. Example. A steel pipe made of steel 5ХНМ with a length of 190 mm, an outer diameter of 66 mm and a tire wall of 8 mm is used as a holder. In the middle of the height of the cage place the reference part. As fibers for working surface parts located on the closed cavity of the cavity, the use of puncture is made of 25X5FMS steel with a diameter of 0.8 mm with a cladding layer of copper 0.05 mm thick. For the rest of the working surface, a wire of steel is used. A diameter of 1.15 mm with a planning layer of copper 0.08 mm thick. Ammonite Kv 6GV with a charge layer thickness of 80 mm is used as an explosive. After crimping, they cut the casing with the extraction of the reference part and manufacture two twin inserts, which are used to shrink the heated billets on the presses. To eliminate welding of the reference part, a layer of lubricant or thin elastic: io gasket is applied to its ends of the fibers on its nonepxiioci. The reference part can be reused.

Claims (3)

1. A stamp for hot stamping of forgings containing deforming elements with cavities of engravings of streams, made in the form of blocks of fibers, characterized in that, in order to increase tool life the engravings are made with a hardness exceeding the fiber hardness of the remaining sections of the engraving 1.3-2.0 times. 3. A method of manufacturing a stamp for hot stamping of forgings, consisting in joint deformation of the fibers in the cage and subsequent machining of the workpiece, characterized in that the fibers are deformed together with the reference part placed on the ends of the moment, the fibers in the blocks are arranged in parallel, the deformation is carried out impellately to the longitudinal axis of the punch, while the fibers placed in the places of curvature of the engraving surfaces are made with a cross-sectional area of 20-50% of the cross-sectional area Cheney fibers remaining portions engraving, fiber clad material on the side surfaces with the thermal coefficient of 10-30 times greater than the thermal coefficient of the material of fibers, cross-sectional area of the cladding material is 1 - 15% of the cross sectional area of the fiber material. 2. A stamp in accordance with claim 1, characterized in that the fibers in the places of curvature of the surfaces 4 s the engravings are made with a hardness exceeding the fiber hardness of the remaining sections of the engraving 1.3-2.0 times. 3. A method of manufacturing a stamp for hot stamping of forgings, consisting in joint deformation of the fibers in the cage and subsequent machining of the workpiece, characterized in that the fibers are deformed together with the reference part placed on the fiber ends, and they are deformed 0 pulsed loading created by the explosion of an external ring charge, the thickness of the explosive layer of which is chosen from the ratio n m h 1 no-po-ppm G1vv IU, D ... O, DJ Eve in 1 1m where is the thickness of the outer layer ring explosive charge; But - the wall thickness of the cage; Po.Pv in, PP m, PM - density, respectively, of the material of the cage, explosive, cladding material and fiber material. 5 3 1 Type A one Fig.Z /// /// // J (/// /// Л Fia.Ts