A deformation control process applied to a die forging after forging

Abstract

The application discloses a kind of deformation control processes applied to die forging after forging, and the deformation control process steps are as follows: first step: the flash of the flash die forging with flash is placed to corresponding trimming die to carry out trimming flash processing;Second step: the die forging after trimming prepared after first step processing is placed to corresponding internal stress improvement forging die, which can improve its internal residual stress state and make internal residual stress become compressive stress entirely.Die forging after trimming is in the die set of upper die and lower die, and the flat flash surface forms flash drum surface, and the height b of flash drum surface is greater than or equal to 1mm.The gap h of upper die and lower die die set is less than the flash thickness H of flash die forging.After the treatment of forging die mold, the plastic deformation of forging die part makes internal residual stress become compressive stress entirely, and the release of residual compressive stress in subsequent heat treatment process does not affect the shape and size of die forging, and the size precision of die forging is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of die forging manufacturing technology, and in particular to a deformation control process for die forgings after forging. Background Technology

[0002] Forging dies are a general term for molds used to form metal in a hot or cold state. Due to the different working characteristics of various forging equipment, the structures of their forging dies vary considerably, and there are also slight differences in the die cavity design. A sound forging die design process should first consider: obtaining forgings that meet dimensional accuracy requirements and have good microstructure properties, while also meeting productivity requirements; secondly, it should also consider that the forging die has sufficient strength and a long service life, and is simple to manufacture, easy to install, adjust, and maintain. Therefore, a comprehensive analysis should be conducted when designing forging dies.

[0003] Currently, during long-term use, forging dies experience uneven wear near the flash, uneven gap between the upper and lower dies of the trimming die, uneven wear of the lower die of the trimming die, insufficient equipment guiding accuracy, deviation in the placement of the trimming edge of the forging with flash, and excessively low trimming temperature. These factors cause the forgings to have varying degrees of planar bending, warping, or twisting after trimming. If the temperature of the forging is too low or the pressure of the forging equipment is insufficient during shaping, some residual tensile stress will still exist inside the forging after shaping. Once the residual tensile stress is released during subsequent aging or heat treatment, it will cause deformation of the forging shape and dimensional deviations, which will bring great inconvenience to the dimensional control work in the manufacturing process of forging dies. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention aims to provide a deformation control process for forgings after die forging. This deformation control process is ingeniously designed and easy to operate. After trimming, during the die-forming process of the upper and lower forging dies, the flat flash surface forms a flash drum-shaped surface, with a height b ≥ 1 mm. The gap h between the upper and lower forging dies is less than the flash thickness H of the forging with flash, where H – h ≥ 1 mm. The internal plastic deformation of the forging after die treatment transforms all internal residual stress into compressive stress. The release of residual compressive stress during subsequent aging or heat treatment does not affect the shape and dimensions of the forging, ensuring dimensional accuracy and greatly facilitating dimensional control during the forging manufacturing process.

[0005] To solve the above technical problems, the present invention adopts the following technical solution:

[0006] A deformation control process applied to die forgings after forging, characterized by the following steps:

[0007] First step: Place the forging part with flash on the corresponding trimming die to trim the flash;

[0008] The second step is to place the trimmed forging prepared in the first step into a corresponding internal stress improvement forging die that can improve the internal residual stress state and turn all the internal residual stress into compressive stress, and then use the internal stress improvement forging die to treat the internal stress of the trimmed forging.

[0009] In a preferred embodiment of the present invention, the trimming die includes an upper trimming die and a lower trimming die that cooperates with it. The lower end of the upper trimming die has a trimming upper die cavity that cooperates with the upper surface of the forging with flash, and an upper trimming edge is formed around the upper trimming upper die cavity. The upper end of the lower trimming die has a trimming lower die cavity that cooperates with the lower surface of the forging with flash, and a lower trimming edge that cooperates with the upper trimming edge is formed around the lower trimming lower die cavity. The forging with flash is placed in the lower trimming lower die cavity, and the flash of the forging with flash is located between the upper trimming edge and the lower trimming edge.

[0010] In a preferred embodiment of the present invention, the internal stress improvement forging die includes an upper forging die and a lower forging die that cooperates with it. An upper forging die cavity that cooperates with the upper surface of the forged part after trimming is provided at the lower end of the upper forging die, and an upper pressure surface is formed around the upper forging die cavity. A lower forging die cavity that cooperates with the lower surface of the forged part after trimming is provided at the upper end of the lower forging die, and a lower pressure surface that cooperates with the upper pressure surface is formed around the lower forging die cavity. The forged part with trimmed edges is placed in the lower forging die cavity. During the mold closing and shaping process of the upper and lower forging dies, the flat flash surface obtained by trimming the flash-bearing forging part with flash by the trimming die is formed into a flash drum-shaped surface.

[0011] In a preferred embodiment of the present invention, the height b of the burr-shaped surface is ≥ 1 mm.

[0012] In a preferred embodiment of the present invention, the closing compression amount of the upper and lower forging dies is greater than the bending amount of the forging plane after trimming, and the closing gap h between the upper and lower forging dies is less than the flash thickness H of the forging with flash.

[0013] In a preferred embodiment of the present invention, the difference between the flash thickness H of the forging with flash and the gap h between the upper and lower forging dies is ≥1mm, i.e., H–h≥1mm.

[0014] In a preferred embodiment of the present invention, the forged part after trimming can be carbon steel, alloy steel, stainless steel, other alloys and non-ferrous metals.

[0015] Compared with existing technologies, the present invention features a clever process design and convenient operation. During the die-forming process after trimming, the flat flash surface of the forging part forms a flash drum-shaped surface during the closing and shaping of the upper and lower forging dies, with a height b ≥ 1mm. The gap h between the upper and lower forging dies is less than the flash thickness H of the forging part with flash, H – h ≥ 1mm. The internal plastic deformation of the forging part after die treatment transforms all internal residual stress into compressive stress. The release of residual compressive stress during subsequent aging or heat treatment does not affect the shape and size of the forging part, ensuring dimensional accuracy and greatly facilitating dimensional control during the forging part manufacturing process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the edge-cutting mold of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal stress improvement forging die of the present invention.

[0019] Figure 3 This is a schematic diagram of the structure of the burr-shaped surface of the present invention. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0021] Reference Figures 1-3 As shown in the figure, a deformation control process applied to die forgings after forging is illustrated. The steps of this deformation control process are as follows:

[0022] First step: Place the forging part 300 with flash on the corresponding trimming die 100 to trim the flash;

[0023] The second step is to place the trimmed forging 400 prepared in the first step into the corresponding internal stress improvement forging die 200, which can improve the internal residual stress state and turn all the internal residual stress into compressive stress, and to process the internal stress of the trimmed forging 400 through the internal stress improvement forging die 200.

[0024] The trimming die 100 includes an upper trimming die 110 and a lower trimming die 120 that cooperates with it. The lower end of the upper trimming die 110 is provided with an upper trimming die cavity 111 that cooperates with the upper surface of the forging with flash 300, and an upper trimming edge 112 is formed around the upper trimming die cavity 111. The upper end of the lower trimming die 120 is provided with a lower trimming die cavity 121 that cooperates with the lower surface of the forging with flash 300, and a lower trimming edge 122 that cooperates with the upper trimming edge is formed around the lower trimming die cavity 121.

[0025] The forging part 300 with flash is placed in the lower die cavity 121 with the flash 310 positioned between the upper cut edge 112 and the lower cut edge 122, and the gap a between the upper cut edge 112 and the lower cut edge 122 is between 0.5-1mm.

[0026] The flash of the forging 300 is located between the upper cutting edge 112 and the lower cutting edge 122. During the fitting process, the upper cutting die 110 and the lower cutting die 120 can cut off the flash 310 located between the upper cutting edge 112 and the lower cutting edge 122, and form a straight flash surface 500 around the forging. After cutting, the forging has a certain temperature, which is >600℃. The forging equipment has sufficient forging energy, and the forging energy value is 0.5 to 0.8 times the final forging impact force or pressure.

[0027] The internal stress improvement forging die 200 includes an upper forging die 210 and a lower forging die 220 that cooperates with it. An upper forging die cavity 211 that cooperates with the upper surface of the forged part 400 after trimming is opened at the lower end of the upper forging die 210, and an upper pressing surface is formed around the upper forging die cavity 211. A lower forging die cavity 221 that cooperates with the lower surface of the forged part 400 after trimming is opened at the upper end of the lower forging die 220, and a lower pressing surface that cooperates with the upper pressing surface is formed around the lower forging die cavity 221.

[0028] The forging part 400 with the trimmed edge is placed in the lower forging die cavity 221. During the mold closing and shaping process of the upper forging die 210 and the lower forging die 220, the flat flash surface 500 obtained by trimming the flash forging part with the flash through the trimming die forms a flash drum-shaped surface 600, and the drum height b of the flash drum-shaped surface 600 is ≥1mm.

[0029] If the flash and bulging surface b of the forging after trimming is greater than 3mm after internal stress improvement forging die treatment, the trimming die needs to trim the edge again. After trimming, the amount of pressing down when the upper and lower forging dies are closed should also be greater than the amount of bending of the forging plane after trimming.

[0030] The closing pressure of the upper forging die 210 and the lower forging die 220 is greater than the bending amount of the plane of the forging 400 after trimming. The closing gap h between the upper forging die 210 and the lower forging die 220 is less than the flash thickness H of the forging with flash. The difference between the flash thickness H of the forging 310 of the forging with flash and the closing gap h between the upper forging die and the lower forging die is ≥1mm, i.e., H–h≥1mm.

[0031] The 400mm die forging after trimming can be made of carbon steel, alloy steel, stainless steel, other alloys and non-ferrous metals. The specific selection of the die forging after trimming can be made according to the actual production needs.

[0032] In summary, the entire process design of this invention is ingenious and easy to operate. After trimming, during the die-forming process of the upper and lower forging dies, the straight flash surface of the forging part forms a flash drum-shaped surface, with a height b ≥ 1 mm. The gap h between the upper and lower forging dies is less than the flash thickness H of the forging part with flash, H – h ≥ 1 mm. The internal plastic deformation of the forging part after forging die treatment transforms all internal residual stress into compressive stress. The release of residual compressive stress during subsequent aging or heat treatment does not affect the shape and size of the forging part, ensuring the dimensional accuracy of the forging part and greatly facilitating dimensional control during the forging part manufacturing process.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A deformation control process applied to die forgings after forging, characterized in that, The deformation control process steps are as follows: First step: Place the forging with flash onto the corresponding trimming die to trim the flash, so as to form a flat flash surface around the forging; The second step is to place the trimmed forging prepared in the first step into the corresponding internal stress improvement forging die. The internal stress improvement forging die is used to close and shape the trimmed forging, so that the flat flash surface is plastically deformed into a flash drum-shaped surface, thereby converting all the residual stress inside the trimmed forging into compressive stress. The internal stress improvement forging die includes an upper forging die and a lower forging die that cooperates with it. An upper forging die cavity is formed at the lower end of the upper forging die to cooperate with the upper surface of the forging after trimming, and an upper pressure surface is formed around the upper forging die cavity. A lower forging die cavity is formed at the upper end of the lower forging die to cooperate with the lower surface of the forging after trimming, and a lower pressure surface is formed around the lower forging die cavity to cooperate with the upper pressure surface. The forging after trimming is placed in the lower forging die cavity. During the mold closing and shaping process of the upper and lower forging dies, the flat flash surface obtained by trimming the flash-bearing forging by the trimming die is formed into a flash drum-shaped surface.

2. The deformation control process for die forgings as described in claim 1, characterized in that: The trimming die includes an upper trimming die and a lower trimming die that cooperates with it. The lower end of the upper trimming die has a trimming upper die cavity that cooperates with the upper surface of the forging with flash, and an upper trimming edge is formed around the upper trimming upper die cavity. The upper end of the lower trimming die has a trimming lower die cavity that cooperates with the lower surface of the forging with flash, and a lower trimming edge that cooperates with the upper trimming edge is formed around the lower trimming lower die cavity. The forging with flash is placed in the lower trimming lower die cavity, and the flash of the forging with flash is located between the upper trimming edge and the lower trimming edge.

3. The deformation control process applied to die forgings after forging, as described in claim 1, is characterized in that: The height b of the burr-shaped surface is greater than or equal to 1 mm.

4. The deformation control process applied to die forgings after forging, as described in claim 1, is characterized in that: The closing pressure of the upper and lower forging dies is greater than the bending amount of the forging plane after trimming, and the closing gap h between the upper and lower forging dies is less than the flash thickness H of the forging with flash.

5. The deformation control process for die forgings as described in claim 4, characterized in that: The difference between the flash thickness H of the forging with flash and the gap h between the upper and lower forging dies is ≥1mm, i.e., H–h≥1mm.

6. The deformation control process applied to die forgings after forging, as described in claim 1, is characterized in that: The forged parts after trimming can be made of carbon steel, stainless steel, other alloys, and non-ferrous metals.

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