CN204657472U - The pre-pressing die of the hot-forming goods of metal dust - Google Patents

Abstract

The utility model discloses a pre-pressing mold for metal powder hot-pressed molding products, which includes a mold frame, a template is arranged in the mold frame, and an adjusting clamping element is arranged in a hole on the mold frame, and the adjusting clamping element passes through the end of the mold frame Act on the formwork, compress the formwork by adjusting the clamping elements. Through the pre-pressing mold of the utility model, the templates are combined to form a filling cavity, and the metal powder is cold-pressed in the filling cavity, and the side is pressed by adjusting the clamping element to squeeze the template, and the upper part is pressed by the pressure equipment to squeeze out the filling cavity. Various bubble-forming bodies inside the molded product to obtain a compact with uniform quality and no delamination.

Description

Pre-compression dies for metal powder hot-pressed products

technical field

The utility model belongs to the technical field of powder metallurgy molding, in particular to a pre-pressing mold for pre-pressing and molding metal powder before hot-pressing the metal powder.

Background technique

Powder metallurgy is a new type of metal forming technology that uses metal powder or a mixture of metal powder and non-metal powder as a raw material, and undergoes powder forming → sintering → forming to manufacture metal products. The processing process of powder metallurgy technology has no chips, high material utilization rate, clean and efficient, low production cost, and can manufacture various processed products with complex structures. Usually, the energy consumption of the general casting method can reach 80%, while the loss of metal products produced by the powder metallurgy method is only 1% to 5%, and high-purity products can be produced. In the process of mass production, the production line can also be strictly and accurately controlled, so that the size of powder metallurgy parts can achieve high precision and consistency.

Among them, powder molding is one of the main processes of powder metallurgy. Powder molding mold design is an important link in powder molding. It is related to the quality of powder metallurgy products and production costs, safety, productivity and automation. With the rapid development of powder molding technology in the fields of automobiles, home appliances, aerospace, light industry, etc., the rigidity, precision and complexity of powder metallurgy precision molding molds have also put forward higher requirements.

In the pressing process of powder molding, due to raw materials, part design, mold design, molding equipment tooling, mold assembly, pressing process, etc., defects in powder metallurgy pressed parts (green compacts) are caused, and powder metallurgy parts are eventually scrapped in batches. The common compact defects are: non-uniform compact density, delamination, cracks, dropped edges and corners, excessive burrs, surface scratches, and poor coaxiality. Defects are hard to prevent. Even products that have been produced for many years may have defects, which will lead to the scrapping of products in batches. These problems have plagued powder metallurgy products enterprises for a long time.

Most of the existing pressing molds are pressed up and down or left and right by a die-casting machine, so that the powder inside the pre-pressing mold is formed. The direction of pressure is determined by the die-casting machine, which is relatively single, and the pre-compression mold cannot realize pre-compression in other directions except the direction of pressure of the die-casting machine. Due to the one-way preloading of the die-casting machine, the sides of the slab cannot be compacted, which is not conducive to the discharge of air bubbles, and at the same time, the density of the slab is uneven and stratified.

Utility model content

In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a pre-pressing die for metal powder hot-pressed products, which can realize the self-locking pre-pressing of the die, so that the green compact of the pre-pressing die is in the direction of pressing the die-casting machine. It can be pressed in other directions and can be adjusted to obtain a high-quality compact with no bubbles and uniform quality.

In order to achieve the above purpose and other related purposes, the utility model provides a pre-pressing mold for metal powder hot-pressed products, including a mold frame, a backing plate and at least one set of pressure plates are arranged in the mold frame, and the backing plate is located on the side of the pressure plate. On the outside, each set of pressing plates includes an upper pressing plate and a lower pressing plate, a filling cavity is formed between the upper pressing plate and the lower pressing plate, and an adjusting clamping element is arranged between the backing plate and the mold frame. The filling cavity is filled with metal powder, and the top is pressed by the upper pressure plate through the external pressure equipment, and the side is pressed by adjusting the distance between the end of the clamping element and the backing plate, so that the side of the filling cavity is pressed tight. Through the pre-pressing die of the utility model, the templates are combined to form a filling cavity, and the metal powder is cold-pressed in the filling cavity, and the side is pressed by adjusting the clamping element to squeeze the template, and the upper part is pressed by the pressure equipment to squeeze out the filling cavity. Various bubble-forming bodies inside the molded product to obtain a compact with uniform quality and no delamination.

Preferably, the mold frame is a rectangular frame surrounded by four side plates. The pressure on the side is distributed to the mold frame. The mold frame is an integrated rigid structure, which clamps the internal pressure plate, backing plate and the following partitions, and will not be deformed due to the extrusion of fastening bolts and pressure equipment. Guarantee the shape and surface quality of the green compact.

Preferably, the adjusting clamping elements are arranged on two adjacent side plates of the mold frame. Two adjacent surfaces of the mold frame are evenly provided with adjusting clamping elements, and the adjusting clamping elements act on the corresponding two backing plates, and the remaining two backing plates are directly positioned by the inner wall of the mold frame. It is arranged in an adjacent position to ensure that the two directions of the packing cavity are squeezed and adjusted.

Preferably, the adjusting clamping element is composed of fastening bolts threaded on the mold frame. The adjusting clamping element cooperates with the mold frame through threads. The clamping element is adjusted by thread advancement, the structure is simple, the mechanical operation is convenient, and the advancement accuracy is also easy to control. Other controls can also be used to regulate the advancement of the clamping elements.

Preferably, there are at least two sets of the pressing plates, and adjacent pressing plates are separated by partitions. Due to the adjustability of the clamping elements, multiple groups of pressing plates can be installed in the mold frame, and according to the processing needs, multiple compacts can be pressed at the same time to improve the processing efficiency.

Preferably, the side of the packing chamber is surrounded by the upper pressing plate, the adjacent backing plate and (or) partition plate adjacent to the lower pressing plate.

Preferably, the upper end surface of the upper platen is higher than the upper end surface of the mold frame, the upper end surface of the backing plate and the upper end surface of the partition plate. Ensure that the upper surface of the upper platen is at the highest position of the mold after filling, so as to avoid the interference of other parts when the pressure equipment exerts pressure on the upper platen, making it impossible to process and damage the mold.

Preferably, a base plate is also included, and the mold frame is arranged on the base plate. The base plate is pre-set with positioning holes corresponding to the backing plate, partition plate and lower pressing block. The size of the holes is slightly larger than that of the pressing plate, which is convenient for position adjustment.

Preferably, the separator is made of high-quality carbon structural steel.

Preferably, the backing plate is made of cold-work die steel.

As mentioned above, adopting the pre-pressing mold of the metal powder hot-pressed product of the present invention has the following beneficial effects:

1. The metal powder is cold-pressed and formed by the pre-pressing die of the present invention, and various bubble-forming bodies inside the molding in the filler cavity are extruded.

2. The use of metal molds is convenient for repeated use, and multiple compacts can be pressed at the same time to improve processing efficiency.

3. The cold pressing process is used to save the consumption of the hot pressing mold and suppress the oxidation of the green compact.

Description of drawings

Fig. 1 is a structural schematic diagram of a pre-pressing mold according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a pre-pressing mold according to an embodiment of the present invention.

Fig. 3 is a working schematic diagram of the pre-pressing mold of the embodiment of the present invention.

Part number description

1- mold box,

11 - first side panel,

12 - second side panel,

13-Third side panel,

14- Fourth side panel,

2- fastening bolts,

3- Press against the plate,

31-first backing board,

32-second backing board,

33-third backboard,

34-the fourth backing board,

4-platen,

41-upper platen,

42-lower platen,

5- packing cavity,

6- partition,

7- Substrate.

Detailed ways

The implementation of the present utility model is illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification.

In order to describe the utility model in detail, first of all, the pre-pressing mold of the metal powder hot-pressed product of the utility model will be specifically described:

Referring to accompanying drawing 1, the prepressing mold of the present utility model comprises mold frame 1, and mold frame 1 comprises four side plates, is respectively first side plate 11, second side plate 12, the 3rd side plate 13 and the 4th side plate 14. Four side panels form a rectangular frame. Two of the adjacent side plates of the four side plates are provided with mounting holes, and the mounting holes are equipped with adjusting clamping elements. The adjusting clamping elements of this embodiment adopt fastening bolts 2, and the fastening bolts 2 are connected to the mold frame 1 through threads. In cooperation, other adjustable clamping elements that can be pushed in on the mold frame can also be used. The end of the fastening bolt 2 acts on the backing plate 3, and by rotating the fastening bolt 2, the end of the fastening bolt 2 exerts force on the backing plate 3 and presses the backing plate tightly. The first side plate 11 of the mold frame 1 of the present embodiment is provided with 4 fastening bolts arranged in the middle of the first side plate in a 2x2 pattern, and 6 fastening bolts are arranged on the fourth side plate 14 in a 2x3 pattern. arranged in the middle of the fourth side panel.

A template is provided in the mold frame 1, and the template includes a backing plate and a pressing plate. Among them, there are four backing boards 3 near the four side boards, namely the first backing board 31, the second backing board 32, the third backing board 33 (see Figure 2) and the fourth backing board 34. The four backing boards The boards are arranged parallel to the four side boards respectively, wherein the ends of the fastening bolts 2 on the first side board 11 act directly on the surface of the first backing board 31 . The ends of the fastening bolts 2 on the fourth side plate 14 directly act on the surface of the fourth backing plate 34 .

Referring to Fig. 2, at least one group of pressure plates 4 is arranged between the four backing plates, each group of pressure plates 4 includes an upper pressure plate 41 and a lower pressure plate 42, and an upper pressure plate 41 is arranged above the lower pressure plate 42, and a gap between the upper pressure plate 41 and the lower pressure plate 42 is provided. Filling cavity 5 is formed between them. When there are two or more groups of pressing plates 4, a partition 6 is provided between each group of pressing plates 4. In this embodiment, three groups of pressing plates are provided, and adjacent pressing plates 4 are separated by partitions 6 . Stuffing chamber 5 is made up of upper pressing plate 41, lower pressing plate 42, and upper pressing plate, adjacent backing plate 33 and dividing plate of lower pressing plate. Metal powder filler is extruded into this cavity.

Since the pre-pressing mold works under high pressure, the working surface of the mold is subject to severe powder friction, so the requirements for the mold material are strict. The choice of mold material is related to blank quality (density distribution, precision, surface finish, etc.), mold life, production safety, product or cost, productivity and other issues. Therefore, the main mold parts materials should meet the requirements of high strength, high hardness, high wear resistance, high stiffness and small thermal expansion coefficient, excellent heat treatment performance, certain toughness and good machinability, etc. The dividing plate 6 of this embodiment is made of high-quality carbon structural steel, and the backing plate 3 is made of cold-work die steel. The backing plate 3 has undergone vacuum quenching heat treatment, and the Rockwell hardness is between HRB 80-115. The mold frame 1, the upper briquetting block 41, the lower briquetting block 42, and the separator 6 have all been quenched and tempered, and the Rockwell hardness is between HRB 60-100.

Referring to accompanying drawing 3, use the technique of the pre-press mold of present embodiment:

1. Set the base plate 7. The base plate 7 is pre-set with positioning holes corresponding to the support plate 3, the partition plate 6, and the lower pressure block 41. The size of the holes is slightly larger than that of the pressure plate, which is convenient for position adjustment.

2. After positioning the backing plate 3, the lower pressing plate 41, and the partition 6, put the mold frame 1 on the outside, and tighten the fastening bolt 2 with a little force. Just check that there are no gaps in each part, and do not lock it completely yet.

3. After fully stirring the powder to be sintered, fill it into the filler cavity 5 and press it tightly.

4. Install the upper platen 42, and tighten the fastening bolts 2 completely.

5. Put the filled pre-pressing mold device on the base of the working position of the pre-pressing machine.

6. The pre-pressing machine starts to work, and the impact hammer 8 exerts a pressure of 40 to 60 tons downward on the upper pressing plate 42 in the mold frame 1 .

7. Decompression, release.

8. Repeat step 6, the impact hammer 8 applies a pressure of 40 to 60 tons downward to the upper platen 42 in the mold frame 1 .

9. Remove the mold frame 1, and the formed pre-pressed block is demoulded.

10. Put the demolded pre-pressed block into the graphite mold and sinter in the vacuum sintering furnace.

Through the pre-pressing mold of this embodiment, the metal powder can be pre-pressed before sintering, and the following beneficial effects can be obtained.

1. Use the pre-pressing mold of this embodiment to suppress the oxidation of the sintered body.

The metal powder body is pre-pressed by the pre-pressing die of this embodiment, and the bulk density, Rockwell hardness, bending strength and wear resistance of the formed body are all improved.

2. Effectively control the formation of air bubbles (pores).

In the original one-time hot pressing molding process, in order to make the sintered body have good light transmittance, the porosity in the hot pressing molding body must be minimized, but it is difficult to eliminate the gap between grains in the hot pressing molding process in the air. There are isolated pores in between. In order to prevent the oxidation of the sintered body, the method of atmosphere sintering can be selected.

Pre-pressing is carried out by the pre-pressing mold of this embodiment, and a dense hot-pressed molded body with uniform microstructure and effectively eliminated pores is prepared. Because it can reduce or even eliminate the remaining pores in the sintered body and heal surface cracks, thereby increasing the density and strength of the sintered product.

3. Improve the inhomogeneity of hardness distribution.

Due to the existence of internal pores in powder metallurgy parts, the effective bearing area is reduced, resulting in the uneven distribution of stress along the microstructure of the material.

The pre-pressing by the pre-pressing mold of this embodiment reduces the concentration of thermal stress during the simultaneous process of pressurization and heating during the hot-press forming process, and improves the inhomogeneity of hardness distribution.

The above-mentioned embodiments only illustrate the principles and effects of the present utility model, but are not intended to limit the present utility model. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the utility model should still be covered by the claims of the utility model.

Claims (9)

1. the pre-pressing die of the hot-forming goods of metal dust, it is characterized in that, comprise mould frame, backup plate and at least one group of pressing plate is provided with in mould frame, described backup plate is positioned at the outside of pressing plate, often organize pressing plate and comprise top board and lower platen, form packing cavity between described top board and lower platen, between described backup plate and mould frame, be provided with adjustment clamping element.

2. pre-pressing die according to claim 1, is characterized in that, described mould frame is the rectangle frame surrounded by four blocks of side plates.

3. pre-pressing die according to claim 2, is characterized in that, described adjustment clamping element is arranged in two pieces of adjacent side plates of mould frame.

4. pre-pressing die according to claim 1, is characterized in that, described pressing plate is provided with at least 2 groups, is isolated between adjacent pressing plates by dividing plate.

5. pre-pressing die according to claim 1, is characterized in that, described adjustment clamping element is made up of the fastening bolt be threaded on mould frame.

6. pre-pressing die according to claim 4, is characterized in that, the upper surface of described top board is higher than the upper surface of described mould frame, backup plate upper surface and dividing plate upper surface.

7. pre-pressing die according to claim 1, is characterized in that, also comprises substrate, and described mould frame is arranged on substrate.

8. pre-pressing die according to claim 4, is characterized in that, described dividing plate adopts high-quality carbon element structural steel to make.

9. pre-pressing die according to claim 1, is characterized in that, described backup plate adopts cold work die steel to make.