CN115815494A - Radial forging method for aluminum-based composite material - Google Patents

Abstract

The invention discloses a radial forging method of an aluminum-based composite material, and belongs to the field of metal material processing. The method comprises the following steps: placing the aluminum-based composite material blank in a heating furnace, heating to 350-500 ℃ along with the furnace, preserving heat for 6-16 hours, transferring the blank to a radial forging machine for radial forging, turning around the blank, forging the unforged blank, immediately transferring the aluminum-based composite material blank to the heating furnace at 350-500 ℃ for preserving heat for 6-16 hours, and repeating the steps S2 and S3 until the blank is forged to the required diameter. The invention adopts a radial forging method with small deformation and multiple deformations to realize similar extrusion effect, accurate control of the diameter of the blank and uniform distribution of the deformation and the microstructure in the radial direction of the blank, effectively improves the uniformity of the structure and the stability of the product performance, and can realize high-quality, high-productivity and low-cost preparation of the aluminum matrix composite bar when being used for the aluminum matrix composite.

Description

A kind of radial forging method of aluminum matrix composite material

technical field

The invention belongs to the field of metal material processing, and in particular relates to a radial forging method of an aluminum-based composite material.

Background technique

The aluminum matrix composite material is obtained by adding hard ceramic particles to the aluminum alloy, so that it has the advantages of both aluminum alloy and ceramics, and integrates high specific strength, high specific stiffness, corrosion resistance and other excellent properties. The field has broad application prospects. The introduction of ceramic particles leads to the inhibition of the plastic flow of the aluminum matrix composite material during the deformation, the increase of the deformation resistance, and the defects such as cracks and wrinkles are prone to appear during the processing. Traditionally, extrusion is often used to process aluminum matrix composites, but the effect is not ideal. The main problems are: 1) long extrusion time and low production efficiency; 3) the surface quality of extruded products is rough, requiring follow-up Multiple surface processing; 2) The extrusion head is easy to crack, and there is residual material at the tail that cannot be extruded completely. When using, it is necessary to cut off the head and tail parts, wasting some materials, and the material utilization rate is not high; 4) The deformation of the billet during the extrusion process is seriously uneven , resulting in severe uneven distribution of microstructure characteristics such as grain size, particle dispersion degree, and crystal orientation of the aluminum-based composite material after extrusion, and coarse-grained rings are easily formed on the extrusion cross-section, which affects the uniformity of the performance and quality of the final product. stability.

To sum up, in the field of aluminum-based composite material processing, the existing technology cannot achieve the goals of high production efficiency, high material utilization rate, and stable product performance. For this reason, the present invention proposes a radial forging method of an aluminum-based composite material.

Contents of the invention

In order to solve the deficiencies of the prior art, the object of the present invention is to provide a radial forging method for aluminum matrix composite materials, which provides technical support for realizing high-quality and high-efficiency processing of aluminum matrix composite material rods.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A radial forging method for an aluminum-based composite material provided by the present invention comprises the following steps:

S1: Place the aluminum-based composite billet in a heating furnace and keep it warm at 350-500°C for 6-16 hours to fully heat and soften the billet, reduce deformation resistance, avoid cracking during forging, and prepare for forging; heating temperature If it is too low, it will lead to high hardness of the billet, weak deformation ability, and easy cracking during forging; if the heating temperature is too high, it will cause the melting of the eutectic phase of the billet, resulting in defects; It cannot be deformed uniformly; if the heat preservation time is too long, it will cause waste of energy and time;

S2: Transfer the fully heated and softened aluminum-based composite billet to the radial forging machine with mechanical clamps, perform radial forging on the billet, then turn the billet around, and forge the unforged billet, the first fire forging diameter The radial feed rate is 3-8mm; the radial feed rate of the first fire forging is too large, which will cause the deformation of the surface layer of the billet to be larger than that of the core, and it is easy to form a fine-grained layer and cracks in the subsequent forging; small deformation The amount makes the billet deform uniformly, and the microstructure and properties are evenly distributed in the cross section of the bar.

It is conducive to the subsequent acquisition of products with stable performance and stable and controllable quality;

S3: After the first fire forging is completed, immediately transfer the aluminum matrix composite material billet to a heating furnace that has been heated in advance to 350-500°C for heat preservation to achieve the purpose of recovering defects and softening the billet; after forging, the temperature in some areas of the billet will After forging, a large number of dislocations and other defects will be formed in the microstructure of the billet, which will reduce the deformation ability of the billet. Heating and heat preservation is required to reduce the defect density and stress concentration, improve the deformation ability, and prepare for subsequent forging;

S4: Repeat steps S2 and S3 to forge the billet to the desired diameter, air-cool, and end; the radial feed rate of each subsequent fire forging is increased by 5-10 mm compared with the first fire; the radial feed rate of each fire is The feed rate is gradually increased, compared with the fixed radial feed rate, it can save forging time and forging fire times, and improve production efficiency; the holding time of each subsequent fire is 2 to 8 hours longer than that of the first fire; As the number of forging fires increases, the cumulative deformation of the billet gradually increases, and the deformation of the microstructure becomes more serious. It is necessary to increase the holding time to recover defects such as dislocations in the microstructure, so as to obtain a billet with uniform distribution of microstructure and properties; repeat steps S2 and S3, the diameter of the billet is continuously reduced, without the need for multiple molds, which saves production costs; in the traditional extrusion method, the diameter of the billet is strictly limited by the size of the die, and each pair of dies can only process billets of one diameter, which is expensive.

The above-mentioned radial forging method of the aluminum-based composite material of the present invention adopts a radial forging method with small deformation and multiple deformations, including multiple heating and heat preservation of the aluminum-based composite material blank and multiple "radial forging-turning-radial forging" Steps to achieve a similar extrusion effect, that is, the shrinkage of the billet in the radial direction and the elongation in the axial direction; by controlling the deformation parameters such as the forging temperature and the radial feed of the hammer head, the precise control of the billet diameter, as well as the amount of deformation and the apparent The uniform distribution of the microstructure in the radial direction of the blank avoids defects such as coarse crystal rings, uneven performance, and head cracks that are prone to occur during the extrusion process, and effectively improves the uniformity of the structure and the stability of product performance.

Preferably, in step S2 and repeating step S2, during forging, infrared thermometers are used to monitor the temperature at 2 to 6 points of the blank, and the temperature measurement points are symmetrically distributed in the radial direction and equally spaced in the axial direction; in traditional forging Using a single point to monitor the temperature of the billet cannot accurately control the temperature change. Using multi-point temperature monitoring can obtain a more accurate temperature change of the billet; the temperature rise of the billet during the radial forging process is less than 30°C, and the temperature rise is too large to cause the billet to overburn , resulting in void defects; the temperature drop must be less than 40°C, excessive temperature drop will result in increased deformation resistance, reduced deformation capacity, and easy cracking.

As a preference, the axial feeding speed of the billet during the radial forging process is 10-50 mm/s. If the axial feeding speed is too high, the billet cannot be completely forged. If the axial feeding speed is too low, the forging time will be prolonged and the billet will be lost. If the temperature range increases, it is easy to crack; the rotation speed of the billet is 20-60r/min, if the rotation speed is too fast or too slow, the billet will be repeatedly forged and folded easily.

As a preference, the transfer time of the blank from the heating furnace to the radial forging machine is less than 300s, and the inside of the transfer mechanical clamp is covered with a refractory cotton cushion to avoid scratching the surface of the blank during the process of clamping the blank.

Preferably, the heating furnace is a muffle furnace or an induction heating furnace, and the furnace temperature control accuracy is ±5°C within the range of 300-550°C.

Compared with the prior art, the present invention applies the radial forging method to the aluminum-based composite material to realize high-quality, high-productivity, and low-cost preparation of the aluminum-based composite material bar. In the radial forging method provided by the invention, only a small amount of cutting is required at the head and tail of the bar after processing, and the material utilization rate is improved; in the extrusion method, the head of the billet is easy to burst, but the tail cannot be completely extruded, wasting a lot of material.

Description of drawings

Fig. 1 is a scanning electron microscope picture of the microstructure of the aluminum matrix composite material after radial forging in the embodiment.

Detailed ways

The invention provides a radial forging method of an aluminum-based composite material, which provides technical support for realizing high-quality and high-efficiency processing of aluminum-based composite material rods.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

A radial forging method for an aluminum-based composite material is provided in the following embodiments, including the following steps:

S1: Place the aluminum-based composite material billet in a heating furnace with a heating rate of 5-15°C/min, and raise the temperature to 350-500°C with the furnace, and keep it warm for 6-16 hours;

S2: Transfer the aluminum matrix composite material billet to the radial forging machine, perform radial forging on the billet, then turn the billet around, and forge the unforged billet;

S3: Immediately after the first fire forging is completed, the aluminum-based composite material billet is transferred to a heating furnace that has been heated in advance to 350-500°C, and kept for 6-16 hours;

S4: Steps S2 and S3 are repeated until the billet is forged to the desired diameter, air-cooled, and finished.

Specifically, the forging radial feed rate for the first fire is 3-8 mm, the radial feed rate for each subsequent fire is 5-10 mm higher than that of the first fire, and the holding time is 2 mm longer than that of the first fire. ~8 hours.

Specifically, during the forging process, infrared thermometers are used to monitor the temperature of 2 to 6 points of the billet. The temperature measurement points are symmetrically distributed in the radial direction and equally spaced in the axial direction. The temperature rise of the billet during the radial forging process is less than 30°C , the temperature drop is less than 40°C.

Specifically, during the radial forging process, the axial feed speed of the blank is 10-50 mm/s, and the rotation speed of the blank is 20-60 r/min.

Specifically, the time for the billet to be transferred from the heating furnace to the radial forging machine is less than 300s, and the inner side of the transfer mechanical clamp is covered with a refractory cotton cushion.

Specifically, the heating furnace is a muffle furnace or an induction heating furnace, and the furnace temperature control accuracy is ±5°C within the range of 300-550°C.

Example 1

Place the aluminum matrix composite material billet in the heating furnace with a heating rate of 10°C/min, raise the temperature to 400°C with the furnace, and keep it for 12 hours; then transfer the aluminum matrix composite material billet to the radial forging machine, the transfer time is 180s, The inner side of the clamp is covered with a refractory cotton cushion; set the radial feed rate to 3mm, carry out radial forging on the billet, and then turn the billet around to forge the unforged billet.

After the first fire forging is completed, the aluminum matrix composite material billet is immediately transferred to a heating furnace that has been heated in advance to 400°C and kept for 6 hours.

After the heat preservation is over, transfer the billet to the radial forging machine, set the radial feed rate to 9mm, perform the second fire forging, and then turn the billet around to forge the unforged billet.

After the second fire forging is completed, the aluminum matrix composite material billet is immediately transferred to a heating furnace that has been heated in advance to 400°C and kept for 10 hours.

After the heat preservation is over, transfer the billet to the radial forging machine, set the radial feed rate to 16mm, perform the third fire forging, then turn the billet around, and forge the unforged billet. After the forging is completed, it is air-cooled and finished.

During the forging process, the axial feeding speed is 20mm/s, and the billet rotation speed is 10r/min. The infrared thermometer is used to monitor the temperature at 4 points of the billet. The temperature measuring points are symmetrically distributed in the radial direction and equidistant in the axial direction. Distribution, during the radial forging process, the temperature rise of the billet is less than 30°C, and the temperature drop is less than 40°C; the heating furnace used in the forging process is a muffle furnace, and the furnace temperature control accuracy is ±5°C within the range of 300-550°C.

Five samples were taken from the center to the edge of the aluminum-based composite bar forged in this example at the same distance for testing. The sample numbers are A, B, C, D, and E in sequence. The scanning electron microscope picture of the microstructure of the aluminum matrix composite after radial forging is shown in Figure 1.

Table 1: Axial Room Temperature Mechanical Properties of Forged Bars in Example 1

Sampling position Tensile strength/MPa Yield strength/MPa Elongation after break/% Elastic modulus/GPa A 590 520 11.1 76 B 597 529 10.5 76 C 595 523 10.7 77 D. 596 525 11.3 78 E. 592 527 11.0 77

Example 2

Place the aluminum matrix composite billet in a heating furnace with a heating rate of 8°C/min, raise the temperature to 350°C with the furnace, and keep it warm for 6 hours; then transfer the aluminum matrix composite billet to the radial forging machine, the transfer time is 240s, the transfer machine The inner side of the clamp is covered with a refractory cotton cushion; set the radial feed rate to 8mm, carry out radial forging on the billet, and then turn the billet around to forge the unforged billet.

Immediately after the first fire forging is completed, the aluminum-based composite material billet is transferred to a heating furnace that has been heated in advance to 350°C and kept for 8 hours.

After heat preservation, transfer the billet to the radial forging machine, set the radial feed rate to 13mm, carry out the second fire forging, then turn the billet around, and forge the unforged billet.

After the second fire forging is completed, the aluminum matrix composite material billet is immediately transferred to a heating furnace that has been heated to 350°C in advance and kept for 12 hours.

After the heat preservation is over, transfer the billet to the radial forging machine, set the radial feed rate to 18mm, perform the third fire forging, then turn the billet around, and forge the unforged billet. After the forging is completed, it is air-cooled and finished.

During the forging process, the axial feeding speed is 10mm/s, and the billet rotation speed is 60r/min. Two points of the billet are monitored by infrared thermometers, and the temperature measuring points are distributed at equal intervals in the axial direction. The heating range of the middle billet is less than 30°C, and the cooling range is less than 40°C. The heating furnace used in the forging process is a muffle furnace, within the range of 300-550 °C, the furnace temperature control accuracy is ±5 °C.

Five samples were taken from the center to the edge of the forged aluminum-based composite bar in this example at the same distance for testing. The sample numbers were A, B, C, D, and E in turn. Show.

Table 2: Axial Room Temperature Mechanical Properties of Forged Bars in Example 2

Sampling position Tensile strength/MPa Yield strength/MPa Elongation after break/% Elastic modulus/GPa A 610 540 11.0 77 B 608 539 10.5 76 C 605 543 10.0 78 D. 615 545 11.3 78 E. 612 537 11.2 77

Example 3

Place the aluminum matrix composite billet in a heating furnace with a heating rate of 15°C/min, raise the temperature to 500°C with the furnace, and keep it warm for 16 hours; then transfer the aluminum matrix composite billet to a radial forging machine, the transfer time is less than 300s, transfer The inner side of the mechanical clamp is covered with a refractory cotton cushion; set the radial feed rate to 6mm, carry out radial forging on the billet, and then turn the billet around to forge the unforged billet.

Immediately after the first fire forging is completed, the aluminum-based composite material billet is transferred to a heating furnace that has been heated in advance to 500°C and kept for 16 hours.

After heat preservation, transfer the billet to the radial forging machine, set the radial feed rate to 16mm, carry out the second fire forging, then turn the billet around, and forge the unforged billet.

After the second fire forging is completed, the aluminum matrix composite material billet is immediately transferred to a heating furnace that has been heated to 500°C in advance and kept for 24 hours.

After the heat preservation is over, transfer the billet to the radial forging machine, set the radial feed rate to 26mm, perform the third fire forging, then turn the billet around, and forge the unforged billet. After the forging is completed, it is air-cooled and finished.

During the forging process, the axial feeding speed is 50mm/s, and the billet rotation speed is 40r/min. The temperature is monitored by infrared thermometers at 6 points of the billet. The temperature measurement points are symmetrically distributed in the radial direction and equidistant in the axial direction. Distribution, during the radial forging process, the temperature rise of the billet is less than 30°C, and the temperature drop is less than 40°C. The heating furnace used in the forging process is an induction heating furnace, and the furnace temperature control accuracy is ±5°C within the range of 300-550°C.

Five samples were taken from the center to the edge of the aluminum-based composite bar forged in this embodiment at the same distance for testing. The sample numbers are A, B, C, D, and E in turn, and their axial performance data are shown in Table 3. Show.

Table 3: Axial Room Temperature Mechanical Properties of Forged Bars in Example 3

Sampling position Tensile strength/MPa Yield strength/MPa Elongation after break/% Elastic modulus/GPa A 635 553 9.4 79 B 631 559 9.3 78 C 637 555 9.0 77 D. 634 550 10.0 78 E. 632 552 9.5 77

The above description of the embodiments is for those of ordinary skill in the art to understand and use the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the principles of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (6)

1. The radial forging method of the aluminum-based composite material is characterized by comprising the following steps of:

s1: placing the aluminum-based composite material blank in a heating furnace, heating the blank to 350-500 ℃ along with the furnace at the heating rate of 5-15 ℃/min, and keeping the temperature for 6-16 hours;

s2: transferring the aluminum-based composite material blank to a radial forging machine, carrying out radial forging on the blank, turning the blank around, and forging the unforged blank, namely carrying out first-time forging;

s3: after the first hot forging is finished, immediately transferring the aluminum-based composite material blank into a heating furnace at 350-500 ℃, and preserving heat for 6-16 hours;

s4: and (5) repeating the steps S2 and S3 until the blank is forged to the required diameter, cooling in air and finishing.

2. The radial forging method of the aluminum-based composite material as recited in claim 1, wherein the radial feed of the first hot forging is 3-8 mm, the radial feed of each subsequent hot forging is increased by 5-10 mm compared with the first hot forging, and the holding time is increased by 2-8 hours compared with the first hot forging.

3. The radial forging method of the aluminum-based composite material as claimed in claim 1, wherein 2-6 points of the blank are monitored for temperature by an infrared thermometer in the radial forging process, the temperature measuring points are symmetrically distributed in the radial direction and are distributed at equal intervals in the axial direction, and the temperature rise amplitude of the blank is less than 30 ℃ and the temperature drop amplitude of the blank is less than 40 ℃ in the radial forging process.

4. The radial forging method of aluminum matrix composite according to claim 1, wherein the axial feeding speed of the billet during the radial forging is 10-50 mm/s, and the rotating speed of the billet is 20-60 r/min.

5. The aluminum matrix composite radial forging method as recited in claim 1, wherein the time for transferring the billet from the heating furnace to the radial forging machine is less than 300s, and the inside of the transferring mechanical clamp is covered with a refractory cotton cushion.

6. The radial forging method of aluminum matrix composite according to claim 1, wherein the heating furnace is a muffle furnace or an induction heating furnace, and the furnace temperature control precision is ± 5 ℃ within the range of 300-550 ℃.

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