CN106825091A - The method and device therefor of a kind of continuous large plastometric set its application - Google Patents

Abstract

The invention relates to a method for continuous large plastic deformation, the equipment used and the application thereof, and belongs to the technical field of plastic processing and forming. In the present invention, the material to be processed with an equivalent diameter of d is continuously extruded into an extruded product with an equivalent diameter of D; the extruded product with an equivalent diameter of D is stretched to obtain a material to be processed with an equivalent diameter of d; then repeat Squeeze and stretch until the nominal cumulative strain reaches the set value. The invention has simple process and simple control, and the obtained product has excellent performance, and can be widely used in the industrial production of large-length, medium- and small-sized pipes, rods, profiles and wires.

Description

A method of continuous large plastic deformation and the equipment used and its application

technical field

The invention relates to a method for continuous large plastic deformation, the equipment used and the application thereof, and belongs to the technical field of plastic processing and forming.

Background technique

Studies have shown that: the large plastic deformation process can make metals and their alloys obtain sub-micron crystals, or even nano-crystals, thereby greatly improving the comprehensive properties of metal materials. In recent years, many novel large plastic deformation methods have been proposed and developed. In recent decades, the large plastic deformation (Severe plastic deformation, SPD), which has attracted much attention, can obtain extremely fine or even nanocrystalline structures for metals or alloys, thereby greatly improving Improving the mechanical properties of metal materials has been developed rapidly. Commonly used large plastic deformation techniques include equal radial angular extrusion (ECAP), repeated stack rolling (ARB), high pressure torsion (HPT), and multidirectional compression (MAC). With the rapid development of large plastic deformation, more combined and continuous large plastic deformation methods have been proposed, such as repeated extrusion-upsetting (REU), reciprocating extrusion-compression (CEC), repeated wrinkling-straightening ( RCS), continuous shearing (Conshearing), equal-diameter angular extrusion-continuous extrusion (ECAP-Conform), repeated continuous extrusion (R-Conform), etc. Although the ultrafine grains prepared by large plastic deformation can greatly increase the strength of the material, usually, part of the plasticity of the material will be sacrificed, and even the plasticity of the material will be greatly reduced. Therefore, how to ensure the plasticity and toughness of large-deformation fine-grained materials while improving the strength is still a problem to be solved. At present, materials obtained by annealing after low-temperature large deformation not only exhibit high plasticity, but also retain a certain strength.

At present, most of the large plastic deformation methods are in the experimental stage, even if some large plastic deformation methods have been applied to the actual industrial production process, but the scale is limited. Therefore, people are still trying to gradually advance the large plastic deformation method from the laboratory research stage to commercial application, indicating that this field urgently needs to continuously research and develop large plastic deformation process methods for commercial applications.

Contents of the invention

The invention provides a method for continuous large plastic deformation aiming at the shortcomings of existing large plastic deformation methods.

A kind of method of continuous large plastic deformation of the present invention, its embodiment is:

The material to be processed with an equivalent diameter of d1 is continuously extruded into an extruded product with an equivalent diameter of D1; the extruded product with an equivalent diameter of D1 is stretched to obtain a material to be processed with an equivalent diameter of d2; and then the equivalent diameter Continuously extrude the material to be processed with d2 to obtain an extruded product with an equivalent diameter of D2; stretch the extruded product with an equivalent diameter of D2 to obtain a material to be processed with an equivalent diameter of d3; The material to be processed is continuously extruded to obtain an extruded product with an equivalent diameter of Di, and the extruded product with an equivalent diameter of Di is stretched to obtain a material to be processed with an equivalent diameter of d(i+1), where i is Positive integer and greater than or equal to 2; repeat continuous extrusion-stretching until the finished product is obtained;

The D1 is greater than d1, and the D1 is greater than d2; the D2 is greater than d2, and the D2 is greater than d3; the Di is greater than di, and the Di is greater than d(i+1).

As a preferred scheme, said D1=D2=Di.

As a preferred solution, the d1=d2=di=d(i+1).

When D1=D2=Di, d1=d2=di=d(i+1), a cycle is defined; said one cycle is: continuous extrusion and stretching of the product obtained by this continuous extrusion; After the loop, the nominal cumulative strain is:

In Formula 1, n is the number of cycles, D=D1=D2=Di, d=d1=d2=di=d(i+1).

As a preferred solution, the i is selected from any integer in 2-10. More preferably, it is any integer of 3-5, and it is still more preferably 3 or 4.

In the present invention, the material to be processed with an equivalent diameter of d1 is continuously extruded into an extruded product with an equivalent diameter of D1; the extruded product with an equivalent diameter of D1 is stretched to obtain a material to be processed with an equivalent diameter of d2 ; At this time, n counts as 1.

The present invention proposes a cyclic continuous extrusion-stretching continuous large plastic deformation method, which includes continuously extruding a rod material with a diameter of d into an extruded product with a diameter of D (that is, D is greater than d) by using the expansion die technology, Then it is stretched into a wire with a diameter of d, and then the wire with a diameter of d is expanded and continuously extruded into a product with a diameter of D, so as to achieve continuous large plastic deformation.

In the present invention, when stretching an extruded product with an equivalent diameter of Di to obtain a material to be processed with an equivalent diameter of d(i+1), it can be directly stretched to d(i+1) at one time, or After multi-pass stretching to d(i+1).

As a preferred solution, Di/di=1.5-1.8, more preferably 1.55-1.6.

As a preferred solution, the ambient temperature of the continuous extrusion and stretching is room temperature.

The present invention is a continuous large plastic deformation equipment, the equipment includes a continuous extrusion device and a stretching device, the continuous extrusion device includes a feeding part, an extrusion part, a plug, and an extrusion die; the fed material After being extruded by the continuous extrusion device, an extruded product with a set equivalent diameter is obtained; the stretching device includes a stretching die; after the material is processed by the stretching device, a stretched product with a set equivalent diameter is obtained.

The invention is a device for continuous large plastic deformation, wherein the feeding part is a feeding wheel, and the extruding part is an extruding wheel.

The invention relates to continuous large plastic deformation equipment. The continuous extrusion device also includes a groove sealing block and a shoe body seat.

The invention is a continuous large plastic deformation equipment, the gap between the extrusion wheel and the groove sealing block is d.

The invention is a continuous large plastic deformation equipment. The material to be extruded is sent into the gap between the extrusion wheel and the groove sealing block through the feeding wheel, and is sent into the extrusion die through the extrusion wheel for extrusion. The plug Prevent the material to be extruded from being carried out by the extrusion wheel.

The application of the continuous large plastic deformation method of the present invention includes applying the method to at least one of pure aluminum, aluminum alloy, magnesium alloy and copper alloy. It is preferably pure aluminum or aluminum alloy.

In the application of a method for continuous large plastic deformation of the present invention, as a preferred solution, the aluminum alloy is selected from at least one of 1XXX, 3XXX and 5XXX aluminum alloys.

For the convenience of industrial application, in the present invention, D=D1=D2=Di, d=d1=d2=di=d(i+1).

Principles and advantages

Conform continuous extrusion has special deformation thermodynamic conditions. As the metal continues to enter the deformation zone, its deformation temperature will gradually increase due to the joint action of plastic deformation heat and friction heat, and there is an intense shear band (Intense Internal Shear) in the deformation zone. Band, IISB), IISB can not only improve the uniformity of deformation but also improve the plastic processing performance of metals. At the same time, during the continuous extrusion process, the alloy undergoes strong shear deformation, resulting in a large number of dislocations and dislocation entanglements, forming a subgrain structure with a small orientation difference; as the degree of deformation increases, the temperature of the alloy increases, The occurrence of dynamic recrystallization is promoted, and the small-angle grain boundaries grow into high-angle grain boundaries by absorbing dislocations, etc., so that the subgrains gradually transform into fine and uniform equiaxed grains, effectively improving the overall performance of the material. Using computer simulation technology to study the temperature field of the continuous extrusion forming process, it is shown that the temperature field of the deformed body and the mold is constantly changing due to the frictional heat and deformation heat while the deformed body is plastically deformed. The temperature of the billet rises from 20°C at the entrance to 400-500°C at the exit, and the temperature reaches a higher level when extruding the copper alloy, and the temperature of the deformed body increases with the increase of the extrusion wheel speed.

Drawing can achieve a certain amount of cold deformation. During this process, the alloy undergoes work hardening, the strength increases and the plasticity decreases. Usually, a large plastic deformation is achieved through an intermediate annealing process.

The microstructure refinement mechanism of large plastic deformation is that a large number of dislocations are generated with the increase of deformation, and the dislocations interact to form high-angle grain boundaries, so that strain induces continuous dynamic recrystallization and grain refinement. Therefore, large plastic deformation is usually performed at room temperature. However, the plasticity of the material at room temperature is poor, and it is often prone to large work hardening or fracture, and the structure is extremely unstable after deformation. Therefore, the present invention cleverly combines large plastic deformation with heat treatment to improve material performance. In the present invention, through suitable tooling and mold design, the cross-sectional size of the material can be increased after continuous extrusion, and can be deformed to the original size after subsequent stretching deformation, so that large plastic deformation can be realized continuously and the material is improved. performance.

The present invention has the following advantages

(1) It is a simple and feasible continuous large plastic deformation method, which can be widely used in the production of large-length and medium-sized and small-sized pipes, rods, profiles, and wires;

(2) The structure and performance of the product are uniform;

(3) Cold and hot deformation are carried out alternately, and continuous extrusion can be used to perform dynamic annealing or aging treatment on drawing cold deformation;

(4) Extruded or drawn products after different passes can be obtained respectively.

Description of drawings

Accompanying drawing 1 is the structure of the equipment designed by the present invention and schematic diagram of process principle.

detailed description:

Example 1

First, the continuous casting and rolling 1050 aluminum alloy disc rod material with a diameter of d = 9.5mm is continuously extruded into an extruded product with a diameter of D = 15mm by using the expansion die technology, the extrusion wheel speed is 22rpm, and the extrusion outlet temperature The temperature is 460°C, and the die outlet is 1500mm into the water tank for cooling, drying, and winding; then, the extruded product with a diameter of D = 15mm is drawn into a wire rod with a diameter of d = 9.5mm after 8 passes; The surface of the drawn wire rod with a diameter of d=9.5mm is cleaned, rinsed and dried, and then continuously extruded under the same conditions into an extruded product with a diameter of D=15mm by using the expanding die technology. After 4 cycles like this, the tensile mechanical properties of the 1050 aluminum alloy after continuous extrusion and drawing of each pass were measured respectively. The results are shown in Table 1. It can be seen that the mechanical properties have been significantly improved.

Table 1 Tensile mechanical properties of 1050 aluminum alloy after n cycles of continuous extrusion and drawing

Claims (10)

1. a kind of method of continuous large plastometric set, it is characterised in that：

By equivalent diameter for the material to be processed of d1 is the extruded product of D1 by being continuously extruded into equivalent diameter；To equivalent diameter For the extruded product of D1 is stretched, the material to be processed that equivalent diameter is d2 is obtained；Then it is the to be added of d2 to equivalent diameter Work material carry out it is continuously extruded, obtain equivalent diameter be D2 extruded product；To equivalent diameter for the extruded product of D2 draws Stretch, obtain the material to be processed that equivalent diameter is d3；To equivalent diameter for the material to be processed of di carries out continuously extruded, worked as The extruded product of a diameter of Di is measured, to equivalent diameter for the extruded product of Di is stretched, it is d's (i+1) to obtain equivalent diameter Material to be processed, the i is for positive integer and more than or equal to 2；Continuously extruded-stretching is repeated until obtaining finished product；

The D1 is more than d1, and the D1 is more than d2；The D2 is more than d2, and the D2 is more than d3；The Di is more than di, and the Di is big In d (i+1).

2. the method for a kind of continuous large plastometric set according to claim 1, it is characterised in that：The D1=D2=Di.

3. the method for a kind of continuous large plastometric set according to claim 1, it is characterised in that：The d1=d2=di= d(i+1)。

4. the method for a kind of continuous large plastometric set according to claim 1, it is characterised in that：Work as D1=D2=Di, d1 During=d2=di=d (i+1), a circulation is defined；One circulation is：It is continuously extruded and to this continuously extruded gained Product is stretched；After being circulated through n, nominal accumulation strain amount is：

${\mathrm{\ϵ}}_n=4nln\frac{D}{d}---\left(1\right)$

In formula 1, n is cycle-index, D=D1=D2=Di, d=d1=d2=di=d (i+1).

5. the method for a kind of continuous large plastometric set according to claim 4, it is characterised in that：The i is selected from 2-10 Any one integer.

6. the method for a kind of continuous large plastometric set according to claim 1, it is characterised in that：Described continuously extruded and drawing The environment temperature stretched is room temperature.

7. the equipment used by a kind of method of continuous large plastometric set as claimed in any one of claims 1 to 6, it is characterised in that： The equipment includes continuous extrusion device and stretching device, and the continuous extrusion device includes charging part, extruder member, blocks up Head, extrusion die；After the material sent into is extruded through continuous extrusion device, obtain setting the extruded product of equivalent diameter；The stretching Device includes stretching die；After the treatment of material drawn device, obtain setting the elongated article of equivalent diameter.

8. the equipment of a kind of continuous large plastometric set according to claim 7, it is characterised in that：The charging part is to add Material wheel, the extruder member is extruding wheel；

The continuous extrusion device also includes sealing groove block and boots housing；

Gap between the extruding wheel and sealing groove block is d.

9. the equipment of a kind of continuous large plastometric set according to claim 8, it is characterised in that：Material to be extruded is through charging Gap between wheel feeding extruding wheel and sealing groove block, through being extruded in extruding wheel feeding extrusion die, the plug prevents to wait to squeeze Pressure material is extruded wheel and takes out of.

10. a kind of application of the method for continuous large plastometric set as claimed in any one of claims 1 to 6, it is characterised in that：Bag Include at least one that methods described is used in fine aluminium, aluminium alloy, magnesium alloy, copper alloy.