KR101580975B1

KR101580975B1 - Continuous extrusion apparatus and method for metal

Info

Publication number: KR101580975B1
Application number: KR1020150157146A
Authority: KR
Inventors: 구제율
Original assignee: 구제율
Priority date: 2015-11-10
Filing date: 2015-11-10
Publication date: 2015-12-31

Abstract

The present invention relates to an apparatus and a method for continuous extrusion of metal, and more particularly, to a method of continuously extruding a metal by applying a continuous extrusion process to a rigid forming process, thereby producing a high quality extruded product having a high productivity and excellent grain refinement efficiency, , The shape and the cross-sectional area of the raw materials to be charged, the charging temperature range, and the position and shape of the continuous extruder die chamber are changed to apply extreme plastic deformation to the material and the product and to precisely control the temperature of the material and the product, The present invention relates to a continuous extrusion apparatus for a metal capable of producing a high-quality extruded product with excellent efficiency.

Description

[0001] Continuous extrusion apparatus and method for metal [0002]

The present invention relates to an apparatus and a method for continuous extrusion of metal, and more particularly, to a method of continuously extruding a metal by applying a continuous extrusion process to a rigid forming process, thereby producing a high quality extruded product having a high productivity and excellent grain refinement efficiency, , Extrusion temperature range, and the position and shape of the continuous extruder dice chambers are changed to apply extreme plastic deformation to materials and products, and high-quality extrusion with excellent grain refining efficiency due to high productivity through precise temperature control The present invention relates to a continuous metal extrusion apparatus capable of producing a product.

The technique of simultaneously improving strength and toughness in metal materials is one of the ultimate research goals.

Traditional metal strengthening mechanisms generally reduce toughness when strength is improved.

Grain refinement of a metal is one of very useful methods for improving mechanical properties such as strength and toughness of a metal material. However, when the existing plastic working method such as extrusion, forging, and rolling is applied for grain refinement, the thickness and the cross-sectional area of the material decrease with the increase of the processing amount, and the predetermined strain energy (strain energy U = V × σ × ε, It is impossible to miniaturize the grain size of the material to be less than microns (탆) because there is a limitation in accumulating V: volume, σ: stress and ε: strain.

Severe Plastic Deformation (SPD), which is a typical method for refining the crystal grains of metals, is a processing technique that enables finer grain refinement by applying extreme plastic deformation to the material compared with general plastic forming.

Conventional grain refinement techniques include thermo-mechanical processing, mechanical alloying, rapid solidification, and recrystallization of amorphous powders, but it is difficult to produce a sufficient amount of bulk and a considerable amount And the porosity of the material is present. Therefore, it is difficult to apply to mass production. The Jiangsu process is a method of refining the crystal grains in the material by applying a large amount of plastic deformation to the metal material, and it can be applied to most metals, and a relatively large material can be produced without any defects therein. In the Jiangsu process, since the cross-sectional area of the material does not change after the process, it is possible to refine the crystal grains by accumulating strain energy to a desired level through repeated processing.

The Jiangsu process uses an apparatus and a method designed to add a lot of plastic deformation without changing the initial shape. The Jiangsu process can be classified into intermittent batch type processing and continuous processing according to characteristics of the manufacturing process.

1A is a diagram illustrating a conventional batch type and continuous processing techniques. Referring to FIG. 1A, a batch type processing technique is shown in FIG. 1A, (ECT), equal channel angular extrusion (ECAE), high pressure torsion (HPT), cyclic extrusion compression (CEC), and multi directional forging (MDF) Processing techniques include accumulative roll bonding (ARB), repetitive corrugation straightening (RCS), and shear rolling (SR).

And there is ECAP-Conform method, which is a modification of a continuous conforming machine, such as an isostatic pressing (ECAP) process.

The above-mentioned rigorous processing methods are difficult to serialize by the intermittent process, and it is impossible to manufacture large-sized materials even though it is necessary to repeatedly process them. In the continuous process, the shape of the product is limited to the plate material and the edge and surface cracks Production, commercialization and production due to low productivity and high production cost due to many problems such as generation of unevenness of grain size, non-uniformity of grain refinement according to a change in thickness, and processing for securing bonding property of an overlapping surface.

In order to solve the above-mentioned problems, the effect of the rigid processing is achieved through a continuous conforming machine which is used for continuous extrusion of aluminum and copper products.

2A shows a structure of a conventional continuous extruder. Referring to FIG. 2A, a conform continuous extrusion forming process by a continuous conforming machine is described in D. Green, And is the only continuous extrusion method which is applied in mass production in the present industrial field. Aluminum, copper, magnesium, titanium, etc., and has high economical efficiency in products such as pipe and tube for air-conditioning which have small sectional area or thin thickness. The principle of conform extrusion is that when a coining roll pushes a feedstock of the same shape and dimensions into a continuous rotating wheel with a groove, the shoe block and extrusion The abutment is prevented from coming out of the wheel due to the rotating force and the frictional force of the wheel while the wheel is tightly fitted into the groove of the wheel so that the end face of the wheel groove and the inlet side face of the dies chamber are not subjected to isostatic extrusion (ECAP / E), each of the passages is intersected with an intersecting angle (?) Of 90 degrees, the material is filled in the die chamber by severe shear deformation, and extrusion is continuously performed through the extrusion die. Figures 2a and 2b are schematic diagrams of a conform continuous extruder. The superiority of the consecutive continuous extrusion process is that the product of long length (desired length), which does not need to heat the material, can save energy and is excellent in productivity efficiency and homogeneity with high extrusion ratio, It can be produced.

At present, the continuous continuous casting and rolling process is used for the continuous casting and pressing process. In the case of aluminum, the diameter of the wire rod is mainly 9.5 mm, I never do that. Therefore, in order to solve the problem that the size (cross-sectional area) of the product to be produced is limited and the cost of the raw material increases, the inventor of the present invention continuously casts the cast bar produced in the continuous casting process into the continuous casting extruder, (Patent No. 10-1392178) for a manufacturing method and apparatus.

This conform continuous extrusion process is known to break down grains in cast state and homogenize the tissue homogeneously, which is reported to occur histologically, primarily during the isometric extrusion (ECAP / E) process.

The inventor of the present invention has proposed a method and an apparatus for producing a product having a finer structure than a product manufactured by continuous casting and continuous extrusion of the extruded material for forging as a continuous process by a conventional extrusion and casting process as described above, The registered patent is to continuously produce the product without deforming the shape and the cross-sectional area of the feedstock supplied to the continuous extruder and the charging temperature range and the part of the device, and to manufacture a product having a grain refinement of micron or less It is difficult to do.

Previous studies on grain refinement using the ECAP / E process have theoretically proved to be advantageous to apply large deformation at once, rather than repeatedly applying small deformation.

The back pass angular extrusion (ECAP / E) process has the same cross-sectional area as shown in FIG.

(Φ) and the curvature angle (Ψ) at the intersection of the two channels at the intersection where the two channels meet. The material is pressed (extruded) through a die having two channels A simple shear deformation is given.

This process is an iterative process that does not involve reduction of the cross-sectional area of the workpiece even if the amount of work is increased. Therefore, it is possible to accumulate a high strain energy in the material, thereby achieving grain refinement.

However, even if the ECAP / E process is used, since the process must be repeated about 8 times in order to obtain the submicron level of grains, the productivity is lowered and the time and cost are excessively required.

Recent studies have shown that to produce ultra fine grains of equiaxial grains divided by high angle boundaries and to increase the grain refinement efficiency, The results were reported to be more efficient. In order to efficiently produce ultrafine crystal grains through the Jiangsu process, it is necessary to increase the amount of plastic deformation applied in one process and minimize the number of iterations to accumulate uniform plastic deformation of the material.

Recently, a half channel angular extrusion (HCAE) process, which integrates the ECAP / E process and the front extrusion process, has been proposed to maximize the amount of plastic deformation applied in one Jiangsu process, It was confirmed that plastic deformation amount of 2.5 or more can be applied to the material in the pouring process.

This is an increase of more than 100% compared with the plastic deformation that can be done in the ECAP / E process, and the grain refinement effect obtained by the four or more back passageway extrusion processes can be obtained by one extrusion process .

FIGS. 3 and 4 are diagrams showing the cylinder extruding process. Referring to FIGS. 3 and 4, the cylinder extruding process increases the amount of plastic deformation applied to a workpiece in one machining process, In order to generate the shear deformation, shear deformation in the extrusion process and the tensile deformation in the extrusion process are combined with the conventional shear deformation due to the intersection angle, .

The HCAE process has two channels intersecting at a constant crossing angle? As in the ECAP / E process, but the cross-sectional area of the exit channel decreases with a constant extrusion angle? Therefore, the cross-sectional area of the material subjected to the one-time processing becomes 1/2. Since the cross-sectional shape of the material changes, in order to perform the repeated processing in each extrusion step by the cylinder, two materials having undergone the first molding as shown in Fig. 4 are simultaneously placed in the inlet channel to advance the second molding, And an extrusion process is performed. Generally, the possible processing routes in the back channel extrusion process are known to be four, depending on the direction of rotation of the specimen in the extrusion direction. The path A applies the iterative process as it is without rotating the material. The path Ba rotates the specimen ± 90 ° around the extrusion direction during re-machining. The path Bc rotates the specimen 90 ° in the same direction and repeats the process. , And the path C rotates the specimen 180 °, and repeats the process.

Since the width of the material is reduced to 1/2 after each step in the extrusion process, it is not possible to apply the processing route of the step-end face extrusion process as it is, and the width of the initial material is designed to be twice the thickness, When the second step is started at the start of the second step, in the same way as the machining path in the step-end surface extrusion step, the path A (0 °, 90 °, 180 °) , B, and C, respectively.

The size of the initial material is 25 × 50 × 80 각 for each extrusion, 25 × 25 × 80 등 for the backward extrusion, and 25 × 25mm2 after each extrusion.

(Φ) of 90 °, a curvature angle (ψ) of 10 °, and an extrusion angle (α) of 45 °. In each extrusion process, the same angle of intersection angle and curvature angle as that of each extrusion die are used. Respectively. The first and the rear part of the first molded part were removed due to the uneven strain and applied to the second molding by rotating according to the working path. (Φ) of 90 ° and a curvature angle (ψ) of 10 °, and having the same crossing and curvature angles as the respective channel extrusion processes, and having a 45 ° extrusion angle (α) The results of the finite element analysis of FIG. 5 are shown in FIG.

In order to observe the distribution of the effective strain inside the material, the effective strain distribution with respect to the half-cut surface in the y-axis direction is shown, and the distribution of the effective strain in the steady state of the entire A-A section is shown. The effective strain inside the material is in the range of about 0.7 to 1.2 for the material subjected to the back passage extrusion process, and 1.6 to 3.0 for the material subjected to the extrusion process. The effective strain distribution of the material subjected to the backing channel extrusion process exhibits a substantially constant strain distribution in the cross sectional area direction (Y direction), but a large change in the effective strain in the longitudinal direction (Z direction) . It can be seen that the effective strain increases radially around the upper surface of the cross section of the material subjected to each extrusion process. The effective strain of the material after the first process is maintained and the front and back of the material are removed and applied to the second process. FIG. 6 shows the shape and effective strain distribution of the material used in the second step.

In the second step, three kinds of second processes were carried out by rotating 0 ° (path A), 90 ° (path B), and 180 ° (path C) around the extrusion direction. Referring to the effective strain distribution shown on the left side of FIG. 6, there is no change in the cross-sectional shape of the specimen in the case of the back-to-back angular extrusion process. Referring to the effective strain distribution shown on the right side of FIG. 6, Thereafter, the sectional shape of the material becomes 12.5 x 25 mm < 2 >.

In the case of a material subjected to each second extrusion process, since the deformation was concentrated on the bottom portion of the material in the first process, the material after the second process is effective in the portion where the bottom portion of the first material is located along the path It can be seen that there is a large difference in effective strain between the effective strain in the material and the bottom portion of the first material. On the other hand, it can be seen that the material that has undergone each extrusion process by the second cycle has significantly improved the effective strain distribution irregularity compared to the material which has undergone the first process. It can be seen that the non-uniformity of the effective strain of the material passing through the path B is most remarkable in both the extrusion of the back channel and the extrusion of the annulus.

The average effective strain at the cross section was calculated to quantitatively compare and analyze the size and distribution of the effective strain applied to the material according to the process and the path.

In order to quantitatively compare the unevenness of the effective strain distribution in the cross section, we define the deformation in-homogeneity index, C, as shown in the following equation (1) Respectively.

--- Equation (1)

Where ε _max and ε _min are the maximum and minimum values of the effective strain at the section of the material, and ε _ave is the mean value of the effective strain.

7 shows the average effective strain and the strain non-uniformity index according to the process and the route. From the results, it can be seen that both of the extrusion of the annulus and the extrusion of the back passage are uniformly effective strain distribution It can be seen that the unevenness of strain is improved by repeated processing, but in the case of the semi-tubular extrusion process, a significantly uniform effective strain distribution is generated as compared with the process of each step of an isostatic tube extrusion process. Both pathway angular extrusion showed the most uniform effective strain distribution when the second machining was done through path A and showed the most non-uniform distribution when path B was used. In the second material, the average effective strain, which is increased by 1.8 times, is almost constant in the extrusion process as compared with the process of the extrusion process, regardless of the path, regardless of the path. , And it can be confirmed that each extrusion process is more efficient than the extrusion process.

Therefore, the above-mentioned half-tubular extrusion process is an efficient process to increase the effective strain evenly, but it is necessary to develop the intermittent process as a continuous process for mass production and commercialization.

1. Korean Registered Patent No. 10-1392178 (2014.05.08.) 2. Korean Registered Patent No. 10-1066817 (September 23, 2011) 3. Korean Patent No. 10-1274502 (June 23, 2013) 4. Korean Patent No. 10-1298013 (2013.08.26.)

In order to solve the above problems, the present invention provides a method of manufacturing a high-quality extruded product having a high productivity and a high grain refinement efficiency by applying a continuous extrusion process to refine the crystal grains by the rigid- And a continuous extrusion apparatus using the same.

It is a further object of the present invention to provide a method and apparatus for changing the shape and cross-sectional area of a raw material continuously charged into a continuous extruder, the charging temperature range, and the position and shape of the continuous extruder die chamber to apply extreme plastic deformation to the material and the product, And to provide a continuous extrusion apparatus using a rigid metal working process capable of manufacturing a high-quality extruded product having high productivity and excellent grain refining efficiency by precisely controlling the temperature.

In order to accomplish the above object, the continuous extrusion apparatus using the rigid fabrication process of metal according to the present invention is for continuously extruding the ultra fine grain metal extrudate by continuously charging the casting bar provided from the continuous casting machine, A wheel; A pressing roller disposed at one side of the extrusion wheel for loading the casting bar; a shoe block for guiding the movement of the casting bar loaded in the extrusion wheel; A pedestal disposed at one end of the shoe block; A die chamber disposed at one side of the shoe block to receive a casting bar bent by the pedestal; And a die disposed at one side of the die chamber to extrude the casting bar, wherein the casting bar is provided between the extrusion wheel and the shoe block and has a charging part for charging the casting bar, And the other side is connected to the die chamber, and a first bending section, which is extruded from the die via the die chamber, passes through the first bending section provided between the loading section and the connecting section, A second deformation is made while passing through the second bending section, and a third deformation is performed while being extruded through the die in the die chamber.

Further, in the continuous extrusion apparatus using the rigid fabrication process of metal according to the present invention, the first bending section and the second bending section are each bent at right angles.

Further, in the continuous extrusion apparatus using the rigid fabrication process of the metal according to the present invention, the first bending section and the second bending section are bent in the same direction.

In addition, in the continuous extrusion apparatus using the rigid fabrication process of metal according to the present invention, the cross-sectional area of the connecting portion is smaller than the cross-sectional area of the die chamber, and the casting bar expands while passing through the second bending section .

Further, in the continuous extruding apparatus using the rigid fabrication process of the metal according to the present invention, when the casting bar is made of aluminum, it is supplied to the loading part while being controlled at 100 to 400 캜.

Further, in the continuous extruding apparatus using the rigid metal working process according to the present invention, the cross section of the casting bar charged into the charging section is formed into a trapezoidal shape, and the length of the trapezoidal lower surface divided by the length of the upper surface ([Lower surface (c) + side surface (b) + side surface (d)] / upper surface (a)] is 2.2 or more.

Further, in the continuous extruding apparatus using the rigid fabrication process of the metal according to the present invention, the cross-sectional area of the casting bar at the loading section is determined by the cross-sectional area of the casting bar at the connecting section and the sectional area of the extruding bar through the mold And the like.

Further, in a continuous extrusion method using a rigid fabrication process of a metal using a continuous extrusion apparatus using a rigid fabrication process of a metal according to the present invention, the casting bar is asymmetrically rolled by the extrusion wheel and the stamp roller, A process; A moving process in which the casting bar is moved between the extrusion wheel and the shoe block and is stretched, sheared or sheared by shear deformation and stretched, compressed, and expanded; A first deformation process in which the casting bar is deformed while being bent while passing through the first bending section; A second deformation process in which the casting bar is deformed while being bent while passing through the second bending section; And a third deformation process in which the casting bar is deformed while passing through the mold. In the first and second bending sections, the casting bar is bent at an angle of 90 degrees and bent and deformed into a " , And at least two or more complex plastic deformation such as shearing, expansion, tensile, and compression is performed in the first, second, and third deforming processes.

In addition, in the continuous extrusion method using a rigid fabrication process of a metal using a continuous extrusion apparatus using a rigid fabrication process of a metal according to the present invention, the casting bar is inflated while flowing into the die chamber through the second bending section .

Further, in a continuous extrusion method using a rigid fabrication process of a metal using a continuous extrusion apparatus using a rigid fabrication process of a metal according to the present invention, the continuous extrusion process may be performed by continuously introducing the metal from the first bending section into the die chamber without the second bending section. The cross-sectional area of the casting bar and the cross-sectional area of the connecting portion are adjusted correspondingly to the cross-sectional area of the extruded product in the form of the extruded product, and the sectional area of the material flowing into the die chamber through the first bending section expands, , Tensile, and compression, so that a module capable of maximizing the strain energy accumulation amount in the material can be manufactured and managed by each product.

According to the continuous extrusion apparatus and method using the continuous rigid processing of metal according to the present invention having the above-described structure, high-quality extruded products having excellent grain refinement efficiency with high productivity can be manufactured by applying the continuous extrusion process.

In addition, the continuous extrusion apparatus and method using the continuous rigid fabrication process of metal according to the present invention can be performed by changing the shape and cross-sectional area of the raw material continuously charged into the continuous extruder, the charging temperature range, and the position and shape of the continuous extruder die chamber, And extreme plastic deformation is applied to the product, and the temperature of the material and the product is precisely controlled, thereby making it possible to produce a high-quality extruded product having high productivity and high grain refinement efficiency.

FIG. 1A shows conventional intermittent (batch type) and continuous rigid processing techniques, and FIG. 1B is a detailed explanatory diagram of an isometric extrusion method.
FIGS. 2A and 2B are views showing the structure of the conventional continuous extruder and the plastic deformation of each position, respectively.
Figs. 3 and 4 are diagrams showing the cylinder extrusion angle extrusion process and the machining path, respectively.
FIG. 5 shows the results of the finite element analysis and the effective strain distribution of the material subjected to the first pass of the backward extrusion (isothermal face extrusion) and the cylinder extrusion process.
FIG. 6 shows the shape and effective strain distribution and the size of the material in the second step of the backward extrusion (isothermal face extrusion) and the half extrusion extrusion.
FIG. 7 is a diagram showing distribution tables and processing paths of maximum, minimum, average effective strain, strain non-uniformity, etc. according to one or two passes and machining paths of each of the extrusion and extrusion paths of the back passage.
FIG. 8 is a schematic view of an apparatus for continuously producing an ultrafine grained metal extrusion material by a continuous casting / continuous extrusion process according to the present invention.
FIGS. 9A to 9C are cross-sectional views illustrating an embodiment of a metal extrusion apparatus using the continuous rigid fabrication process according to the present invention, and FIG. 9B is a detailed view of a connection portion and a bending section in FIG. 9A.
10 is a photograph showing the shape and microstructure of the die chamber inlet (a) side and the die outlet side (b) of the present invention during the extrusion.
11 is a graph showing the fractions of the low-tangential grain boundaries and the high-angle grain boundaries on the die chamber inlet (a) side and the die outlet side (b) of the present invention.
Fig. 12 is a graph showing the relationship between the extruded material, the casting materials, the material heating temperature, the size of the material (thickness) of the material for A6061 forging material (Jiangsu process material) And the like, to compare forging moldability.
FIG. 13 is a table summarizing the forging heating temperature, the physical properties and the grain size of each product after forging according to the forging material of FIG.
14 is a view showing the ratio of the cross-sectional shape of the casting bar to the length of each surface according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings and the following description. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the description of the present invention, the same or similar elements are denoted by the same or similar reference numerals, and a detailed description thereof will be omitted.

FIG. 8 is a structural view of an apparatus for continuously producing ultra fine grain metal extrudate by a continuous casting / continuous extrusion process according to the present invention, and FIG. 9 is a sectional view showing an embodiment of a metal extrusion apparatus according to the present invention.

Referring to FIG. 8, the continuous extrusion apparatus using the rigid fabrication process of metal according to the present invention constitutes one of the equipments of the ultrafine crystal grain metal extrudate continuous manufacturing apparatus by performing strong plastic deformation of the casting bar at various stages .

The continuous casting apparatus 100 includes a melt forming unit 110, a continuous casting machine 120, a casting bar processor 130, a continuous extrusion apparatus 140 using a rigid metal working process, a cooler 150, / Winding &

The molten metal forming portion 110 includes a reflow furnace 112, a holding furnace 114, and a molten metal (or ladle) 116 for melting molten metal to form molten metal having a desired alloy composition.

It is preferable that the reflection furnace 112 now has a capacity to dissolve 20 MT (Metric ton).

The holding furnace 114 supplies the melted molten metal from the reflow furnace 112 through the first molten metal 113 and maintains the molten metal injected into the continuous molten metal at a predetermined temperature. (Magnetic Stirrer), which can be composed of two sets of 10MT size for continuous production process.

A slag vessel for removing slag may be provided between the first breeze 113 and the inlet of the holding furnace 114.

The molten metal in the holding furnace 114 is supplied to the molten metal bath 116 through the second molten metal bath 115. A gas bubbling filter (GBF) and a ceramic filter may be provided between the second tundish 115 and the pouring tank 116.

The continuous casting machine (CCM) 120 is for continuously casting the molten metal supplied from the molten metal forming portion through a casting wheel to produce a casting bar maintained at a continuous extruder charging temperature. Although not shown, it may include a drawing pinch roller, a cutter, a straightening roller, a top surface cutting and edge cutter, a drawing pinch roller, a casting bar cooling device, and the like, as disclosed in Korean Patent No. 10-1392178.

8 and 9, the continuous extrusion apparatus 140 using the rigid metal working process of the present invention includes an extrusion wheel 141, an extrusion roller, a shoe block, a pedestal (not shown) abutment, a die chamber 149, and a mold 150.

More specifically, the continuous extrusion apparatus 140 using the rigid fabrication process of the metal according to the present invention includes an extrusion wheel 141 provided with a groove 141a formed in the circumferential direction, A shoe block 143 for guiding the movement of the casting bar B1 loaded in the extrusion wheel 141 and a shoe block 143 for guiding the movement of the casting bar B1, A die chamber 149 disposed at one end of the shoe block 143 to receive a casting bar B1 bent by the pedestal 144, 149 to continuously cut and remove the mold 150 in which the casting bar B1 is extruded and the flash 151 continuously discharged at intervals between the shoe block 143 and the extrusion wheel 141 during extrusion And a scraper 152.

Between the extrusion wheel 141 and the shoe block 143 is provided a charging part 145 for charging the casting bar B1 and has one side connected to the charging part 145 and the other side connected to the die chamber 149, A connecting portion 146 is provided. The shape of the casting bar (B1) is such that the ratio of the length of the upper surface of the trapezoid to the length of the other surface (lower surface and both side surfaces) is 2.2 or more and aluminum is supplied to the loading part Can be exemplified.

The extrusion wheel 141 rotates at a speed of 5 to 10 RPM. The casting bar is moved by the sweep roller 142 disposed at one side, and asymmetric rolling is performed.

A strong shear friction force is generated between the groove wall surface of the extrusion wheel 141 and the shoe block 143 by the rotation of the extrusion wheel 141.

The casting bar B1 is moved in the arc direction of the extrusion wheel 141 toward the pedestal 144 while being compressed in the groove 141a and then bent at a right angle by the pedestal 144, (147), resulting in severe plastic deformation.

Here, the first bending section 147 refers to a region bent at a right angle between the loading section 145 and the connecting section 146.

The casting bar B1 having passed through the first bending section 147 flows into the die chamber 149 through the second bending section 148 provided between the connecting section 146 and the die chamber 149, Since the die chamber 149 is made larger than the cross-sectional area of the connecting portion 146, the casting bar B1 is deformed such as expansion and tensile.

Since the first bending section 147 and the second bending section 148 are continuously bent twice in the same direction, for example, counterclockwise, they have a uniform effective strain distribution, and the first bending section 147 147, which is a conventional contour extrusion forming process as shown in FIG. 2A, the amount of plastic deformation is considerably large, and the crystal grains of the metal can be made finer.

The continuous extrusion method using the metal rigid fabrication process of the present invention includes a stretching and compression process in which the casting bar B1 is asymmetrically rolled by the extrusion wheel 141 and the extrusion roller 142, A movement process in which the casting bar B 1 is moved between the loading section 145 and the shoe block 143 while being stretched or compressed by shearing deformation or shear deformation and tensioning and expansion, A first deformation process in which the casting bar B1 is bent while being passed through a first bending section 147 and a second bending section 148 provided between the connection section 146 and the die chamber 149, A secondary deformation process in which the casting bar B1 is deformed while being bent and a tertiary deformation process in which the casting bar is deformed while passing through the die 150 in the die chamber 149. [ In the first bending section and the second bending section, the casting bar is bent at an angle of 90 °, and is deformed while being bent in a 'C' shape. During the first, second and third transformation processes, shear, expansion, As the accumulated strain energy is increased due to at least two complex plastic deformation, the size of the crystal grains of the metal can be reduced to microns (탆) or less.

Theoretically, it is most effective that the casting bar is bent at an angle of 90 ° in the first bending section and the second bending section. The rationale for the bending of the casting bar at an angle of 90 ° is that, in the ECAP / E isothermal extrusion process, The total deformation can be calculated from the effective strain ε in the Von Mises yield theory, as shown in Equation ( 2 ) below, for strain related to simple shear deformation.

(2) " 竜 = N / √3 [2cot (Φ / 2 + Ψ / 2) + Ψcosec

Where N: the number of times the material has passed through the die

If Φ and Ψ are defined in Eq. ( 2 ), the amount of deformation can be obtained by each compression condition. When N = 1, we obtain the value of Ψ and the amount of deformation for φ value in the range of 90 ° to 180 °. Here, the Ψ value does not affect the amount of deformation, but the change in the value of Φ directly affects the amount of deformation. Especially, in the case of Φ = 90˚, it is possible to obtain a deformation amount close to 1 by one compression regardless of Ψ, which shows that the effect of the isostatic extrusion processing is greatest.

According to the present invention, the cross-sectional area of the feedstock to be fed is varied according to the cross-sectional area of the extruded material B2 produced by the consecutive continuous extrusion process, the cross-sectional area of the die chamber is enlarged, If the continuous extrusion is performed after bending twice at 90 DEG angle of the path A, the effect of the rigid-plastic processing will be greatly increased, and the crystal grains of the extruded material (B2) will be further finely smoothed.

A module capable of maximizing the amount of strain energy accumulation in the material by managing the cross-sectional area of the casting bar and the cross-sectional area of the die chamber differently depending on the cross-sectional area of the extruded material (enlarging the product cross- (Radial type) continuous casting extrusion method widely used in the production of profiles and pipes in the same manner as one pass of the ECAP / E is performed by using a cored material ), The die chamber was modified by a tangential type continuous contour extrusion method applied to the cladding and cladding of the extruded extruded extruded material, Thereby maximizing the size of the plastic deformation amount and improving the efficiency of grain refinement.

The intergranular structure and the shape of the grain in the metal structure are important factors for determining the characteristics of the metal microstructure and have the greatest influence on plastic formability and superplasticity. The grain boundary structure has a high angle boundaries structure which easily causes intergranular sliding, and the shape of the grain is a large grain boundary slip in all directions when equiaxial grains having the same length and width (longitudinal / lateral) Is easily generated and exhibits tensile elongation of several hundreds of percent to failure, and is characterized by being deformed with a small stress.

Referring to FIG. 11, the raw material introduced into the die chamber inlet through the groove of the conforming continuous extruder extrusion wheel is bent 90 ° by an abutment by an abutment angle extrusion method, is filled in the die chamber, In the process of extruding through a mold under a complex deformation such as expansion, tensile, compression, etc., the grain boundary structure at the inlet side of the die chamber and the die outlet side is checked. At the entrance side, Although the fraction of low angle boundaries is 60%, the fraction of high-hardness grain boundaries is 73% (standard of high hardness angle) 15 °), respectively. In the case of refining the crystal grains through one ECAP / E process, the crystal grains are always present at a misorientation angle in the range of 0 to 5 ° due to the dislocation inside the grains generated by the calcining process It is proved that a large increase in the group of misorientation angles of crystal grains in the crystal axis direction of 40 ° or more is a large plastic deformation effect in the die chamber and the mold.

The forging material produced by the continuous extrusion method with conformal and high-hardness grain boundary structure has excellent moldability, so the following economic advantages can be expected compared with the existing extruded material and cast material. The material produced by the Jiangsu process can maintain excellent forging quality even if the material heating temperature and the size of the forged material are reduced compared to the conventional forging material due to high formability. As the heating temperature of the material is lowered, the heating energy consumption is reduced, the yield of the material is improved, the reduction in the occurrence of trimming scrap, the reduction of the redissolution cost and the lowering loads ) And small-sized facilities, as well as to enable production of larger products, which can reduce the operation cost and equipment investment cost of the early stage, and the forging temperature is lowered, so that the wear of the forging mold is reduced, The use of the material becomes possible. In addition, the reduction of the number of forging and the decrease in the number of steps can be expected to reduce wear and operation cost of the mold.

By using the ECAP / E method, it is possible to reduce the heating temperature of the forged material, which has been processed with 3-pass and 4-pass Jiangsu, by up to 145 ° C and to reduce the size of the material by 15% It shows forging processability.

Referring to FIG. 13, it can be seen that the forged material having a fine grain size by the rigid forming process lowers the manufacturing cost due to excellent formability, and that the mechanical properties of the product after forging show a superior quality in comparison with the existing forged materials .

In order to produce a rigid processed product with fine grains and excellent moldability and mechanical properties, the shape of the feedstock to be fed into the conforming continuous extruder is such that the ratio of the length of the upper surface of the trapezoid to the length of the other surface (lower surface and both side surfaces) And the temperature of the casting bar is cooled in the casting bar cooling device to a range of 100 to 400 ° C. and the temperature of the casting bar is adjusted according to the size and shape of the product and the rotation speed of the extruding wheel, do. The shoe block, the extrusion wheel, the abutment and the dies chamber of the continuous extruder of the conforming type prevent the overheating by forcibly circulating the cooling water to the inside of the extruder wheel, It is possible to manage the material temperature in the pedestal and the die chamber at an appropriate temperature. In addition, the cross-sectional area of the casting bar charged in accordance with the cross-sectional area of the product is changed so that the cross-sectional area of the cross-section intersecting at an angle of intersection (Ø) of 90 ° similar to that of the isostatic extrusion (ECAP / E) And the deadzone shape at the entrance and exit sides are modularized so as to maximize the amount of plastic deformation. The continuous extruded product produced through the extrusion die is quenched and discharged through the continuous product cooling device installed in front of the extrusion die to minimize grain growth and recrystallization. In order to maximize the plastic deformation amount, the tangential type continuous casting extrusion method was modified, and the two-pass 90 ° bend similar to the two passes of the A-type path and the cross-sectional enlargement die chamber shape Can be maximized. Conformal continuous extruders prevent the inclusion of oxides into the product by flashing the surface oxides of the material generated during extrusion, in the form of a flash (scrap), rotating along with the extruded wheel through the pedestal and continuously discharging to the lower side. Generally, the flash level is in the range of 1 to 8%, and the distance between the extrusion wheel and the shoe block is controlled by adjusting the distance, so that it is possible to produce an improved uniform quality product.

Referring to FIG. 14, the shape of the casting bar, which is a feedstock continuously fed into the continuous extruder, is preferably a trapezoid with a longer upper side than a lower side.

Concretely, the upper surface (a), which is in contact with the shoe block, is directly responsible for the overheating of the material due to frictional heat and the increase of the oxide film depending on the ratio between the lower surface (c) and both side surfaces (b, d) Proper management of the top surface ratio can increase the rotation speed (RPM) of the extruded wheel to increase the productivity, minimize the generation of the oxide film, and maintain the high quality. The ratio of the length of the top, bottom, and both sides of the casting bar shall be designed to be 2.2 or more as shown below.

2.2 ≤ (bottom surface (c) + side surface (b) + side surface (d)) / top surface (a)

That is, the larger the area ratio of the upper surface of the feedstock to be frictioned with the shoe block, the more frictional heat is generated, and the material is overheated. In addition, if the height (b, d) of the casting bar is small, the amount of shear deformation in the first and second bending sections decreases.

That is, the ratio of the length of the upper surface of the casting bar to the length of the other surface (lower surface and both side surfaces) is controlled to be 2.2 or more, so that high productivity, high recovery rate and high quality can be maintained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Therefore, it is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

140: Continuous extrusion device
141: extrusion wheel 141a: groove
142: stamp roller 143: sho block
144: pedestal 145:
146: connecting portion 147: first bending section
148: second bending section 149: die chamber
150: mold 151: flash
152: scraper B1: casting bar
B2: Extruded material

Claims

Continuously injecting a casting bar provided from a continuous casting machine to continuously extrude ultrafine crystal metal extrudate,
An extrusion wheel in which a groove is formed;
An extrusion roller disposed on one side of the extrusion wheel for loading the casting bar,
A shoe block for guiding the movement of the casting bar loaded on the extrusion wheel;
A pedestal disposed at one end of the shoe block;
A die chamber disposed at one side of the shoe block to receive a casting bar bent by the pedestal;
And a die disposed at one side of the die chamber to perform extrusion of the casting bar,
Wherein the casting bar is provided between the extrusion wheel and the shoe block and has a charging part for charging the casting bar, a connection part for communicating with the charging part at one side and a communication part with the dicing chamber at the other side, ,
And a second bending section provided between the connecting section and the die chamber to perform secondary deformation while passing through the first bending section provided between the loading section and the connecting section, And the third deformation is performed while being extruded.

The method according to claim 1,
Wherein the first bending section and the second bending section are respectively bent at right angles.

3. The method of claim 2,
Wherein the first bending section and the second bending section are bent in the same direction.

The method of claim 3,
Wherein the cross-sectional area of the connecting portion is smaller than the cross-sectional area of the die chamber, and the casting bar expands while passing through the second bending section.

5. The method of claim 4,
Wherein when the casting bar is made of aluminum, it is supplied to the charging part in a controlled state at 100 to 400 ° C.

6. The method of claim 5,
(A bottom surface (c) + a side surface (b) + a side surface (d)] / a side surface (d) obtained by dividing the total length of the lower surface of the trapezoid and both side surfaces by the length of the upper surface, (Upper surface (a)) is 2.2 or more.

The method according to claim 6,
Wherein the cross-sectional area of the casting bar in the loading section
Wherein a cross-sectional area of the casting bar in the connecting portion and a cross-sectional area of an extrusion bar through the metal mold are adjusted.

8. A continuous extrusion method of a metal using the continuous metal extrusion apparatus according to any one of claims 1 to 7,
A charging step in which the casting bar is asymmetrically rolled by the extrusion wheel and the stamping roller and is tensioned and compressed;
A moving process in which the casting bar is moved between the extrusion wheel and the shoe block to stretch, compress, or shear strain by shearing deformation;
A first deformation process in which the casting bar is deformed while being bent while passing through the first bending section;
A second deformation process in which the casting bar is deformed while being bent while passing through the second bending section;
And a third deforming step of deforming the casting bar while passing through the mold,
In the first bending section and the second bending section, the casting bar is bent at an angle of 90 °, and is deformed while being bent in a '
Wherein at least one of plastic deformation of at least two of shearing, expanding, stretching, and compression is performed in the first, second, and third deforming processes.

9. The method of claim 8,
Wherein the casting bar is inflated while flowing into the die chamber through the second bending section.

10. The method of claim 9,
The sectional area of the casting bar and the cross-sectional area of the connecting portion are correspondingly adjusted in accordance with the size of the cross-sectional area of the extruded product, even in the form of the connecting portion of the continuous extrusion method of metal flowing into the die chamber directly from the first bending section without the second bending section , And a cross-sectional area of a material flowing into the die chamber through the first bending section is expanded, so that at least two or more complex plastic deformation such as shearing, expansion, tensile, and compression is performed.