JP2008030101A - Forging method and anvil used for forging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forging method and an anvil used for the forging method with which not only the generation of a dead metal zone at the center part in the width direction of a blank, but also, the generation of flaw on the surface, such as overlap at the corner part, can be prevented and since only one kind of an anvil is used, the working time is not needed to much time. <P>SOLUTION: The forging method is composed of a first process, with which a first pressing part 1 in the anvil A is pressed to the surface of the blank B and recessed surfaces 4 are formed at both side parts in the width direction of this blank B, and a second process, with which a second pressing part 2 with the anvil A, is pressed to the projective surface 5 at the center part in the width direction of the blank B interposed with both recessed surfaces and the surface of the blank B is smoothly finished. Then, in the anvil, the first pressing part 1 and the second pressing part 2 are successively arranged in the conveying direction of the blank B. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a forging method that eliminates defects generated in the inside and surface of a material when forging a material such as a steel ingot or steel material, and an anvil used in the forging method.

  Conventionally, as shown in FIG. 7, in order to forge a material b such as a steel ingot or a steel material, the anvil a having a flat pressing surface 11 can be processed so as to sandwich the top and bottom of the material b. The forging method was generally performed. Specifically, this conventional forging method has been performed using an anvil a having a flat pressing surface 11 for rolling down the material b. That is, the material b has been forged by repeatedly reducing the material B by the pressing surface 11 of the anvil a and transporting the material b.

  However, when the material is processed by such forging work, since the plastic flow is constrained by the anvil on the surface layer of the material that contacts the pressing surface of the anvil, the central portion of the area in contact with the anvil, that is, the center in the width direction of the material In some cases, there was a dead metal region in which almost no distortion was applied.

  Generally, when a material is processed, there will be a portion that undergoes plastic strain and a dead metal region that is hardly subjected to plastic strain. In the part subjected to plastic strain, the characteristics can be made uniform by improving mechanical properties by refining the structure and closing internal defects. However, in the dead metal area, it remains in the rough structure when cast, so there is no refinement of the structure or closure of internal defects, and surface defects such as forging cracks when forging particularly difficult-to-work materials. May occur.

  Then, the forging method invented in order to eliminate generation | occurrence | production of a dead metal area is an invention described in patent document 1. FIG.

  According to Patent Document 1, as shown in FIG. 8, the forging of the material has been performed in two steps. Although the steps are divided into two steps, the shape of the anvil is somewhat different, but the front view is substantially the same as FIG. First, what is performed is a first step shown in FIG. 8A, in which a first anvil having a pressing surface 21 having a width narrower than that of the material b is pressed down only in the center in the width direction of the material b. A recess 22 is formed at the center in the width direction. Next, the second step shown in FIG. 8 (b) is a second anvil a2 having a pressing surface 31 having a width wider than the width of the material b, and the width direction of the material b in which the concave portion 22 is formed. The surface of the material b is finished smoothly by reducing both ends.

According to the forging method described in Patent Document 1, there is certainly an effect of reducing the occurrence of a dead metal region in the center in the width direction of the material. As a result, a problem arises in that a difference in deformation resistance occurs and surface flaws occur in the second step. Furthermore, in the training, the material is rotated in the axial direction, and the crease at the corner is generated in order to perform the rolling down in the vertical and horizontal directions described in FIGS. 8A and 8B in order. There was also the problem of promoting. In addition, the use of two types of anvils has caused a new problem that it takes extra work time.
JP 2002-160036 A

  The present invention was invented in view of the above-mentioned conventional problems, and not only can reduce the occurrence of a dead metal region at the center in the width direction of the material, but also the surface such as the occurrence of folding wrinkles at the corners. It is an object of the present invention to provide a forging method that can prevent wrinkles from occurring and close internal defects, and that does not take much work time because only one kind of anvil is used, and an anvil used for the forging method. To do.

  The invention according to claim 1 includes a first step of reducing the first pressing portion of the anvil to the surface of the material and forming concave surfaces on both sides in the width direction of the material, and a second pressing portion of the anvil. It consists of a second step of rolling down the convex surface of the material in the width direction of the material sandwiched between the concave surfaces to finish the surface of the material smoothly, and the anvil is provided with a non-pressing portion in the width direction center portion. The forging method is characterized in that the first pressing portion and the second pressing portion are provided continuously in the material transport direction.

  In the invention according to claim 2, the conveyance and reduction of the material are repeatedly performed, and the conveyance dimension of each material is 1/2 or less of the dimension of the anvil in the material conveyance direction, and the first pressing portion, The forging method according to claim 1, wherein each of the second pressing portions has a dimension equal to or smaller than a dimension in a material conveyance direction.

  In the invention according to claim 3, the non-pressing portion provided in the central portion in the width direction of the first pressing portion is a concave shape opened to the material side, and the height dimension of the non-pressing portion is the thickness dimension of the material. 3. The forging method according to claim 1, wherein the reduction ratio of the anvil in the first step and the second step is greater than 30% and is 5 to 30% with respect to the thickness dimension of the material.

  In the invention according to claim 4, the first pressing portion and the second pressing portion are continuously provided in the material conveyance direction, and at least at the material side in the center portion in the width direction of the first pressing portion. The anvil used in the forging method according to any one of claims 1 to 3, wherein an open non-pressing portion is provided.

  According to the forging method of the present invention, it is possible not only to reduce the occurrence of a dead metal region at the center in the width direction of the material, but also to prevent the occurrence of surface flaws such as the occurrence of folding flaws at the corners, and the efficiency. Internal defects can be homogenized well. Furthermore, since only a kind of anvil is used, it does not take much work time.

  According to the anvil of the present invention, it is possible not only to reduce the occurrence of a dead metal region at the center in the width direction of the material, but also to prevent the occurrence of surface flaws such as the occurrence of folding flaws at the corners, and efficiently. Internal defects can be homogenized. Furthermore, a forging operation can be performed only with this kind of anvil.

  Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.

  3 and 4, A is an anvil, 1 is a first pressing portion formed on the anvil A, 2 is a second pressing portion formed on the anvil A, and 3 is a center in the width direction of the first pressing portion. It is the non-pressing part provided in the part. Further, B shown in FIG. 1 is a material processed by the anvil A. For example, the material is a metal material such as carbon steel (S55C) or low alloy steel (SCM440). 4 is a concave surface formed on both sides in the width direction of the material B in the first step, and 5 is a convex surface sandwiched between the concave surfaces 4 and 4.

  As shown in FIGS. 3 and 4, the anvil A is formed with a first pressing portion 1 and a second pressing portion 2 that are continuously formed in the conveying direction of the material B as surfaces that are pressed down on the surface of the material B. Yes. The first pressing portion 1 and the second pressing portion 2 have the same length dimension in the conveyance direction of the material B described later. A concave non-pressing portion 3 is provided at the center in the width direction of the first pressing portion 1. When the anvil A is viewed from the front side with the pressing surface down, the non-pressing portion 3 has an isosceles trapezoidal shape with the lower portion widened and is open to the material B side. The height dimension of the non-pressing portion 3 is determined in relation to the thickness dimension of the material B. That is, the height dimension of the non-pressing portion 3 is larger than 30% of the thickness dimension of the material B. In addition, the upper limit of the dimension should just be in the range of the height dimension of the anvil A. In addition, the width dimension of the non-pressing part 3 is different in the upper and lower sides so as to narrow toward the upper part, but the maximum dimension (lower dimension) is smaller than the width dimension of the material B. The first pressing portion 1 has flat surfaces on both sides of the non-pressing portion 3 that press down the surface of the material B. The second pressing portions 2 are all flat surfaces.

  In addition, the non-pressing part 3 does not necessarily have an isosceles trapezoidal shape in which the lower part is widened in a front view, and the width dimension may be narrowed toward the upper part or may be the same. That is, it can be a semicircular shape as shown in FIG.

  Also, for example, as shown in FIG. 4C, it is desirable to provide R at each corner portion of the anvil A (including the corner portion in addition to the protruding corner portion) (R = 1/10 W: W is The dimension of the anvil A in the conveyance direction). Although not shown in all drawings, it is particularly important to provide R at the corner portion of the anvil A that contacts the surface of the material B when the anvil A is crushed by the material B. By providing this R, it is possible to prevent the surface of the material B from wrinkling. An R is also attached to the boundary between the non-pressing portion 3 of the first pressing portion 1 and the second pressing portion 2. This R can prevent the occurrence of folding wrinkles. The safety of the work can be improved by providing R at other corner portions. In addition, the magnitude | size of R may not be 1 / 10W, and it is not necessarily required except the site | part which contacts the raw material B surface.

  The material B is a long steel ingot such as a columnar shape, a prismatic shape, a belt shape, or a steel material. In the drawing, a square columnar steel material is illustrated as the material B, but the casting method is the same for the material B having other shapes such as a columnar shape. As described above, the material B has a thickness dimension smaller than 30% of the height dimension of the non-pressing portion 3 of the anvil A and a width dimension larger than the maximum width dimension of the non-pressing portion 3 of the anvil A. Further, the width dimension of the material B is smaller than the width dimension of the anvil A itself.

  Next, a method for forging the material B will be described with reference to FIGS. The forging of the material B is performed by being divided into a first step shown in FIG. 1 (a) and a second step shown in FIG. 1 (b). In addition, the broken line shown in FIG.1 (b) shows the shape of the raw material B before rolling down by a 2nd process.

  First, as shown to Fig.1 (a), a 1st process is performed by pressing down the 1st press part 1 of the anvil A on the surface of the raw material B. As shown in FIG. When the first pressing portion 1 is pressed down onto the surface of the material B, the surfaces on both sides sandwiching the non-pressing portion 3 press the surface of the material B to form concave surfaces 4 and 4 on both sides in the width direction of the material B. During the reduction, a convex surface 5 is formed at the center in the width direction of the material B sandwiched between the concave surfaces 4 and 4. The rolling reduction in this first step is 5 to 30% of the thickness dimension of the material B. When the rolling reduction is less than 5% of the thickness dimension of the material B, there is no effect of closing the void formed inside the material B. If the rolling reduction exceeds 30%, cracks may occur in the material B. Furthermore, as described above, the height of the non-pressing portion 3 is not less than the height, and the convex surface 5 formed at the central portion in the width direction of the material B also hits the non-pressing portion 3. The rolling reduction is the rolling amount (dimension) of the anvil A / the thickness dimension of the material B.

  Next, as shown in FIG. 2, after returning the anvil A to the original standby position, the material B is placed in a direction indicated by the arrow in FIG. 1), and the second pressing portion 2 of the anvil A is pressed down to the surface of the material B in the second step as shown in FIG. Since the second pressing portion 2 of the anvil A is a flat surface as described above, the convex surface 5 at the center in the width direction of the material B formed in the first step is pressed down. Since the reduction in the second step is performed with the same anvil A as the reduction in the first step, the reduction rate is the same. Therefore, the surface of the material B is finished smoothly. Note that the rolling reduction in the second step may be larger than the rolling reduction in the first step. In that case, the 2nd press part 2 will reduce the whole surface of the raw material B at the time of exceeding the reduction rate in a 1st process.

  In the reduction in the second step, first, only the convex surface 5 at the center portion in the width direction of the material B is pressed down, so that the center portion in the width direction of the material B can be surely reduced. The structure of the part can also be made finer, so that the so-called dead metal region can be prevented and internal defects can be closed.

  In the above description, it has been described that the material B is conveyed by a predetermined dimension (the same dimension as the dimension in the conveyance direction of the first pressing part 1), but it is not necessarily the same dimension as the dimension in the conveyance direction of the first pressing part 1. It is not necessary to transport only the minute. When the conveyance dimension is equal to or smaller than the dimension in the conveyance direction of the first pressing unit 1, an uncompressed part is formed when the second pressing unit 2 performs the reduction, but the first process and the second process convey the material B. Since the reduction is repeatedly performed, the unreduced portion can be reduced in the next second step without causing a problem.

  Next, the present invention will be described more specifically based on an actual forging method.

  First, the upper and lower surfaces of the material B heated to a predetermined temperature are pressed down by the first pressing portions 1 and 1 of the pair of upper and lower anvils A and A. Due to the reduction, concave surfaces 4 and 4 are formed on both sides in the width direction of the upper and lower surfaces of the material B, respectively. Further, the central portion in the width direction of the material B sandwiched between the concave surfaces 4 and 4 becomes the convex surface 5. This is the so-called first step. Next, the material B is rotated by 90 ° about the conveying direction, and the first press of the anvils A and A on the surface different from the surface processed previously (on both sides when the previous processing surface is the upper and lower surfaces) The parts 1 and 1 are pressed down. Due to this reduction, concave surfaces 4 and 4 and a convex surface 5 are formed on both sides in the width direction of both sides of the material B, respectively. This is also the first step.

  Next, the material B is conveyed by a predetermined dimension. The conveyance dimension is only the same dimension as the dimension of the first pressing unit 1 in the conveyance direction. After stopping, when the pair of upper and lower anvils A and A are crushed to the surface of the material B, the convex surfaces 5 formed on the both side surfaces of the material B in the first step are crushed by the second pressing portions 2 and 2, The entire surface is finished flat. This is the so-called second step. Next, the material B is rotated by 90 ° about the conveying direction, and the second press of the anvils A and A on the surface different from the surface processed previously (upper and lower surfaces when the previous processed surfaces are both sides) The parts 2 and 2 are pressed down. By this reduction, the upper and lower surfaces of the material B are also finished flat. This is also the second step. This completes the forging work for a predetermined dimension in the conveying direction.

  In addition, since the site | part which the raw material B continues in the above-mentioned 2nd process is simultaneously crushed by the 1st press part 1 of anvil A, the following 1st process is performed simultaneously with this 2nd process. That is, since the second step of the forging work for a predetermined dimension and the first step of the forging work for the next predetermined dimension are performed simultaneously by reducing one anvil A, the work time can be halved. it can. The material B can be finished in a target shape by sequentially repeating the forging work described above.

  In the above description, the example of rotating the material B by 90 ° to finish it into a quadrangular prism shape has been described. However, if the rotation angle of the material B is changed, it can be finished into a hexagonal column shape, an octagonal column shape, or the like. Moreover, you may perform a 1st process and a 2nd process only on an upper and lower surface. Furthermore, if the anvil A is not a pair of upper and lower parts but only an upper unit, for example, and the side facing the anvil A is simply a flat surface, the anvil A can be crushed and the material B can be forged.

  In the above description, the anvil A is provided with the concave non-pressing portion 3 at the center in the width direction of the first pressing portion 1, that is, the one having a ceiling surface. May not be concave, and may be a space in the upward direction without a ceiling surface as shown in FIG.

  Furthermore, the anvil A is shown with the first pressing portion 1 and the second pressing portion 2 provided one by one in the conveying direction of the material B. A plurality of the second pressing portions 2 may be alternately provided. If comprised in this way, the frequency | count of reduction will reduce and work efficiency will further improve.

  Moreover, although the above description demonstrated the method of conveying the raw material B only by the predetermined dimension after a 1st process and performing a 2nd process after that, the 1st process of rolling down the 1st press part 1 on the surface of a raw material B is demonstrated. After the completion, the anvil A can be moved by the same dimension as the predetermined dimension, and the second step can be performed by pressing the second pressing portion 2 onto the surface of the material B pressed by the first pressing portion 1. is there. In that case, after completion of the second step, the anvil A is returned to the origin. Thereafter, the material B is conveyed by the size of the anvil A.

  By preparing a columnar material B having an initial shape before forging of 1000 mm in diameter, and pressing down the first pressing portion 1 and the second pressing portion 2 of the anvil A on the surface of the material B in this order. The effect of was confirmed. The length dimension of the anvil A in the material B conveyance direction is 500 mm. In the invention example and the comparative example, the length dimension in the conveyance direction of the first pressing portion 1 and the second pressing portion 2 is 250 mm, respectively. is there. In Table 1, the conveyance dimension is a dimension for conveying the material B in order to advance the material B to a position where it is crushed by the second pressing unit 2 after the material B is crushed by the first pressing unit 1. The material B is carbon steel (S55C).

The pass / fail judgment was confirmed by the fact that no flaws were generated on the surface of the material B after forging (surface properties) and that the gap (φ5 mm or more) inside the material B was closed by the pressure of the anvil A before forging. . In the surface texture, if no wrinkle was visually observed, it was accepted as “good”, and if wrinkle was found, it was judged as “poor”. In addition, the material B before reduction includes a plurality of voids having a diameter of φ5 mm or more, and after reduction, all voids have a diameter of less than φ2.5 mm, and if all have a diameter of less than φ5 mm, pass. If even a part does not become less than 5 mm, it is rejected with x.

  In Invention Example 1, the conveyance dimension of the material B was set to 250 mm, which is the same as the length dimension of the first pressing portion 1 in the conveyance direction of the material B, and the reduction ratio was 20%. No flaws were observed on the surface of the material B after forging. Further, the maximum gap was φ0.5 mm, and the internal defects were reliably closed and homogenized.

  In Invention Example 2, the conveyance dimension of the material B is 250 mm, which is the same as the length dimension of the first pressing portion 1 in the material B conveyance direction, and the rolling reduction is 10%, which is different from the Invention Example 1. Even in Invention Example 2, no flaws were observed on the surface of the material B after forging. Further, the maximum gap was 4.5 mm, and the effect of closing the gap was confirmed.

  In the comparative example, the rolling reduction is 20%, which is the same as that of Invention Example 1, and the conveyance dimension of the material B is set to 300 mm, which is larger than the length dimension of the first pressing portion 1 in the material B conveyance direction. Since the position where the second pressing part 2 is rolled down is shifted and an unpressed lower part is formed, wrinkles occurred on the surface of the material B after forging.

  From the above experimental results, it was confirmed that no flaws were generated on the surface of the material B after forging when the conveyance dimension was 250 mm, which is the same as the length dimension of the first pressing portion 1 in the material B conveyance direction. That is, if the conveyance dimension is 250 mm or less, it can be said that no flaws are generated on the surface of the material B after forging.

  Further, it was confirmed that there was an effect of closing the gap even when the rolling reduction was 10%. Even in the case of 5%, it can be estimated that there is an air gap closing effect when it is 10%. In addition, when it is set to 20%, the gap is also φ0.5 mm and is reliably closed, which can be said to be a more preferable reduction ratio.

1 shows an embodiment of the present invention, in which (a) is a longitudinal sectional view of a first step, and (b) is a longitudinal sectional view of a second step. FIG. 2 shows a state in which the anvil is returned to the original standby position after the first step of the embodiment is completed, and is a longitudinal sectional view corresponding to the section taken along the line CC in FIG. It is a perspective view which shows the anvil used in one Embodiment of this invention. 2 shows the same anvil as in FIG. 2, (a) is a plan view (broken line indicates the shape of the bottom surface), (b) is a front view, and (c) is a cross-sectional view taken along line CC in FIG. 4 (b). It is. It is a perspective view which shows the anvil different from the anvil of FIG. It is a perspective view which shows the anvil different from the anvil of FIG. 3, FIG. It is a side view which shows a prior art example. 5A and 5B show a conventional example different from FIG. 5, in which FIG. 5A is a longitudinal sectional view of a first step, and FIG. 5B is a longitudinal sectional view of a second step.

Explanation of symbols

A ... Anvil B ... Material 1 ... First pressing part 2 ... Second pressing part 3 ... Non-pressing part 4 ... Concave surface 5 ... Convex surface

Claims (4)

A first step of rolling down the first pressing part of the anvil to the surface of the material and forming concave surfaces on both sides in the width direction of the material;
The second pressing portion of the anvil is crushed down to the convex surface in the center in the width direction of the material sandwiched between the concave surfaces, and consists of a second step of finishing the surface of the material smoothly,
A forging method characterized in that the anvil is provided with a first pressing portion provided with a non-pressing portion at a central portion in the width direction and a second pressing portion continuously in the material conveying direction.   The conveyance and reduction of the material are repeatedly performed, and the conveyance dimension of the material for each time is 1/2 or less of the dimension of the anvil and the conveyance direction of the material, and each of the first pressing part and the second pressing part, The forging method according to claim 1, wherein the forging method is equal to or less than a dimension in a material conveyance direction.   The non-pressing part provided in the central part in the width direction of the first pressing part is a concave shape opened to the material side, and the height dimension of the non-pressing part is larger than 30% of the thickness dimension of the material. The forging method according to claim 1 or 2, wherein the reduction ratio of the anvil in the second step is 5 to 30% with respect to the thickness dimension of the material.   The first pressing portion and the second pressing portion are continuously provided in the material conveyance direction, and at least the non-pressing portion opened to the material side is provided in the center portion in the width direction of the first pressing portion. An anvil used for the forging method according to any one of claims 1 to 3.

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