Variable anvil width type forging device and method

Abstract

The invention relates to a variable anvil width type forging device and a variable anvil width type forging method, belongs to the technical field of forging of forge pieces, and solves the problems that in the prior art, after drawing-out, a lap joint between anvils on the surface of a shaft body of a forging stock is serious in crease, the surface quality is poor, and finally the compaction effect is poor. The variable anvil width type forging device comprises an upper convex anvil and a lower platform, the lower edge of the upper convex anvil comprises a horizontal section and first straight line sections which are arranged at the two ends of the horizontal section and incline upwards, an included angle is formed between the horizontal section and the first straight line sections, and the horizontal section and the first straight line sections are in transition connection through fillets; and the side edge of the upper convex anvil is a second straight line section inclined towards the anvil main body, an included angle is formed between the second straight line section and the vertical direction, and the second straight line section is in transition connection with the first straight line section through a fillet. The compaction effect of the core of the forging stock can be improved, and surface creases of the forging stock can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of forging forgings, and in particular to a variable anvil width forging device and method. Background Art

[0002] The original cast grains of the super-large alloy steel shaft forgings (about 260t and above) currently produced are relatively coarse, and there are often various ingot defects in the core. This requires a series of deformation measures during the forging process to refine the grains and forge internal holes, shrinkage and other defects. Drawing, as the main deformation mode of large alloy steel shaft forgings, plays a vital role in the compaction effect of the core of the steel ingot. At the same time, because the cross-section of the shaft body is large after upsetting, many conventional drawing methods are limited.

[0003] The main stretching method currently used is the FM stretching method. However, due to the stretching characteristics of the FM stretching method, the surface creases of the forging blank obtained by the overlap between each anvil in the same pass during the stretching process are serious, which further leads to poor final compaction effect. Summary of the invention

[0004] In view of the above analysis, the embodiments of the present invention are intended to provide a variable anvil width forging device and method to solve at least one of the following problems existing in the existing forging devices when forging stretched ultra-large alloy steel shaft forgings: (1) severe creases on the surface of the forging blank shaft after stretching; (2) poor final compaction effect.

[0005] On the one hand, the present invention provides a variable anvil width forging device, which includes an upper anvil and a lower platform. Taking the main viewing surface of the upper anvil as a reference, the lower edge of the upper anvil includes a horizontal segment and a first straight line segment arranged at both ends of the horizontal segment and inclined upward, the horizontal segment forms an angle with the first straight line segment, and the horizontal segment and the first straight line segment are connected by a rounded transition; the side edge of the upper anvil is a second straight line segment inclined toward the anvil body, the second straight line segment forms an angle with the vertical direction, and the second straight line segment is connected to the first straight line segment by a rounded transition.

[0006] Preferably, the angle between the horizontal segment and the first straight segment is 10° to 15°.

[0007] Preferably, the angle between the second straight line segment and the vertical direction is 8° to 10°.

[0008] Preferably, the radius of the circle corresponding to the rounded corner between the horizontal segment and the first straight segment is 500 mm to 600 mm.

[0009] Preferably, the radius of the circle corresponding to the rounded corner between the second straight line segment and the first straight line segment is 200 mm to 300 mm.

[0010] Preferably, the difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil and the length B1 of the horizontal segment is

[0011] Preferably, the projection length of the first straight line segment in the horizontal direction is (B2-B1) / 2.

[0012] Preferably, a distance B2 between intersections of the second straight line extension lines at both ends of the upper anvil and the first straight line extension lines is smaller than a side length B3 of the upper side of the upper anvil.

[0013] Preferably, the difference between the distance B2 between the intersection points of the second straight line extension lines and the first straight line extension lines at both ends of the upper anvil and the length B3 of the upper side of the upper anvil is 200 mm to 300 mm.

[0014] On the other hand, the present invention also provides a variable anvil width forging method, which uses the variable anvil width forging device mentioned above.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0016] 1. The lower side of the upper anvil of the present invention includes a horizontal section and a first straight section arranged at both ends of the horizontal section and inclined upward, and the horizontal section forms an angle with the first straight section. During the pulling operation, as the upper anvil presses down on the blank, the contact area between the upper anvil and the blank gradually increases, that is, the anvil width is in a state of gradual increase (gradually increasing from the length B1 of the horizontal section to the distance B2 between the intersection of the extension line of the second straight section at both ends of the upper anvil and the extension line of the first straight section). At the same time, the height of the blank is gradually decreasing. In terms of process parameters, the anvil width ratio (anvil width / blank height) can be effectively improved, and the optimal parameter coverage range of the anvil width ratio in actual production can be improved, thereby optimizing the compaction effect of the core of the forging blank, avoiding the generation of axial tensile stress, and inhibiting crack propagation. In addition, when the contact area between the upper anvil and the forging blank is small, it is beneficial to reduce the load applied by the press in the initial stage and improve the forging limit of the equipment. As the pressure is pressed down, the contact area between the upper anvil and the forging blank becomes larger and larger, which is beneficial to reduce the number of anvils in the same pass, thereby reducing the number of overlaps between hammers in the same pass, and further inhibiting the generation of creases on the surface of the forging blank.

[0017] 2. Compared with the traditional flat anvil drawing, the angle between the horizontal segment and the first straight segment in the upper convex anvil of the present invention and its rounded transition, the angle between the second straight segment and the vertical direction and its rounded transition make the overlap of the pressed area and the unpressed area of ​​the forging blank form a certain gentle slope, so that the subsequent overlapping area transitions smoothly, which can effectively inhibit the formation of creases, ensure the amount of pressing, reduce the cleaning process, improve the forging and drawing efficiency, and reduce manufacturing costs.

[0018] 3. The present invention controls the amount of reduction in the compaction pass and the octagonal inversion pass, and gives fixed values ​​to the number of compaction passes and the octagonal inversion pass, both of which are four passes (the number of compaction passes in the existing FM drawing method using an upper flat anvil is five passes), and at the same time does not limit the number of finishing passes. While solidifying the drawing process, it is given a certain flexibility, which is beneficial to improving the actual forging production efficiency and reducing manufacturing costs.

[0019] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0021] Figure 1 The invention relates to a variable anvil width forging device.

[0022] Figure 2 It is a schematic diagram of the front view structure of the upper convex anvil of the present invention;

[0023] Figure 3 It is a schematic diagram of the compaction pass process of the present invention;

[0024] Figure 4 It is a schematic diagram of the process of the octagonal inversion pass of the present invention;

[0025] Figure 5 It is a schematic diagram of compaction pass overlap of the present invention;

[0026] Figure 6 It is a schematic diagram of the shape of the overlap between the pressed down area and the unpressed area after the forging blank is pressed down by the variable anvil width upper convex anvil of the present invention and the traditional flat anvil;

[0027] Figure 7 This is a photograph of the forging obtained in Example 2;

[0028] Figure 8 This is a photograph of the forging obtained in Comparative Example 1.

[0029] Reference numerals:

[0030] 1-upper anvil; 2-lower platform; 3-forging blank;

[0031] H1-height of forging blank; H2-height of upper anvil; B1-length of horizontal segment; B2-distance between the intersection of the extension line of the second straight segment at both ends of upper anvil and the extension line of the first straight segment; B3-length of the upper side of upper anvil; A-angle between horizontal segment and the first straight segment; B-angle between the second straight segment and the vertical direction; C1-first straight segment; C1'-horizontal projection length of the first straight segment; C2-second straight segment; C2'-horizontal projection length of the second straight segment; D-overlap amount of adjacent passes; R1-radius between horizontal segment and first straight segment; R2-radius between second straight segment and first straight segment. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0033] It should be noted that the “upper side”, “lower side”, “side”, “straight line segment” and “horizontal segment” in the present invention are all referred to as Figure 2 The main viewing surface of the upper anvil shown is used as the reference.

[0034] The FM drawing method uses an upper flat anvil, the upper side of which is the same length as the lower side, and the two side sides are vertically downward, that is, the existing upper flat anvil is a cubic structure, and the side and lower sides are connected by a rounded transition. The existing upper flat anvil has the following disadvantages: after drawing, the forging billet shaft body surface creases are serious, if not cleaned in time, it is easy to expand toward the center, increase the forging fire, and greatly reduce production efficiency. At the same time, because its cross-section after upsetting is large, it makes it difficult for the anvil width ratio γ to be in the optimal range (γ≥0.5) during drawing, thereby generating axial tensile stress, which seriously affects the surface quality of the forging billet obtained by the FM drawing method and the final compaction effect.

[0035] The present invention provides a variable anvil width forging device, such as Figure 1 and Figure 2 As shown, the variable anvil width forging device comprises an upper anvil 1 and a lower platform 2. Figure 2 Taking the main viewing surface of the upper anvil shown as a reference, the lower side of the upper anvil 1 includes a horizontal segment and a first straight line segment C1 arranged at both ends of the horizontal segment and inclined upward, the horizontal segment forms an angle A with the first straight line segment C1, and the horizontal segment and the first straight line segment C1 are transitionally connected by a rounded corner R1; the side of the upper anvil 1 is a second straight line segment C2 inclined toward the anvil body, the second straight line segment C2 forms an angle B with the vertical direction, and the second straight line segment C2 is transitionally connected to the first straight line segment C1 by a rounded corner R2.

[0036] During implementation, the forging blank 3 is placed between the upper anvil 1 and the lower platform 2, and the upper anvil 1 is pressurized to perform a stretching operation.

[0037] Compared with the prior art, during the pulling operation, as the upper anvil presses down on the forging blank, the contact area between the upper anvil and the forging blank gradually increases, that is, the anvil width is in a state of gradually increasing (gradually increasing from the length B1 of the horizontal segment to the distance B2 between the intersection of the second straight line segment extension line and the first straight line segment extension line at both ends of the upper anvil), and at the same time, the height of the forging blank is gradually decreasing. In terms of process parameters, the anvil width ratio (anvil width / forging blank height H1) can be effectively improved, and the coverage range of the optimal parameters of the anvil width ratio in actual production can be improved, thereby optimizing the compaction effect of the core of the forging blank, avoiding the generation of axial tensile stress, and inhibiting crack propagation. In addition, when the contact area between the upper anvil and the forging blank is small, it is beneficial to reduce the load applied by the press in the initial stage and improve the forging limit of the equipment. As the pressure is pressed down, the contact area between the upper anvil and the forging blank becomes larger and larger, which is beneficial to reduce the number of anvils in the same pass, thereby reducing the number of overlaps between hammers in the same pass, and further inhibiting the generation of creases on the surface of the forging blank.

[0038] Exemplarily, the angle A between the horizontal segment and the first straight segment C1 is 10° to 15°. If the angle is too large, the pressing amount of the blank contacted by the first straight segment C1 will be affected during pressing; if the angle is too small, it is not conducive to suppressing creases.

[0039] For example, the angle B between the second straight line segment C2 and the vertical direction is 8°-10°. If the angle is too large, it will affect the anvil width and thus the pulling efficiency; if the angle is too small, it will not be conducive to suppressing creases.

[0040] Exemplarily, the radius of the circle corresponding to the rounded corner R2 between the horizontal segment and the first straight segment C1 is 500 mm to 600 mm.

[0041] Exemplarily, the radius of the circle corresponding to the rounded corner R1 between the second straight line segment C2 and the first straight line segment C1 is 200 mm to 300 mm.

[0042] For example, the difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil 1 and the length B1 of the horizontal segment is If the difference is too large and the angle B is too small, it will not be conducive to suppressing the formation of creases during the stretching process; if the difference is too small, the stretching efficiency will be reduced.

[0043] Exemplarily, the horizontal projection length C1' of the first straight line segment C1 is (B2-B1) / 2. If the projection length is too long, it will affect the inclination of the second straight line segment C2 on the side, which is not conducive to suppressing creases. If the projection length is too short, it will greatly reduce production efficiency.

[0044] Exemplarily, the distance B2 between the intersections of the second straight line extension lines and the first straight line extension lines at both ends of the upper anvil 1 is smaller than the length B3 of the upper side of the upper anvil 1 .

[0045] For example, the difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil 1 and the upper side length B3 of the upper anvil is 200mm to 300mm. In theory, the larger the difference, the more it can suppress the generation of creases, but too large a difference will reduce production efficiency.

[0046] It can be understood that the length of the upper side of the upper anvil 1 is B3 = 2*(C1'+C2')+B1.

[0047] Exemplarily, the difference between the length B3 of the upper side of the upper anvil 1 and the length B1 of the horizontal section is 2*(C1'+C2'). In the present invention, the suppression of creases during the pulling process is due to the combined design of "C1'+C2'". The larger the value, the more conducive to suppressing the generation of creases, but at the same time, B1 will be smaller, thereby affecting the pulling efficiency. The appropriate "C1'+C2'" can be obtained through the preferred angle A, angle B and the length relationship between B1, B2, and B3 mentioned above.

[0048] Exemplarily, a projection length C1' of the first straight line segment C1 in the horizontal direction is 150 mm to 200 mm, and a projection length C2' of the second straight line segment C2 in the horizontal direction is 100 mm to 150 mm.

[0049] It can be understood that the upper anvil 1 is an inverted trapezoid that is "wide at the top and narrow at the bottom" as a whole, that is, B3>B1. By reducing the contact area between the upper anvil 1 and the forging blank, the press pressure during the initial pressing can be further reduced.

[0050] During the pulling process, the angle A, the angle B, the first straight line segment C1, and the second straight line segment C2 make the overlap between the pressed area and the unpressed area form a certain slope (such as Figure 6 As shown in the figure, the generation of creases is further effectively suppressed. The angle A makes the anvil width of the upper anvil 1 in a variable stage: B1-B2 as the contact surface between the upper anvil 1 and the forging blank 3 increases when the upper anvil 1 is stretched and pressed down. In this stage, the anvil width is gradually increasing and the height of the forging blank is gradually decreasing. In terms of process parameters, the anvil width ratio can be effectively improved, and the optimal parameter coverage range of the anvil width ratio in actual production can be increased.

[0051] Exemplarily, the length of the lower platform 2 is greater than or equal to the length of the forging blank after drawing.

[0052] Exemplarily, the width of the lower platform 2 is greater than or equal to the maximum width of the forging blank during the drawing process.

[0053] Exemplarily, the sum of the upper anvil height H2, the lower platform height and the maximum value of the blank height during the drawing process is less than the vertical clear spacing of the press.

[0054] On the other hand, the present invention also provides a variable anvil width forging method, which uses the variable anvil width forging device mentioned above.

[0055] Specifically, the variable anvil width forging method comprises the following steps:

[0056] (1) Compacting and stretching;

[0057] (2) Finishing and lengthening;

[0058] (3) Inverted octagon.

[0059] Among them, Figure 3 As shown, step (1) includes:

[0060] Step (1-1): connecting the upper anvil to the output end of the press, and placing the forging blank between the upper anvil and the lower platform;

[0061] Step (1-2): Compact and lengthen the first pass, set the press stroke target value according to the given process pressure reduction, press the upper anvil down to the press stroke target value, so that the height of the forging billet reaches the first pass target size, and flip the forging billet 180°.

[0062] Step (1-3): Compact and lengthen the second pass, set the press stroke target value according to the given process pressure reduction, press the upper anvil down to the press stroke target value, so that the height of the forging billet reaches the second pass target size, and flip the forging billet 90°.

[0063] Step (1-4): Compact and lengthen the third pass, set the press stroke target value according to the given process pressure reduction, press the upper anvil down to the press stroke target value, so that the height of the forging billet reaches the target size of the third pass, and flip the forging billet 180°.

[0064] Step (1-5): compact and lengthen the fourth pass, set the press stroke target value according to the given process pressure reduction, press the upper anvil down to the press stroke target value, so that the height of the forging billet reaches the fourth pass target size, and the compaction pass is completed.

[0065] The compaction passes of the variable anvil width forging method of the present invention are four (the compaction passes of the existing FM drawing method using an upper flat anvil are five), and the compaction passes are few, which is conducive to improving the actual forging production efficiency and reducing the manufacturing cost. At the same time, the use of the variable anvil width forging device can improve the surface quality of the forging and the compaction effect of the core.

[0066] It should be noted that Figure 3In the figure, H11 is the height of the forging billet before the first pressing pass; H11' is the height of the forging billet after the first pressing pass, H12 is the height of the forging billet before the second pressing pass, H12' is the height of the forging billet after the second pressing pass, H13 is the height of the forging billet before the third pressing pass, H13' is the height of the forging billet after the third pressing pass, H14 is the height of the forging billet before the fourth pressing pass, and H14' is the height of the forging billet after the fourth pressing pass.

[0067] Exemplarily, in step (1-1), before compaction and stretching, it is necessary to ensure that the center lines of the upper anvil, the forging blank and the lower platform in the width direction coincide with each other.

[0068] Exemplarily, in step (1-1), the length of the lower platform is greater than the length of the forging blank shaft after drawing.

[0069] Exemplarily, in step (1-2), the first pass of compaction and stretching has a reduction amount △11=(H11-H14') / 2+100.

[0070] Exemplarily, in step (1-3), the second pass of compaction and stretching has a reduction amount △12=(H11-H14') / 2+100.

[0071] Exemplarily, in step (1-4), the third pass of compaction and stretching has a reduction amount △13=(H13-H14') / 2+100.

[0072] Exemplarily, in step (1-5), the fourth pass of compaction and stretching has a reduction amount Δ14 = (H13-H14') / 2-100.

[0073] Exemplarily, in steps (1-2) to (1-5), the overlap amount D of adjacent passes is (1 / 2 to 1)*B1.

[0074] It should be noted that in the same pass, no pressure leakage area is allowed between two adjacent hammers.

[0075] The compaction and drawing of the present invention is performed in four passes in total. Due to its deformation characteristics, the difference between the target size of the second pass of compaction and drawing and the target size of the fourth pass of compaction and drawing is 150 mm to 300 mm, that is, H14'-H12'=(150-300) mm, so that when the fourth pass reaches the target size, the horizontal size of the forging blank is also close to the final target size.

[0076] Exemplarily, step (2) includes:

[0077] Step (2-1): Turn 90°, finish the first stretching pass, and press down to the target size of the first stretching pass.

[0078] Step (2-2): Turn 90°, perform the second pass of finishing and stretching, and press down to the target size of the second pass of finishing and stretching.

[0079] For example, Figure 4 As shown, step (3) includes: chamfering the octagon in four passes, and turning the forging blank 90° between adjacent passes.

[0080] It should be noted that Figure 4 In the figure, H21 is the height of the forging billet before the first pressing pass of the inverted octagonal shape; H21' is the height of the forging billet after the first pressing pass of the inverted octagonal shape, H22 is the height of the forging billet before the second pressing pass of the inverted octagonal shape, H22' is the height of the forging billet after the second pressing pass of the inverted octagonal shape, H23 is the height of the forging billet before the third pressing pass of the inverted octagonal shape, H23' is the height of the forging billet after the third pressing pass of the inverted octagonal shape, H24 is the height of the forging billet before the fourth pressing pass of the inverted octagonal shape, and H24' is the height of the forging billet after the fourth pressing pass of the inverted octagonal shape.

[0081] Exemplarily, the reduction amount of the first pass of the forging process is △21 = (H21-H14') / 2, the reduction amount of the second pass of the forging process is △22 = (H22-H14') / 2, the reduction amount of the third pass of the forging process is △23 = H23-H14'-100, and the reduction amount of the fourth pass is controlled according to the target size after forging blank finishing.

[0082] It should be noted that the device and method of the present invention are more suitable for ultra-large alloy steel shaft forgings weighing more than 260 tons.

[0083] The variable anvil width forging device and method of the present invention are further described below through specific embodiments.

[0084] Example 1

[0085] This embodiment provides a variable anvil width forging device, which includes an upper anvil 1 and a lower platform 2. The lower side of the upper anvil 1 includes a horizontal section and a first straight section C1 arranged at both ends of the horizontal section and inclined upward. The horizontal section forms an angle A with the first straight section C1, and the horizontal section and the first straight section C1 are transitionally connected through a fillet R1. The side of the upper anvil 1 is a second straight section C2 inclined toward the anvil body, the second straight section C2 forms an angle B with the vertical direction, and the second straight section C2 is transitionally connected with the first straight section C1 through a fillet R2. The angle A between the horizontal section and the first straight section C1 is 13°; the angle B between the second straight section C2 and the vertical direction is 9°; the radius of the circle corresponding to the fillet R2 between the horizontal section and the first straight section C1 is 550 mm; the radius of the circle corresponding to the fillet R1 between the second straight section C2 and the first straight section C1 is 250 mm. The horizontal projection length C1' of the first straight line segment C1 is 150mm; the horizontal projection length C2' of the second straight line segment is 100mm; the length B1 of the lower horizontal segment is 1500mm; B2=1800mm, the upper side length B3 of the upper anvil is 2000mm; the length of the lower platform 2 is greater than or equal to the length of the forging blank after drawing. The width of the platform 2 is greater than the maximum width of the forging blank during the drawing process. The sum of the upper anvil height H2, the lower platform height and the maximum height of the blank during the drawing process is less than the vertical clear spacing of the press.

[0086] Example 2

[0087] This embodiment provides a variable anvil width forging method, using the device of embodiment 1, for ultra-large alloy steel shaft forgings (30Cr2Ni4MoV, weight 300t), after upsetting, the forging billet shaft diameter is about H11 = 3300mm, and then drawn to a square billet of H14' = 2300mm according to the process, and then the octagonal is chamfered, specifically comprising:

[0088] (1) Connect the upper anvil to the output end of the press and place the forging blank between the upper anvil and the lower platform.

[0089] (2) The first pass of compaction and elongation, the pressing amount △11=(H11-H14') / 2+100=600mm, the press stroke target value is set, the upper anvil is pressed down to the press stroke target value, so that the forging billet height reaches the first pass target size H11'=H11-△11=2700mm, and the forging billet is turned 180°. In this process, the anvil width ratio B / H=(B1~B2) / (H11~H11')=0.45~0.67.

[0090] (3) The second pass of compaction and elongation, the pressing amount △12=(H11-H14') / 2+100=600mm, set the press stroke target value, press the upper anvil down to the press stroke target value, so that the forging billet height reaches the second pass target size H12'=H12-△12=2100mm, and the forging billet is turned 90°. In this process, the anvil width ratio B / H=(B1~B2) / H12=0.56~0.85.

[0091] (4) The third pass of compaction and elongation, after the first two passes of pressing, the forging blank is widened to H13≈3750mm, the pressing amount △13=(H13-H14') / 2+100, the press stroke target value is set, the upper anvil is pressed down to the press stroke target value, so that the forging blank height reaches the third pass target size H13'=H13-△13=2925mm, and the forging blank is turned 180°. In this process, the anvil width ratio B / H=(B1~B2) / H12=0.40~0.61.

[0092] (5) The fourth pass of compaction and elongation, the pressing amount △14 = (H13-H14') / 2-100, set the press stroke target value, press the upper anvil down to the press stroke target value, so that the forging height reaches the second pass target size H14' = H14-△14 = 2300mm. In this process, the anvil width ratio B / H = (B1~B2) / H12 = 0.51~0.78.

[0093] At this point, the compaction pass is completed. In summary, it can be seen that except for the first and third passes when the anvil width ratio is less than 0.5 during the initial pressing, the anvil width ratio in the remaining processes is higher than 0.5, and the optimal range of the anvil width ratio in the actual pressing process of each pass covers a wide range, which can effectively suppress the axial tensile stress appearing on the forging billet shaft body during the drawing process, thereby effectively avoiding the occurrence of cracks.

[0094] (6) Turn 90°, finish the first stretching pass, and press down to the target size of the first stretching pass.

[0095] (7) Turn 90°, perform the second pass of finishing and stretching, and press down to the target size of the second pass of finishing and stretching.

[0096] (8) The octagonal beveling process is performed in four passes, with the forging blank flipped 90° between passes.

[0097] The steel is flipped 90° between each pass. The reduction in the first pass is calculated according to △21=(H21-H14') / 2, the reduction in the second pass is calculated according to △22=(H22-H14') / 2, the reduction in the third pass is calculated according to △23=H23-H14'-100, and the reduction in the fourth pass is controlled according to the target size after forging billet finishing.

[0098] The forging obtained in this embodiment is as follows Figure 7As shown, it can be seen that its surface quality is good, which is different from that of Comparative Example 1. Figure 8 In comparison, the crease is significantly improved, which can significantly reduce the number of subsequent cleaning fires, effectively shorten the forging cycle, and reduce the manufacturing cost; at the same time, the forgings obtained in this embodiment are subjected to flaw detection, and the maximum equivalent diameter of the excessive defects in various regions of the finished forgings is less than Φ0.8. Compared with comparative example 1, the flaw detection quality of the core of the forging is significantly improved, and the bottom attenuation is smaller.

[0099] Example 3

[0100] This embodiment provides a variable anvil width forging method similar to that of Embodiment 2, except that the angle A between the horizontal segment and the first straight segment C1 is 8°.

[0101] The surface quality of the forging obtained in this embodiment is improved (compared with comparative example 1), but there are still a few obvious creases on the surface of the forging blank shaft body. At the same time, the finished forging after drawing in the embodiment is subjected to flaw detection, and it is found that the flaw detection quality of the core of the finished forging is improved (compared with comparative example 1), the bottom wave has no obvious attenuation, and the equivalent diameter of the maximum defect signal is less than Φ1.3.

[0102] Example 4

[0103] This embodiment provides a variable anvil width forging method similar to Embodiment 2, except that the difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil 1 and the upper side length B3 of the upper anvil is 150 mm.

[0104] The surface quality of the forging obtained in this embodiment is slightly improved (compared with comparative example 1), but there are still a few obvious creases on the surface of the shaft body. At the same time, the finished forging after drawing in the embodiment is subjected to flaw detection, and it is found that the flaw detection quality of the core of the finished forging is improved (compared with comparative example 1), the bottom wave has no obvious attenuation, and the equivalent diameter of the maximum defect signal is less than Φ1.4.

[0105] Example 5

[0106] This embodiment provides a variable anvil width forging method similar to that of Embodiment 2, except that the angle B between the second straight line segment C2 and the vertical direction is 6 degrees.

[0107] The surface quality of the forging obtained in this embodiment is improved (compared with comparative example 1), but there are still a few obvious creases on the surface of the shaft body. At the same time, the finished forging after drawing in the embodiment is subjected to flaw detection, and it is found that the flaw detection quality of the core of the finished forging is improved (compared with comparative example 1), the bottom wave has no obvious attenuation, and the equivalent diameter of the maximum defect signal is less than Φ1.4.

[0108] Example 6

[0109] This embodiment provides a variable anvil width forging method similar to that of embodiment 2, except that the angle B is reduced and the angle B2 is increased, so that the difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil 1 and the length B1 of the horizontal segment is

[0110]

[0111] The surface quality of the forging obtained in this embodiment is slightly improved (compared with comparative example 1), but there are still a few obvious creases on the surface of the forging blank shaft body. At the same time, the finished forging after drawing in this embodiment is subjected to flaw detection, and it is found that the flaw detection quality of the core of the finished forging is improved (compared with comparative example 1), the bottom wave has no obvious attenuation, and the equivalent diameter of the maximum defect signal is less than Φ1.5.

[0112] Comparative Example 1

[0113] This comparative example provides a forging method similar to that of Example 2, except that a conventional upper flat anvil is used, and the anvil width of the upper flat anvil used is 1500 mm. For ultra-large alloy steel shaft forgings (30Cr2Ni4MoV, weight 300 t), the diameter of the forged billet shaft after upsetting is about H11 = 3300 mm, and it is drawn to a square billet of H14' = 2300 mm according to the process, and then chamfered into an octagonal shape.

[0114] The specific steps include:

[0115] (1) Connect the upper flat anvil to the output end of the press, and place the forging blank between the upper flat anvil and the lower platform.

[0116] (2) The first pass of compaction and elongation, the pressing amount △11==400mm, set the press stroke target value, press the upper flat anvil down to the press stroke target value, so that the forging billet height reaches the first pass target size H11'=H11-△11=2900mm, and then the forging billet is turned 180°. In this process, the anvil width ratio B / H=0.45~0.53.

[0117] (3) The second pass of compaction and elongation, the pressing amount △12 = 500mm, set the press stroke target value, press the upper flat anvil down to the press stroke target value, so that the forging billet height reaches the second pass target size H12' = H12-△12 = 2400mm, and then the forging billet is turned 90°. In this process, the anvil width ratio B / H is 0.51-0.62.

[0118] (4) The third pass of compaction and elongation: After the first two passes of pressing, the forging blank is widened to H13≈3700mm, the pressing amount △13=600mm, the press stroke target value is set, the upper flat anvil is pressed down to the press stroke target value, so that the forging blank height reaches the third pass target size H13'=H13-△13=3100mm, and then the forging blank is turned 180°. In this process, the anvil width ratio B / H=(B1~B2) / H12=0.40~0.48.

[0119] (5) The fourth pass of compaction and elongation, the pressing amount △14 = 600mm, set the press stroke target value, press the upper flat anvil down to the press stroke target value, so that the forging billet height reaches the second pass target size H14' = H14-△14 = 2500mm, and then the billet is turned 90°. In this process, the anvil width ratio B / H = 0.48 ~ 0.60.

[0120] (6) Compact and elongate the fifth pass. After the third and fourth passes, the forging blank is widened to H15≈3000mm, the pressing amount △15=500mm, the press stroke target value is set, and the upper flat anvil is pressed down to the press stroke target value, so that the forging blank height reaches the third pass target size H13'=H15-△13=2500mm. In this process, the anvil width ratio B / H=0.50~0.60.

[0121] At this point, the compaction pass is completed.

[0122] (7) Turn 90°, perform the first pass of finishing and lengthening, and press down to the target size of 2500 mm.

[0123] (8) Turn 90°, perform the second finishing and lengthening pass, and press down to the target size of 2500 mm.

[0124] (9) Octagonal chamfering process: There are four passes for chamfering, and the forging blank is turned 90° between passes. The single-sided pressing amount of each pass is controlled to be 300mm.

[0125] This comparative example has a total of 5 passes. Compared with Example 2, the actual pressing passes are increased (the more pressing passes, the more overlap times, and the easier it is to produce creases). In addition, except for the second and fifth passes, the coverage range of the optimal interval of the anvil width ratio during the actual pressing process is narrower, as shown in Table 1, resulting in the creases at the overlap of the shaft body during the pressing process further expanding into cracks due to the axial tensile stress, resulting in poor surface quality of the forging blank and obvious creases on the surface of the forging, such as Figure 8 As shown, in order to clean it up and prevent the cracks from further aggravating, a longer cleaning fire time will be required later; at the same time, the finished forgings after drawing were tested for flaw detection, and it was found that the flaw detection quality of the core of the finished forgings was general, and a defect wave with unqualified core flaw detection appeared, the bottom wave was obviously attenuated, and the maximum defect signal equivalent diameter reached Φ1.9.

[0126] Table 1

[0127] path First pass Second pass Third Pass Fourth Pass Fifth Pass Size after pressing 2900mm 2400mm 3100mm 2500mm 2500mm anvil width ratio 0.45～0.53 0.51～0.62 0.40～0.48 0.48～0.60 0.50～0.60

[0128] Comparative Example 2

[0129] This comparative example provides a forging method similar to that of Example 2, except that an upper flat anvil is used, and the other steps are the same as those of Example 2.

[0130] The surface quality of the forging blank obtained in this comparative example is poor, the surface creases of the forging are obvious, the core flaw detection quality of the finished forging is poor, and a defect wave that fails the core flaw detection appears. The bottom wave attenuation is obvious, and the maximum defect signal equivalent diameter reaches Φ2.8.

[0131] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A variable anvil width forging device, characterized in that: The variable anvil width forging device includes an upper anvil and a lower platform. Taking the main viewing surface of the upper anvil as a reference, the lower side of the upper anvil includes a horizontal segment and a first straight segment arranged at both ends of the horizontal segment and inclined upward, the horizontal segment forms an angle with the first straight segment, and the horizontal segment and the first straight segment are connected by a rounded transition; the side of the upper anvil is a second straight segment inclined toward the anvil body, the second straight segment forms an angle with the vertical direction, and the second straight segment is connected to the first straight segment by a rounded transition.

2. The variable anvil width forging device according to claim 1, characterized in that: The included angle between the horizontal segment and the first straight segment is 10° to 15°.

3. The variable anvil width forging device according to claim 1, characterized in that: The included angle between the second straight line segment and the vertical direction is 8° to 10°.

4. The variable anvil width forging device according to claim 1, characterized in that: The radius of the circle corresponding to the rounded corner between the horizontal segment and the first straight line segment is 500 mm to 600 mm.

5. The variable anvil width forging device according to claim 1, characterized in that: The radius of the circle corresponding to the rounded corner between the second straight line segment and the first straight line segment is 200 mm to 300 mm.

6. The variable anvil width forging device according to claim 1, characterized in that: The difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil and the length B1 of the horizontal segment is 7. The variable anvil width forging device according to claim 1, characterized in that: The projection length of the first straight line segment in the horizontal direction is (B2-B1) / 2.

8. The variable anvil width forging device according to claim 1, characterized in that: The distance B2 between the intersections of the second straight line extension lines and the first straight line extension lines at both ends of the upper anvil is less than the length B3 of the upper side of the upper anvil.

9. The variable anvil width forging device according to claim 1, characterized in that: The difference between the distance B2 between the intersection of the second straight line extension line and the first straight line extension line at both ends of the upper anvil and the upper side length B3 of the upper anvil is 200 mm to 300 mm.

10. A variable anvil width forging method, characterized in that: A variable anvil width forging device is used as described in any one of claims 1 to 9.

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