A forging method for a circular ring or arc-shaped forging with a full-section boss

Abstract

The present invention discloses a forging forming method of a circular ring or arc-shaped forging with a full-section boss, and belongs to the field of metal processing technology. In view of the problem of poor continuity of the overall forged texture of the forging, the present invention performs the following forging steps on the circular ring blank: S310 performs upsetting on the end face of the circular ring blank; S321 performs leaking anvil upsetting on the end face of the blank after upsetting in S310 to form a full-section boss at the corresponding position; S322 performs one circle and two upsetting on the end face of the blank formed with the full-section boss, that is, after setting a dividing circle between the outer circle and the inner circle of the blank, the two areas are upset respectively to form a circular ring forging with a full-section boss; when forging an arc-shaped forging, it also includes: S330 divides the blank after upsetting in S322 to form an arc-shaped forging with a full-section boss. The present invention realizes integral forming, improves material utilization rate compared with segmented forging, improves forging rheology, ensures product forging texture, and improves forging product quality.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, in particular to a forging method for a circular ring or arc-shaped forging with a full-section boss. Background Art

[0002] A circular or arc-shaped forging with a full-section boss, that is, one or both of the upper and lower end surfaces of the circular or arc-shaped body have a boss consistent with its wall thickness, such as the circular forgings shown in Figures 6(a) and 6(b), or any arc-shaped forging divided along its height direction.

[0003] Taking arc forgings as an example, the traditional forging method of arc forgings is to divide the arc forgings into sections, forge a single thin plate and then weld them together. This method has low forging difficulty, but it also causes serious damage to the continuity of the overall forging texture of the forging, and there is a great risk to product quality.

[0004] In addition, some arc-shaped forgings have an outer diameter of 10m, an inner diameter of 7m, a wall thickness of nearly 1.5m, a height of only about 300mm in the non-boss area, and a height of only about 500mm in the boss area. The arc length is 15m, and there is a full-section boss with an arc length of nearly 1 meter. They are extra-large equipment forgings with complex shapes and high requirements for flaw detection and performance. Very few domestic companies can successfully manufacture such forgings. Summary of the invention

[0005] In order to solve the problem of poor overall forging texture continuity of annular or arc-shaped forgings with full-section bosses, the present invention provides a forging forming method of annular or arc-shaped forgings with full-section bosses. The technical solution is:

[0006] A forging method for a circular ring or arc-shaped forging with a full-section boss, using a circular ring blank to perform the following forging steps:

[0007] S310: upsetting the end surface of the circular ring blank;

[0008] S321 performs leak anvil upsetting on the end surface of the blank that has been upsetting in S310 to form a full-section boss at a corresponding position;

[0009] S322 performs two-time upsetting of the end face of the blank formed with the full-section boss, that is, after setting a split circle between the outer circle and the inner circle of the blank, the two areas are upset respectively to form a circular ring forging with a full-section boss;

[0010] When forging curved forgings, it also includes:

[0011] S330 splits the blank that has been upset by S322 to form an arc forging with a full-section boss.

[0012] In a preferred embodiment of the present invention, during upsetting in S310, the outer side edge of the upper flat anvil is aligned with the outer ring of the circular ring blank for upsetting.

[0013] In a preferred embodiment of the present invention, during S310 upsetting, the pressing amount of each anvil is 100±20 mm, and / or the rotation angle of each anvil is 20°±3°.

[0014] In a preferred embodiment of the present invention, during the upsetting in S310, the circular ring blank is upset for at most four turns.

[0015] In a preferred embodiment of the present invention, during S322 upsetting, the amount of pressure reduction per anvil on the end surface of the full-section boss area is 50±10 mm, the amount of pressure reduction per anvil on the end surface of the non-full-section boss area is 100±20 mm, and / or the rotation angle of each anvil in the two areas is 20°±3°.

[0016] In a preferred embodiment of the present invention, during the upsetting in S322, the annular blank area formed by the outer ring and the sub-ring is firstly upset, and then the annular blank area formed by the sub-ring and the inner ring is upset.

[0017] In a preferred embodiment of the present invention, during the upsetting step S322, the split ring is located at the center of the outer ring and the inner ring.

[0018] In a preferred embodiment of the present invention, the dimensions of the ring blank and the formed forging satisfy:

[0019] (D1 2 -d1 2 )×H1=(D2 2 -d2 2 )×H2×(360°-2β)÷360°+(D2 2 -d2 2 )×H3×2β÷360°,

[0020] Among them, the dimensions of the ring blank are: D1 is the outer diameter, d1 is the inner diameter, and H1 is the height;

[0021] The dimensions of formed forgings, i.e., annular or arc-shaped forgings with full-section bosses, are as follows: D2 is the outer diameter, d2 is the inner diameter, H2 is the height of the non-full-section boss area, H3 is the height of the full-section boss area, and β is the degree of the central angle of the inner arc of the full-section boss.

[0022] In a preferred embodiment of the present invention, the height of the circular ring blank does not exceed twice the wall thickness, and / or the inner diameter of the circular ring blank does not exceed the inner diameter of the formed forging.

[0023] In a preferred embodiment of the present invention, the ring blank is obtained by rolling.

[0024] In a preferred embodiment of the present invention, after both end faces of the circular ring blank are upset in S310, S321 and S322 are sequentially performed on one end face, and then S321 and S322 are repeated on the other end face.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention realizes integral forming by upsetting and forging the circular ring blank, thereby improving material utilization rate and forging rheology, ensuring product forging texture and improving forging product quality compared with segmented forging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a 200-ton electroslag ingot used in an embodiment of the present invention, wherein T represents the riser end of the ingot and B represents the bottom end of the ingot;

[0028] Figure 2 It is a schematic diagram of a blank to be expanded after upsetting and punching according to the present invention;

[0029] Figure 3 It is a schematic diagram of a circular ring blank after ring rolling forming according to the present invention;

[0030] Figure 4 The figure is a schematic diagram of the relative positions of the upper flat anvil, the ring blank and the backing plate when the ring blank is upsetting in the present invention, and it is a case of upsetting twice instead of one circle;

[0031] FIG5( a ) is a schematic diagram of a boss formed by anvil upsetting and stripping according to the present invention;

[0032] FIG5( b ) is a schematic diagram of an outer upsetting boss formed in a circle of two upsettings of the present invention;

[0033] FIG6( a ) is a schematic top view of the blank after all upsetting is completed in the present invention;

[0034] FIG6( b ) is a cross-sectional view taken along line AA in FIG6( a ). DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] In the description of the present invention, it is to be understood that when an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0037] Approximate terms in the specification and claims are used to modify quantities, indicating that the present invention is not limited to the specific quantity, but also includes acceptable and modified parts close to the quantity without causing changes in the relevant basic functions. Accordingly, the use of "about", "approximately", etc. to modify a numerical value means that the present invention is not limited to the exact numerical value. In some examples, the approximate terms may correspond to the accuracy of the instrument for measuring the numerical value. In the specification and claims of this application, range limitations can be combined and / or interchanged, and if not otherwise stated, these ranges include all subranges contained therein.

[0038] Embodiment 1:

[0039] An arc forging with a full-section boss is manufactured. The forging is semicircular and has bosses on both upper and lower end surfaces. The angle α between the center line of the boss and the edge of its arc body is 45°.

[0040] Using upper flat anvil Figure 3 For forging the circular ring blank shown, the anvil width should not be less than the wall thickness of the formed forging, that is, the wall thickness of the arc forging, that is, in this embodiment, the anvil width is not less than 1 / 2 (D2-d2) (Figure 6). In this embodiment, an upper flat anvil with a width of 1600mm can be used, which is the most commonly used upper flat anvil and is easy to obtain. The circular ring blank needs to have good roundness, and preferably, the difference between its major and minor axes does not exceed 50mm. The height of the circular ring blank is preferably not more than 2 times the wall thickness, so as to avoid shrinkage or even folding during subsequent upsetting. Specifically, if the height of the circular ring blank is greater than 2 times the wall thickness, that is, H1>D1-d1, there is a great risk of shrinkage in the height center area during upsetting, resulting in a shortage of the diameter size of the forging body, and even a risk of folding, which seriously affects the quality of the forging. The inner diameter of the ring blank is preferably not larger than the inner diameter of the formed forging, that is, the inner diameter of the arc forging, that is, d1≤d2. Based on the simulation results, after the ring blank is upset, the inner diameter of the ring blank will be reduced by 50-100mm. This size reduction is used as the forging allowance to ensure that the product forging size requirements are met. At the same time, the ring blank dimensions d1, D1 and H1 should satisfy the formula, which is as follows:

[0041] (D1 2 -d1 2 )×H1=(D2 2 -d2 2 )×H2×(360°-2β)÷360°+(D2 2 -d2 2 )×H3×2β÷360°,

[0042] Among them, the dimensions of the ring blank are: D1 is the outer diameter, d1 is the inner diameter, and H1 is the height;

[0043] The dimensions of formed forgings, that is, arc forgings with full-section bosses, are: D2 is the outer diameter, d2 is the inner diameter, H2 is the height of the non-full-section boss area, H3 is the height of the full-section boss area, and β is the degree of the central angle of the inner arc of the full-section boss.

[0044] When the arc forging is large in size, such as a super large equipment forging, the ring blank is preferably rolled. Rolling the ring blank can not only reduce the forging difficulty and improve the forging efficiency, but also avoid multiple re-forging due to the improved forging efficiency, and the blank undergoes sufficient metal rheology, so that a finer and more uniform product structure can be obtained, thereby obtaining better performance.

[0045] The following forging steps are performed on the ring blank:

[0046] S310 performs upsetting on the end surface of the ring blank.

[0047] At this time, the ring blank is a relatively tall and thin blank, and its height is also higher than the boss height. The main forming purpose of this step is to upset as quickly as possible and convert the height reduction into the increase of the outer diameter as soon as possible. Therefore, the amount of depression per anvil is preferably 100±20mm, and the rotation angle of each anvil is 20°±3°. Preferably, the amount of depression is set to 100mm, which is a large single deformation amount, so as to improve the forging efficiency. If it exceeds 100mm, there will be a greater risk of anvil connection, and there will be many anvil marks, which will affect the quality of the forging. The rotation angle of 20° is the approximate maximum angle at which the anvil will not be missed during rotary upsetting.

[0048] At the same time, since the width of the upper flat anvil is much larger than the thickness of the ring blank before the upsetting (the width of the upper flat anvil is about 1600mm), conventional upsetting will cause a high risk of folding the "waist" of the forging blank. In this method, as shown in Figure 5(a), the outer edge of the upper flat anvil is aligned with the outer ring of the ring blank, so that the excess part of the upper flat anvil that is not in contact with the blank is on the inner side of the ring blank. In this way, during upsetting, the outer blank undergoes free flow, and the situation of the difficult deformation area of ​​general upsetting will not occur. At the same time, the position of half the height of the ring blank is not prone to stress concentration and shrinkage, thereby reducing the risk of the "waist" expanding from shrinkage to folding. Since the inner side of the ring blank is relatively less deformed, its own folding risk is much smaller than that of the outer side of the ring. Therefore, the excess part of the upper flat anvil that is not in contact with the blank can be placed on the inner side of the ring blank.

[0049] During upsetting, the circular ring blank is subjected to upsetting for at most four turns. This forging deformation is basically the deformation that can be performed in one fire. If upsetting is continued, the forging temperature will be very low. Even when the forging temperature is about 850°C, only half of the rotation upsetting is performed, causing serious quality problems. In this embodiment, the upper and lower end surfaces of the arc forging have full-section bosses, so the upper and lower end surfaces of the circular ring blank are subjected to upsetting for two turns respectively.

[0050] S321 performs anvil-less upsetting on the end face of the blank that has been upsetting in S310 to form a full-section boss at the corresponding position, that is, a full-section boss position is reserved, and no pressing is performed at this position, and only the non-full-section boss area is upset, so as to form a full-section boss at the reserved position. During upsetting, the pressing amount of each anvil is 50±10mm. In order to avoid excessive single pressing amount causing the boss to collapse, or even causing cracks or large anvil marks, which will affect the end face size of the forging, the pressing amount is adjusted to half of the original 100mm, and / or the rotation angle of each anvil is 20°±3°.

[0051] S322 performs two-time upsetting of the end face of the blank formed with the full-section boss, that is, after setting a sub-circle between the outer and inner circles of the blank, the two areas are upset respectively, so as to promote radial rheology, especially when the wall thickness of the blank is large, and a single upsetting of one circle is difficult to ensure sufficient radial rheology during upsetting. The outer circle is the outermost edge of the blank, and the inner circle is the innermost edge of the blank.

[0052] During upsetting, the annular blank area formed by the outer ring and the split ring is firstly upset, and then the annular blank area formed by the split ring and the inner ring is upset. The split ring is located at the center of the outer ring and the inner ring, that is, d=(D0+d0) / 2 is used to determine the outer and inner upsetting dividing lines, d is the diameter of the split ring, D0 is the actual outer diameter of the blank in this step, and d0 is the actual inner diameter of the blank in this step. In this embodiment, the split ring is about 800mm away from the outer ring.

[0053] That is, the outer side is first upset and then the inner side is upset. As shown in FIG5(b), during the first upsetting, the upper flat anvil only upsets the outer side area with a wall thickness of about 800 mm, and during the second upsetting, the remaining wall thickness area is upset.

[0054] At the same time, in order to avoid excessive local rheological deformation, different reductions are used for upsetting the boss and non-boss areas. The reduction per anvil on the end face of the full-section boss area is 50±10mm, and the reduction per anvil on the end face of the non-full-section boss area is 100±20mm. The rotation angle of each anvil in the two areas is 20°±3°. In addition, attention should be paid to the anvil connection in the transition area between the boss and the non-boss. In conventional upsetting and stripping anvils, the rotation angle of each anvil is 20°±3°, but in the arc length of 1000mm in the transition area between the boss and the non-boss, the rotation angle of each anvil is 10°±3°, and the pressing amount is 50mm in the boss area, 75mm in the transition area, and 100mm in the non-boss area. Here, since the arc length of the transition area is 1000mm, only one anvil connection is required, so the pressing amount is 75mm at this time, that is, 50 and 100 are the initial and final values ​​of the geometric progression. When the anvil is connected once, the pressing amount is the middle value of the two, and when the anvil is connected multiple times, it is calculated according to the geometric progression, so as to avoid uneven deformation and the appearance of ellipses.

[0055] After S321 and S322 are sequentially performed on one end face of the blank, the blank is turned over and S321 and S322 are repeated on the other end face, thereby forming full-section bosses on both end faces.

[0056] In order to avoid damaging the full-section boss on one end face that has been formed, the blank is placed on a special pad after turning over. The special pad contains a groove with a size corresponding to the boss, that is, the groove fits with the boss, and then subsequent forging is carried out.

[0057] Finally, S330 divides the blank that has completed all the upsetting to form an arc forging with a full-section boss. As shown in Figure 6(a), the blank is divided into two semicircular arcs in the machining process, and the α angle is 45°.

[0058] Embodiment 2:

[0059] Based on Example 1, this embodiment includes a forging method for a ring blank, specifically:

[0060] S100 pre-forming stage:

[0061] The steel ingot is subjected to upsetting and drawing-upsetting and punching-core rod expansion in sequence to obtain a preform.

[0062] It is preferred to perform overall upsetting and stretching at a large deformation rate twice.

[0063] like Figure 1 The 200-ton electroslag ingot shown in the figure was subjected to two large deformation rate overall upsetting and drawing compaction operations, and then put into the furnace for insulation at 1180℃~1220℃ for 23±2h, and then taken out of the furnace for upsetting and punching to obtain Figure 2 The forging billet shown is placed in a furnace and kept at 1180°C to 1220°C for 17±2h, and then the hole is expanded with a mandrel to obtain a prefabricated ring.

[0064] During the drawing process, the temperature of the forging billet is always kept in the range of 850℃~1220℃, which is the forgeable temperature for forging. Above this temperature, there is a higher risk of cracking. When forging below this temperature, the forging deformation resistance is large and the forming efficiency is low.

[0065] The preform obtained by expanding the hole has an inner diameter of 4000 mm, a single-side wall thickness of 800 mm, a height of 1600 mm, and good roundness.

[0066] S200 intermediate forming stage:

[0067] The preform is rolled to obtain a circular ring blank.

[0068] The prefabricated ring is placed in a heating furnace for insulation heating at 1200℃~1250℃ for 15±2h, and then taken out of the furnace for rolling. During rolling, it is necessary to pay attention to the uniformity of the pressing amount of each circle. The height is rolled from 1600mm to 1000mm circle by circle. The roundness of the ring blank is controlled after rolling. The difference between the major and minor axes of the ring does not exceed 50mm. The obtained ring blank has an inner diameter of ~7000mm, a single-side wall thickness of ~800mm, and a height of ~1000mm.

[0069] After the ring blank is obtained, the S300 final forming stage is carried out:

[0070] The ring blank is placed in a heating furnace for heat preservation at 1180℃~1220℃ for 10±2h and then forged, i.e., S310, S321, S322 and S330 are performed. After S310, the blank height is ~600mm, and the total height of the boss in the final S330 is ~500mm, and the height of other areas is ~300mm.

[0071] In the above forging process, in order to ensure the uniformity of the final forging deformation, it is necessary to control the heating conditions and evenly heat the billet to avoid high local temperature of the billet, uneven deformation, and affect the size of the forging.

[0072] When manufacturing a circular ring forging with a full-section boss, Example 1 or Example 2 may be used, except that the S330 segmentation is not included.

[0073] In summary, the present invention realizes integral forming by upsetting and forging the circular ring blank, which improves material utilization compared to segmented forging, improves forging rheology, ensures product forging texture, and improves forging product quality.

[0074] In addition, it should be understood that the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A forging method for a circular ring or arc-shaped forging with a full-section boss, characterized in that: The following forging steps are performed using a ring blank, and the height of the ring blank does not exceed 2 times the wall thickness: S310: upsetting the end surface of the circular ring blank, aligning the outer side of the upper flat anvil with the outer ring of the circular ring blank for upsetting, the anvil width is not less than the wall thickness of the formed forging, the pressing amount of each anvil is 100±20mm, and the rotation angle of each anvil is 20°±3°; S321 performs leak anvil upsetting on the end surface of the blank that has been upsetting in S310 to form a full-section boss at a corresponding position; S322: The end face of the blank formed with the full-section boss is subjected to two upsettings in one circle, that is, a split circle is set between the outer circle and the inner circle of the blank, and the two areas are respectively upset to form a circular ring forging with a full-section boss, and the pressing amount of each anvil on the end face of the full-section boss area is 50±10mm, and the pressing amount of each anvil on the end face of the non-full-section boss area is 100±20mm, and the rotation angle of each anvil in the two areas is 20°±3°; When forging curved forgings, it also includes: S330 splits the blank that has been upset by S322 to form an arc forging with a full-section boss.

2. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to claim 1, characterized in that: During the upsetting step S310, the circular ring blank is upset for at most four turns.

3. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to claim 1, characterized in that: When S322 is upsetting, the split ring is located in the center of the outer ring and the inner ring.

4. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to claim 1, characterized in that: The dimensions of the ring blank and the formed forging meet the following requirements: (D1 2 -d1 2 )×H1=(D2 2 -d2 2 )×H2×(360°-2β)÷360°+(D2 2 -d2 2 )×H3×2β÷360°, Among them, the dimensions of the ring blank are: D1 is the outer diameter, d1 is the inner diameter, and H1 is the height; The dimensions of formed forgings, i.e., annular or arc-shaped forgings with full-section bosses, are as follows: D2 is the outer diameter, d2 is the inner diameter, H2 is the height of the non-full-section boss area, H3 is the height of the full-section boss area, and β is the degree of the central angle of the inner arc of the full-section boss.

5. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to claim 1, characterized in that: The inner diameter of the circular ring blank does not exceed the inner diameter of the formed forging.

6. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to claim 1, characterized in that: The circular ring blank is obtained by rolling.

7. The forging method of a circular ring-shaped or arc-shaped forging with a full-section boss according to any one of claims 1 to 6, characterized in that: After both end faces of the circular ring blank are upset in S310, S321 and S322 are sequentially performed on one end face, and then the blank is turned over and S321 and S322 are repeated on the other end face.

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