A large complex head forging forming method and forming tooling

Abstract

The present invention discloses a large-scale complex head forging forming method and forming tooling, which belongs to the field of head forming manufacturing technology, and solves the technical problem that the existing forging forming tooling and forging forming method cannot forge large-scale complex head forgings. The tooling includes an upper ring body and a forming ring, wherein the upper ring body is connected to a press, and the forming ring is detachably connected to the upper ring body; it also includes a punch base, which is a hollow hemispherical shape, with the spherical surface of the punch base facing upward and its opening facing downward, and the outer wall of the spherical surface of the punch base is provided with a first annular step to a fourth annular step with increasing radius from top to bottom; the first annular step to the fourth annular step are correspondingly provided with a first support ring to a fourth support ring; the center line of the punch base coincides with the center line of the forming ring; the head blank is arranged between the forming ring and the top surface of the punch base. The present invention can effectively improve the microstructure of the head forging, improve the forging performance, and greatly reduce the manufacturing cost of the auxiliary tool.

Description

Technical Field

[0001] The invention relates to the technical field of end cap manufacturing, and in particular to a forging forming method and forming tooling for a large and complex end cap. Background Art

[0002] With the rapid development of national energy, chemical, aerospace, marine engineering and other industries, my country's industrial equipment is gradually evolving towards integration and large-scale development. At present, pressure vessels are also showing a trend of large-scale development, and the head, as a key component of the container, also has high requirements for strength, toughness, impact performance, low temperature performance, corrosion resistance and radiation performance to adapt to harsh working conditions.

[0003] The forming quality of the head will determine the service life of the pressure vessel. The current manufacturing processes mainly include welding and stamping. Although the welding process has been greatly improved, the structure spliced ​​by welding can never form a complete metal streamline. Since the pressure vessel is in a harsh operating environment of high temperature and high pressure for a long time, it is very easy to cause uneven stress distribution and stress concentration, and it is easy to cause fatigue, creep and damage. Moreover, this welding manufacturing method has complex process, long welding cycle and high manufacturing cost.

[0004] In the prior art, a circular punch is often used for stamping. Although the structure of the head formed by such stamping is simple, it is not suitable for forging large and complex heads. In addition, when the existing circular punch is used for stamping, it is difficult to operate on site and is not easy to demould, which is not conducive to actual production. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a large complex head forging method and forming tooling to solve the existing technical problem of difficult forging of ultra-large complex head forgings.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] On the one hand, the present invention provides a forging tool for a large complex head, comprising an upper die assembly and a lower die assembly, wherein the upper die assembly comprises an upper ring body and a forming ring, the upper ring body is connected to a press, and the forming ring is detachably connected to the upper ring body;

[0008] The lower die assembly includes a punch base, which is a hollow hemispherical shape, with the spherical surface of the punch base facing upward and the opening facing downward. The outer wall surface of the spherical surface of the punch base is provided with a first annular step, a second annular step, a third annular step and a fourth annular step with increasing radius from top to bottom in sequence; the first annular step, the second annular step, the third annular step and the fourth annular step are provided with a first support ring, a second support ring, a third support ring and a fourth support ring respectively;

[0009] The center line of the punch base coincides with the center line of the forming ring; the head blank is arranged between the forming ring and the top surface of the punch base.

[0010] In one possible design, the upper ring body is a hollow hood type, and the top of the upper ring body is connected to the press;

[0011] The forming ring is a hollow annular belt; the top surface of the forming ring is detachably connected to the upper ring body through a pin assembly;

[0012] The head blank is in the shape of a round cake; the outer diameter of the round cake-shaped head blank is equal to the outer diameter of the forming ring; the forming ring is arranged above the round cake-shaped head blank, and the forming ring can exert downward pressure on the round cake-shaped head blank to deform the round cake-shaped head blank into a head shape;

[0013] An annular cavity is arranged on the bottom surface of the round pancake-shaped head blank, and the annular cavity can be embedded with the first supporting ring arranged on the top surface of the punch base.

[0014] In a possible design, the top surface of the first support ring is a first annular arc surface, the top surface of the second support ring is a second annular arc surface, the top surface of the third support ring is a third annular arc surface, and the top surface of the fourth support ring is a fourth annular arc surface;

[0015] When the press applies downward pressure to the head plate blank through the upper ring body and the forming ring, the ring edge of the head plate blank deforms downward, gradually and sequentially fits onto the first annular arc surface, the second annular arc surface, the third annular arc surface and the fourth annular arc surface.

[0016] In a possible design, the pin shaft assembly includes a plurality of first pin shafts, second pin shafts and connecting pin irons, and the number of the first pin shafts, the second pin shafts and the connecting pin irons are the same;

[0017] The upper ring body is provided with a plurality of first pin holes; the forming ring is provided with a plurality of second pin holes, and the connecting pin iron is provided with a third pin hole and a fourth pin hole at the same time, and the number of the first pin holes, the second pin holes, the third pin holes and the fourth pin holes are equal;

[0018] When the upper ring body and the forming ring are connected by the pin shaft assembly, after aligning the first pin hole and the third pin hole, the first pin shaft is inserted into the third pin hole and the first pin hole; after aligning the second pin hole and the fourth pin hole, the second pin shaft is inserted into the fourth pin hole and the second pin hole.

[0019] On the other hand, the present invention also provides a forging method for a large complex head, using the forging tool for the large complex head, the forging method comprises the following steps:

[0020] Step 1, forging the steel ingot to obtain a cylindrical steel billet;

[0021] The hot-delivered steel ingot is subjected to jaw pressing, chamfering, gas cutting nozzle discarding, upsetting, KD drawing and jaw cutting in turn;

[0022] Step 2, performing double-sided rotary forging on the cylindrical steel billet to obtain a head plate billet;

[0023] The cylindrical steel billet is subjected to upsetting and spinning to obtain a head plate billet, and the spinning is performed by a double-sided rotary forging method;

[0024] Step 3: Use the forging tooling of large and complex heads to perform stamping and forming of the head blank;

[0025] The round cake-shaped head blank is placed between the forming ring and the top surface of the punch base; the annular cavity on the bottom surface of the head blank is engaged with the first support ring, the press is started and the downward stroke is set, and the press can exert downward pressure on the round cake-shaped head during the downward movement of the forming ring driven by the upper ring body. After being subjected to the downward pressure, the round cake-shaped head blank begins to gradually deform from the initial round cake shape to a head shape. When the downward stroke is reached, the stamping forming is completed, and a large and complex head is obtained.

[0026] Furthermore, in step 1, the steel ingot is heated to 1250°C-1270°C and kept warm for 35-40 hours, and after the heat preservation, the ingot body is chamfered, the jaws are pressed, the nozzles are discarded and the jaws are discarded.

[0027] Furthermore, in step 1, after the gas cutting nozzle and jaw discard, the steel ingot is heated to 1250°C and kept warm for 50-60 hours, and then upsetting and KD stretching are performed after the insulation, and the gas cutting jaw is unloaded after completion.

[0028] Furthermore, in step 1, the upsetting ratio and the drawing ratio during upsetting and drawing are both controlled within the range of 2.2 to 2.5.

[0029] Furthermore, in step 1 and step 2, the forging temperature during upsetting and drawing is 750°C-1250°C.

[0030] Furthermore, in step 3, during the stamping process, the inner surface of the head plate blank contacts the second annular arc surface, the third annular arc surface and the fourth annular arc surface in sequence. When the inner surface of the head plate blank contacts the fourth annular arc surface, the stamping process is stopped.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] (1) In the prior art, stamping is mostly performed using a round punch, such as Figure 2As shown, the stamped head has a simple structure, and for large-sized complex heads, this stamping method is difficult to operate on site, not easy to demould, and not conducive to actual production. Compared with the prior art, the large-scale complex head forging tooling provided by the present invention has the characteristics of strong versatility and wide application range, which can greatly reduce the manufacturing cost of auxiliary tools.

[0033] (2) The present invention provides an annular cavity on the bottom surface of the head blank, and the annular cavity of the head blank is embedded with the first support ring, which can meet the forming requirements and positioning of the boss pipe at the bottom of the head and support the head blank.

[0034] (3) The forging method for a large complex head provided by the present invention can effectively improve the microstructure of the head forging and enhance the performance of the forging.

[0035] (4) The large and complex head of the present invention contains a large-sized connecting pipe and a complex structure. The head plate blank used for punching is difficult to forge and has a complex structure. The present invention adopts a double-sided rotary forging method. On the one hand, it can form a boss connecting pipe structure, and on the other hand, it can ensure that the deformation of both sides of the plate is uniform, thereby avoiding the scrapping of the forging due to the different diameters of the upper and lower planes of the plate due to single-sided forging.

[0036] (5) The present invention controls the upsetting ratio and the drawing ratio of the steel ingot within the range of 2.2-2.5 because the steel ingot is a solid forging. Controlling them within the above range can ensure the compaction of the core of the solid forging, thereby ensuring the quality of flaw detection at the core of the forging.

[0037] 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 embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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.

[0039] Figure 1 This is a schematic diagram of the structure of a large and complex head;

[0040] Figure 2 It is a structural schematic diagram of an existing circular punch head;

[0041] Figure 3 It is a structural schematic diagram of the forging forming tooling;

[0042] Figure 4 Schematic diagram of the preparation process of the head slab Figure 1 ;

[0043] Figure 5 Schematic diagram of the preparation process of the head slab Figure 2 ;

[0044] Figure 6 Schematic diagram of the preparation process of the head slab Figure 3 ;

[0045] Figure 7 Schematic diagram of the preparation process of the head slab Figure 4 ;

[0046] Figure 8 Schematic diagram of the preparation process of the head slab Figure 5 ;

[0047] Fig. 9 Schematic diagram of the preparation process of the head slab Figure 5 ;

[0048] Fig.10 This is a schematic diagram before the head plate blank is stamped using a forging tool;

[0049] Fig.11 This is a schematic diagram of stamping the head plate blank using a forging tool;

[0050] Fig.12 This is a schematic diagram of the before and after comparison of the head plate blank after stamping using the forging forming tool;

[0051] Fig.13 is a cross-sectional view of the first support ring;

[0052] Fig.14 is a cross-sectional view of the second support ring;

[0053] Fig.15 is a cross-sectional view of the third support ring;

[0054] Fig.16 is a cross-sectional view of the fourth support ring.

[0055] Reference numerals:

[0056] 1-upper ring body; 2-forming ring; 3-head blank; 4-punch base; 5-first support ring; 6-second support ring; 7-third support ring; 8-fourth support ring; 9-widening hammer head; 10-bottom washer; 11-pin assembly; 12-first annular arc surface; 13-second annular arc surface; 14-third annular arc surface; 15-fourth annular arc surface; 16-first pin shaft; 17-second pin shaft; 18-connecting pin iron; 19-pad; 20-fifth support ring; 21-sixth support ring.

[0057] Among them, SR represents the radius of the spherical head; H1 for Figure 4 The height of the boss reserved in the middle of the middle head slab, mm; D1 is Figure 4 The diameter of the boss reserved in the middle of the middle head slab, mm; H 2 for Figure 7 Boss height before medium upsetting, mm; h 1 for Figure 6 The height of the boss after pressing down, mm; h 2 for Figure 8 Boss height after medium upsetting, mm. DETAILED DESCRIPTION

[0058] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention 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.

[0059] Figure 1 This is a rough processing diagram of a large pressure vessel head of the present invention. This head, as the main pressure-bearing component of the pressure vessel, is not only oversized and thin-walled with a thickness of 100-250mm, but also has a large boss connection on the top, a complex shape, and is difficult to form. Therefore, it has high requirements on the production process and forming method.

[0060] In view of the above large and complex head structure, the present invention provides a forging tool for a large and complex head, such as Figures 2 to 12 As shown, the forging forming tooling includes an upper die assembly and a lower die assembly, the upper die assembly includes an upper ring body 1 and a forming ring 2, the upper ring body 1 is connected to a press, and the forming ring 2 is detachably connected to the upper ring body 1; the lower die assembly includes a punch base 4, the punch base 4 is a hollow hemispherical shape, the spherical surface of the punch base 4 faces upward, and the opening faces downward, and the outer wall of the spherical surface of the punch base 4 is provided with a first annular step, a second annular step, a third annular step and a fourth annular step with increasing radius from top to bottom; the first annular step, the second annular step, the third annular step and the fourth annular step are arranged parallel to each other, and a first support ring 5, a second support ring 6, a third support ring 7 and a fourth support ring 8 are correspondingly arranged thereon; the center line of the punch base 4 coincides with the center line of the forming ring 2; the head blank 3 is arranged between the upper die assembly and the lower die assembly.

[0061] Specifically, Figure 3As shown, the upper ring body 1 is installed on a press (for example, a 10,000-ton hydraulic press), and the forming ring 2 is connected to the upper ring body 1; the punch base 4 is hemispherical, the spherical surface of the punch base 4 faces upward, and its opening faces downward, and the first annular step, the second annular step, the third annular step and the fourth annular step are processed on the outer wall of the spherical surface from top to bottom in sequence, and the radii of the first annular step, the second annular step, the third annular step and the fourth annular step increase in sequence and are arranged parallel to each other, a first supporting ring 5 is arranged on the first annular step, a second supporting ring 6 is arranged on the second annular step, a third supporting ring 7 is arranged on the third annular step, and a fourth supporting ring 8 is arranged on the fourth annular step; the first annular step to the fourth annular step and the correspondingly arranged thereon are The first to fourth support rings 5 ​​and the punch base 4 together constitute the lower die assembly. The lower die assembly is adjusted so that the center line of the punch base 4 of the lower die assembly coincides with the center line of the forming ring 2 of the upper die assembly. The head blank 3 is placed between the forming ring 2 and the top surface of the punch base 4. An annular cavity is provided on the bottom surface of the head blank 3 (the matching surface with the top surface of the punch base 4). Since the first support ring 5 is located on the top surface of the punch base 4, the cavity on the bottom surface of the head blank 3 is embedded with the first support ring 5 located on the top surface of the punch base 4. When the head blank 3 is placed between the forming ring 2 and the top surface of the punch base 4, the first support ring 5 can not only support the head blank 3, but also position the head blank 3. In addition, when the head blank 3 is stamped, the 10,000-ton hydraulic press is started to press the forming ring 2 downward at a uniform speed. Under the pressure of the forming ring 2, the edge of the head blank 3 begins to move downward and deform. The head blank 3 begins to deform from an initial round cake shape to a head shape. During the deformation process, the bottom surface of the head blank 3 gradually becomes an inner surface and contacts the top surface of the second support ring 6, the top surface of the third support ring 7 and the top surface of the fourth support ring 8 in turn. When the inner surface of the head blank 3 fits with the top surface of the fourth support ring 8, the head blank 3 is stamped successfully. At this time, the 10,000-ton hydraulic press is closed.

[0062] In the prior art, stamping is usually performed using a round punch, such as Figure 2 As shown, the stamped head has a simple structure, and for large-sized complex heads, this stamping method is difficult to operate on site, not easy to demould, and not conducive to actual production. Compared with the prior art, the large-scale complex head forging tooling provided by the present invention has the characteristics of strong versatility and wide application range, which can greatly reduce the manufacturing cost of auxiliary tools.

[0063] It should be noted that if Fig.12As shown, the upper ring body 1 is a hollow cover type, and the top of the upper ring body 1 is connected to the press; the forming ring 2 is a hollow annular belt; the top surface of the forming ring 2 is detachably connected to the upper ring body 1 through a pin shaft assembly 11; the head blank 3 is a disc-shaped head blank 3; the outer diameter of the disc-shaped head blank 3 is equal to the outer diameter of the forming ring 2; the forming ring 2 is arranged above the disc-shaped head blank 3, and the forming ring 2 can apply downward pressure to it from the edge of the top surface of the disc-shaped head blank 3, so that the disc-shaped head blank 3 is deformed into a head shape.

[0064] It should also be emphasized that the cross-section of the hollow annular belt forming ring 2 of the present invention along the vertical direction is an inverted right-angled trapezoid, and the inner side surface of the forming ring 2 is an arc-shaped surface and can fit with the upper surface (deformed outer surface) of the head blank 3 during the stamping process of the head blank 3.

[0065] In order to meet the forming requirements of the boss pipe at the bottom of the head and position the head blank 3, an annular cavity is provided on the bottom surface of the head blank 3, and the annular cavity of the head blank 3 is embedded with the first support ring 5.

[0066] Compared with the prior art, the present invention can not only support the head blank 3 but also position the head blank 3 by providing the first support ring 5, so that the boss pipe at the bottom of the head blank 3 can finally meet the forming requirements.

[0067] In order to meet the forming requirements of the boss pipe of the head blank 3, such as Figures 13 to 16 As shown, the top surface of the first support ring 5 of the present invention is a first annular arc surface 12. The first annular arc surface 12 can not only fit with the top surface of the annular concave cavity of the head blank 3, but also, setting the top surface of the first support ring 5 as an annular arc surface can increase its contact area with the bottom surface of the head blank 3, so that the first support ring 5 can better support and fix the head blank 3.

[0068] It should be noted that there are gaps between the inner and outer sides of the first support ring and the head plate blank, and the size of the gaps is 5-10 mm.

[0069] Similarly, in order to better support and fix the head blank 3, the contact area between the top surface of the second support ring 6, the top surface of the third support ring 7 and the top surface of the fourth support ring 8 and the bottom surface (or inner surface) of the head blank 3 is increased. The top surface of the second support ring 6 of the present invention is the second annular arc surface 13, the top surface of the third support ring 7 is the third annular arc surface 14, and the top surface of the fourth support ring 8 is the fourth annular arc surface 15; when the hydraulic press applies pressure to the head blank 3 through the upper ring body 1 and the forming ring 2, the head blank 3 is sequentially attached to the first annular arc surface 12, the second annular arc surface 13, the third annular arc surface 14 and the fourth annular arc surface 15.

[0070] It should be noted that the relative heights of the first support ring 5 , the second support ring 6 , the third support ring 7 , and the fourth support ring 8 in the vertical direction can be adjusted according to the radius of the large and complex head.

[0071] In order to ensure the firmness of the connection between the upper ring body 1 and the forming ring 2 , the forming ring 2 of the present invention is connected to the upper ring body 1 via a pin assembly 11 .

[0072] Specifically, Fig.12 As shown, the pin shaft assembly 11 includes a plurality of first pin shafts 16, a plurality of second pin shafts 17 and a plurality of connecting pin irons 18, and the number of the first pin shafts 16, the second pin shafts 17 and the connecting pin irons 18 is the same; a plurality of first pin holes are provided on the upper ring body 1; a plurality of second pin holes are provided on the forming ring 2, and a third pin hole and a fourth pin hole are provided on the connecting pin iron 18 at the same time, and the number of the first pin hole, the second pin hole, the third pin hole and the fourth pin hole is equal; when connecting the upper ring body 1 and the forming ring 2, the first pin hole and the third pin hole are aligned and the second pin hole and the fourth pin hole are aligned, at this time, the first pin shaft 16 is inserted into the third pin hole and the first pin hole on the connecting pin iron 18, and the second pin shaft 17 is inserted into the fourth pin hole and the second pin hole of the connecting pin iron 18, thereby connecting the upper ring body 1 and the forming ring 2 together.

[0073] It should be noted that, for the large complex head of the present invention, the head slab 3 is in the shape of a round cake, the diameter of the head slab 3 is 6700mm-6900mm, the weight of the head slab 3 forging is 100t-150t, and the weight of the steel ingot required for forging the head slab 3 is 150t-225t.

[0074] The ball radius of the large complex head of the present invention is 3000-5000mm. For large complex heads with different ball radii, they can be formed by adjusting the heights of the first support ring 5, the second support ring 6, the third support ring 7 and the fourth support ring 8.

[0075] Compared with the prior art, the present invention enables the forging tool to punch heads with different ball radii by adjusting the heights of the first support ring 5 to the fourth support ring 8, thereby increasing the applicability of the forging tool.

[0076] In order to adjust the height of the first support ring 5 to the fourth support ring 8 so as to be suitable for complex heads with different ball radii, the forging tooling of the present invention further includes a ring-shaped or arc-shaped pad 19; Fig.11 and Fig.12As shown, taking the first support ring 5 as an example, when the height of the first support ring 5 needs to be adjusted, the annular or arc-shaped pad 19 is placed under the first support ring 5 (that is, placed on the first annular step), thereby increasing the height of the first support ring 5; similarly, when the height of the second support ring 6 to the fourth support ring 8 needs to be adjusted, the annular or arc-shaped pads 19 of corresponding sizes are placed on the corresponding annular steps.

[0077] Compared with the prior art, the present invention can increase the height of the first support ring 5 to the fourth support ring 8 by arranging a pad 19 at the bottom of the first support ring 5 to the fourth support ring 8, which not only ensures that the forging forming tooling can punch large and complex heads with different ball radii, but also, arranging annular or arc-shaped pads 19 on each annular step of the punch base 4 is relatively easy to operate and has strong applicability.

[0078] It should be emphasized that the present invention can adjust the heights of the first support ring 5 to the fourth support ring 8 at the same time, and can also adjust the height of a certain support ring individually, so as to achieve the purpose of stamping large and complex heads with different ball radii; in addition, according to the different stamping strokes corresponding to the ball radii of large and complex heads of different sizes, the stamping stroke of the press of the present invention is 1000-3000mm.

[0079] It should be noted that, in order to better support the head blank 3, the forging tooling of the present invention further includes a fifth support ring 20 and a sixth support ring 21. Fig.12 As shown, the punch base 4 is also provided with a fifth annular step and a sixth annular step, the fifth annular step is provided below the fourth annular step, and the sixth annular step is provided below the fifth annular step. The fifth support ring 20 is provided on the fifth annular step, and the sixth support ring 21 is provided on the sixth annular step; the top surface of the fifth support ring 20 is the fifth annular arc surface, and the top surface of the sixth support ring 21 is the sixth annular arc surface; when the head plate blank 3 is stamped, the inner surface of the head plate blank 3 gradually contacts the second annular arc surface 13 to the fourth annular arc surface 15, and then contacts the fifth annular arc surface and the sixth annular arc surface in sequence, at which time, the fifth annular arc surface and the sixth annular arc surface are in contact with the inner surface of the head plate blank 3 at the corresponding position, so that the fifth support ring 20 and the sixth support ring 21 play the role of supporting the head plate blank 3.

[0080] It should also be emphasized that the number of support rings can be adjusted according to actual conditions.

[0081] The present invention also provides a forging method for a large complex head, comprising the following steps:

[0082] Step 1, forging the steel ingot to obtain a cylindrical steel billet;

[0083] Step 2, performing double-sided rotary forging on the cylindrical steel billet to obtain a head plate billet 3;

[0084] Step 3: Use forging tooling to perform stamping of the slab.

[0085] It should be noted that in the above step 1, since the weight of the head slab 3 is 100t-150t, the weight of the steel ingot used to forge the head slab 3 is generally 1.5 times the weight of the final forging (head slab 3), in order to compensate for the nozzle removal amount, the riser removal amount and the fire consumption of each fire, and the head slab 3 is manufactured by a large steel ingot obtained by the method of vacuum smelting + vacuum casting. The present invention can improve the purity of the steel ingot by selecting the double vacuum mode of vacuum smelting + vacuum casting. Vacuum smelting can greatly reduce the gas and inclusions in the steel ingot, improve the purity of the steel ingot, and thus improve the performance of the steel ingot.

[0086] In the above step 1, the process of steel ingot forging is: pressing jaws → chamfering → gas cutting nozzle discarding → upsetting → KD drawing → cutting jaws for material. The purpose of forging is to make the structure of the steel ingot uniform, transform the cast structure produced during the solidification process of the steel ingot into an equiaxed structure, and weld the internal holes to improve the density of the forging.

[0087] It should be noted that in the above step 1, the temperature of the hot-delivered steel ingot is 400℃-600℃. After the hot-delivered steel ingot is loaded into the furnace, the heating furnace is heated to 700℃-750℃, kept warm for 15-20h, and then heated to 1250℃-1270℃ and kept warm for 35-40h. After keeping warm, the ingot body is chamfered, the jaws are pressed at a position where the riser occupies 100mm of the ingot body, and then the gas cutting nozzle discards and the jaw discards are carried out.

[0088] In the above step 1, since the forgings are solid forgings, in order to ensure the quality of core flaw detection, upsetting + KD drawing and compaction processes are required. The upsetting ratio and drawing ratio during upsetting and drawing are controlled within the range of 2.2 to 2.5, and the forging temperature during upsetting and drawing is 750℃-1250℃. Specifically, the steel ingot is heated to 1250℃ and then kept warm for 50-60h, and then upsetting and KD drawing are performed after the heat preservation, and the gas cutting jaws are used to cut the material after completion.

[0089] It should be noted that in the above step 1, the upsetting ratio and the drawing ratio of the steel ingot are controlled within the range of 2.2-2.5 because the steel ingot is a solid forging. Controlling it within the above range can ensure the core compaction of the solid forging, thereby ensuring the quality of flaw detection at the core of the forging.

[0090] In the above step 2, the steel ingot is upset and spun after cutting, and the spinning adopts the double-sided rotary forging method. First, the steel billet after blanking forging is heated to 1230℃-1250℃, and then kept warm for 50-60h. After keeping warm, it is upset to the maximum diameter that can be upset by the maximum load of the 10,000-ton hydraulic press, that is, it is upset to a diameter of 4.5m~5.0m; then the head slab 3 is turned 180° and returned to the furnace to be heated to 1230℃-1250℃, and kept warm at this temperature for 50-60h. The slab is widened by double-sided rotary forging. The widening hammer head 9 is a flat hammer head. The first boss is reserved in the middle of the slab. The height H of the first boss is 1 In the range of 200-500 mm, the diameter D of the first boss 1 Within the range of 1000-3000mm; the head slab 3 is turned 180° and returned to the furnace for heating to 1230℃-1250℃ and then kept warm for 13-17h. Then the head slab 3 is placed on the bottom gasket 10, and the first boss reserved in the previous fire is pressed down to a certain height with a cover plate, and then the flat hammer is used to continue to widen the other side of the slab, and finally the second boss reserved in the middle of the slab is upset to obtain the finished forging. This ensures that a boss of a certain height and diameter is reserved in the middle of the head slab 3, and is also conducive to removing the deformation dead zone caused by upsetting. The forged head slab is rough-machined to the slab punching size (such as Fig. 9 As shown in the figure), after the flaw detection is qualified, it is waiting for stamping forming. The schematic diagram of the head blank 3 before stamping by using the forging forming tool is as shown in the figure Fig.10 As shown, the schematic diagram of the head plate blank 3 after being stamped by the forging forming tool is as shown in Fig.11 shown.

[0091] It should be emphasized that in the above steps 1 and 2, the forging temperature during blanking, roughing and rotary forging is controlled at 750℃-1250℃ and different holding times are adopted to ensure that large and complex head forgings can be evenly heated through, so that the heating temperature of the core and surface areas of the forgings is consistent, and to avoid temperature stress caused by temperature difference in the cross section, which may lead to cracking of the forging ingot.

[0092] The large and complex head of the present invention contains a large-sized connecting pipe and a complex structure. The slab used for punching is difficult to forge and has a complex structure. Therefore, the present invention adopts a double-sided rotary forging method, which can form a boss connecting pipe structure on the one hand, and ensure uniform deformation of both sides of the slab on the other hand, thereby avoiding the scrapping of the forging due to the different diameters of the upper and lower planes of the slab caused by single-sided forging.

[0093] In the above step 3, the stamping forming of the slab includes: returning the forged slab to the furnace after rough machining and flaw detection, heating it to 900℃-1000℃ and keeping it warm for 6-8h, assembling the above forming tooling for hot stamping, wherein the forging temperature during stamping is 700℃-1000℃.

[0094] It should be noted that the stamping temperature of the head blank 3 is controlled within the range of 700℃-1000℃. On the one hand, it can ensure that the head blank 3 has good plasticity under the thermal conditions and is easy to form; on the other hand, because the microstructure grains of the head blank 3 tend to grow at higher temperatures, affecting the final performance and quality of the head, the stamping temperature cannot be higher than 1000℃.

[0095] The process of assembling the above-mentioned forming tooling includes: connecting the upper ring body 1 of the upper mold assembly to a 10,000-ton hydraulic press, and then connecting the upper ring body 1 to the forming ring 2 through the pin shaft assembly 11. Specifically, first align the first pin hole and the third pin hole, and align the second pin hole and the fourth pin hole at the same time, and then insert the first pin shaft 16 into the third pin hole and the first pin hole on the connecting pin iron 18, and insert the second pin shaft 17 into the fourth pin hole and the second pin hole of the connecting pin iron 18, thereby connecting the upper ring body 1 and the forming ring 2 together.

[0096] After connecting the upper ring body 1 and the forming ring 2, place the first support ring 5 on the first annular step of the punch base 4, place the second support ring 6 on the second annular step, place the third support ring 7 on the third annular step, and place the fourth support ring 8 on the fourth annular step; then place the head blank 3 between the upper die assembly and the lower die assembly, that is, place the head blank 3 between the forming ring 2 and the top surface of the punch base 4, and the forming ring 2 is arranged above the head blank 3. When the press is started, the head blank 3 is pressed against the pressure of the forming ring 2. Under the action, its edge part (that is, the annular area formed by the contact part between the head blank 3 and the lower bottom surface of the forming ring 2) begins to move downward and gradually deforms. The head blank 3 begins to deform from the initial round cake shape to the head shape. During the deformation process, the bottom surface of the head blank 3 gradually becomes the inner surface and contacts the second annular arc surface 13, the third annular arc surface 14 and the fourth annular arc surface 15 in turn; when the inner surface of the head blank 3 fits with the fourth annular arc surface 15, the head blank 3 is stamped successfully. At this time, the 10,000-ton hydraulic press is closed.

[0097] It should be noted that the cross-section of the forming ring 2 of the present invention in the vertical direction is an inverted right-angled trapezoid, and the hypotenuse of the right-angled trapezoid is close to the center line of the forming ring 2; the arc surface of the forming ring 2 can fit the outer surface of the deformed head blank 3. During the stamping process of the head blank 3, at the beginning of the stamping, downward pressure is applied to the head blank 3 through the bottom surface of the forming ring 2. When the head blank 3 is gradually deformed from a round cake shape, the contact area between the bottom surface of the forming ring 2 and the head blank 3 decreases. At this time, the arc surface of the forming ring 2 begins to contact the head blank 3 and applies downward pressure to the head blank 3 until the inner surface of the head blank 3 contacts the fourth annular arc surface 15, and the stamping is stopped to obtain a qualified head forging.

[0098] It should be noted that, before the forged head forging of the present invention is installed in a large pressure vessel, it is necessary to perform machine processing on the head forging, that is, drilling processing is performed on the boss pipe.

[0099] When the hydraulic press of the present invention performs stamping, the stamping stroke is 1000-3000mm (for example, 1500mm), and the stamping speed is 18-22mm / s (for example, 20mm / s). Controlling the stamping speed within the range of 18-22mm / s can ensure a gradual and balanced change in the microstructure of the head plate blank 3, thereby avoiding the formation of metal structure defects such as internal cracks in the forging during the stamping process and ensuring the integrity of the metal streamline.

[0100] Example 1

[0101] A complex head forging weighs 103.6 tons and is forged using a 185-ton steel ingot. The specific implementation process is as follows:

[0102] Step 1, the temperature of the hot-delivered steel ingot is 410°C. After the hot-delivered steel ingot is loaded into the furnace, the heating furnace is heated to 705°C and kept warm for 16 hours, then heated to 1250°C and kept warm for 36 hours. After keeping warm, the ingot body is chamfered, the jaws are pressed, and the nozzles and jaws are discarded by gas cutting;

[0103] Step 2, upsetting KD: Since the forgings are solid forgings, in order to ensure the quality of core flaw detection, upsetting and compaction processes are required. Generally, the upsetting ratio and drawing ratio are controlled at 2.2; the steel ingot is heated to 1250℃ for more than 52h, and upsetting and KD drawing are performed. After completion, the gas cutting jaws are used for unloading. The forging temperature range of this fire is 760℃;

[0104] Step 3, after the steel ingot is cut, it is upset and spun, and the spinning adopts a double-sided rotary forging method; first, the head slab 3 after the blanking forging is heated to 1230°C, and then kept warm for 51 hours, and then upset to the maximum diameter that can be upset by the maximum load of the 10,000-ton hydraulic press, that is, upset to a diameter of 4.5m; then the head slab 3 is turned 180° and returned to the furnace to be heated to 1230°C, and kept warm at this temperature for 52 hours, and the slab is widened by double-sided rotary forging, and the widening hammer head 9 is a flat hammer head, such as Figure 4 As shown, the height H of the first boss reserved in the middle of the head blank 3 is 1 To 210mm, the diameter D of the first boss 1 1100mm;

[0105] Step 4: After the slab is turned 180°, it is returned to the furnace and heated to 1230°C and kept warm for 14 hours. Then, the head slab 3 is placed on the bottom gasket 10 (such as Figure 5 As shown), and use the cover plate to press the first boss reserved in the previous fire to h1 = 200mm (as shown Figure 6Then, the widening hammer is used to further widen the other side of the head slab 3 (as shown in FIG. Figure 7 As shown), finally the height reserved in the middle of the slab is H 2 The second boss is upset to h2 = 365 mm to obtain a forged product (such as Figure 8 This not only ensures that a boss of a certain height and diameter is reserved in the middle of the slab, but also helps to remove the deformation dead zone caused by upsetting. The forged head slab is rough-machined to the slab punching size (such as Fig. 9 As shown in the figure), after the flaw detection is qualified, it is waiting for stamping forming. The schematic diagram of the head blank 3 before stamping by using the forging forming tool is as shown in the figure Fig.10 As shown, the schematic diagram of the head plate blank 3 after being stamped by the forging forming tool is as shown in Fig.11 shown.

[0106] Step 5: After the rough machining and flaw detection are qualified, the slab is returned to the furnace and heated to 1000°C according to the process requirements. After being kept warm for 7 hours, the forging tooling is assembled for stamping.

[0107] The specific operation procedures for blank punching are as follows: install the upper ring body 1 on the 10,000-ton hydraulic press, and connect the forming ring 2 to the upper ring body 1 through the pin shaft, so that the pressure of the 10,000-ton hydraulic press can be transferred to the forming ring 2. Then place the first support ring 5 on the first annular step, the second support ring 6 on the second annular step, the third support ring 7 on the third annular step, and the fourth support ring 8 on the fourth annular step, adjust the lower die assembly so that the center line of the punch base 4 coincides with the center line of the forming ring 2, and finally move the hot blank to the first support ring 5 for positioning, so that the annular cavity on the lower bottom surface of the head blank 3 is engaged with the first support ring 5 on the top surface of the punch base 4. At this time, start the 10,000-ton hydraulic press to make the forming ring 2 punch downward at a uniform speed of 20mm / s. After the downward stroke is 1450mm, the inner surface of the head blank 3 is in contact with the fourth annular arc surface 15 of the fourth support ring 8, and the finished head forging is successfully punched.

[0108] Example 2

[0109] A complex head forging weighs 125 tons and is forged using a 210-ton steel ingot. The specific implementation process is as follows:

[0110] Step 1, the temperature of the hot-delivered steel ingot is 500°C. After the hot-delivered steel ingot is loaded into the furnace, the heating furnace is heated to 725°C and kept warm for 17 hours, then heated to 1260°C and kept warm for 37 hours. After keeping warm, the ingot body is chamfered, the jaws are pressed, and the nozzle and jaws are discarded by gas cutting;

[0111] Step 2, upsetting KD: Since the forgings are solid, in order to ensure the quality of core flaw detection, upsetting and compaction processes are required. Generally, the upsetting ratio and drawing ratio are controlled at 2.3; the steel ingot is heated to 1250℃ for 55h, upsetting and KD drawing are performed, and after completion, the gas cutting jaws are used to unload the material. The forging temperature range of this fire is 950℃;

[0112] Step 3: After blanking, the steel ingot is upset and spun. The spinning is performed by double-sided rotary forging. First, the cylindrical steel billet after blanking is heated to 1240°C, and then kept warm for 57 hours. After being kept warm, it is upset to the maximum diameter that can be upset by the maximum load of the 10,000-ton hydraulic press, that is, upsetting to a diameter of 4.7m; then the head slab 3 is turned 180° and returned to the furnace to be heated to 1240°C, and kept warm at this temperature for 55 hours. The slab is widened by double-sided rotary forging, and the widening hammer head 9 is a flat hammer head, such as Figure 4 As shown, the height H of the first boss reserved in the middle of the slab 1 To 300mm, the first boss diameter D 1 Up to 2000mm;

[0113] Step 4: After the slab is turned 180°, it is returned to the furnace and heated to 1240℃ and kept warm for 15h. Then the slab is placed on the bottom gasket 10, and the first boss reserved for the first firing is pressed to h1=200mm with the cover plate. Then, the widening flat hammer is used to continue widening the other side of the slab. Finally, the height reserved in the middle of the slab is H 2 The second boss of the forging is upset to h2 = 365mm to obtain the finished forging. This not only ensures that a boss of a certain height and diameter is reserved in the middle of the head plate blank 3, but also helps to remove the deformation dead zone generated during upsetting; the forged plate is rough-machined to the plate blank punching size, and after passing the flaw detection, it is ready for stamping;

[0114] Step 5: After the rough machining and flaw detection are qualified, the slab is returned to the furnace and heated to 1000°C according to the process requirements. After being kept warm for 7 hours, the forging tooling is assembled for stamping.

[0115] The specific operation procedures for blank punching are as follows: install the upper ring body 1 on the 10,000-ton hydraulic press, and connect the forming ring 2 to the upper ring body 1 through the pin shaft, so that the pressure of the 10,000-ton hydraulic press can be transferred to the forming ring 2. Then place the first support ring 5 on the first annular step, the second support ring 6 on the second annular step, the third support ring 7 on the third annular step, and the fourth support ring 8 on the fourth annular step, adjust the lower die assembly so that the center line of the punch base 4 coincides with the center line of the forming ring 2, and finally move the hot blank to the first support ring 5 for positioning, so that the annular concave cavity on the lower bottom surface of the head blank 3 is engaged with the first support ring 5 on the top surface of the punch base 4. At this time, start the 10,000-ton hydraulic press to make the forming ring 2 punch downward at a uniform speed of 22mm / s. After the downward stroke is 1500mm, the inner surface of the head blank 3 is in contact with the fourth annular arc surface 15 of the fourth support ring 8, and the finished head forging is successfully punched.

[0116] Example 3

[0117] A complex head forging weighs 145 tons and is forged using a 230-ton steel ingot. The specific implementation process is as follows:

[0118] Step 1, the temperature of the hot-delivered steel ingot is 590°C. After the hot-delivered steel ingot is loaded into the furnace, the heating furnace is heated to 750°C and kept warm for 19 hours, then heated to 1270°C and kept warm for 39 hours. After keeping warm, the ingot body is chamfered, the jaws are pressed, and the nozzle and jaws are discarded by gas cutting;

[0119] Step 2, upsetting KD: Since the forgings are solid, in order to ensure the quality of core flaw detection, upsetting and compaction processes are required. Generally, the upsetting ratio and drawing ratio are controlled at 2.5; the steel ingot is heated to 1250℃ for 60h, upsetting and KD drawing are performed, and after completion, the material is cut by gas cutting jaws. The forging temperature range of this fire is 1250℃;

[0120] Step 3: After the ingot is cut, it is upset and spun. The spinning is done by double-sided rotary forging. First, the billet after forging is heated to 1250°C, then kept warm for 59 hours. After being kept warm, it is upset to the maximum diameter that can be upset by the maximum load of the 10,000-ton hydraulic press, that is, upsetting to a diameter of 5.0m; then the slab is turned 180° and returned to the furnace to be heated to 1250°C, and kept warm for 60 hours at this temperature. The slab is widened by double-sided rotary forging. The widening hammer 9 is a flat hammer. The height H of the first boss reserved in the middle of the slab is 1 is 500mm, the diameter of the first boss D 1 It is 3000mm.

[0121] Step 4: Turn the slab 180° and return it to the furnace to heat it to 1250°C. Keep it warm for 17 hours after heating. Then place the slab on the bottom gasket 10 and use the cover plate to press the first boss reserved for the upper fire to h1=200mm. Then use the widening flat hammer to continue widening the other side of the slab. Finally, press the height reserved in the middle of the slab to H 2 The second boss is upset to h2 = 365 mm to obtain the forging head blank 3 finished product.

[0122] Step 5: After the rough processing and flaw detection are qualified, the slab is returned to the furnace and heated to 1000°C according to the process requirements. After being kept warm for 10 hours, the forging forming tool is assembled for stamping.

[0123] The specific operating procedures for slab punching are as follows: install the upper ring body 1 on the 10,000-ton hydraulic press, and connect the forming ring 2 to the upper ring body 1 through a pin shaft, so that the pressure of the 10,000-ton hydraulic press can be transferred to the forming ring 2. Then place the first support ring 5 on the first annular step, the second support ring 6 on the second annular step, the third support ring 7 on the third annular step, and the fourth support ring 8 on the fourth annular step; it should be noted that when placing the fifth support ring 20, first place the upper annular pad 19 on the fifth annular step to increase the height of the fifth support ring 20. After placing the pad 19, place the fifth support ring 208 on the fifth annular step, and the sixth support ring 218 on the sixth annular step; after placement is completed , adjust the lower die assembly so that the center line of the punch base 4 coincides with the center line of the forming ring 2, and finally move the hot slab to the first support ring 5 which serves as a positioning function, so that the annular cavity on the lower bottom surface of the head slab 3 is engaged with the first support ring 5 on the top surface of the punch base 4. At this time, start the 10,000-ton hydraulic press to make the forming ring 2 punch downward at a uniform speed of 24mm / s. After the downward stroke is 1600mm, the inner surface of the head slab 3 is fitted with the fourth annular arc surface 15 of the fourth support ring 8, and the finished head forging is stamped successfully.

[0124] 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 forging tool for large and complex heads. It is characterized in that It comprises an upper die assembly and a lower die assembly, wherein the upper die assembly comprises an upper ring body and a forming ring, the upper ring body is connected to a press, and the forming ring is detachably connected to the upper ring body; The lower die assembly comprises a punch base, which is a hollow hemispherical shape, with the spherical surface of the punch base facing upward and the opening facing downward, and the outer wall surface of the spherical surface of the punch base is provided with a first annular step, a second annular step, a third annular step and a fourth annular step with increasing radius from top to bottom in sequence; the first annular step, the second annular step, the third annular step and the fourth annular step are provided with a first support ring, a second support ring, a third support ring and a fourth support ring respectively; The center line of the punch base coincides with the center line of the forming ring; the head blank is arranged between the forming ring and the top surface of the punch base; The upper ring body is a hollow cover type, and the top of the upper ring body is connected to the press; The forming ring is a hollow annular belt; the top surface of the forming ring is detachably connected to the upper ring body through a pin assembly; The head blank is in the shape of a round cake; the outer diameter of the round cake-shaped head blank is equal to the outer diameter of the forming ring; the forming ring is arranged above the round cake-shaped head blank, and the forming ring can apply downward pressure to the round cake-shaped head blank to deform the round cake-shaped head blank into a head shape; An annular cavity is provided on the bottom surface of the circular pancake-shaped head blank, and the annular cavity can be embedded with the first supporting ring provided on the top surface of the punch base.

2. The forging tool for a large complex head according to claim 1, It is characterized in that The top surface of the first support ring is a first annular arc surface, the top surface of the second support ring is a second annular arc surface, the top surface of the third support ring is a third annular arc surface, and the top surface of the fourth support ring is a fourth annular arc surface; When the press applies downward pressure to the head plate blank through the upper ring body and the forming ring, the annular edge of the head plate blank deforms downward, gradually and sequentially fits onto the first annular arc surface, the second annular arc surface, the third annular arc surface and the fourth annular arc surface.

3. The forging tool for a large complex head according to claim 2, It is characterized in that The pin shaft assembly comprises a plurality of first pin shafts, second pin shafts and connecting pin irons, and the number of the first pin shafts, the second pin shafts and the connecting pin irons are the same; The upper ring body is provided with a plurality of first pin holes; the forming ring is provided with a plurality of second pin holes, and the connecting pin iron is provided with a third pin hole and a fourth pin hole at the same time, and the number of the first pin hole, the second pin hole, the third pin hole and the fourth pin hole are equal; When the upper ring body and the forming ring are connected by using the pin shaft assembly, after aligning the first pin hole and the third pin hole, the first pin shaft is inserted into the third pin hole and the first pin hole; after aligning the second pin hole and the fourth pin hole, the second pin shaft is inserted into the fourth pin hole and the second pin hole.

4. A forging method for a large and complex head. It is characterized in that The forging tool for the large complex head according to claim 3 is used, and the forging method comprises the following steps: Step 1, forging the steel ingot to obtain a cylindrical steel billet; The hot-delivered steel ingot is subjected to jaw pressing, chamfering, gas cutting nozzle discarding and jaw discarding, upsetting, KD drawing and jaw cutting in sequence; Step 2, performing double-sided rotary forging on the cylindrical steel billet to obtain a head plate billet; The steel billet is subjected to upsetting and spinning to obtain a head plate billet, wherein the spinning is performed by a double-sided rotary forging method; Step 3, using the forging tooling of the large and complex head to perform stamping and forming of the head plate blank; The round cake-shaped head blank is placed between the forming ring and the top surface of the punch base; the annular cavity on the bottom surface of the head blank is engaged with the first support ring, the press is started and the downward stroke is set, and the press can exert downward pressure on the round cake-shaped head during the downward movement of the forming ring driven by the upper ring body. After being subjected to the downward pressure, the round cake-shaped head blank begins to gradually deform from the initial round cake shape to a head shape. When the downward stroke is reached, the stamping forming is completed, and a large and complex head is obtained.

5. The forging method for a large complex head according to claim 4, It is characterized in that In the step 1, the steel ingot is heated to 1250° C.-1270° C. and kept warm for 35-40 hours. After the heat preservation, the jaws are pressed and the ingot body is chamfered, and the nozzle and jaws are discarded by gas cutting.

6. The forging method for a large complex head according to claim 4, It is characterized in that In the step 1, after the gas cutting nozzle and jaw discard, the steel ingot is heated to 1250°C and then kept warm for 50-60 hours, and then upsetting and KD drawing are performed after the insulation, and the gas cutting jaw is cut after completion.

7. The forging method for a large complex head according to claim 4, It is characterized in that In step 1, the upsetting ratio and the drawing ratio during upsetting and drawing are both controlled within the range of 2.2 to 2.

5.

8. The forging method for a large complex head according to claim 7, It is characterized in that In step 1 and step 2, the forging temperature during upsetting and drawing is 750° C.-1250° C.

9. The forging method for a large complex head according to any one of claims 4 to 8, It is characterized in that In step 3, during the stamping process, the inner surface of the head plate blank contacts the second annular arc surface, the third annular arc surface and the fourth annular arc surface in sequence. When the inner surface of the head plate blank contacts the fourth annular arc surface, the stamping process is stopped.

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