A stamping forming method for a complex head

Abstract

The present invention discloses a stamping forming method for a complex head, belonging to the technical field of head forming manufacturing, and solving the technical problem that the existing forging forming tooling and forging forming method cannot forge large complex head forgings. The stamping forming method for the complex head includes: Step 1, ingot cogging forging; Step 2, performing double-sided rotary forging on the steel billet obtained in Step 1 to obtain a head blank; Step 3, using the forging tooling for a large complex head to perform stamping forming on the head blank; placing the head blank between the forming ring and the top surface of the punch base, starting the press, and the press drives the forming ring through the upper ring body to apply a downward pressure on the head blank. After the head blank is subjected to the pressure, it begins to gradually deform from the initial round cake shape into a head shape. When the downward pressing stroke is reached, the stamping forming ends, and a large complex head is obtained. The present invention can effectively improve the microstructure of the head forging and improve the performance of the forging.

Description

Technical Field

[0001] The present invention relates to the technical field of head manufacturing, and in particular to a stamping forming method for complex heads. Background Art

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

[0003] The forming quality of the head will determine the service life of the pressure vessel. Currently, the manufacturing processes mainly include butt welding, stamping, etc. Although the welding process has been greatly improved today, the structure spliced by welding always cannot 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 extremely easy to cause uneven stress distribution and stress concentration, and is prone to fatigue, creep, and damage. Moreover, such a welding manufacturing method has a complex process, a long welding cycle, and a high manufacturing cost. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a stamping forming method for complex heads to solve the technical problem of difficult forging and forming of existing super-large and complex head forgings.

[0005] The object of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a stamping forming method for complex heads, including the following steps:

[0007] Step 1: Open-die forging of the ingot to obtain a cylindrical billet;

[0008] The hot-delivered ingot is successively subjected to clamping jaw pressing, chamfering, gas cutting of the nozzle waste, upsetting, KD drawing, and clamping jaw cutting and blanking.

[0009] Step 2: Double-sided rotary forging and forming of the cylindrical billet to obtain a cylindrical billet;

[0010] The cylindrical billet is upset and spun. During upsetting, the billet after open-die forging is heated to 1230°C - 1250°C, and then held for 50 - 60 h. After holding, it is upset to a diameter of 4.5 m - 5.0 m; subsequently, the slab is flipped 180° and returned to the furnace for heating to 1230°C - 1250°C, and held for 50 - 60 h.

[0011] Step 3: Stamping and forming of the head slab.

[0012] Further, in step 3, the stamping forming of the slab includes: rough machining the forged head slab, returning it to the furnace and heating it to 1100°C-1200°C after passing the flaw detection, then keeping it warm for 6-8 hours, and then stamping it after keeping it warm.

[0013] Furthermore, in step 3, the stamping speed during stamping is 18-22 mm / s.

[0014] Furthermore, in step 2, after upsetting, the slab is widened by double-sided rotary forging, a flat hammer is used as the widening hammer, and a first boss is reserved in the middle of the slab; the height H1 of the first boss is in the range of 200-500 mm, and the diameter D1 of the first boss is in the range of 1000-3000 mm.

[0015] Furthermore, in step 2, after reserving the first boss, the slab is flipped 180° and returned to the furnace to be heated to 1230℃-1250℃, and then kept warm for 13-17 hours. After keeping warm, the slab is placed on the bottom gasket, and the first boss is pressed down to the set height with a cover plate, and then a flat hammer is used to continue to widen the other side of the slab, and finally the second boss of the head slab is upset to obtain a round pancake-shaped head slab.

[0016] Furthermore, in step 1, the temperature of the hot-delivered steel ingot is 400°C-600°C. After the hot-delivered steel ingot is loaded into the furnace, the heating furnace is heated to 700°C-750°C and kept warm for 15-20 hours.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] Furthermore, in step 1 and step 2, the forging temperature during upsetting and drawing is 750°C-1250°C.

[0021] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0022] (1) The stamping forming method of the complex head provided by the present invention can effectively improve the microstructure of the head forging and enhance the performance of the forging.

[0023] (2) The large and complex head of the present invention contains large-sized nozzles and has a complex structure. The head blank used for stamping is difficult to forge and has a complex structure. The present invention adopts a double-sided rotary forging method, which can, on the one hand, ensure uniform deformation on both sides of the blank, and on the other hand, avoid the situation where the diameters of the upper and lower planes are different due to single-sided forging of the blank, resulting in the scrapping of forgings.

[0024] (3) The reason why the upsetting ratio and drawing ratio of the ingot in the present invention are both controlled within the range of 2.2 - 2.5 is that the ingot is a solid forging. Controlling it within the above range can ensure the compaction of the core of the solid forging, and thus ensure the flaw detection quality of the core of the forging.

[0025] In the present invention, the above 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 specification. Moreover, some advantages can be made obvious from the specification, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained from the content specifically pointed out in the embodiments of the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings are only used for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs represent the same components.

[0027] Figure 1 is a schematic structural diagram of a large and complex head;

[0028] Figure 2 is a schematic structural diagram of an existing circular stamping head;

[0029] Figure 3 is a schematic structural diagram of a forging and forming tooling;

[0030] Figure 4 is a schematic diagram of the preparation process of a head blank Figure 1 ;

[0031] Figure 5 is a schematic diagram of the preparation process of a head blank Figure 2 ;

[0032] Figure 6 is a schematic diagram of the preparation process of a head blank Figure 3 ;

[0033] Figure 7 is a schematic diagram of the preparation process of a head blank Figure 4 ;

[0034] Figure 8 is a schematic diagram of the preparation process of a head blank Figure 5 ;

[0035] Figure 9Schematic diagram of the preparation process of the head slab Figure 5 ;

[0036] Figure 10 This is a schematic diagram before the head plate blank is stamped using a forging tool;

[0037] Figure 11 This is a schematic diagram of stamping the head plate blank using a forging tool;

[0038] Figure 12 This is a schematic diagram of the before and after comparison of the head plate blank after stamping using the forging forming tool;

[0039] Figure 13 is a cross-sectional view of the first support ring;

[0040] Figure 14 is a cross-sectional view of the second support ring;

[0041] Figure 15 is a cross-sectional view of the third support ring;

[0042] Figure 16 is a cross-sectional view of the fourth support ring.

[0043] Reference numerals:

[0044] 1-upper ring body; 2-forming ring; 3-head plate 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 shaft 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.

[0045] Among them, SR represents the radius of the spherical head; H1 is 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; H2 is Figure 7 Boss height before mid-upsetting, mm; h1 is Figure 6 The height of the boss after pressing down, mm; h2 is Figure 8 Boss height after medium upsetting, mm. DETAILED DESCRIPTION

[0046] 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.

[0047] The present invention also provides a stamping forming method for a large and complex head, comprising the following steps:

[0048] Step 1: Perform blooming forging on an ingot to obtain a cylindrical billet;

[0049] Step 2: Perform double-sided rotary forging on the cylindrical billet to obtain a head blank;

[0050] Step 3: Use a forging forming tooling to perform stamping forming on the blank.

[0051] It should be noted that in the above Step 1, since the weight of the head blank 3 is 100t - 150t, the weight of the ingot used for forging the head blank 3 is generally 1.5 times the weight of the final forging (the head blank 3) to compensate for the gating cut-off amount, riser cut-off amount, and the burning loss of each heat. A large ingot obtained by the method of vacuum melting + vacuum casting is used to manufacture the head blank 3. The present invention can improve the purity of the ingot by selecting the double-vacuum mode of vacuum melting + vacuum casting. Vacuum melting can greatly reduce the gas and inclusions in the ingot, improve the purity of the ingot, and thus improve the performance of the ingot.

[0052] In the above Step 1, the process of blooming forging of the ingot is: pressing the tongs, chamfering, gas cutting and discarding the gating waste, upsetting, KD drawing, and cutting the tongs and blanking. The purpose of blooming forging is to make the structure of the ingot uniform, transform the as-cast structure generated during the solidification process of the ingot into an equiaxed structure, and weld the internal holes to improve the density of the forging.

[0053] It should be noted that in the above Step 1, the temperature of the hot-delivered ingot is 400°C - 600°C. After the hot-delivered ingot is charged into the furnace, the heating furnace is heated to 700°C - 750°C, held for 15 - 20h, then heated to 1250°C - 1270°C and held for 35 - 40h. After holding, chamfering of the ingot body is carried out, pressing the tongs at 100mm from the riser to the ingot body, and then gas cutting and discarding the gating waste and the tongs waste.

[0054] In the above Step 1, since the forging to be manufactured is a solid forging, in order to ensure the quality of the internal flaw detection of the core, upsetting + KD drawing and compaction processes are required. The upsetting ratio and the drawing ratio during upsetting and drawing are both controlled within the range of 2.2 - 2.5, and the forging temperature during upsetting and drawing is 750°C - 1250°C. Specifically, the ingot is heated to 1250°C and then held. After the holding time of 50 - 60h, upsetting and KD drawing are carried out after holding, and after completion, gas cutting and cutting the tongs and blanking are carried out.

[0055] It should be noted that in the above Step 1, the upsetting ratio and the drawing ratio of the ingot are both controlled within the range of 2.2 - 2.5 because the ingot is a solid forging, and controlling it within the above range can ensure the compaction of the core of the solid forging, and thus ensure the quality of the internal flaw detection of the forging.

[0056] In the above step 2, after the ingot is cut, it is upset and spun. The spinning adopts a double-sided rotary forging method. First, the billet after blooming forging is heated to 1230°C - 1250°C, and then held for 50 - 60 h. After holding, it is 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 4.5 m - 5.0 m. Subsequently, the slab is flipped 180° and returned to the furnace for heating to 1230°C - 1250°C, and held at this temperature for 50 - 60 h. The slab is widened by using the double-sided rotary forging method. The widening hammer head 9 is a flat hammer head, and a first boss is reserved at the middle position of the slab. The height H1 of the first boss is in the range of 200 - 500 mm, and the diameter D1 of the first boss is in the range of 1000 - 3000 mm. After the slab 3 is flipped 180° and returned to the furnace for heating to 1230°C - 1250°C and held for 13 - 17 h, then the slab is placed on the bottom washer 10, and the first boss reserved in the previous heat is pressed down to a certain height by using the cover plate, and then the slab is further widened on the other side by using the flat hammer head. Finally, the second boss reserved in the middle of the slab is upset to obtain the finished forging. This not only ensures that bosses with a certain height and diameter are reserved at the middle position of the head slab 3, but also helps to eliminate the deformation dead zone generated during upsetting. The forged tube sheet is rough-machined to the slab stamping size (as Figure 9 shown), and after passing the flaw detection, it waits for stamping forming. The schematic diagram of the head slab 3 before stamping by using the forging forming tooling is as Figure 10 shown, and the schematic diagram of the head slab 3 after stamping by using the above forging forming tooling is as Figure 11 shown.

[0057] It should be emphasized that in the above steps 1 and 2, the forging temperatures during blooming, upsetting and rotary forging are all controlled at 750°C - 1250°C and different holding times are adopted to ensure that the large and complex head forgings can be evenly heated through, so that the heating temperatures in the core, surface and other regions of the forgings are consistent, and to avoid the cracking of the ingot due to the temperature stress generated by the cross-sectional temperature difference.

[0058] The large and complex head of the present invention contains large-size nozzles and has a complex structure. The slab used for stamping has great forging difficulty and a complex structure. Therefore, the double-sided rotary forging method is adopted in the present invention. On the one hand, it can form the shape of the boss nozzle, and on the other hand, it can ensure uniform deformation on both sides of the slab, thus avoiding the situation that the upper and lower plane diameters are different due to single-sided forging of the slab, resulting in the scrapping of the forging.

[0059] In the above step 3, the stamping forming of the slab includes: after the forged slab is rough-machined and passes the flaw detection, it is returned to the furnace for heating to 900°C - 1000°C and held for 6 - 8 h, and the above-mentioned forming tooling is assembled for hot stamping forming. Among them, the forging temperature during stamping forming is 700°C - 1000°C.

[0060] It should be noted that controlling the stamping forming temperature of the head blank 3 within the range of 700°C - 1000°C can, on the one hand, ensure that the head blank 3 has good plasticity under this thermal condition for easy forming; on the other hand, because the grains of the microstructure of the head blank 3 are prone to grow at higher temperatures, affecting the final performance and quality of the head, the stamping forming temperature cannot be higher than 1000°C.

[0061] 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 trapezoid, and the hypotenuse of the right trapezoid is close to the center line side of the forming ring 2; the arc surface of the forming ring 2 can be fitted with the outer surface of the deformed head blank 3. During the stamping process of the head blank 3, at the beginning of stamping and forming, a downward pressure is applied to the head blank 3 through the bottom surface of the forming ring 2. When the head blank 3 gradually deforms from a disc 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 a 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 and forming is stopped to obtain a qualified head forging.

[0062] It should be noted that before the head forging forged by the present invention is installed on a large pressure vessel, the head forging also needs to be machined by a machine tool, that is, drilling treatment is carried out at the boss nozzle.

[0063] When the hydraulic press of the present invention performs stamping and forming, the stamping stroke is 1000 - 3000 mm (for example, 1500 mm), and the stamping speed is 18 - 22 mm / s (for example, 20 mm / s). Controlling the stamping speed within the range of 18 - 22 mm / s can ensure the gradual and balanced change of the microstructure of the head blank 3, so as to avoid the formation of metal structure defects such as internal cracks in the forging during the stamping process and ensure the integrity of the metal streamline.

[0064] It should be emphasized that Figure 1 is the rough machining drawing of the head of a certain large pressure vessel of the present invention. As the main pressure-bearing component of the pressure vessel, this kind of head not only has an oversized size and a relatively thin wall thickness of 100 - 250 mm, but also has a large boss nozzle at the top, with a complex shape and difficult forming, so it has relatively high requirements for the production process and forming method.

[0065] For the above-mentioned large and complex head structure, the present invention provides a forging and forming tooling for a large and complex head, such as Figures 2 to 12As shown in the figure, the forging and 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, which is a hollow hemispherical shape with its spherical surface facing upward and the opening facing downward. On the outer wall of the spherical surface of the punch base 4, there are successively arranged a first annular step, a second annular step, a third annular step, and a fourth annular step with increasing radii 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.

[0066] Specifically, as Figure 3 shown in the figure, the upper ring body 1 is installed on a press (such as a ten-thousand-ton hydraulic press), and the forming ring 2 is connected to the upper ring body 1. The punch base 4 is hemispherical, with its spherical surface facing upward and the opening facing downward. On the outer wall of the spherical surface of the punch base 4, a first annular step, a second annular step, a third annular step, and a fourth annular step are successively machined from top to bottom. 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 support ring 5 is arranged on the first annular step, a second support ring 6 is arranged on the second annular step, a third support ring 7 is arranged on the third annular step, and a fourth support ring 8 is arranged on the fourth annular step. The first annular step to the fourth annular step, the first support ring 5 to the fourth support ring 8 correspondingly arranged thereon, and the punch base 4 together constitute the lower die assembly. Adjust the lower die assembly 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. Place the head blank 3 between the forming ring 2 and the top surface of the punch base 4. There is an annular cavity on the bottom surface of the head blank 3 (the mating 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 fitted 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 play a role in positioning the head blank 3. In addition, when stamping and forming the head blank 3, start the ten-thousand-ton hydraulic press to make the forming ring 2 press down evenly. Under the pressure of the forming ring 2, the edge part of the head blank 3 starts to move downward and deform. The head blank 3 starts to deform from the initial round cake shape into a head shape. During the deformation process, the bottom surface of the head blank 3 gradually becomes the inner surface and successively 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. When the inner surface of the head blank 3 fits with the top surface of the fourth support ring 8, the stamping of the head blank 3 is successful. At this time, turn off the ten-thousand-ton hydraulic press.

[0067] In the prior art, circular punches are mostly used for stamping forming. As Figure 2 shown, the head structure formed by this kind of stamping is simple. However, for large-sized and complex heads, this stamping method is difficult to operate on-site, not easy to demold, and is not conducive to actual production. Compared with the prior art, the forging forming tooling for large and complex heads provided by the present invention has the characteristics of strong versatility and wide application range, and can greatly reduce the manufacturing cost of auxiliary tools.

[0068] It should be noted that, as Figure 12 shown, the upper ring body 1 is a hollow cover type, and the top of the upper ring body 1 is connected to a press; the forming ring 2 is a hollow ring 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 disc-shaped; 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 a downward pressure to the disc-shaped head blank 3 from the edge part on the top surface of the disc-shaped head blank 3, so that the disc-shaped head blank 3 is deformed into a head shape.

[0069] It should also be emphasized that the cross-section of the hollow ring belt forming ring 2 of the present invention in the vertical direction is an inverted right trapezoid, and the inner side surface of the forming ring 2 is an arc surface and can be attached to the upper surface (the deformed outer surface) of the head blank 3 during the stamping process of the head blank 3.

[0070] In order to meet the forming requirements of the boss nozzle at the bottom of the head and position the head blank 3, a ring-shaped concave cavity is provided on the bottom surface of the head blank 3, and the ring-shaped concave cavity of the head blank 3 is fitted with the first support ring 5.

[0071] Compared with the prior art, by setting the first support ring 5, the present invention can not only support the head blank 3, but also position the head blank 3, and finally make the boss nozzle at the bottom of the head blank 3 meet the forming requirements.

[0072] In order to meet the forming requirements of the boss nozzle of the head blank 3, as Figures 13 to 16 shown, the top surface of the first support ring 5 of the present invention is a first ring-shaped arc surface 12. The first ring-shaped arc surface 12 can not only be attached to the top surface of the ring-shaped concave cavity of the head blank 3, but also, setting the top surface of the first support ring 5 as a ring-shaped 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 realize the functions of supporting and fixing the head blank 3.

[0073] It should be noted that there are gaps between the inner side surface and the outer side surface of the first support ring and the head blank, and the size of the gap is 5 - 10 mm.

[0074] Similarly, in order to better support and fix the head plate blank 3 and increase the contact area between the top surfaces of the second support ring 6, the third support ring 7, the fourth support ring 8 and the bottom surface (or inner surface) of the head plate blank 3, the top surface of the second support ring 6 of the present invention is a second annular arc surface 13, the top surface of the third support ring 7 is a third annular arc surface 14, and the top surface of the fourth support ring 8 is a fourth annular arc surface 15; when the hydraulic press applies pressure to the head plate blank 3 through the upper ring body 1 and the forming ring 2, the head plate blank 3 is successively 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.

[0075] 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.

[0076] In order to ensure the firm 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 through a pin shaft assembly 11.

[0077] Specifically, as Figure 12 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 simultaneously provided on the connecting pin iron 18, and the number of the first pin holes, the second pin holes, the third pin holes and the fourth pin holes is equal; when connecting the upper ring body 1 and the forming ring 2, align the first pin hole and the third pin hole and align the second pin hole and the fourth pin hole. At this time, 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, so as to connect the upper ring body 1 and the forming ring 2 together.

[0078] It should be noted that for the large and complex head of the present invention, the head plate blank 3 is in a round cake shape, the diameter of the head plate blank 3 is 6700 mm - 6900 mm, the weight of the forging of the head plate blank 3 is 100 t - 150 t, and the weight of the ingot required for forging the head plate blank 3 is 150 t - 225 t.

[0079] The spherical radius of the large and complex head of the present invention is 3000 - 5000 mm. For large and complex heads with different spherical radii, forming can be carried out 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.

[0080] Compared with the prior art, the present invention adjusts the heights of the first support ring 5 to the fourth support ring 8, so that the forging and forming tooling can stamp heads with different spherical radii, thereby increasing the applicability of the forging and forming tooling.

[0081] To achieve the adjustment of the heights of the first support ring 5 to the fourth support ring 8 so that they are applicable to complex heads with different spherical radii, the forging and forming tooling of the present invention further includes a circular or arc-shaped spacer block 19; as Figure 11 and Figure 12 shown, taking the first support ring 5 as an example, when the height of the first support ring 5 needs to be adjusted, the circular or arc-shaped spacer block 19 is placed below the first support ring 5 (i.e., on the first annular step), thereby increasing the height of the first support ring 5; similarly, when the heights of the second support ring 6 to the fourth support ring 8 need to be adjusted, the circular or arc-shaped spacer blocks 19 of corresponding sizes are respectively placed on the corresponding annular steps.

[0082] Compared with the prior art, by arranging the spacer blocks 19 at the bottoms of the first support ring 5 to the fourth support ring 8, the present invention can increase the heights of the first support ring 5 to the fourth support ring 8, which not only ensures that the forging and forming tooling can stamp large and complex heads with different spherical radii, but also, it is relatively easy to operate by arranging the circular or arc-shaped spacer blocks 19 on each annular step of the punch base 4, and the applicability is relatively strong.

[0083] It should be emphasized that the present invention can adjust the heights of the first support ring 5 to the fourth support ring 8 simultaneously, or can also adjust the height of a certain support ring alone, so as to achieve the purpose of stamping large and complex heads with different spherical radii; in addition, according to the different stamping strokes corresponding to the spherical radii of large and complex heads of different sizes, the stamping stroke of the press of the present invention is 1000 - 3000 mm.

[0084] It should be noted that, in order to better support the head blank 3, the forging and forming tooling of the present invention further includes a fifth support ring 20 and a sixth support ring 21, as Figure 12 shown, the punch base 4 is further provided with a fifth annular step and a sixth annular step, the fifth annular step is arranged below the fourth annular step, and the sixth annular step is arranged below the fifth annular step. The fifth support ring 20 is arranged on the fifth annular step, and the sixth support ring 21 is arranged on the sixth annular step; the top surface of the fifth support ring 20 is a fifth annular arc surface, and the top surface of the sixth support ring 21 is a sixth annular arc surface; when stamping and forming the head blank 3, after the inner surface of the head blank 3 gradually contacts the second annular arc surface 13 to the fourth annular arc surface 15, it starts to contact the fifth annular arc surface and the sixth annular arc surface in sequence. At this time, the fifth annular arc surface and the sixth annular arc surface are attached to the inner surface of the head blank 3 at the corresponding positions, so that the fifth support ring 20 and the sixth support ring 21 play a role in supporting the head blank 3.

[0085] It should also be emphasized that the number of support rings can be adjusted according to the actual situation.

[0086] It should be pointed out that the process of assembling the above-mentioned forming tooling includes: connecting the upper ring body 1 of the upper mold assembly to the 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 aligning the first pin hole and the third pin hole, and aligning the second pin hole and the fourth pin hole at the same time, and then inserting the first pin shaft 16 into the third pin hole and the first pin hole on the connecting pin iron 18, and inserting 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.

[0087] After the upper ring body 1 and the forming ring 2 are connected, the first support ring 5 is placed on the first annular step of the punch base 4, the second support ring 6 is placed on the second annular step, the third support ring 7 is placed on the third annular step, and the fourth support ring 8 is placed on the fourth annular step; then the head blank 3 is placed between the upper die assembly and the lower die assembly, that is, the head blank 3 is placed 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.

[0088] Example 1

[0089] A complex head forging weighs 103.6 tons and is forged using a 185-ton steel ingot. The specific implementation process is as follows:

[0090] 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 jaws are pressed, the ingot body is chamfered, and the nozzle and jaws are discarded by gas cutting;

[0091] 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℃;

[0092] Step 3: After blanking, the ingot is upset and spun. The spinning adopts a double-sided rotary forging method. First, the billet after cogging forging is heated to 1230 °C, and then held for 51 h. After holding, it is 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 4.5 m. Subsequently, the slab is flipped 180° and returned to the furnace for heating to 1230 °C, and held at this temperature for 52 h. The slab is widened by using the double-sided rotary forging method. The spreading hammer head 9 is a flat hammer head. As Figure 4 shown, the height H1 of the first boss reserved at the middle position of the head slab 3 is up to 210 mm, and the diameter D1 of the first boss is 1100 mm;

[0093] Step 4: After the slab is flipped 180°, it is returned to the furnace for heating to 1230 °C and held for 14 h. Then the slab is placed on the bottom washer 10 (as Figure 5 shown), and the first boss reserved in the previous heat is pressed to h1 = 200 mm with a cover plate (as Figure 6 shown). Then, the slab is further widened on the other side with a spreading flat hammer head (as Figure 7 shown). Finally, the second boss with a height of H2 reserved in the middle of the slab is upset to h2 = 365 mm to obtain the finished forged head slab 3 (as Figure 8 shown). This not only ensures that bosses with a certain height and diameter are reserved at the middle position of the head slab 3, but also helps to eliminate the deformation dead zone generated during upsetting. The forged tube sheet is rough machined to the blanking size of the slab (as Figure 9 shown). After passing the flaw detection, it waits for stamping. The schematic diagram of the head slab 3 before stamping using the forging and forming tooling is as Figure 10 shown, and the schematic diagram of the head slab 3 after stamping using the above forging and forming tooling is as Figure 11 shown.

[0094] Step 5: The slab after rough machining and passing the flaw detection is returned to the furnace for heating to 1000 °C according to the process requirements, held for 7 h, and then assembled with the forging and forming tooling for stamping.

[0095] The specific operating procedures for slab stamping are as follows: Install the upper ring body 1 on a ten-thousand-ton hydraulic press, and connect the forming ring 2 to the upper ring body 1 through a pin shaft, so as to transfer the pressure of the ten-thousand-ton hydraulic press 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. Finally, move the hot slab to the first support ring 5 that plays a positioning role, so that the annular cavity on the lower bottom surface of the head slab 3 fits into the first support ring 5 on the top surface of the punch base 4. At this time, start the ten-thousand-ton hydraulic press to make the forming ring 2 press downward at a uniform speed of 20 mm / s. After the downward stroke of 1450 mm, make the inner surface of the head slab 3 fit with the fourth annular arc surface 15 of the fourth support ring 8, and the stamping of the head finished forging is successful.

[0096] Example 2

[0097] A certain complex head forging weighs 125 t and is forged from a 210 t steel ingot. The specific implementation process is as follows:

[0098] Step 1: The temperature of the hot-delivered steel ingot is 500 °C. After the hot-delivered steel ingot is loaded into the furnace, heat the heating furnace to 725 °C, keep it warm for 17 h, then heat it to 1260 °C and keep it warm for 37 h. After heat preservation, chamfer the ingot body, press the tongs, gas-cut the nozzle waste and the tongs waste.

[0099] Step 2: Upsetting KD: Since the forged part to be manufactured is a solid forged part, in order to ensure the quality of the internal flaw detection of the core, it is necessary to carry out the upsetting and drawing compaction process. Generally, the upsetting ratio and the drawing ratio are controlled at 2.3. Heat the steel ingot to 1250 °C and keep it warm for 55 h, carry out upsetting and KD drawing, and after completion, gas-cut the tongs and cut the material. The forging temperature range of this heat treatment is 950 °C.

[0100] Step 3: After the steel ingot is cut, it is upset and spun. The spinning adopts a double-sided rotary forging method. First, heat the billet after cogging forging to 1240 °C, then keep it warm for 57 h. After heat preservation, upset it to the maximum diameter that can be upset by the maximum load of the ten-thousand-ton hydraulic press, that is, upset it to a diameter of 4.7 m. Then turn the slab 180° and return it to the furnace to heat it to 1240 °C, and keep it warm at this temperature for 55 h. Use the double-sided rotary forging method to widen the slab. The spreading hammer head 9 is a flat hammer head. As Figure 4 shown, the height H1 of the first boss reserved in the middle position of the slab is up to 300 mm, and the diameter D1 of the first boss is up to 2000 mm;

[0101] Step 4: After the slab is flipped 180°, it is returned to the furnace for heating to 1240°C and holding for 15 h. Then, the slab is placed on the bottom washer 10, and the first boss reserved on the upper fire is pressed to h1 = 200 mm with a cover plate. Then, the slab is further widened on the other side with a widening flat hammer head. Finally, the second boss with a height of H2 reserved in the middle of the slab is upset to h2 = 365 mm to obtain the finished forged head slab 3. This not only ensures that bosses with a certain height and diameter are reserved at the middle position of the slab but also helps to eliminate the deformation dead zone generated during upsetting. The forged head slab is rough-machined to the blank sizing for stamping, and after passing the flaw detection, it waits for stamping forming.

[0102] Step 5: After the slab passes the rough machining flaw detection, it is returned to the furnace for heating to 1000°C according to the process requirements. After holding for 7 h, the forging and forming tooling is assembled for stamping.

[0103] The specific operating procedures for blank sizing are as follows: The upper ring body 1 is installed on a ten-thousand-ton hydraulic press, and the forming ring 2 is connected to the upper ring body 1 through a pin shaft, so that the pressure of the ten-thousand-ton hydraulic press can be transmitted to the forming ring 2. Then, the first support ring 5 is placed on the first annular step, the second support ring 6 is placed on the second annular step, the third support ring 7 is placed on the third annular step, and the fourth support ring 8 is placed on the fourth annular step. The lower die assembly is adjusted so that the center line of the punch base 4 coincides with the center line of the forming ring 2. Finally, the hot slab is moved to the first support ring 5 for positioning, so that the annular cavity on the lower bottom surface of the head slab 3 is fitted with the first support ring 5 on the top surface of the punch base 4. At this time, the ten-thousand-ton hydraulic press is started, and the forming ring 2 is pressed downward at a uniform speed of 22 mm / s. After the downward stroke of 1500 mm, 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 stamping of the finished forged head is successful.

[0104] Example 3

[0105] A complex head forging weighs 145 t and is forged and formed using a 230 t steel ingot. The specific implementation process is as follows:

[0106] Step 1: The temperature of the hot-delivered steel ingot is 590°C. After the hot-delivered steel ingot is charged into the furnace, the heating furnace is heated to 750°C, held for 19 h, then heated to 1270°C and held for 39 h. After holding, chamfering of the ingot body, pressing the tongs, gas cutting the nozzle waste and tong waste are carried out.

[0107] Step 2: Upsetting KD: Since the forgings to be manufactured are solid forgings, in order to ensure the flaw detection quality of the core, the upsetting and drawing compaction process needs to be carried out. Generally, the upsetting ratio and drawing ratio are controlled at 2.5. The steel ingot is heated to 1250°C and held for 60 h, then upsetting and KD drawing are carried out. After completion, the tong waste is cut by gas cutting. The forging temperature range for this heat is 1250°C.

[0108] Step 3: After blanking, the ingot is upset and spun. The spinning adopts a double-sided rotary forging method. First, the ingot after cogging forging is heated to 1250 °C, and then held for 59 h. After holding, it is 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 5.0 m. Subsequently, the slab is flipped 180° and returned to the furnace for heating to 1250 °C, and held at this temperature for 60 h. The slab is widened by the double-sided rotary forging method. The flattening hammer head 9 is a flat hammer head. The height H1 of the first boss reserved in the middle of the head slab 3 is 500 mm, and the diameter D1 of the first boss is 3000 mm.

[0109] Step 4: The slab is flipped 180° and returned to the furnace for heating to 1250 °C. After heating, it is held for 17 h. Then the slab is placed on the bottom washer 10, and the first boss reserved on the upper fire is pressed to h1 = 200 mm with a cover plate. Then, the slab is further widened on the other side with a flattening hammer head. Finally, the second boss with a height of H2 reserved in the middle of the slab is upset to h2 = 365 mm to obtain the finished forged head slab 3.

[0110] Step 5: After the slab passes the rough machining flaw detection, it is returned to the furnace for heating to 1000 °C according to the process requirements. After holding for 10 h, the forging and forming tooling is assembled for stamping.

[0111] The specific operating procedures for stamping the slab 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 as to transfer the pressure of the 10,000-ton hydraulic press 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 circular cushion block 19 on the fifth annular step to increase the height of the fifth support ring 20. After placing the cushion block 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, 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. Finally, move the hot slab to the first support ring 5 that plays a positioning role, so that the annular cavity on the lower bottom surface of the head slab 3 is fitted 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 press downward at a uniform speed of 24 mm / s. After the downward stroke of 1600 mm, 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 stamping of the finished head forging is successful.

[0112] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A stamping forming method for a complex head, characterized in that, It includes the following steps: Step 1: The ingot is bloomed and forged to obtain a cylindrical billet; The hot-charged ingot is successively subjected to pressing the jaw, chamfering, gas cutting the nozzle waste and jaw waste, upsetting, KD drawing out, and cutting the jaw and blanking; Step 2: The cylindrical billet is subjected to double-sided rotary forging to form a head blank; The cylindrical billet is upset and spun. During upsetting, the billet after blooming and forging is heated to 1230°C - 1250°C, and then held for 50 - 60 h. After holding, it is upset to a diameter of 4.5 m - 5.0 m. Subsequently, the head blank is flipped 180° and sent back to the furnace for heating to 1230°C - 1250°C, and held for 50 - 60 h; Step 3: The head blank is subjected to stamping forming; The stamping forming method uses a forging forming tooling for large and complex heads. The forging forming tooling includes an upper die assembly and a lower die assembly; the upper die assembly includes 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 cross-section of the forming ring in the vertical direction is an inverted right trapezoid, and the hypotenuse of the right trapezoid is close to the center line side of the forming ring; The lower die assembly includes a punch base. The punch base is a hollow hemisphere with its spherical surface facing upward and the opening facing downward. The outer wall of the spherical surface of the punch base is successively provided with a first annular step, a second annular step, a third annular step, and a fourth annular step with increasing radii from top to bottom; the first annular step, the second annular step, the third annular step, and the fourth annular step are respectively provided with a first support ring, a second support ring, a third support ring, and a fourth support ring; A ring-shaped cavity is provided on the bottom surface of the head blank, and the ring-shaped cavity of the head blank is fitted with the first support ring; The arc surface of the forming ring can be fitted with the outer surface of the deformed head blank. During the stamping process of the head blank, at the beginning of stamping and forming, a downward pressure is applied to the head blank through the bottom surface of the forming ring. When the head blank gradually deforms from a round cake shape, the contact area between the bottom surface of the forming ring and the head blank decreases. At this time, the arc surface of the forming ring begins to contact the head blank and applies a downward pressure to the head blank until the inner surface of the head blank contacts the fourth annular arc surface of the fourth support ring, and the stamping and forming stops.

2. The stamping forming method for a complex head according to claim 1, characterized in that, In the said Step 3, the stamping forming of the blank includes: rough machining the forged head blank, returning it to the furnace for heating to 900°C - 1000°C after non-destructive testing is qualified, then holding for 6 - 8 h, and performing stamping and forming after holding.

3. The stamping forming method for a complex head according to claim 2, characterized in that, In the said Step 3, the stamping speed during stamping forming is 18 - 22 mm / s.

4. The stamping forming method for a complex head according to claim 3, characterized in that, In the said Step 2, after upsetting, the blank is widened by double-sided rotary forging. The widening hammer head uses a flat hammer head, and a first boss is reserved at the middle position of the blank; the height H1 of the first boss is in the range of 200 - 500 mm, and the diameter D1 of the first boss is in the range of 1000 - 3000 mm.

5. The stamping forming method for a complex head according to claim 4, characterized in that, In step 2, after reserving the first boss, the slab is flipped 180° and then returned to the furnace for heating to 1230°C - 1250°C, and then held for 13 - 17 h. After holding, the slab is placed on the bottom washer, and the first boss is pressed down to the set height with a cover plate. Then, a flat hammer head is used to continue spreading on the other side of the slab. Finally, the second boss of the slab is upset to obtain a round cake-shaped head slab.

6. The stamping forming method for a complex head according to claim 5, characterized in that, In step 1, the temperature of the hot-delivered ingot is 400°C - 600°C. After the hot-delivered ingot is charged into the furnace, the heating furnace is heated to 700°C - 750°C and held for 15 - 20 h.

7. The stamping forming method for a complex head according to claim 6, characterized in that, In step 1, the ingot is heated to 1250°C - 1270°C and held for 35 - 40 h. After holding, chamfering of the ingot body, pressing the tongs, gas cutting the nozzle waste and the tongs waste are carried out.

8. The stamping forming method for a complex head according to claim 1, characterized in that, In step 1, after gas cutting the nozzle waste and the tongs waste, the ingot is heated to 1250°C and then held for 50 - 60 h. After holding, upsetting and KD drawing are carried out, and after completion, the tongs are gas cut for blanking.

9. The stamping forming method for a complex head according to claim 1, characterized in that, In step 1, both the upsetting ratio and the drawing ratio during upsetting and drawing are controlled within the range of 2.2 - 2.

5.

10. The stamping forming method for a complex head according to any one of claims 1 to 9, characterized in that, In step 1, the forging temperature during upsetting and drawing is 750°C - 1250°C.

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