Forging method for lower anvil block forging of hydraulic pile hammer

Abstract

A forging method for a lower anvil block forging of a hydraulic pile hammer, used for solving the problem in the prior that in-die forging and out-of-die forging cannot be conducted for ultra-large lower anvil block forgings having diameters exceeding 7.5 m. The method comprises: providing a cylindrical billet, providing a lower surface internal circular boss at one end of the cylindrical billet, turning the cylindrical billet, providing an upper surface internal circular boss at the other end of the cylindrical billet, and providing steps around the upper surface internal circular boss; using a contour hammer head to perform profile forging at the stepped position to obtain a lower anvil block forging billet; and using a profile hammer to forge an out-of-die forging reserved area of the lower anvil block forging billet to obtain a lower anvil block forging.

Description

A forging method for a lower anvil forging of a hydraulic pile hammer Technical Field

[0001] The invention belongs to the technical field of in vitro forging, and in particular relates to a forging method for a lower anvil forging of a hydraulic pile hammer. Background Art

[0002] The lower anvil forging is one of the core forgings of a hydraulic pile hammer and is generally made of high-quality forgings. As the capacity of offshore wind turbines increases, the required diameters of hydraulic pile hammers and the lower anvil forgings are also increasing.

[0003] Limited by the specifications of the current forging equipment, the maximum diameter of the existing lower anvil forging is 6.65 meters and the weight is 170 tons. It can be forged mainly in the following two ways:

[0004] One of the methods is to upset the cylindrical blank, and then use a flat hammer to open the edge, forging the inclined surface into multiple steps; the other method is to use the in-die forming method, first upsetting it in the die, and then opening the large end. Both of the above methods are only suitable for lower anvil forgings with relatively small weight. However, for ultra-large lower anvil forgings, especially those with a blank diameter of more than 7.5 meters, only in vitro forging can be used. Due to the pressure-bearing capacity of the lifting beam, the length of the lifting beam cannot be too long, resulting in the hammer head on one side of the lifting beam being unable to reach the center of the forging blank for forging.

[0005] Summary of the Invention

[0006] In view of the above analysis, the present invention aims to provide a forging method for a hydraulic pile hammer lower anvil forging to solve the problem in the prior art that both internal forging and external forging are unable to forge ultra-large lower anvil forgings with a diameter exceeding 7.5m.

[0007] The purpose of the present invention is mainly achieved through the following technical solutions.

[0008] The present invention provides a forging method for a lower anvil forging of a hydraulic pile hammer, comprising the following steps:

[0009] Step 1: providing a cylindrical blank;

[0010] Step 2: Opening an inner circular boss on the lower surface of one end of the cylindrical blank, turning the cylindrical blank over, opening an inner circular boss on the upper surface of the other end of the cylindrical blank, and opening steps around the inner circular boss on the upper surface;

[0011] Step 3: Use the shaped hammer to forge the step position to obtain the lower anvil forging blank;

[0012] Step 4: Forging the in vitro forging reserved area of ​​the lower anvil forging blank with a profiling hammer to obtain the lower anvil forging;

[0013] Steps 2 to 3 are forging steps inside the hydraulic press, and step 4 is forging step outside the hydraulic press;

[0014] The lower anvil forging blank is divided into an internal forging forming area and an external forging reserved area in a direction gradually away from the center line of the blank. The upper surface of the internal forging forming area is conformal to the upper surface of the lower anvil forging. The external forging reserved area includes an outer cylindrical boss arranged on the periphery of the internal forging forming area, and the upper surface of the outer cylindrical boss protrudes from the upper surface of the internal forging forming area close to the outer cylindrical boss; the lower anvil forging is divided into an internal forging area and an external forging area in a direction gradually away from the center line of the blank. The internal forging forming area is used to form the internal forging area, and the external forging reserved area is used to form the external forging area.

[0015] Furthermore, the diameter of the internal forging forming area is 5500mm-6000mm, the diameter of the external forging reserved area is less than or equal to 7000mm, and the thickness of the external forging reserved area is 1000mm-1500mm.

[0016] Furthermore, step 1 includes the following steps:

[0017] Step 11: Providing a steel ingot;

[0018] Step 12: Press the steel ingot into a jaw, remove the discarded material at the nozzle end, and obtain the billet to be processed;

[0019] Step 13: The blank to be processed is subjected to multiple upsetting and forging compaction, and the waste materials of the riser, jaws and nozzle are removed to obtain a cylindrical blank.

[0020] Furthermore, the steel ingot is a double vacuum steel ingot smelted by a multi-ladle casting method.

[0021] Furthermore, the weight of the double vacuum steel ingot is 2.2-2.7 times the final weight of the lower anvil forging.

[0022] Furthermore, in step 13, a forging method without Mannesmann effect and a central compaction forging method are used in combination to perform forging and compaction.

[0023] Furthermore, step 2 includes the following steps:

[0024] Step 21: Place the cylindrical blank on a rotary table and upset the cylindrical blank until it stops moving;

[0025] Step 22: Rotating forging the cylindrical blank to form an inner circular boss on the upper surface at one end of the cylindrical blank;

[0026] Step 23: Turn over the cylindrical blank, perform rotary forging, and open an inner circular boss on the lower surface at the other end of the cylindrical blank.

[0027] Furthermore, in step 23, a widened hammer head is used for rotary forging, and the width of the flat-head widened hammer head is 400 mm-600 mm.

[0028] Furthermore, in step 2, the diameter of the cylindrical blank is opened to 0.95-0.98 times the final diameter of the inner forging zone.

[0029] Furthermore, in step 4, the forging surface of the contoured hammer head is an inclined surface, and the inclination angle of the inclined surface is the same as the inclination angle of the upper surface of the lower anvil forging.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects.

[0031] A) The forging method of the lower anvil forging of the hydraulic pile hammer provided by the present invention utilizes the method of forming the inner tire mold of the hydraulic press in combination with forging the edge of the outer tire mold to divide the lower anvil forging blank into an inner forging forming area and an outer forging reserved area. The shape of the inner forging forming area is basically consistent with the shape of the inner forging area of ​​the lower anvil forging. The outer forging reserved area adopts the method of outer forging. Through the setting of the outer circular boss, the overall diameter of the blank can be effectively reduced, so that the diameter of the blank is less than or equal to the column spacing of the hydraulic press, which is convenient for forging the inner forging forming area. Subsequently, the outer forging reserved area is forged by the method of outer forging to expand the diameter of the outer forging reserved area so that the shape of the outer forging reserved area is consistent with that of the outer forging area of ​​the lower anvil forging, thereby obtaining a finished product of the lower anvil forging.

[0032] B) The forging method for the hydraulic pile hammer lower anvil forging provided by the present invention, in actual application, uses an ultra-large double vacuum steel ingot to produce an ultra-large lower anvil forging with a diameter of 7.68 meters and a weight of 240 tons. During the forging process, the diameter of the blank exceeds 7.8 meters and the gross weight reaches 370 tons. Lower anvil forgings with diameters of 7.88 meters, 8.1 meters, and even larger can also be produced.

[0033] In the present invention, the above-mentioned technical solutions can 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 will become apparent from the description or be understood through practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the embodiments of the description and the contents particularly pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying 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 parts throughout the drawings.

[0035] FIG1 is a flowchart of forging a cylindrical blank in step 1 of a forging method for a lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention;

[0036] FIG2 is a forging flow chart of step 2 of the forging method for the lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention, in which an inner circular boss is formed on one end of the cylindrical blank;

[0037] 3 is a forging flow chart of step 2 of the forging method for the lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention, wherein an inner circular boss is formed on the other end of the cylindrical blank and steps are formed around the inner circular boss;

[0038] FIG4 is a schematic structural diagram of a swivel assembly in a forging method for a lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention;

[0039] 5 is a flow chart of turning over a cylindrical blank in a forging method for a lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention;

[0040] 6 is a forging flow chart of step 3 in the forging method of the lower anvil forging of the hydraulic pile hammer provided in Example 1 of the present invention;

[0041] 7 is a schematic structural diagram of a lower anvil forging blank in a forging method for a hydraulic pile hammer lower anvil forging provided in Example 1 of the present invention;

[0042] FIG8 is a forging flow chart of step 4 in the forging method of the lower anvil forging of the hydraulic pile hammer provided in Example 1 of the present invention;

[0043] FIG9 is a schematic structural diagram of a contoured hammer head in a forging method for a lower anvil forging of a hydraulic pile hammer provided in Example 1 of the present invention.

[0044] Reference numerals:

[0045] 1-internal forging forming area; 2-external forging reserved area; 3-longitudinal rib; 4-first transverse rib; 5-second transverse rib; 6-lifting ear; 7-arc rib. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention will be described in detail below with reference to 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] Example 1

[0048] This embodiment provides a forging method for a lower anvil forging of a hydraulic pile hammer, comprising the following steps:

[0049] Step 1: providing a cylindrical blank;

[0050] Step 2: Open an inner circular boss on the lower surface of one end of the cylindrical blank, see Figure 2, turn the cylindrical blank over, open an inner circular boss on the upper surface of the other end of the cylindrical blank, and open steps around the inner circular boss on the upper surface, see Figure 3;

[0051] Step 3: Using a conformable hammer, forge the step position to obtain a lower anvil forging blank. Referring to FIG6 , the shape is a mountain-shaped shape. Referring to FIG7 , the shape is divided into an internal forging forming area 1 and an external forging reserved area 2 in a direction gradually away from the center line of the blank. The upper surface of the internal forging forming area 1 is conformal to the upper surface of the lower anvil forging. The external forging reserved area 2 includes an outer circular boss provided on the periphery of the internal forging forming area 1. The upper surface of the outer circular boss protrudes from the upper surface of the internal forging forming area 1 on the side close to the outer circular boss.

[0052] It should be noted that the lower anvil forging is divided into an internal forging area and an external forging area in the direction gradually away from the center line of the billet. The internal forging forming area 1 of the billet is used to form the internal forging area of ​​the lower anvil forging, and the external forging reserved area 2 of the billet is used to form the external forging area of ​​the lower anvil forging. The volume of the external forging reserved area 2 is greater than or equal to the volume of the external forging area of ​​the lower anvil forging. From the perspective of fire consumption, the volume of the external forging reserved area 2 is greater than the volume of the external forging area of ​​the lower anvil forging.

[0053] Step 4: The last fire is performed outside the hydraulic press body. The hydraulic press load is transferred to the outside of the press by using the external forging lifting beam. The external forging reserved area 2 of the lower anvil forging blank is forged by using the profiling hammer to complete the near-net forming of the unformable part inside the hydraulic press body, as shown in Figure 8, to obtain the lower anvil forging.

[0054] Compared with the prior art, the forging method of the lower anvil forging of the hydraulic pile hammer provided in this embodiment divides the lower anvil forging blank into an internal forging forming area 1 and an external forging reserved area 2 by combining the internal die forming of the hydraulic press with the external die forging edge opening. The shape of the internal forging forming area 1 is basically consistent with the shape of the internal forging area of ​​the lower anvil forging. The external forging reserved area 2 is forged in vitro. By setting the external cylindrical boss, the overall diameter of the blank can be effectively reduced, so that the diameter of the blank is less than or equal to the column spacing of the hydraulic press, which is convenient for forging the internal forging forming area 1. Subsequently, the external forging reserved area 2 is forged in vitro to expand the diameter of the external forging reserved area 2 so that the shape of the external forging reserved area 2 is consistent with that of the external forging area of ​​the lower anvil forging, thereby obtaining a finished product of the lower anvil forging.

[0055] In actual application, ultra-large double vacuum steel ingots are used. Through the above forging method, ultra-large lower anvil forgings with a diameter of 7.68 meters and a weight of 240 tons can be produced. During the forging process, the diameter of the blank exceeds 7.8 meters and the gross weight reaches 370 tons. Lower anvil forgings with a diameter of 7.88 meters, 8.1 meters or even larger can also be produced.

[0056] In order to achieve a lower anvil forging with a larger diameter, for example, the diameter of the internal forging forming area 1 is 5500mm-6000mm, the diameter of the external forging reserved area 2 is less than or equal to 7000mm, and the thickness of the external forging reserved area 2 is 1000mm-1500mm.

[0057] In order to facilitate the subsequent in vitro forging, the shape of the upper surface of the outer cylindrical boss, specifically, includes an inclined segment, a platform segment and an arc segment connected in sequence along the direction gradually away from the in vivo forging forming area 1, and the angle α between the inclined segment and the platform segment is greater than 90°. Exemplarily, the angle α between the inclined segment and the platform segment is 120°-150°.

[0058] It can be understood that in order to achieve the forging of the internal forging forming zone 1 of the above-mentioned lower anvil forging blank, its diameter is less than or equal to the column spacing of the hydraulic press. For example, the diameter of the lower anvil forging blank is 50-100mm smaller than the column spacing of the hydraulic press.

[0059] Exemplarily, in order to obtain a cylindrical blank, referring to FIG1 , the above step 1 includes the following steps:

[0060] Step 11: Providing a steel ingot;

[0061] It should be noted that due to the large size of the lower anvil forging, it is necessary to achieve near-net shape as much as possible under the conditions of existing forging equipment, fully reduce the forging allowance, and effectively control the size of the steel ingot. Therefore, the above-mentioned steel ingot is a double vacuum steel ingot produced by smelting multiple ladles. By adjusting the smelting composition of each ladle to control the macrosegregation of the steel ingot, the weight of the double vacuum steel ingot is controlled to be 2.2-2.7 times the final weight of the lower anvil forging.

[0062] Step 12: Press the steel ingot into a jaw, remove the discarded material at the nozzle end, and obtain the billet to be processed;

[0063] Step 13: The blank to be processed is subjected to multiple (for example, 2) upsetting and forging compaction, and the waste materials of the riser, jaws and nozzle are removed to obtain a cylindrical blank.

[0064] It should be noted that in the above step 13, considering that the lower anvil forging is a solid forging and the core thickness is super thick, in this step, the forging method without Mannesmann effect (i.e., FM method) and the center compaction forging method (i.e., JTS hard shell forging method) are used in combination for forging and compaction, so that the internal microstructure of the blank to be processed is fully crushed, reducing shrinkage holes and holes in the blank to be processed.

[0065] Specifically, the upper end of the cylindrical blank is provided with an inner circular boss on the upper surface, and the lower end of the cylindrical blank is provided with an inner circular boss on the lower surface. Referring to FIG. 2 and FIG. 3 , the above step 2 includes the following steps:

[0066] Step 21: Place the cylindrical blank on the turntable, and use the cover plate to upset the cylindrical blank until it stops moving;

[0067] Step 22: Using a flat hammer head to perform rotary forging on the cylindrical blank, forming an inner circular boss on the upper surface at one end of the cylindrical blank;

[0068] Step 23: Turn over the cylindrical blank and use a flat-head widened hammer for rotary forging to open an inner circular boss on the lower surface at the other end of the cylindrical blank.

[0069] Considering the excessive weight of the cylindrical blank, existing lifting and operation methods are essentially unsuitable. Therefore, in step 23, a hoisting assembly is used to flip the cylindrical blank. Specifically, the hoisting assembly includes a crane, an arc-shaped member, and two horizontal members. The arc-shaped member is arranged in a vertical direction, with the end of the arc-shaped member connected to one end of the horizontal member. The other end of the horizontal member is provided with a lifting lug 6, and the crane main hook is hung on the lifting lug 6.

[0070] For example, referring to FIG4 , the horizontal member includes a plurality of arcuate ribs 7 arranged side by side and in parallel, and the arc of the arcuate rib 7 is 180°, that is, the arcuate rib 7 is a semicircular arcuate rib 7. The horizontal member includes a longitudinal rib 3, a first transverse rib 4, and a second transverse rib 5, wherein the number of the first transverse rib 4 is two, and the longitudinal rib 3 and the second transverse rib 5 are both arranged between the two first transverse ribs 4. The end of the longitudinal rib 3 is connected to the first transverse rib 4, and one end of the first transverse rib 4 and one end of the second transverse rib 5 are both connected to the end of the arcuate rib 7. The other end of the first transverse rib 4 is provided with a lifting ear 6, and the other end of the second transverse rib 5 is connected to the longitudinal rib 3. In this way, the swivel assembly adopting the above structure can integrate the arcuate rib 7, the longitudinal rib 3, the first transverse rib 4, and the second transverse rib 5 into one body, thereby reducing the weight of the swivel assembly itself while ensuring the structural strength and swivel function of the swivel assembly.

[0071] As for the lifting lug 6 , grooves are provided on both sides of the end portion of the first transverse rib 4 to form an I-shaped structure, thereby serving as the lifting lug 6 .

[0072] Based on the structure of the above-mentioned lifting and rotating assembly, in step 23, referring to FIG5 , turning the cylindrical blank includes the following steps:

[0073] Step 231: Provide a platform, place the swivel assembly on one side of the platform, and suspend the end with the hanging ear in the air;

[0074] Step 232: Using the overhead crane's portal crane to move the cylindrical blank into the lifting assembly;

[0075] Step 233: Use an alloy chain or a steel wire rope to lock the end of the hanging assembly provided with the hook, so that the cylindrical blank will not fall out of the flipping assembly during the movement and flipping process;

[0076] Step 234: Connect the main hook of the overhead crane to the lifting eye 6 via a lifting chain, and start the overhead crane, so that the end of the tilting assembly provided with the lifting eye 6 rotates around the arc-shaped member, so that the tilting assembly is lifted to the other side of the platform;

[0077] Step 235: Use the gantry crane of the overhead crane to move the cylindrical blank out of the lifting assembly to complete the flipping of the cylindrical blank.

[0078] In order to ensure that the cylindrical blank can be smoothly moved into the hanging and rotating assembly, the height difference between the internal height of the hanging and rotating assembly and the height of the cylindrical blank is 50-100 mm.

[0079] It should be noted that in the above step 23, the width of the flat-head widened hammer head is 400mm-600mm. In this way, limiting the width of the flat-head widened hammer head within the above range is conducive to the full growth of the diameter of the cylindrical blank. In this step 23, the diameter of the lower end of the cylindrical blank is opened to 0.95-0.98 times (for example, 0.96 times) the final diameter of the forging zone in the body.

[0080] To form a stepped surface around the inner cylindrical boss on the upper surface, a flat hammer head can be used to create steps around the inner cylindrical boss on the upper surface. The width and height of each step should conform to the slope of the final lower anvil forging product. That is, if the slope angle of the final lower anvil forging product is α, the height of each step h = the width of each step L × tanα. It should be noted that in this step, the diameter of the end face of the cylindrical blank to be stepped is increased to 0.95-0.98 times (e.g., 0.96 times) the final diameter of the inner forging zone.

[0081] It should be noted that in the above step 4, in order to achieve near-net-shape forming of the lower anvil forging, for the contoured hammer head, see Figure 9, its forging surface is an inclined surface, and the inclination angle of the inclined surface is the same as the inclination angle of the upper surface of the lower anvil forging.

[0082] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A forging method for a hydraulic pile hammer lower anvil forging, characterized in that: The steps include: Step 1: providing a cylindrical blank; Step 2: Opening a lower surface inner circular boss at one end of the cylindrical blank, turning the cylindrical blank over, opening an upper surface inner circular boss at the other end of the cylindrical blank, and opening steps around the upper surface inner circular boss; Step 3: Use a shaped hammer to forge the step position to obtain a lower anvil forging blank; Step 4: forging the in vitro forging reserved area of ​​the lower anvil forging blank with a profiling hammer to obtain the lower anvil forging; Steps 2 to 4 are all forging steps inside the hydraulic press, and step 5 is a forging step outside the hydraulic press; The lower anvil forging blank is divided into an internal forging forming zone and an external forging reserved zone in a direction gradually away from the center line of the blank, the upper surface of the internal forging forming zone is conformal with the upper surface of the lower anvil forging, the external forging reserved zone includes an outer cylindrical boss arranged on the periphery of the internal forging forming zone, the upper surface of the outer cylindrical boss protrudes from the upper surface of the internal forging forming zone close to the outer cylindrical boss; the lower anvil forging is divided into an internal forging zone and an external forging zone in a direction gradually away from the center line of the blank, the internal forging forming zone is used to form the internal forging zone, and the external forging reserved zone is used to form the external forging zone.

2. The forging method of the hydraulic pile hammer lower anvil forging according to claim 1, characterized in that: The diameter of the internal forging forming area is 5500mm-6000mm, the diameter of the external forging reserved area is less than or equal to 7000mm, and the thickness of the external forging reserved area is 1000mm-1500mm.

3. The forging method of the lower anvil forging of the hydraulic pile hammer according to claim 1, characterized in that: The step 1 comprises the following steps: Step 11: providing a steel ingot; Step 12: Press the steel ingot to obtain the blank to be processed; Step 13: The blank to be processed is subjected to multiple upsetting and forging compaction, and the discarded materials of the riser, the jaws and the nozzle are cut off to obtain a cylindrical blank.

4. The forging method of the hydraulic pile hammer lower anvil forging according to claim 3, characterized in that: The steel ingot is a double vacuum steel ingot smelted by a multi-ladle casting method.

5. The forging method of the lower anvil forging of the hydraulic pile hammer according to claim 4, characterized in that: The weight of the double vacuum steel ingot is 2.2-2.7 times the final weight of the lower anvil forging.

6. The forging method of the hydraulic pile hammer lower anvil forging according to claim 3, characterized in that: In the step 13, a forging method without Mannesmann effect and a central compaction forging method are used in combination for forging and compaction.

7. The forging method of the lower anvil forging of the hydraulic pile hammer according to claim 1, characterized in that: The step 2 comprises the following steps: Step 21: placing the cylindrical blank on a rotary table, and upsetting the cylindrical blank until the upsetting stops; Step 22: Rotating forging the cylindrical blank to form an inner circular boss on the upper surface at one end of the cylindrical blank; Step 23: Turn over the cylindrical blank, perform rotary forging, and open an inner circular boss on the lower surface at the other end of the cylindrical blank.

8. The forging method of the lower anvil forging of the hydraulic pile hammer according to claim 7, characterized in that: In the step 23, a flat-head widened hammer is used for rotary forging, and the width of the flat-head widened hammer is 400mm-600mm.

9. The forging method of the hydraulic pile hammer lower anvil forging according to claim 1, characterized in that: In step 2, the diameter of the cylindrical blank is opened to 0.95-0.98 times the final diameter of the in-body forging zone.

10. The forging method of the lower anvil forging of the hydraulic pile hammer according to claim 1, characterized in that: In the step 4, the forging surface of the profiling hammer head is an inclined surface, and the inclination angle of the inclined surface is the same as the inclination angle of the upper surface of the lower anvil forging.

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