Large-diameter outer circle belt multi-convex platform cylinder reaming method and hammer head

Abstract

The application discloses a large-diameter outer circle belt multi-convex platform cylinder hole expanding method and a hammer head, and belongs to the field of forging technology, and solves the problem of difficult forming of a large-diameter outer circle belt multi-convex platform cylinder in the prior art. The hole expanding method comprises the following steps: preparing a small-diameter cylinder blank of the outer circle belt convex platform; placing a horse lever on a horse frame, inserting the horse lever into a punching hole of the cylinder blank, and then placing a large-diameter outer circle belt multi-convex platform cylinder hole expanding hammer head above the cylinder blank; in the process of forging and hole expanding, the hole expanding is performed at different positions by adjusting the sliding anvil in real time according to the positions of the convex platforms; and after a plurality of rounds of hole expanding, the hole expanding forming of the large-diameter outer circle belt multi-convex platform cylinder product is completed. The method can make the forging process smooth and improve the overall performance of the forged part.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and in particular to a method for expanding the hole of a large-diameter outer cylindrical body with multiple bosses and a hammer head. Background Technology

[0002] With the rapid development of China's energy, chemical, aerospace, and marine engineering industries, my country's industrial equipment is gradually evolving towards integration and large-scale production. Currently, pressure vessels are also showing a trend towards large-scale, integrated development. As a key component of these vessels, nozzles require high performance in terms of strength, toughness, impact resistance, low-temperature performance, corrosion resistance, and radiation resistance to withstand harsh working conditions. Figure 1 The diagram shows a large-diameter outer circumference cylindrical structure with multiple bosses. As the main pressure-bearing component of a pressure vessel, this type of cylindrical structure is not only extremely large in size and thin in wall thickness, but also has many bosses and connecting pipes on its outer circumference, making it complex in shape and difficult to form. Therefore, it places high demands on the production process and forming methods.

[0003] Currently, the main forging method for this type of forging involves forging a large-diameter cylinder, machining welding holes at the nozzle location, and then connecting the nozzle to the cylinder by welding. This process is not only labor-intensive, but also involves repeated preheating and post-weld heat treatment during the assembly welding process, which leads to deterioration of the forging's performance due to multiple heat cycles. Furthermore, during equipment operation, the weld locations require in-service inspection, which hinders the improvement of in-service inspection efficiency. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a method for expanding the hole of a large-diameter outer cylindrical body with multiple bosses and a hammer head, so as to solve the problem of the difficulty in forming large-diameter outer cylindrical bodies with multiple bosses.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] This invention provides a method for expanding the bore of a large-diameter cylindrical body with multiple protrusions on its outer circumference. The large-diameter cylindrical body with multiple protrusions on its outer circumference includes a cylindrical body base and multiple protrusions disposed on the outer periphery of the cylindrical body base, with notches formed between adjacent protrusions. The method for expanding the bore includes the following steps:

[0007] Step 1: Prepare a small-diameter cylindrical blank with an outer boss;

[0008] Step 2: Place the lever on the frame, insert the lever into the punch hole of the cylindrical blank, and then place the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions above the cylindrical blank; the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions includes a fixed anvil block and a sliding anvil block, and the distance between the fixed anvil block and the sliding anvil block is adjustable.

[0009] Step 3: Perform multi-turn hole expansion. During the forging and hole expansion process, adjust the distance between the fixed anvil and the sliding anvil to adapt to the changes in the position of the boss and notch of the cylinder, and avoid the boss.

[0010] Furthermore, in step 3, both the fixed anvil and the sliding anvil face the cylinder to be forged. When the forging position is at the boss, the sliding anvil moves to open the gap between the fixed anvil and the sliding anvil, leaving space for the boss, and applies the pressing force to the cylinder on both sides of the boss.

[0011] Furthermore, in step 3, when the forging position is the gap between the two bosses, the sliding anvil moves to close the gap between the fixed anvil and the sliding anvil, and applies the pressing force to the entire length of the cylinder, including the gap between the two bosses.

[0012] Furthermore, in step 1, a small-diameter cylindrical blank with an outer circumference boss is obtained by mandrel drawing and machining.

[0013] Furthermore, the inner diameter of the cylindrical blank is d0, the outer diameter of the cylindrical blank is D0, the inner diameter of the finished product is d1, and the outer diameter is D1, wherein...

[0014] Furthermore, the shapes of the surfaces of the fixed anvil block and the sliding anvil block that contact the cylinder base match the outer circle of the finished cylinder.

[0015] Furthermore, the arc diameter of the surfaces of the fixed anvil block and the sliding anvil block that contact the cylinder base is D1.

[0016] Furthermore, in step 3, the sliding anvil is moved by the retractable component to adjust the distance between the fixed anvil and the sliding anvil.

[0017] Furthermore, one end of the telescopic component is a fixed section, and the other end is a free end, which is connected to the sliding anvil block.

[0018] On the other hand, the present invention provides a large-diameter outer cylindrical enlargement hammer with multiple protrusions, which is used in the above-mentioned enlargement method. The large-diameter outer cylindrical enlargement hammer with multiple protrusions includes a hammer base, a fixed anvil block, and a sliding anvil block. Both the fixed anvil block and the sliding anvil block are disposed on the hammer base facing the cylindrical body to be forged. The fixed anvil block and the hammer base are fixedly connected, and the sliding anvil block and the hammer base are slidably connected. The distance between the fixed anvil block and the sliding anvil block can be adjusted to adapt to changes in the position of the protrusions and notches on the cylindrical body.

[0019] Furthermore, when the fixed anvil and the sliding anvil correspond to the positions of the bosses on the cylinder, the gap between the fixed anvil and the sliding anvil is equal to the axial length of the bosses on the cylinder; when the fixed anvil and the sliding anvil correspond to the positions of the notches on the cylinder, the gap between the fixed anvil and the sliding anvil is zero.

[0020] Furthermore, the sliding anvil block and the hammer base are slidably connected by a sliding rail and a sliding groove that cooperate with each other, wherein the sliding rail is set on the sliding anvil block and the sliding groove is set on the hammer base.

[0021] Furthermore, the fixed anvil block and the sliding anvil block are connected by a telescopic component.

[0022] Furthermore, the telescopic component includes a hydraulic cylinder and a lug. The sliding anvil is connected to one end of the hydraulic cylinder via the lug, and the hammer base is connected to the other end of the hydraulic cylinder. The position of the sliding anvil on the hammer base is controlled by pushing and pulling the hydraulic cylinder.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] a) The method for expanding the outer diameter of a cylindrical body with multiple bosses according to the present invention obtains a cylindrical body blank with multiple bosses on a small diameter outer diameter by drawing and machining a mandrel. Then, a large-diameter cylindrical body with multiple bosses expansion hammer is used, which can apply the pressing force to different areas of the forging in a time-sharing and regional manner without changing the relative position of the press and supporting fixtures. The forging is forged into a large-diameter cylindrical body with multiple bosses through the expansion forging method. The method of the present invention can directly forge the outer bosses in one expansion process. It not only makes the metal flow lines more complete, greatly improves the overall performance of the forging, and increases the safety of the forging, but also improves the material utilization rate, reduces the machining allowance, shortens the production cycle, and reduces the production cost.

[0025] (b) The method for expanding the hole of a large-diameter outer cylindrical body with multiple bosses in this invention uses a fixed anvil and a sliding anvil. During the expansion process, the distance between the fixed anvil and the sliding anvil is adjusted to adapt to the changes in the position of the bosses and notches of the cylinder. This allows for multiple expansions of the hole without the bosses, making the forging process continuous and smooth. The outer cylindrical bosses can be forged directly in one expansion process. This not only makes the metal flow lines more complete but also greatly improves the overall performance of the forging and increases the safety of the forging in use.

[0026] c) The present invention can quickly adjust the fixed anvil and the sliding anvil through the telescopic component, which can form a cylindrical body with multiple bosses on the outer circle; it can apply the pressing force to different areas of the forging in a time-sharing and regional manner without changing the relative position of the press and the supporting auxiliary tool, so as to make the forging process smooth.

[0027] d) The large-diameter outer cylindrical enlargement hammer with multiple bosses provided by the present invention adopts a design of fixed anvil block and sliding anvil block with adjustable distance. Multiple sliding anvil blocks and fixed anvil blocks of various sizes can be designed under the premise of one hammer head base, which can be replaced for different forgings, with greater process flexibility and wider application scenarios.

[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of what is particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0030] Figure 1 A schematic diagram of a large-diameter outer cylindrical body with multiple bosses;

[0031] Figure 2 One of the structural schematic diagrams of a large-diameter outer cylindrical hammer with multiple bosses for expanding holes;

[0032] Figure 3 Schematic diagram 2 of a large-diameter outer cylindrical hammer with multiple bosses for expanding holes;

[0033] Figure 4 This is a schematic diagram of a small-diameter cylindrical blank.

[0034] Figure 5 This is a schematic diagram when the forging position is a boss;

[0035] Figure 6 This is a schematic diagram when the forging position is the notch position;

[0036] Figure 7 This is a large-diameter outer cylindrical body with multiple bosses obtained after hole enlargement;

[0037] Figure 8 This is a cross-sectional schematic diagram of a finished product with a large-diameter outer circumference and multiple bosses.

[0038] Figure label:

[0039] 1-Hammer base, 2-Fixed anvil block, 3-Hydraulic cylinder, 4-Sliding anvil block, 5-Hanging ear, 6-Neutral, 701-Cylinder base, 702-Boss, 703-Notch position, 8-Horse lever, 9-Horse frame, 10-Cylinder billet. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0041] This invention provides a method for expanding the bore of a large-diameter outer cylindrical body with multiple bosses, such as... Figure 1As shown, the aforementioned large-diameter outer cylindrical body with multiple bosses includes a cylindrical body base 701 and multiple bosses 702 disposed on the outer periphery of the cylindrical body base 701, with notches 703 formed between adjacent bosses 702; the hole enlargement method includes the following steps:

[0042] Step 1: Prepare a small-diameter cylindrical blank 10 with an outer boss, such as... Figure 4 As shown;

[0043] Step 2: Place the lever 8 on the frame 9, insert the lever 8 into the punch hole of the cylindrical blank 10, and then place the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions above the cylindrical blank 10; the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions includes a fixed anvil block 2 and a sliding anvil block 4, and the distance between the fixed anvil block 2 and the sliding anvil block 4 is adjustable;

[0044] Step 3: Perform multi-turn hole expansion. During the forging and hole expansion process, adjust the distance between the fixed anvil block 2 and the sliding anvil block 4 to adapt to the changes in the position of the boss 702 and the notch 703 of the cylinder, and avoid the boss 702.

[0045] Specifically, in step 3 above, both the fixed anvil block 2 and the sliding anvil block 4 face the cylinder to be forged. When the forging position is at the boss 702, the sliding anvil block 4 moves to open the gap 6 between the fixed anvil block 2 and the sliding anvil block 4, leaving the position of the boss 702, and applying the pressing force to the cylinder on both sides of the boss 702.

[0046] Specifically, in step 3 above, when the forging position is the gap between the two bosses, the sliding anvil 4 moves to close the gap 6 between the fixed anvil 2 and the sliding anvil 4, and applies the pressing force to the entire length of the cylinder including the gap between the two bosses.

[0047] Specifically, in step 1 above, a small-diameter cylindrical blank 10 with an outer circumference boss is obtained by drawing a mandrel and machining.

[0048] Specifically, in step 1 above, considering that the diameter of the cylindrical blank 10 is small while the diameter required for the finished product is large, in order to ensure the overall performance of the finished product, the diameter of the cylindrical blank 10 and the diameter of the finished product are controlled to meet the following conditions: the inner diameter of the cylindrical blank 10 is d0, the outer diameter of the cylindrical blank 10 (excluding the boss) is D0, the inner diameter of the finished product is d1, and the outer diameter (excluding the boss) is D1, where... and

[0049] Specifically, the shapes of the surfaces (i.e., the lower arc surfaces) of the fixed anvil block 2 and the sliding anvil block 4 that contact the cylinder base 701 match the outer circle of the finished cylinder.

[0050] Specifically, in order to ensure the outer diameter of the cylinder after the hole is enlarged, the arc diameter of the lower arc surface of the fixed anvil block 2 and the sliding anvil block 4 is D1.

[0051] Specifically, the surfaces (i.e. side surfaces) of the fixed anvil block 2 and the sliding anvil block 4 that contact the boss 702 match the shape of the side surface of the boss 702.

[0052] Specifically, in step 3, the sliding anvil 4 is moved by the telescopic component to adjust the distance between the fixed anvil 2 and the sliding anvil 4. One end of the telescopic component is a fixed section, and the other end is a free end, which is connected to the sliding anvil 4.

[0053] This invention also provides a large-diameter outer cylindrical hammer with multiple bosses for expanding holes; such as Figure 2 and Figure 3 As shown, the above-mentioned large-diameter outer cylindrical enlargement hammer with multiple protrusions includes a hammer base 1, a fixed anvil block 2, and a sliding anvil block 4. Both the fixed anvil block 2 and the sliding anvil block 4 are located on the hammer base 1 facing the cylindrical body to be forged. The fixed anvil block 2 and the hammer base 1 are fixedly connected, and the sliding anvil block 4 and the hammer base 1 are slidably connected. The distance between the fixed anvil block 2 and the sliding anvil block 4 can be adjusted to adapt to the changes in the position of the protrusions and notches on the cylindrical body.

[0054] Specifically, when the fixed anvil block 2 and the sliding anvil block 4 correspond to the positions of the bosses on the cylinder, the gap between the fixed anvil block 2 and the sliding anvil block 4 is equal to the axial length of the bosses on the cylinder; when the fixed anvil block 2 and the sliding anvil block 4 correspond to the positions of the notches on the cylinder, the gap between the fixed anvil block 2 and the sliding anvil block 4 is zero.

[0055] Specifically, the sliding anvil 4 and the hammer base 1 are slidably connected by a sliding rail and a sliding groove that cooperate with each other. The sliding rail is set on the sliding anvil 4, and the sliding groove is set on the hammer base 1. When the sliding anvil 4 needs to be moved, the hammer needs to be raised. At this time, the sliding groove contacts the sliding rail, and the supporting force of the sliding rail on the sliding groove counteracts the weight of the sliding anvil. After the position of the sliding anvil 4 is adjusted, when downward pressure needs to be applied, the hammer is lowered. When the sliding anvil 4 contacts the cylinder, the outer circle of the cylinder gives the sliding anvil an upward force. Due to the huge downward pressure, it completely counteracts the weight of the sliding anvil 4. Therefore, the sliding rail and the sliding groove are not under force at this time. The downward pressure is transmitted by the pressure generated by the upper surface of the sliding anvil and the lower surface of the base. Meanwhile, in the connection between the slide rail and the slide groove, sliding friction or rolling friction can be used. If sliding friction is used, the slide rail and the slide groove can be polished smooth and coated with a corresponding semi-solid lubricant. Since the force between the slide rail and the slide groove is only to counteract the weight of the sliding anvil, rolling friction can also be used, and corresponding grooves can be machined on the slide rail and the slider, and balls, rollers or support wheels with bearings can be placed in the grooves.

[0056] To ensure a stable connection between the sliding anvil block 4 and the hammer base 1, and to drive the sliding anvil block 4 to reciprocate relative to the fixed anvil block 2, the fixed anvil block 2 and the sliding anvil block 4 are connected by a telescopic component. The telescopic component drives the sliding anvil block 4 to move, thereby adjusting the distance between the fixed anvil block 2 and the sliding anvil block 4.

[0057] Specifically, the telescopic component includes a hydraulic cylinder 3 and a lug 5. The sliding anvil block 4 is connected to one end of the hydraulic cylinder 3 via the lug 5, and the hammer base 1 is connected to the other end of the hydraulic cylinder 3. The position of the sliding anvil block 4 on the hammer base 1 is controlled by pushing and pulling the hydraulic cylinder 3.

[0058] Specifically, in order to achieve stable sliding of the sliding anvil block 4, hydraulic cylinders 3 are provided on both sides of the sliding anvil block 4.

[0059] Specifically, when the hydraulic cylinder 3 extends, it pushes the sliding anvil block 4, opening the gap 6 between the sliding anvil block 4 and the fixed anvil block 2; when the hydraulic cylinder 3 retracts, it pulls the sliding anvil block 4, closing the gap 6 between the sliding anvil block 4 and the fixed anvil block 2.

[0060] Specifically, such as Figure 8 The diagram shows a cross-sectional view of a finished cylindrical body with a large-diameter outer circle and multiple protrusions. The length of the side of the finished body base 701 that contacts the fixed anvil block 2 is L2, the length of the protrusion is L1, and the length of the side of the finished body base 701 that contacts the sliding anvil block 4 is L3. Therefore, the length of the fixed anvil block 2 should be ≥ L2, the length of the sliding anvil block 4 should be ≥ L1 + L3, and the stroke of the hydraulic cylinder 3 should be ≥ L1.

[0061] In this invention, the structural forms that enable the adjustable distance between the fixed anvil block 2 and the sliding anvil block 4 include, but are not limited to, the above-described structural forms, and can adopt a variety of possible structural forms in the prior art.

[0062] The present invention discloses a method for expanding the outer diameter of a cylindrical body with multiple bosses. This method involves obtaining a small-diameter cylindrical body blank with multiple bosses through mandrel drawing and machining. Then, a large-diameter cylindrical body with multiple bosses expansion hammer is used. This allows for the application of pressing force to different areas of the forging in a phased and regional manner without altering the relative positions of the press and supporting fixtures. The expansion forging method forges the forging into a large-diameter cylindrical body with multiple bosses. The method of the present invention can directly forge the outer bosses in a single expansion process. This not only makes the metal flow lines more complete, greatly improving the overall performance of the forging and increasing its safety in use, but also improves material utilization, reduces machining allowance, shortens the production cycle, and reduces production costs.

[0063] The large-diameter outer cylindrical enlarging hammer of the present invention includes a fixed anvil block and a sliding anvil block. The fixed anvil block and the sliding anvil block can be quickly adjusted by the telescopic component, which can form the outer cylindrical body with multiple protrusions. By using the large-diameter outer cylindrical enlarging hammer of the present invention, the pressing force can be applied to different areas of the forging in a time-sharing and regional manner without changing the relative position of the press and the supporting auxiliary tool, so that the forging process is smooth.

[0064] The large-diameter outer cylindrical enlarged hammerhead of the present invention has a modular design. Under the premise of a single hammerhead base, multiple sliding anvil blocks and fixed anvil blocks of various sizes can be designed for replacement according to different forgings.

[0065] Example 1

[0066] This embodiment provides a large-diameter outer cylindrical enlargement hammer with multiple bosses, such as... Figure 1 As shown, the aforementioned large-diameter outer cylindrical body with multiple protrusions includes a cylindrical body base 701 and multiple protrusions 702 disposed on the outer periphery of the cylindrical body base 701, with notches 703 formed between adjacent protrusions 702; as Figure 2 As shown, the aforementioned large-diameter outer cylindrical enlargement hammer with multiple protrusions includes a hammer base 1, a fixed anvil block 2, and a sliding anvil block 4. Both the fixed anvil block 2 and the sliding anvil block 4 are located on the hammer base 1 facing the cylindrical body to be forged. The fixed anvil block 2 and the hammer base 1 are fixedly connected, and the sliding anvil block 4 and the hammer base 1 are slidably connected. The fixed anvil block 2 and the sliding anvil block 4 correspond to the protrusions on the cylindrical body, so the gap between the fixed anvil block 2 and the sliding anvil block 4 is equal to the length of the protrusions on the cylindrical body. The fixed anvil block 2 and the sliding anvil block 4 correspond to the notch on the cylindrical body, so the gap between the fixed anvil block 2 and the sliding anvil block 4 is zero.

[0067] Specifically, the sliding anvil block 4 and the hammer base 1 are slidably connected by a sliding rail and a sliding groove that cooperate with each other. The sliding rail is set on the sliding anvil block 4, and the sliding groove is set on the hammer base 1.

[0068] The fixed anvil block 2 and the sliding anvil block 4 are connected by a telescopic component; the telescopic component includes a hydraulic cylinder 3 and a lug 5. The sliding anvil block 4 is connected to one end of the hydraulic cylinder 3 through the lug 5, and the hammer base 1 is connected to the other end of the hydraulic cylinder 3; the position of the sliding anvil block 4 on the hammer base 1 is controlled by pushing and pulling the hydraulic cylinder 3; hydraulic cylinders 3 are provided on both sides of the sliding anvil block 4.

[0069] Specifically, when the hydraulic cylinder 3 extends, it pushes the sliding anvil block 4, opening the gap 6 between the sliding anvil block 4 and the fixed anvil block 2; when the hydraulic cylinder 3 retracts, it pulls the sliding anvil block 4, closing the gap 6 between the sliding anvil block 4 and the fixed anvil block 2.

[0070] Example 2

[0071] This embodiment provides a method for expanding the bore of a large-diameter outer cylindrical body with multiple bosses, using the large-diameter outer cylindrical body expanding hammer head of Embodiment 1 above, and includes the following steps:

[0072] Step 1: Prepare a small-diameter cylindrical blank 10 with an outer boss, such as... Figure 3 As shown;

[0073] Step 2: Place the lever 8 on the frame 9, insert the lever 8 into the punch hole of the cylindrical blank 10, and then place the large-diameter outer circle cylindrical enlarging hammer with multiple protrusions above the cylindrical blank 10.

[0074] Step 3: During the forging and reaming process, adjust the sliding anvil 4 in real time according to the position and width of the boss 702. When the desired forging position is the boss 702, the hydraulic cylinder 3 extends, pushing out the sliding anvil 4, opening the neutral position 6, reserving space for the boss 702, and applying the pressing force to the cylinders on both sides of the boss 702. Figure 4 As shown;

[0075] Step 4: When the desired forging position is the gap between the two bosses, the hydraulic cylinder 3 retracts, pulling back the sliding anvil block 4 to close the gap 6, thus applying the pressing force to the entire length of the cylinder, including the gap between the two bosses. Figure 5 As shown;

[0076] Step 5: After multiple rounds of reaming, the reaming and forming of the large-diameter outer circumference cylinder with multiple bosses is completed; the final forming effect is shown in the figure below. Figure 6 As shown.

[0077] Specifically, in step 1 above, a small-diameter cylindrical blank 10 with an outer circumference boss is obtained by drawing a mandrel and machining.

[0078] Specifically, in step 1 above, the inner diameter of the cylindrical blank 10 is d0, the outer diameter of the cylindrical blank 10 (excluding the boss) is D0, the inner diameter of the finished product is d1, and the outer diameter (excluding the boss) is D1. And D1-d1 / D0-d0 is 2.

[0079] Specifically, the shapes of the surfaces (i.e., the lower arc surfaces) of the fixed anvil block 2 and the sliding anvil block 4 that contact the cylinder base 701 match the outer circle of the finished cylinder.

[0080] Specifically, in order to ensure the outer diameter of the cylinder after the hole is enlarged, the arc diameter of the lower arc surface of the fixed anvil block 2 and the sliding anvil block 4 is D1.

[0081] Specifically, the surfaces (i.e. side surfaces) of the fixed anvil block 2 and the sliding anvil block 4 that contact the boss 702 match the shape of the side surface of the boss 702.

[0082] Specifically, such as Figure 7The figure shows a cross-sectional schematic diagram of a finished cylindrical body with a large-diameter outer circle and multiple protrusions. The length of the side of the finished body base 701 that contacts the fixed anvil block 2 is L2, the length of the protrusion is L1, and the length of the side of the finished body base 701 that contacts the sliding anvil block 4 is L3. Therefore, the length of the fixed anvil block 2 is ≥ L2, the length of the sliding anvil block 4 is ≥ L1 + L3, and the stroke of the hydraulic cylinder 3 is ≥ L1.

[0083] The large-diameter outer cylindrical body with multiple bosses prepared in this embodiment has complete metal flow lines, which greatly improves the overall performance of the forging. It reduces forging and machining allowances, improves material utilization, and shortens manufacturing time; moreover, it eliminates weld seams by not using welding, thus avoiding the number of in-service inspections of weld seams.

[0084] Comparative Example 1

[0085] This comparative example provides a method for expanding the bore of a large-diameter outer cylindrical body with multiple bosses, including the following steps:

[0086] Step 1: After forging the large-diameter cylinder, the welding holes are machined, and then the boss is connected to the cylinder by welding.

[0087] The large-diameter outer cylindrical body with multiple bosses obtained in this comparative example exhibits discontinuous metal flow lines at the welding points of the bosses, affecting the mechanical properties and radiation resistance of the forging. Furthermore, because the bosses are welded to the cylinder, weld seams exist, requiring periodic in-service inspections of these seams, increasing costs and impacting the forging's usability.

[0088] The above description is only a preferred 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 conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for expanding the bore of a large-diameter outer cylindrical body with multiple bosses, characterized in that, The large-diameter outer cylindrical body with multiple protrusions includes a cylindrical body base (701) and multiple protrusions (702) arranged on the outer periphery of the cylindrical body base (701), with a notch (703) formed between adjacent protrusions (702); the hole enlargement method includes the following steps: Step 1: Prepare a small-diameter cylindrical blank (10) with an outer circle boss. Step 2: Place the lever (8) on the frame (9), insert the lever (8) into the punch hole of the cylindrical blank (10), and then place the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions above the cylindrical blank (10); the large-diameter outer circle cylindrical enlargement hammer with multiple protrusions includes a fixed anvil block (2) and a sliding anvil block (4), and the distance between the fixed anvil block (2) and the sliding anvil block (4) is adjustable; Step 3: Perform multi-circle hole expansion. During the forging and hole expansion process, adjust the distance between the fixed anvil block (2) and the sliding anvil block (4) to adapt to the changes in the position of the boss (702) and the notch (703) of the cylinder, and avoid the boss (702). In step 3, both the fixed anvil block (2) and the sliding anvil block (4) face the cylinder to be forged. When the forging position is at the boss (702), the sliding anvil block (4) moves to open the gap (6) between the fixed anvil block (2) and the sliding anvil block (4), leaving the position of the boss (702) and applying the pressing force to the cylinder on both sides of the boss (702). In step 3, when the forging position is the gap between the two bosses, the sliding anvil (4) moves to close the gap (6) between the fixed anvil (2) and the sliding anvil (4), and applies the pressing force to the entire length of the cylinder including the gap between the two bosses.

2. The hole enlargement method according to claim 1, characterized in that, In step 1, a small-diameter cylindrical blank (10) with an outer circumference boss is obtained by mandrel drawing and machining.

3. The hole enlargement method according to claim 1, characterized in that, The inner diameter of the cylindrical blank (10) is The outer diameter of the cylindrical blank (10) is The inner diameter of the finished product is The outer diameter is ,in .

4. The hole enlargement method according to claim 1, characterized in that, The shapes of the surfaces of the fixed anvil block (2) and the sliding anvil block (4) that contact the cylinder base (701) match the outer circle of the finished cylinder.

5. The hole enlargement method according to claim 3, characterized in that, The arc diameter of the surfaces of the fixed anvil (2) and the sliding anvil (4) that contact the cylindrical base (701) is: .

6. The hole enlargement method according to claim 1, characterized in that, In step 3, the sliding anvil (4) is moved by the telescopic component to adjust the distance between the fixed anvil (2) and the sliding anvil (4).

7. The hole enlargement method according to claim 6, characterized in that, One end of the telescopic member is a fixed section, and the other end is a free end. The free end is connected to the sliding anvil block (4).

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