Forging process for annular blowout preventer housing

Abstract

The application discloses a forging process of an annular blowout preventer shell, and is specifically implemented according to the following steps: step 1, a cylindrical blank is drawn out of a step, is upset in a blank making die, and is punched to complete blank making; step 2, the blank in step 1 is heated and kept warm, a forming sleeve die is sleeved on the blank making die, a guide column is arranged at the bottom of the blank making die, and a forming combined die is formed; step 3, the blank heated in step 2 is placed in the forming combined die to perform flanging extrusion, and an upper blind hole of the forging is formed; step 4, a pad iron is used to flatten and shape the surface of the forging; and step 5, the forging is taken out of the die and is annealed. The annular blowout preventer shell forged by the application has a greatly reduced forging allowance, improved material utilization rate, reduced forging thickness, effectively deformed and forged through inside the forging, and improved quality.

Description

Technical Field

[0001] This invention belongs to the field of metal hot working and forging technology, specifically relating to the forging process of annular blowout preventer housings. Background Technology

[0002] Annular blowout preventers (BOPs) are used in conjunction with gate BOPs and choke manifolds to achieve soft shut-in in the event of overflow or blowout accidents, effectively sealing various drill strings. The casing is a crucial component of the annular BOP, with a significant difference in diameter between its upper and lower inner bores. It withstands high pressure during operation, making its quality paramount. The casing is machined from a forged steel blank.

[0003] Due to their large size and weight, casings are mostly forged using free forging. Free forging blanks have simple shapes, but large machining allowances, low material utilization, and thick walls, making it difficult to forge through to the interior. This results in ineffective internal deformation and poses quality risks. Traditional die forging often uses a die-casting plate to form the flange shape at the bottom of the forging, which does not effectively reduce the machining amount of the forging.

[0004] In order to minimize the forging allowance, reduce the forging load, and enable effective deformation of the forging interior, a new forging process for blowout preventer housings is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a forging process for the shell of an annular blowout preventer, which can reduce forging allowance and improve material utilization.

[0006] The technical solution adopted in this invention is a forging process for the annular blowout preventer housing, which is implemented according to the following steps:

[0007] Step 1: Pull the cylindrical blank out of the step, upset it in the blanking mold, and punch holes to complete the blanking process;

[0008] Step 2: Heat and keep the blank from step 1 at the same time, put the forming mold on the blank mold and place the guide post at the bottom of the blank mold to form a forming combination mold.

[0009] Step 3: Place the heated billet from Step 2 into a forming die and press it to form a blind hole at the top of the forging;

[0010] Step 4: Use shims to flatten and shape the surface of the forging;

[0011] Step 5: Remove the forging from the mold and perform annealing.

[0012] The invention is further characterized in that,

[0013] Step 1 is implemented in the following steps:

[0014] Step 1.1: Heat and keep the cylindrical billet at a constant temperature, pull out one end of it to form a step, and then put the billet into the blanking mold and upset it under pressure.

[0015] Step 1.2: Punch through holes in the upset billet to obtain the blank.

[0016] In step 1.1, the step diameter is not greater than the blanking mold diameter, and the step length is not less than the height of the small step in the inner hole of the blanking mold.

[0017] The thickness of the upper circular flange of the blank is 5% greater than the wall thickness of the upper blind hole of the forging.

[0018] Step 3 is implemented in the following steps:

[0019] Step 3.1: After removing the oxide scale from the heated blank, place it onto the guide post;

[0020] Step 3.2: Place the upper forming mold onto the guide post and apply pressure to the upper forming mold. Under the guidance of the guide post, press the blank into the forming assembly mold.

[0021] The angle between the inner wall of the forming mold and the center line is 15°.

[0022] Step 5 is implemented in the following steps:

[0023] Step 5.1: Support the bottom of the forming assembly mold, remove the guide pillar from the top, flip the mold and forging onto the slotted plate, and remove the forging in the opposite direction;

[0024] Step 5.2: Rotate the outer circle of the light-pressing forging to slightly deform the blind hole, remove it from the forming upper die, and at the same time, the forging is removed from the die;

[0025] Step 5.3: After the forging is removed from the mold, it should be loaded into the furnace in time, heated, and then cooled to room temperature in the furnace.

[0026] The furnace temperature is 640-660℃.

[0027] The beneficial effects of this invention are:

[0028] 1. Compared with free forging and traditional die forging, the annular blowout preventer shell forged using this method has a significantly reduced forging allowance, improved material utilization, reduced forging thickness, and effective internal deformation and forging penetration, resulting in improved quality.

[0029] 2. The annular blowout preventer shell forged using this method has an outer contour that closely resembles the part, and the internal metal flow lines of the forging are rationally distributed. The metal flow lines are not cut off during subsequent machining, resulting in higher overall mechanical properties of the forging.

[0030] 3. When forging the annular blowout preventer shell using this scheme, the forging process is divided into blanking and forming steps. The blanking mold and forming mold are designed separately, which reduces the weight of the mold and the processing difficulty.

[0031] 4. When forging the annular blowout preventer shell using this scheme, the blanking die forms the lower flange boss of the annular blowout preventer shell in the blanking step. The forming step and the forming die are used in combination to restrict the flow of metal in the lower part of the forging. The blanking die can be reused, reducing the investment in dies and improving the utilization rate of dies.

[0032] 5. The blind hole at the top of the annular blowout preventer housing has a large diameter and thin wall thickness. It adopts a flanging and extrusion process, which reduces the forging load compared with the traditional punching and reaming process. The required equipment tonnage is smaller and the forging energy consumption is greatly reduced. Attached Figure Description

[0033] Figure 1 This is a cross-sectional view of the annular blowout preventer housing forging;

[0034] Figure 2 This is a cross-sectional view of the blanking mold for the annular blowout preventer housing;

[0035] Figure 3 This is a cross-sectional view of the annular blowout preventer housing during prefabrication;

[0036] Figure 4 This is a cross-sectional view of the forming mold for the annular blowout preventer housing;

[0037] Figure 5 This is a cross-sectional view of the upper die for forming the annular blowout preventer housing;

[0038] Figure 6 This is a diagram of the guide pillars for the annular blowout preventer housing;

[0039] Figure 7 This is a cross-sectional view of the ring-shaped blowout preventer housing pad.

[0040] Figure 8 This is a schematic diagram of the forming process (before forging) of the annular blowout preventer housing;

[0041] Figure 9 This is a schematic diagram of the forming process (after forming) of the annular blowout preventer housing.

[0042] In the diagram, 1. Forging, 2. Blanking mold, 3. Blanking, 4. Forming die, 5. Upper forming die, 6. Guide post, 7. Shim. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0044] The forging process of the annular shell blowout preventer housing of this invention, such as... Figure 1-9 As shown, the blank is made in the blanking mold and formed by the flanging extrusion process in the forming mold. The blanking mold and the forming mold include: blanking mold, forming sleeve mold, forming upper mold, guide post, and pad.

[0045] The blanking die has an annular stepped hole structure, with the interior being a stepped hole in the shape of the lower flange of the annular blowout preventer housing. The blanking die also functions as a forming die. During the forming stage, it is combined with the forming sleeve die to restrict the flow of metal in the lower part of the forging and ensure that it does not deviate during the flanging and extrusion.

[0046] The forming die has a ring-shaped structure with an inverted frustum-shaped inner hole. The lower part has an annular positioning groove that mates with the upper part of the blanking die. The upper end face of the inner hole has a 150° radius rounded corner, which is smoothly polished to facilitate the introduction of the blank, reduce friction between the blank and the die in the forming step, and allow the blank to be smoothly extruded into the die. In the forming step, a flanging extrusion process is used to flanging and extruding the flanged disc portion of the blank, forming the blind hole structure on the upper part of the annular blowout preventer housing.

[0047] The guide post is a T-shaped mold with a disc base. The circular rod has a taper to facilitate detachment from the forging after forming. During the forming stage, the guide post positions and guides the forming upper die and the blank, preventing them from being misaligned before forging and ensuring that the blank and the forming upper die do not deviate when descending during the forming process.

[0048] The forming upper die is a frustum-shaped die with a through hole and a protruding annular structure at the bottom. The through hole mates with guide pillars to ensure no deviation during the forming process. The outer circumference has a 5° draft angle for easy demolding after forming. In the forming step, the forming upper die presses the blank downwards into the forming die, flanging and pressing the disc portion of the blank into the upper blind hole of the forging.

[0049] The forging process of the annular shell blowout preventer housing of the present invention is specifically implemented according to the following steps:

[0050] Step 1: Pull out the cylindrical blank from the step, upset it in the blanking mold 2, and punch holes to complete the blanking 3;

[0051] Step 1 is implemented in the following steps:

[0052] Step 1.1: Heat and keep the cylindrical billet warm, and pull out a step from one end. Then, put the billet into the blanking mold 2 and pressurize it for upsetting. The small end is upset into an annular flange step of the blowout preventer housing in the blanking mold 2, and the large end is upset into a round disc shape on the upper surface of the blanking mold 2 with a thickness of about 300 mm and an outer diameter of about 2200 mm.

[0053] Step 1.2: Punch through holes in the upset billet. The inner diameter of the punched through holes is about 220mm, to obtain billet 3;

[0054] In step 1.1, the step diameter is slightly smaller than the diameter of blanking mold 2, and the step length is slightly larger than the height of the small step in the inner hole of blanking mold 2;

[0055] The thickness of the upper circular flange of blank 3 is about 5% greater than the wall thickness of the upper blind hole of forging 1.

[0056] Step 2: Heat and keep the blank 3 from Step 1 at the same time, put the forming mold 4 on the blank mold 2, and place the guide post 6 at the bottom of the blank mold 2 to form a forming combination mold.

[0057] Step 3: Place the heated billet 3 from step 2 into the forming assembly mold and extrude it to form a blind hole on the upper part of the forging 1;

[0058] Step 3 is implemented in the following steps:

[0059] Step 3.1: After removing the oxide scale from the heated blank 3, place it onto the guide post 6; the blank 3 is supported by the forming mold 4 and positioned by the guide post 6;

[0060] Step 3.2: Place the upper forming mold 5 onto the guide post 6 and apply pressure to the upper forming mold 5. Under the guidance of the guide post 6, press the blank 3 into the forming assembly mold.

[0061] In order to smoothly press the blank 3 into the forming mold 4, the angle between the inner wall of the forming mold 4 and the center line is 15°. The disc of the blank 3 is pressed inward under the restriction of the forming mold 4 to form a blind hole on the upper part of the annular blowout preventer shell forging 1.

[0062] Step 4: Use the shim 7 to flatten the raised arc on the surface of the shell forging 1, and make the metal fully fill the space between the upper forming die 5 and the forming sleeve die 4.

[0063] Step 5: Demold the forging and perform annealing treatment;

[0064] Step 5 is implemented in the following steps:

[0065] Step 5.1: Support the bottom of the forming assembly mold, remove the guide post 6 from the top. The guide post 6 has a tapered rod for easy removal. Flip the mold and forging 1 onto the slotted plate and remove the forging 1 in the opposite direction.

[0066] Step 5.2: Rotate the outer circle of the lightly pressed forging 1 to slightly deform the blind hole, and remove the upper forming die 5. The outer circle of the upper forming die 5 has a taper to facilitate removal, and the forging 1 is removed from the die at the same time.

[0067] Step 5.3: After the forging 1 is removed from the mold, it should be loaded into the furnace in a timely manner. The furnace temperature should be 640-660℃. After heating, it should be cooled to room temperature in the furnace and then annealed.

[0068] The forged annular blowout preventer shell of this invention has a significantly reduced forging allowance, improved material utilization, reduced forging thickness, and effective internal deformation and forging penetration, resulting in improved quality.

Claims

1. The forging process of the annular blowout preventer housing, characterized in that, The specific steps are as follows: Step 1: Pull the cylindrical blank out of the step, upset it in the blanking mold, and punch holes to complete the blanking process; Step 2: Heat and keep the blank from step 1 at the same time, put the forming mold on the blank mold and place the guide post at the bottom of the blank mold to form a forming combination mold. Step 3: Place the heated billet from Step 2 into a forming die and press it to form a blind hole at the top of the forging; Step 4: Use shims to flatten and shape the surface of the forging; Step 5: Demold the forging and perform annealing treatment; Step 1 is implemented in the following steps: Step 1.1: Heat and keep the cylindrical billet at a constant temperature, pull out one end of it to form a step, and then put the billet into the blanking mold and upset it under pressure. Step 1.2: Punch through holes in the upset billet to obtain the blank; In step 1.1, the step diameter is not greater than the blanking mold diameter, and the step length is not less than the height of the small step in the inner hole of the blanking mold; The thickness of the upper disc-shaped flange of the blank is 5% greater than the wall thickness of the upper blind hole of the forging; Step 3 is implemented in the following steps: Step 3.1: After removing the oxide scale from the heated blank, place it onto the guide post; Step 3.2: Place the upper forming mold onto the guide post and apply pressure to the upper forming mold. Under the guidance of the guide post, press the blank into the forming assembly mold.

2. The forging process of the annular blowout preventer housing according to claim 1, characterized in that, The angle between the inner wall of the forming mold and the center line is 15°.

3. The forging process of the annular blowout preventer housing according to claim 1, characterized in that, Step 5 is implemented in the following steps: Step 5.1: Support the bottom of the forming assembly mold, remove the guide pillar from the top, flip the mold and forging onto the slotted plate, and remove the forging in the opposite direction; Step 5.2: Rotate the outer circle of the light-pressing forging to slightly deform the blind hole, remove it from the forming upper die, and at the same time, the forging is removed from the die; Step 5.3: After the forging is removed from the mold, it should be loaded into the furnace in time, heated, and then cooled to room temperature in the furnace.

4. The forging process of the annular blowout preventer housing according to claim 3, characterized in that, The furnace temperature is 640-660℃.

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