High-pressure-resistant deep sea forge piece and manufacturing method and application thereof

Abstract

The invention discloses a high-pressure-resistant deep sea forge piece and a manufacturing method and application thereof, and belongs to the technical field of forge pieces. The high-pressure-resistant deep sea forging comprises the following components in percentage by mass: 0.30 to 0.33 percent of C, 0.15 to 0.35 percent of Si, 0.80 to 0.95 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, 0.90 to 1.00 percent of Cr, 0.35 to 0.45 percent of Mo, 0.80 to 0.90 percent of Ni, 0.020 to 0.030 percent of Al, less than or equal to 0.15 percent of Cu, less than or equal to 0.010 percent of Nb, less than or equal to 0.010 percent of Ti and 0.030 to 0.050 percent of V. The high-pressure-resistant deep sea forge piece is prepared by combining an alloy and microalloy formula with a forging-heat treatment (waste heat annealing, quenching and four times of tempering) process, and the problems of leakage and deep sea mining under the working condition of high pressure (200 MPa or above) can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-pressure deep-sea forgings and its manufacturing method and application, belong to forging technical field. BACKGROUND

[0002] Tubing head is the industrial device component in the field of oil and gas engineering, as the intermediate component of gas well head device, connecting casing head and gas production tree. Its core functions include suspending tubing string, sealing tubing and casing annulus, and providing water injection, well flushing and other operation interfaces. According to the data in 2025, tubing head is composed of large four-way with flange at both ends, tubing head upper flange and tubing hanger, wherein the tubing hanger realizes double sealing through gravity or threaded connection. In the wellhead standardization system implemented by Northwest Oilfield in 2020, tubing head has covered 35-140MPa pressure level, effectively reducing well control risk.

[0003] With the increasing demand for deep-sea oil and gas exploitation, new challenges are posed to the pressure resistance performance of deep-sea forgings. How to effectively solve the leakage and exploitation problems under high pressure (above 200MPa) working conditions is a technical problem to be solved at present. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-pressure deep-sea forging with excellent high-pressure resistance.

[0005] Meanwhile, the present application provides a manufacturing method of high-pressure deep-sea forging.

[0006] Meanwhile, the present application provides an application of high-pressure deep-sea forging in deep-sea oil production equipment.

[0007] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0008] A high-pressure deep-sea forging, comprising the following components in mass percentage: C: 0.30-0.33%, Si: 0.15-0.35%, Mn: 0.80-0.95%, P≤0.010%, S≤0.005%, Cr: 0.90-1.00%, Mo: 0.35-0.45%, Ni: 0.80-0.90%, Al: 0.020-0.030%, Cu≤0.15%, Nb≤0.010%, Ti≤0.010%, V: 0.030-0.050%, H≤2ppm, O≤20ppm; N≤80ppm; As≤0.010%, Sn≤0.010%, Sb≤0.005%, Pb≤0.010%, B≤0.0005%, Ca≤0.005%, Bi≤0.010%, V+Nb+Ti≤0.060%, and the balance is Fe.

[0009] The high-pressure-resistant deep-sea forging includes an oil and gas equipment tubing head forging.

[0010] The method for manufacturing the high-pressure-resistant deep-sea forging comprises the following steps:

[0011] S01, sequentially smelting, refining and casting the raw material to obtain a steel ingot;

[0012] S02, steel ingot heating and holding: heating the steel ingot to 1150-1200℃ and holding for 1.5-2h;

[0013] S03, forging: the initial forging temperature of the steel ingot is 1150-1200℃, the final forging temperature is 850-900℃, and the forging ratio is greater than or equal to 4:1, and the workpiece is air-cooled to room temperature;

[0014] S04, heat treatment: the steps of after-heat annealing, quenching and four times of tempering;

[0015] The after-heat annealing treatment step comprises: heating the forged workpiece to 850-900℃, holding for 2-5h and then furnace cooling;

[0016] The quenching treatment step comprises: quenching the workpiece after the after-heat annealing to room temperature;

[0017] The tempering treatment comprises four times of tempering, and the specific steps comprise:

[0018] First time of tempering: heating the quenched workpiece to 700-750℃, holding for 1-2h and then air-cooling to room temperature;

[0019] Second time of tempering: the temperature is 650-680℃, holding for 2-4h and then air-cooling to room temperature;

[0020] Third time of tempering: the temperature is 500-550℃, holding for 0.5-1h and then air-cooling to room temperature;

[0021] Fourth time of tempering: the temperature is 300-320℃, holding for 2-4h and then air-cooling to room temperature.

[0022] In S01, the smelting method is: using a direct current arc furnace to smelt, and the tapping temperature is 1600-1700℃.

[0023] In S01, the refining method is: first LF refining and then VD refining.

[0024] The LF refining method is: transferring the smelted molten steel into an LF refining furnace, heating to 1750-1800℃, adding a refining agent, blowing in argon, refining for 30-50min to obtain refined molten steel one;

[0025] The refining agent comprises fluorite CaF2 and ferrosilicon Fe-Si in a mass ratio of 1:(2-5), and the added amount of the refining agent is equivalent to 1-3wt% of the smelted molten steel.

[0026] The VD refining method is: transferring the refined molten steel to a VD vacuum furnace, vacuumizing, and vacuum degassing the refined molten steel.

[0027] The VD refining vacuum degree is 60-65Pa, the VD refining temperature is 1800-1900℃, and the VD refining time is 1-2h.

[0028] In S01, the casting method is: the casting temperature of the molten steel is 1600-1700℃, the casting speed is 1-40mm / s, the electromagnetic stirring of the crystallizer is used during the casting process, the electromagnetic stirring current is 300-500A, and the electromagnetic stirring frequency is 5-10Hz.

[0029] The high-pressure deep-sea forge piece of the application is prepared into an oil and gas equipment oil pipe head forge piece, which is used under the simulation of deep-sea environment at 200MPa pressure and 250MPa pressure respectively, and the service life is tested, and the service life reaches more than 4000h.

[0030] The high-pressure deep-sea forge piece obtained by the application has a service life of more than 4000h under the deep-sea high-pressure environment.

[0031] The application of the high-pressure deep-sea forge piece of the application in deep-sea oil extraction equipment.

[0032] Preferably, the deep-sea oil extraction equipment includes a deep-sea underwater wellhead and a Christmas tree device or a blowout preventer.

[0033] Compared with the prior art, the application has the following beneficial effects:

[0034] The high-pressure deep-sea forge piece is prepared by the alloy and micro-alloy formula combined with the forging-heat treatment (residual annealing, quenching and four times tempering) process, which can effectively solve the leakage under high pressure (more than 200MPa) working condition and deep-sea mining problem. DETAILED DESCRIPTION

[0035] The application will be further described in detail below in combination with specific examples. The following examples are only used to illustrate the application and not to limit the scope of the application.

[0036] Example 1

[0037] A high-pressure deep-sea forging, i.e., an oil and gas equipment oil pipe head forging, comprises the following components in percentage by mass: C: 0.31%, Si: 0.25%, Mn: 0.87%, P: 0.005%, S: 0.001%, Cr: 0.95%, Mo: 0.40%, Ni: 0.85%, Al: 0.025%, Cu: 0.05%, Nb: 0.001%, Ti: 0.005%, V: 0.040%, H: 1 ppm, O: 10 ppm, N: 30 ppm, As: 0.002%, Sn: 0.007%, Sb: 0.003%, Pb: 0.001%, B: 0.0003%, Ca: 0.001%, Bi: 0.005%, and the balance of Fe.

[0038] A method for manufacturing a high-pressure deep-sea forging, comprising the following steps:

[0039] S01, sequentially smelting, refining and casting the raw material to obtain a steel ingot; the smelting method is: smelting by using a direct current arc furnace, and the tapping temperature is 1650℃. The refining method is: first LF refining and then VD refining; the LF refining method is: transferring the molten steel into an LF refining furnace, heating to 1780℃, adding a refining agent, blowing in argon, and refining for 40min to obtain refined molten steel one; the refining agent comprises fluorite CaF2 and ferrosilicon Fe-Si in a mass ratio of 1:3, and the addition amount of the refining agent is equivalent to 2wt% of the molten steel; the VD refining method is: transferring the refined molten steel one into a VD vacuum furnace, vacuumizing, and vacuum degassing treating the refined molten steel one; the VD refining vacuum degree is 63Pa, the VD refining temperature is 1850℃, and the VD refining time is 1.5h. The casting method is: the casting molten steel temperature is 1650℃, the casting speed is 20mm / s, and the electromagnetic stirring is used during the casting process, the electromagnetic stirring current is 400A, and the electromagnetic stirring frequency is 8Hz.

[0040] S02, heating and holding the steel ingot: heating the steel ingot to 1180℃ and holding for 1.5h;

[0041] S03, forging: the initial forging temperature of the steel ingot is 1180℃, the final forging temperature is 880℃, the forging ratio is 4:1, and the workpiece is air cooled to room temperature;

[0042] S04, heat treatment: after-heat annealing, quenching and four times of tempering treatment;

[0043] The method for after-heat annealing treatment is: heating the workpiece after forging to 880℃, holding for 3h and then cooling in the furnace;

[0044] The method for quenching is: quenching the workpiece after after-heat annealing to room temperature;

[0045] The method for four times of tempering treatment is:

[0046] First tempering: the quenched workpiece is heated to 720 DEG C, and after holding for 1.5 h, it is air-cooled to room temperature;

[0047] Second tempering: the temperature is 665 DEG C, and after holding for 3 h, it is air-cooled to room temperature;

[0048] Third tempering: the temperature is 520 DEG C, and after holding for 0.5 h, it is air-cooled to room temperature;

[0049] Fourth tempering: the temperature is 310 DEG C, and after holding for 3 h, it is air-cooled to room temperature.

[0050] The application of a high-pressure-resistant deep-sea forge piece in deep-sea oil extraction equipment.

[0051] The high-pressure-resistant deep-sea forge piece obtained in the embodiment is used in a simulated deep-sea environment under a pressure of 200 MPa and a pressure of 250 MPa respectively, and the service life is tested, and the service life reaches 5000 h.

[0052] Example 2

[0053] A high-pressure-resistant deep-sea forge piece, i.e. an oil and gas equipment oil pipe head forge piece, comprises the following components in mass percentage: C: 0.30%, Si: 0.15%, Mn: 0.80%, P: 0.010%, S: 0.005%, Cr: 0.90%, Mo: 0.35%, Ni: 0.80%, Al: 0.020%, Cu: 0.15%, Nb: 0.010%, Ti: 0.010%, V: 0.040%, H: 2 ppm, O: 20 ppm, N: 80 ppm, As: 0.010%, Sn: 0.010%, Sb: 0.005%, Pb: 0.010%, B: 0.0005%, Ca: 0.005%, Bi: 0.010%, and the balance is Fe.

[0054] In the embodiment, V+Nb+Ti=0.060%.

[0055] A manufacturing method of a high-pressure-resistant deep-sea forge piece, comprising the following steps:

[0056] S01, the raw materials are sequentially subjected to smelting, refining and casting to obtain a steel ingot; the smelting method is: smelting by using a direct current arc furnace, and the tapping temperature is 1600℃. The refining method is: LF refining followed by VD refining; the LF refining method is: transferring the molten steel into an LF refining furnace, heating to 1750℃, adding a refining agent, blowing in argon, and refining for 30 min to obtain refined molten steel I; the refining agent comprises fluorite CaF2 and ferrosilicon Fe-Si in a mass ratio of 1:2, and the addition amount of the refining agent is equivalent to 1wt% of the molten steel; the VD refining method is: transferring the refined molten steel I into a VD vacuum furnace, vacuumizing, and vacuum degassing the refined molten steel I; the VD refining vacuum degree is 60Pa, the VD refining temperature is 1800℃, and the VD refining time is 1h. The casting method is: the casting temperature of the molten steel is 1600℃, the casting speed is 1mm / s, and the electromagnetic stirring of the crystallizer is used during the casting process, the electromagnetic stirring current is 300A, and the electromagnetic stirring frequency is 5Hz.

[0057] S02, the steel ingot is heated and kept for 1.5h;

[0058] S03, forging: the initial forging temperature of the steel ingot is 1150℃, the final forging temperature is 850℃, the forging ratio is 5:1, and the workpiece is air-cooled to room temperature;

[0059] S04, heat treatment: after-heat annealing, quenching and four times of tempering treatment;

[0060] The method of the after-heat annealing treatment is: heating the forged workpiece to 850℃, keeping for 2h and then furnace cooling;

[0061] The method of the quenching is: quenching the workpiece after the after-heat annealing to room temperature;

[0062] The method of the four times of tempering treatment is:

[0063] First time of tempering: heating the quenched workpiece to 700℃, keeping for 1h and then air-cooling to room temperature;

[0064] Second time of tempering: the temperature is 650℃, keeping for 2h and then air-cooling to room temperature;

[0065] Third time of tempering: the temperature is 500℃, keeping for 0.5h and then air-cooling to room temperature;

[0066] Fourth time of tempering: the temperature is 300℃, keeping for 2h and then air-cooling to room temperature.

[0067] The application of the high-pressure deep-sea forged piece in deep-sea oil extraction equipment.

[0068] The high-pressure-resistant deep-sea forging obtained in the embodiment is used in a simulated deep-sea environment under pressures of 200 MPa and 250 MPa respectively, and the service life is tested, and the service life reaches 4000 h.

[0069] Embodiment 3

[0070] A high-pressure-resistant deep-sea forging, i.e., an oil and gas equipment tubing head forging, comprises the following components in percentage by mass: C: 0.33%, Si: 0.35%, Mn: 0.95%, P: 0.002%, S: 0.003%, Cr: 1.00%, Mo: 0.45%, Ni: 0.90%, Al: 0.030%, Cu: 0.10%, Nb: 0.005%, Ti: 0.005%, V: 0.050%, H: 0.5 ppm, O: 5 ppm, N: 10 ppm, As: 0.004%, Sn: 0.002%, Sb: 0.001%, Pb: 0.005%, B: 0.0002%, Ca: 0.003%, Bi: 0.003%, and the balance is Fe.

[0071] In the embodiment, V+Nb+Ti=0.060%.

[0072] A manufacturing method of a high-pressure-resistant deep-sea forging comprises the following steps:

[0073] S01, raw materials are sequentially subjected to smelting, refining and casting to obtain a steel ingot; the smelting method is: smelting by using a direct current arc furnace, and the tapping temperature is 1700℃. The refining method is: LF refining followed by VD refining; the LF refining method is: transferring the smelted molten steel into an LF refining furnace, heating to 1800℃, adding a refining agent, blowing in argon, and refining for 50 min to obtain refined molten steel one; the refining agent comprises fluorite CaF2 and ferrosilicon Fe-Si in a mass ratio of 1:5, and the addition amount of the refining agent is equivalent to 3wt% of the smelted molten steel; the VD refining method is: transferring the refined molten steel one into a VD vacuum furnace, vacuumizing, and vacuum degassing treating the refined molten steel one; the VD refining vacuum degree is 65 Pa, the VD refining temperature is 1900℃, and the VD refining time is 2 h. The casting method is: the casting molten steel temperature is 1700℃, the casting speed is 40 mm / s, and a crystallizer electromagnetic stirring is used during the casting process, the electromagnetic stirring current is 500 A, and the electromagnetic stirring frequency is 10 Hz.

[0074] S02, heating and holding the steel ingot: heating the steel ingot to 1200℃ and holding for 2 h;

[0075] S03, forging: the initial forging temperature of the steel ingot is 1200℃, the final forging temperature is 900℃, the forging ratio is 5:1, and the workpiece is air-cooled to room temperature;

[0076] S04, heat treatment: tempering four times after interannealing and quenching.

[0077] The method of the temper annealing treatment is that the workpiece after forging is heated to 900 DEG C, and then cooled in the furnace after 2h of holding time;

[0078] The method of quenching is that the workpiece after the temper annealing is quenched to room temperature;

[0079] The method of the fourth tempering treatment is that the workpiece after the third tempering treatment is heated to 320 DEG C, and then cooled to room temperature after 4h of holding time.

[0080] The first tempering treatment is that the workpiece after quenching is heated to 750 DEG C, and then cooled to room temperature after 2h of holding time.

[0081] The second tempering treatment is that the workpiece is heated to 680 DEG C, and then cooled to room temperature after 4h of holding time.

[0082] The third tempering treatment is that the workpiece is heated to 550 DEG C, and then cooled to room temperature after 1h of holding time.

[0083] The fourth tempering treatment is that the workpiece is heated to 320 DEG C, and then cooled to room temperature after 4h of holding time.

[0084] The application of the high-pressure-resistant deep-sea forge piece of the embodiment in the deep-sea oil extraction equipment.

[0085] The high-pressure-resistant deep-sea forge piece obtained in the embodiment is used in the deep-sea environment under the pressure of 200MPa and 250MPa respectively, and the service life is tested, and the service life reaches 4500h.

[0086] Example 4

[0087] The V content is 0.030%.

[0088] The rest is the same as in Example 1.

[0089] The embodiment differs from Example 1 only in that it should be understood that, in order to streamline the disclosure and aid in the understanding of one or more of the various inventive aspects, the various features sometimes together grouped in a single embodiment or described with respect to a single embodiment in the foregoing description of the illustrative embodiments of the present application have sometimes been grouped, and that the method of the disclosure should not be interpreted as reflecting a necessity that the claimed application require more features than are explicitly recited in each claim. Rather, the inventive aspects are directed to less than all of the features of the embodiments disclosed before the claims. Thus, the claims following, depending on the particular implementation, are hereby expressly incorporated into this detailed description, with each claim acting as a separate embodiment of this application.

[0090] While the application has been described in terms of several embodiments, it will be apparent to those of ordinary skill in the art that many modifications, additions, and deletions can be made to the embodiments described herein without departing from the scope of the application and its broader aspects. Moreover, division into different embodiments is only for the convenience of the reader. Therefore, the present application is to be limited only by the scope of the appended claims, and it is contemplated that the application will be practiced with in the scope of the claims.

[0091] The above description is merely illustrative of the application and numerous modifications and changes will occur to those skilled in the art. It is therefore intended that the application not be limited to the above description and as claimed but that it cover all modifications and changes as fall within the scope of the application.

Claims

1. A high-pressure deep-sea forging, characterized in that: The invention comprises the following components in mass percentage: C: 0.30-0.33%, Si: 0.15-0.35%, Mn: 0.80-0.95%, P≤0.010%, S≤0.005%, Cr: 0.90-1.00%, Mo: 0.35-0.45%, Ni: 0.80-0.90%, Al: 0.020-0.030%, Cu≤0.15%, Nb≤0.010%, Ti≤0.010%, V: 0.030-0.050%, H≤2ppm, O≤20ppm; N≤80ppm; As≤0.010%, Sn≤0.010%, Sb≤0.005%, Pb≤0.010%, B≤0.0005%, Ca≤0.005%, Bi≤0.010%, and the balance is Fe.

2. The high-pressure deep-sea forging according to claim 1, characterized in that: V+Nb+Ti≤0.060%.

3. The high-pressure deep-sea forging according to claim 1, characterized in that: Under the pressure of 200MPa and 250MPa, the service life reaches more than 4000h.

4. The high-pressure deep-sea forging according to claim 1, characterized in that: High-pressure resistant deep-sea forgings include tubing head forgings for oil and gas equipment.

5. The method for manufacturing a high-pressure resistant deep-sea forging according to any one of claims 1 to 4, characterized in that: The following steps are involved: S01, smelting, refining and casting the raw materials in sequence to obtain steel ingots; S02, ingot heating and insulation: heat the ingot to 1150-1200℃ and keep it warm for 1.5-2h; S03, forging: the initial forging temperature of the steel ingot is 1150-1200℃, the final forging temperature is 850-900℃, the forging ratio is ≥4:1, and the workpiece is air-cooled to room temperature; S04, heat treatment: residual annealing, quenching and four tempering treatments; The method of residual heat annealing treatment is: heat the forged workpiece to 850-900℃, keep it at this temperature for 2-5h and then cool it in the furnace; The quenching method is as follows: the workpiece after residual temperature annealing is quenched to room temperature; The method of four tempering treatment is: First tempering: heat the quenched workpiece to 700-750℃, keep it warm for 1-2 hours and then air cool it to room temperature; Second tempering: temperature is 650-680℃, keep warm for 2-4h and then air cool to room temperature; The third tempering: the temperature is 500-550℃, keep warm for 0.5-1h and then air cool to room temperature; The fourth tempering: the temperature is 300-320℃, keep warm for 2-4 hours and then air cool to room temperature.

6. The manufacturing method according to claim 5, characterized in that In S01, the smelting method is: smelting in a DC arc furnace with a steel tapping temperature of 1600-1700°C.

7. The manufacturing method according to claim 5, characterized in that In S01, the refining method is: LF refining first and then VD refining; The LF refining method comprises: transferring molten steel into an LF refining furnace, heating the molten steel to 1750-1800°C, adding a refining agent, blowing in argon gas, and refining for 30-50 minutes to obtain refined molten steel; the refining agent comprises fluorite CaF2 and ferrosilicon Fe-Si in a mass ratio of 1:(2-5), and the amount of the refining agent added is equivalent to 1-3wt% of the molten steel; The VD refining method is as follows: transferring the refined molten steel to a VD vacuum furnace, evacuating the furnace, and performing vacuum degassing on the refined molten steel; the VD refining vacuum degree is 60-65 Pa, the VD refining temperature is 1800-1900°C, and the VD refining time is 1-2 hours.

8. The manufacturing method according to claim 5, characterized in that In S01, the casting method is as follows: the casting molten steel temperature is 1600-1700°C, the casting speed is 1-40 mm / s, the crystallizer is electromagnetically stirred during the casting process, the electromagnetic stirring current is 300-500 A, and the electromagnetic stirring frequency is 5-10 Hz.

9. Use of the high-pressure resistant deep-sea forging according to any one of claims 1 to 4 in deep-sea oil production equipment.