Production and manufacturing method based on F22 horizontal Christmas tree for deep sea

Abstract

The invention discloses a production and manufacturing method based on an F22 horizontal Christmas tree for deep sea, and relates to the field of production and manufacturing of Christmas trees, the production and manufacturing method comprises the following operation steps: S1, billet selection: billet materials comprise C; mn; p; s; si; cr; ni; mo; cu; as; sn; sb; v; a gas element H; a gas element O; a gas element N; fE; impurity elements; s2, cogging and forging; s3, pre-heat treatment; and S4, heat treatment. According to the production and manufacturing method based on the F22 horizontal Christmas tree for deep sea, through anvil block preheating and temperature control in each step in the forging process, the internal and external temperature difference of the forge piece is delayed, so that the cracking tendency of the forge piece is reduced, and no obvious forging crack is generated on the surface of the forge piece; it is guaranteed that the finish forging temperature is larger than or equal to 850 DEG C, the method has the advantages that the forging ratio is increased, grains are refined, and UT detection is free of defects, the surface of a horizontal Christmas tree body produced through the technology is free of cracking, the forged piece dissection after heat treatment meets the NACE standard, and the grain size grade is larger than 8 grade.

Description

Technical Field

[0001] The invention relates to the field of production and manufacturing of Christmas trees, and in particular to a production and manufacturing method based on a F22 horizontal Christmas tree for deep sea use. Background Art

[0002] F22 alloy steel is known for its excellent corrosion resistance. It can work stably for a long time in low temperature, high pressure and corrosive media environment without obvious corrosion or performance degradation. It is often used to produce key components such as valve bodies and casings of oil production equipment. These components need to withstand low temperature, high pressure and corrosive oil and gas erosion in deep sea environment. The excellent corrosion resistance and comprehensive mechanical properties of F22 steel make it an ideal choice.

[0003] In the manufacturing process of large forgings for deep-sea F22 horizontal oil trees, it is easy to have large temperature differences between the surface and the core of the forgings and uneven deformation, which leads to uneven material properties.

[0004] Therefore, it is necessary to propose a production method based on the F22 horizontal oil production tree for deep sea use to solve the above problems. Summary of the invention

[0005] The main purpose of the present invention is to provide a production method based on a F22 horizontal oil tree for deep sea use, which can effectively solve the problems in the background technology.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A manufacturing method based on a deep-sea F22 horizontal Christmas tree comprises the following steps:

[0008] S1: Billet selection: Billet materials include C; Mn; P; S; Si; Cr; Ni; Mo; Cu; As; Sn; Sb; V; gas element H; gas element O; gas element N; FE; impurity elements; the composition of the billet material must meet the following requirements: C: 0.13-0.15%; Mn: 0.50-0.60%; P: ≤0.010%; S: ≤0.005%; Si: ≤0.50%; Cr: 2.40-2.50%; Ni: ≤0.50%; Mo: 1.05-1.13%; Cu: ≤0.25%; As: ≤0.010%; Sn: ≤0.010%; Sb: ≤0.010%; V: ≤0.03%; gas element H ≤2PPm; gas element O ≤25PPm; gas element N ≤0.012; the remainder is FE and impurity elements;

[0009] S2: Open forging: preheat the anvil and other tooling before forging, place the billet material in the heating furnace, the furnace temperature is ≤300℃, the heating rate is ≤100℃ / h, the initial forging temperature is 1230℃, the final forging temperature is ≥850℃, and the forging ratio of each fire is ≥2 to ensure a tight structure after forging. During the forging process, the coarse grains are broken and the grains are refined;

[0010] S3: Preliminary heat treatment: first perform annealing treatment, heating to 920℃ at ≤200℃ / h, then slowly cool to 400℃ in the furnace and then air cool;

[0011] S4: Heat treatment: including normalizing, quenching and tempering, among which normalizing: heating to 950℃ at ≤200℃ / h, keeping warm and then air cooling to room temperature;

[0012] Quenching: ≤120℃ / h, heat up to 600-650℃, keep warm, then continue to heat up to 930-950℃ at this speed, keep warm, cool to room temperature, water temperature is between 20-35℃, swing left and right through the hanger after entering the water;

[0013] Tempering: Raise the temperature to 620-640℃ at ≤120℃ / h, keep warm and then air cool.

[0014] Preferably, in step S1, the steel billet material is a steel ingot with less impurity segregation.

[0015] Preferably, in step S3, the annealing furnace cooling rate is reduced from the first temperature of 920°C to ensure smooth microstructure spheroidization, and the furnace temperature error of each step is within ±10°C to avoid excessive grain size of the steel billet material after normalizing.

[0016] Preferably, in step S2, the temperature of the steel ingot forging furnace is ≤300°C, the heating temperature is 1230°C, the initial forging temperature is 1150°C, and the final forging temperature is 800-900°C.

[0017] Compared with the prior art, the present invention provides a production method based on a deep-sea F22 horizontal Christmas tree, which has the following beneficial effects:

[0018] 1. The manufacturing method based on the F22 horizontal oil tree for deep sea use can effectively prevent the forgings from cracking during the forging process. While ensuring the product forging ratio, the grain size is >8, and the low-temperature impact toughness and strength performance tests meet the NACE requirements.

[0019] 2. The manufacturing method of the F22 horizontal Christmas tree for deep sea uses a steel ingot, which has less impurity segregation in raw materials and strictly controls the composition of each element, and can effectively improve the hardenability of the product and improve the mechanical properties; preheating the anvil and other tooling before forging in S2 can avoid the large temperature difference and increase the heat diffusion, thereby reducing the forging ratio and increasing the forging times. Here, the forging ratio needs to reach 2, the deformation is large, and the last fire is beaten to a flat square and formed. Controlling the final forging temperature can effectively refine the grains and improve product performance; when performing the annealing process, the furnace cooling rate from the first temperature of 920°C is as slow as possible, which can effectively ensure the smooth spheroidization of the microstructure, and the furnace temperature error of each step is within ±10°C, which can avoid the F22 alloy steel from having too large grains after normalizing.

[0020] 3. The manufacturing method of the F22 horizontal Christmas tree for deep sea use delays the temperature difference between the inside and outside of the forging by preheating the anvil and controlling the temperature at each step of the forging process, so that the cracking tendency of the forging is reduced and no obvious forging cracks are generated on the surface; the final forging temperature is guaranteed to be ≥850℃, which has the advantages of increasing the forging ratio, refining the grains, and no defects in UT detection; the forging is drawn to a flat square during the forging process to make the core of the forging more compact; in addition, the cooling speed of the annealing furnace is controlled to ensure that the furnace temperature is accurate and the alloy structure is smoothly spheroidized. The horizontal Christmas tree body produced by this process has no cracking on the surface, and the anatomy of the forging after heat treatment meets the NACE standard, with a grain size grade of >8. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a forging process diagram of the present invention;

[0022] Figure 2 It is a heat treatment process diagram of the present invention;

[0023] Figure 3 It is a metallographic structure diagram of the main body of the present invention after heat treatment at the maximum wall thickness T / 2. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0025] like Figure 1-Figure 3 As shown, a manufacturing method based on a deep-sea F22 horizontal oil tree comprises the following steps:

[0026] S1: Billet selection: Billet materials include C; Mn; P; S; Si; Cr; Ni; Mo; Cu; As; Sn; Sb; V; gas element H; gas element O; gas element N; FE; impurity elements; the composition of the billet material must meet the following requirements: C: 0.13-0.15%; Mn: 0.50-0.60%; P: ≤0.010%; S: ≤0.005%; Si: ≤0.50%; Cr: 2.40-2.50%; Ni: ≤0.50%; Mo: 1.05-1.13%; Cu: ≤0.25%; As: ≤0.010%; Sn: ≤0.010%; Sb: ≤0.010%; V: ≤0.03%; gas element H ≤2PPm; gas element O ≤25PPm; gas element N ≤0.012; the remainder is FE and impurity elements, and the billet material is selected from the steel ingot with less impurity segregation;

[0027] S2: Open forging: preheat the anvil and other tooling before forging, put the billet material in the heating furnace, the charging temperature is ≤300℃, the heating rate is ≤100℃ / h, the initial forging temperature is 1230℃, the final forging temperature is ≥850℃, the forging ratio of each fire is ≥2, to ensure the tight structure after forging, break the coarse grains and refine the grains during the forging process, the charging temperature of the steel ingot forging is ≤300℃, the heating temperature is 1230℃, the initial forging temperature is 1150℃, and the final forging temperature is 800-900℃;

[0028] S3: Preliminary heat treatment: firstly, annealing treatment is carried out, the temperature is raised to 920℃ at ≤200℃ / h, and then slowly cooled to 400℃ in the furnace after heat preservation, and then air-cooled. The annealing furnace cooling rate is reduced from the first temperature of 920℃ to ensure smooth microstructure spheroidization, and the furnace temperature error of each step is within ±10℃ to avoid excessive grain size of the billet material after normalizing treatment;

[0029] S4: Heat treatment: including normalizing, quenching and tempering, among which normalizing: heating to 950℃ at ≤200℃ / h, keeping warm and then air cooling to room temperature;

[0030] Quenching: ≤120℃ / h, heat up to 600-650℃, keep warm, then continue to heat up to 930-950℃ at this speed, keep warm, cool to room temperature, water temperature is between 20-35℃, swing left and right through the hanger after entering the water;

[0031] Tempering: Raise the temperature to 620-640℃ at ≤120℃ / h, keep warm and then air cool.

[0032] Embodiment 1:

[0033] A manufacturing method based on a deep-sea F22 horizontal Christmas tree comprises the following steps:

[0034] S1: Billet selection: 36-ton large ingot is selected, and the material composition meets the following requirements: C: 0.14%, Mn: 0.57%, P: 0.004%, S: 0.002%, Si: 0.29%, Cr: 2.47%, Ni: 0.48%, Mo: 1.11%, Cu: 0.04%, As: 0.006%, Sn: 0.002%, Sb: 0.003%, gas elements [H]: 0.8PPm, [O]: 8PPm, [N] ≤ 0.012PPm, and the remaining elements are Fe and impurity elements;

[0035] S2: Open forging: Place 36 tons of steel ingot in a heating furnace, with a charging temperature of ≤300℃, a heating rate of ≤100℃ / h, a heating temperature of 1230℃, and a final forging temperature of>850℃. Preheat the anvil and other tooling before forging to avoid excessive temperature dissipation, which will increase the number of forging fires and cause serious decarburization; control the forging ratio of each fire to>2, including the following processes:

[0036] First fire: After heating the billet for 8 hours, control the transfer speed (≤30s), roughen it along the axial direction to a height of 1400mm, chamfer it and draw it to 1100mm parallel to the cross-section line, forging temperature 850-1230℃, forging ratio>1.5, return to the furnace for a holding time of not less than 6h;

[0037] Second fire: roughing to a height of 1400mm, drawing the cross section of 1100mm, forging temperature controlled at 850-1230℃, forging ratio>1.5, re-melting and heat preservation for not less than 6h;

[0038] The third fire: roughen to a height of 1200mm, flatten to 1100×1500mm, trim and shape, control the final forging temperature above 800℃, and then bury in a sand pit and cool to room temperature.

[0039] In the above forging process, each step of forging needs to be precisely controlled, especially the final forging temperature. Except for the correction forming, the final forging temperature must not be lower than 850℃. In the actual forging process, the initial forging temperature of the ingot surface was measured to be 1120℃, and the final forging temperature was 860℃;

[0040] S3: Preparatory heat treatment:

[0041] Annealing: heating to 920℃ at ≤200℃ / h, keeping warm and then slowly cooling to 400℃, then air cooling. Annealing process: heating to 920℃ at ≤200℃ / h, keeping warm and then slowly cooling. In addition, rough processing can be performed after normalizing to remove surface oxide scale and blank surplus. The specific implementation is as follows: Figure 2 As shown;

[0042] S4 heat treatment: Normalizing: heating to 950℃ at ≤200℃ / h, keeping at this temperature for ≥15h, then air cooling to room temperature;

[0043] Quenching: heating to 600-650℃ at ≤120℃ / h and keeping for 5h, then continue heating to 930-950℃ at this speed and keep for more than 15h, water-cooling to room temperature, water temperature between 20-35℃, swinging left and right through the hanger after entering the water;

[0044] Tempering: ≤120℃ / h, heat to 620-640℃, keep warm for >30h, then air cool, and keep the furnace temperature uniform.

[0045] The performance test of the maximum wall thickness of an F22 horizontal Christmas tree body manufactured by the production process of the present invention is as follows:

[0046]

[0047] It can be seen that its grain size reaches above level 8, and the four types of non-metallic inclusions all meet the requirements. The mechanical properties of the product are shown in the above table, which far exceed the specification requirements. The various indicators of forgings produced by this method have been recognized by domestic and foreign customers, reaching the domestic leading level, and have been used in deep-sea oil extraction.

[0048] This method can effectively prevent the forgings from cracking during the forging process. While ensuring the product forging ratio, the grain size is >8, and the low-temperature impact toughness and strength performance tests meet the NACE requirements. By selecting steel ingots from billets, the raw materials have less impurity segregation, and the composition of each element is strictly controlled, which can effectively improve the hardenability of the product and improve the mechanical properties; preheating the anvil and other tooling before forging in S2 can avoid the large temperature difference that increases heat diffusion, thereby reducing the forging ratio and increasing the forging times. Here, the forging ratio needs to reach 2, the deformation is large, and the last fire is beaten to a flat square and formed. Controlling the final forging temperature can effectively refine the grains and improve product performance; during the annealing process, the furnace cooling rate from the first temperature of 920°C is as slow as possible, which can effectively ensure the micro The microstructure spheroidization is smooth, and the furnace temperature error of each step is within ±10℃, which can avoid the excessive grain size of F22 alloy steel after normalizing treatment. By preheating the anvil and controlling the temperature at each step in the forging process, the temperature difference between the inside and outside of the forging is delayed, so that the cracking tendency of the forging is reduced, and no obvious forging cracks are generated on the surface; the final forging temperature is guaranteed to be ≥850℃, which has the advantages of increasing the forging ratio, refining the grains, and no defects in UT detection; the forging is drawn to a flat square during the forging process, making the core of the forging denser; in addition, the cooling speed of the annealing furnace is controlled to ensure that the furnace temperature is accurate and the alloy microstructure is spheroidized smoothly. The horizontal oil tree body produced by this process has no cracking on the surface. The anatomy of the forging after heat treatment meets the NACE standard, and the grain size grade is >8.

[0049] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A production method based on a deep-sea F22 horizontal Christmas tree, characterized in that: The steps include: S1: Billet selection: Billet materials include C; Mn; P; S; Si; Cr; Ni; Mo; Cu; As; Sn; Sb; V; gas element H; gas element O; gas element N; FE; impurity elements; the composition of the billet material must meet the following requirements: C: 0.13-0.15%; Mn: 0.50-0.60%; P: ≤0.010%; S: ≤0.005%; Si: ≤0.50%; Cr: 2.40-2.50%; Ni: ≤0.50%; Mo: 1.05-1.13%; Cu: ≤0.25%; As: ≤0.010%; Sn: ≤0.010%; Sb: ≤0.010%; V: ≤0.03%; gas element H ≤2PPm; gas element O ≤25PPm; gas element N ≤0.012; the balance is FE and impurity elements; S2: Open forging: preheat the anvil and other tooling before forging, place the billet material in the heating furnace, the furnace temperature is ≤300℃, the heating rate is ≤100℃ / h, the initial forging temperature is 1230℃, the final forging temperature is ≥850℃, and the forging ratio of each fire is ≥2 to ensure a tight structure after forging. During the forging process, the coarse grains are broken and the grains are refined; S3: Preliminary heat treatment: first perform annealing treatment, heating to 920℃ at ≤200℃ / h, then slowly cool to 400℃ in the furnace and then air cool; S4: Heat treatment: including normalizing, quenching and tempering. Normalizing: heating to 950℃ at ≤200℃ / h, keeping warm and then air cooling to room temperature; Quenching: ≤120℃ / h, heat up to 600-650℃, keep warm, then continue to heat up to 930-950℃ at this speed, keep warm, cool to room temperature, water temperature is between 20-35℃, swing left and right through the hanger after entering the water; Tempering: heat to 620-640℃ at ≤120℃ / h, keep warm and then air cool.

2. The method for producing a deep-sea F22 horizontal Christmas tree according to claim 1, characterized in that: In the step S1, a steel ingot with less impurity segregation is selected as the steel billet material.

3. The manufacturing method of the deep-sea F22 horizontal Christmas tree according to claim 1, characterized in that: In step S3, the annealing furnace cooling rate is reduced from the first temperature of 920° C. to ensure smooth microstructure spheroidization, and the furnace temperature error of each step is within ±10° C. to avoid excessive grain size of the steel billet material after normalizing.

4. The manufacturing method of the deep-sea F22 horizontal Christmas tree according to claim 1, characterized in that: In the step S2, the temperature of the steel ingot forging furnace is ≤300°C, the heating temperature is 1230°C, the initial forging temperature is 1150°C, and the final forging temperature is 800-900°C.

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