Nuclear power hydraulic oil pipe and forming process

Abstract

The invention belongs to the technical field of nuclear power oil pipes, and particularly relates to a nuclear power hydraulic oil pipe and a forming process. Comprising an outer rubber layer, a middle rubber layer and an inner rubber layer, steel wire layers are arranged between the outer rubber layer and the middle rubber layer and between the middle rubber layer and the inner rubber layer; wherein the outer rubber layer comprises 40 to 60 parts of HNBR, 40 to 55 parts of CSM and 2 to 6 parts of zinc oxide. The nuclear power hydraulic oil pipe has the advantages that the adopted nuclear power hydraulic oil pipe material and the forming process give consideration to both oil resistance and flame retardance, the creep resistance is excellent, the pressed state is stable, changes of deformation and stress of a pipe body, strain energy of all parts, strain energy density and the like are small, carbon black is added in batches in the forming process, the dispersity is larger than or equal to 95%, stress concentration is avoided, and the service life of the nuclear power hydraulic oil pipe is prolonged. And vulcanization heating is controlled in a segmented manner, so that the interlayer stripping risk caused by thermal expansion difference is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power oil pipes, and particularly relates to a nuclear power hydraulic oil pipe and a forming process thereof. Background Art

[0002] Due to the special working environment, nuclear power hoses have the characteristics of high pressure resistance, high temperature resistance, radiation resistance, long life, etc. The requirement for the product life is very high, generally requiring a life of more than ten years. Therefore, the selection of materials, the design of the structure, and the process control are all very strict. According to different hose requirements, different technical solutions are selected for trial production.

[0003] The physical properties of different raw rubber types vary greatly, with different hardness, strength, and stability under pressure. Under the guidance of rubber compounding theory, advanced rubber formulation design methods are applied to accurately find the relationship between the formulation ratio and the properties of new rubber materials, so as to ensure the development of a new inner rubber material with high cost performance and performance exceeding the existing level. Finally, the basic formulation and process control parameters meeting the design performance are determined, ensuring that the involved formulation meets the expected requirements, and thus ensuring that the hose finished product meets the working requirements.

[0004] At present, the service life of the oil pipes manufactured by the existing technology cannot reach 10 years. Generally, under the condition of long-term pressure, it can only meet 6 - 7 years, and under the condition of no pressure, it can meet 7 - 8 years. In addition, after using for more than 5 years, the inner layer of some existing oil pipes shows aging, with debris falling off, causing blockage of the corresponding pipe valves and easily resulting in the abnormal operation of the system. Summary of the Invention

[0005] The purpose of the present invention is to provide a nuclear power hydraulic oil pipe and a forming process thereof, in which the outer rubber, middle rubber, and inner rubber are all formed by a one-step forming process. After pressure tests and other burst tests, the relevant parameters are higher than those of existing similar products.

[0006] The technical solution of the present invention is as follows: A nuclear power hydraulic oil pipe includes an outer rubber layer, a middle rubber layer, and an inner rubber layer. Steel wire layers are provided between the outer rubber layer and the middle rubber layer, and between the middle rubber layer and the inner rubber layer;

[0007] Among them, the outer rubber layer includes 40 - 60 parts of HNBR, 40 - 55 parts of CSM, 2 - 6 parts of zinc oxide, 1 - 2 parts of stearic acid, 40 - 55 parts of carbon black, 2 - 4 parts of active magnesium oxide, 20 - 40 parts of reinforcing agent calcined kaolin, 6 - 15 parts of condensed bromoacenaphthene, 0.5 - 1.5 parts of antioxidant, 3 - 6 parts of resin, 24 - 27 parts of plasticizer, 2 - 4 parts of S, 0.5 - 2 parts of CBS, 0.1 - 0.8 parts of DPTT, and 2 - 6 parts of RC;

[0008] The middle rubber layer comprises 90 - 110 parts of HNBR, 2 - 4 parts of zinc oxide, 1 - 2 parts of stearic acid, 50 - 70 parts of carbon black, 8 - 11 parts of condensed bromoacenaphthene, 0.5 - 2 parts of antioxidant, 3 - 6 parts of resin, 16 - 20 parts of plasticizer, 2 - 5 parts of S, 1 - 4 parts of CBS, and 2 - 6 parts of RC;

[0009] The inner rubber layer comprises 90 - 110 parts of HNBR, 4 - 6 parts of zinc oxide, 1 - 3 parts of stearic acid, 80 - 100 parts of carbon black, 8 - 12 parts of condensed bromoacenaphthene, 0.5 - 1.5 parts of antioxidant, 10 - 14 parts of plasticizer, 1.5 - 3.5 parts of vulcanizing agent, 0.5 - 1.5 parts of triallyl isocyanurate, 0.5 - 2 parts of S, and 100 - 110 parts of CBS.

[0010] The outer rubber layer comprises 50 parts of HNBR, 50 parts of CSM, 5 parts of zinc oxide, 1.5 parts of stearic acid, 50 parts of carbon black, 3.5 parts of active magnesium oxide, 35 parts of reinforcing agent calcined kaolin, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 5 parts of resin, 26 parts of plasticizer, 2.5 parts of S, 1 part of CBS, 0.5 part of DPTT, and 5 parts of RC;

[0011] The middle rubber layer comprises 100 parts of HNBR, 3.5 parts of zinc oxide, 1.5 parts of stearic acid, 60 parts of carbon black, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 5 parts of resin, 18 parts of plasticizer, 3.5 parts of S, 1.5 parts of CBS, and 5 parts of RC;

[0012] The inner rubber layer comprises 100 parts of HNBR, 5 parts of zinc oxide, 1.5 parts of stearic acid, 90 parts of carbon black, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 12 parts of plasticizer, 2.5 parts of vulcanizing agent, 1 part of triallyl isocyanurate, 1 part of S, and 105 parts of CBS.

[0013] The HNBR in the outer rubber layer is hydrogenated nitrile - butadiene rubber with an acrylonitrile content of 34%, and the hydrogenation degree: ≥90%; the carbon black is carbon black N660.

[0014] The HNBR in the middle rubber layer is hydrogenated nitrile - butadiene rubber with an acrylonitrile content of 34%, and the hydrogenation degree: ≥94%; the carbon black is carbon black N660.

[0015] The carbon black in the inner rubber layer is carbon black N660 and carbon black N330, wherein, there are 60 parts of carbon black N660 and 30 parts of carbon black N330.

[0016] The resin is phenolic resin or alkylphenolic tackifying resin, the plasticizer is polyester plasticizer, and the RC is a vulcanization retarder.

[0017] A forming process for a nuclear power hydraulic oil pipe comprises the following steps:

[0018] Step 1: Conduct raw rubber pretreatment, small ingredient addition, mixing of reinforcing agent and softening agent, addition of vulcanization system, and final mixing treatment in sequence;

[0019] Step 2: Conduct preheating of rubber compound, extrusion of inner rubber, calendering of middle rubber layer, wire braiding, outer layer coating and coiling in sequence;

[0020] Step 3: Vulcanization: Vulcanize in a vertical vulcanizing autoclave or a continuous vulcanization production line, with staged temperature increase, where the temperature increases as 50°C → 100°C → 151°C, each stage for 10 minutes; Remove water cloth and core: Immediately remove the water cloth after vulcanization and conduct core removal; Inspection and packaging.

[0021] In the raw rubber pretreatment in Step 1: Place HNBR raw rubber on an open mill, adjust the roll gap to 0.5 - 0.8 mm, and thin pass for 3 - 4 minutes;

[0022] Small ingredient addition: Widen the roll gap to 2 - 3 mm, and sequentially add small ingredients such as zinc oxide, stearic acid, antioxidant, resin, etc.;

[0023] Mixing of reinforcing agent and softening agent: Alternately add carbon black, calcined kaolin and plasticizer in 3 - 4 batches to ensure uniform infiltration of the filler, and the roll temperature ≤ 70°C;

[0024] Addition of vulcanization system: Add vulcanizing agent S, accelerator CBS, DPTT, adjust the roll gap to 0.5 - 0.8 mm, thin pass 3 times, and the vulcanizing agent needs to be added at low temperature;

[0025] Final mixing treatment: Adjust the roll gap to 2 - 3 mm, make 5 triangular bales + 3 rolls to eliminate air bubbles and improve uniformity, take off the sheet and cool, with the thickness of the rubber sheet being 2 - 3 mm, and cool to below 30°C at room temperature.

[0026] In Step 2:

[0027] Preheating of rubber compound: Heat the mixed rubber on an open mill for 5 - 8 minutes;

[0028] Extrusion of inner rubber: Cold feed extruder, with the thickness of the inner rubber being 2.5 - 3.5 mm;

[0029] Calendering of middle rubber layer: Cover a 1.0 - 1.5 mm middle rubber layer on the surface of the braided layer through a four-roll calender;

[0030] Wire braiding: Use a braiding machine, with a braiding angle of 54° - 56° and a coverage rate ≥ 95%. The wire needs to be coated with nylon water (isocyanate adhesive) before braiding;

[0031] Outer layer coating and coiling: Extrude and coat the outer rubber, with a thickness of 2.0 - 2.5 mm, wind a wet water cloth, and shape it to prevent vulcanization deformation.

[0032] In the inspection and packaging:

[0033] Among them, it includes performance testing: maintaining pressure for 5 minutes at 2.5 times the working pressure, filling with nitrogen to the rated pressure, and detecting the leakage rate; appearance inspection: no bubbles, impurities, or exposed braided layer on the surface; packaging: lined with anti-static film, wrapped with woven bags, and marked with the pressure resistance level and batch number.

[0034] The beneficial effects of the present invention are as follows: The nuclear power hydraulic oil pipe material and forming process adopted in the present invention take into account oil resistance and flame retardancy, have excellent anti-creep performance, stable pressure-bearing state, small changes in various deformations, stress changes, strain energy, and strain energy density of the pipe body. During forming, carbon black is added in batches to achieve a dispersion degree of ≥95%, avoiding stress concentration, and the vulcanization temperature rise is controlled in sections to reduce the risk of interlayer peeling caused by thermal expansion differences. Brief Description of the Drawings

[0035] Figure 1 It is a schematic diagram of a forming process for a nuclear power hydraulic oil pipe provided by the present invention. Detailed Embodiments

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Embodiment 1

[0038] In the embodiment of the present invention, a nuclear power hydraulic oil pipe includes an outer rubber layer, a middle rubber layer, and an inner rubber layer; steel wire layers are provided between the outer rubber layer and the middle rubber layer, and between the middle rubber layer and the inner rubber layer;

[0039] Among them, the outer rubber layer includes 40 parts of HNBR, 40 parts of CSM, 2 parts of zinc oxide, 1 part of stearic acid, 40 parts of carbon black, 2 parts of active magnesium oxide, 20 parts of reinforcing agent calcined kaolin, 6 parts of condensed bromoacenaphthene, 0.5 part of antioxidant, 3 parts of resin, 24 parts of plasticizer, 2 parts of S, 0.5 part of CBS, 0.1 part of DPTT, 2 parts of RC;

[0040] The middle rubber layer includes 90 parts of HNBR, 2 parts of zinc oxide, 1 part of stearic acid, 50 parts of carbon black, 8 parts of condensed bromoacenaphthene, 0.5 part of antioxidant, 3 parts of resin, 16 parts of plasticizer, 2 parts of S, 1 part of CBS, 2 parts of RC;

[0041] The inner rubber layer includes 90 parts of HNBR, 4 parts of zinc oxide, 1 part of stearic acid, 80 parts of carbon black, 8 parts of condensed bromoacenaphthene, 0.5 part of antioxidant, 10 parts of plasticizer, 1.5 parts of vulcanizing agent, 0.5 part of triallyl isocyanurate, 0.5 part of S, 100 parts of CBS;

[0042] In the outer rubber layer, the HNBR is hydrogenated nitrile rubber with an acrylonitrile content of 34%, and the hydrogenation degree is ≥90%; the carbon black is carbon black N660;

[0043] In the middle rubber layer, the HNBR is hydrogenated nitrile rubber with an acrylonitrile content of 34%, and the hydrogenation degree is ≥94%; the carbon black is carbon black N660;

[0044] The resin is phenolic resin or alkylphenolic tackifying resin, the plasticizer is polyester plasticizer, and the RC is a vulcanization retarder, and N-cyclohexylthiophthalimide (CTP) can be selected.

[0045] Example 2

[0046] Different from Example 1, a nuclear power hydraulic oil pipe includes an outer rubber layer, a middle rubber layer and an inner rubber layer; steel wire layers are provided between the outer rubber layer and the middle rubber layer, and between the middle rubber layer and the inner rubber layer;

[0047] Among them, the outer rubber layer includes 60 parts of HNBR, 55 parts of CSM, 6 parts of zinc oxide, 2 parts of stearic acid, 55 parts of carbon black, 4 parts of active magnesium oxide, 40 parts of reinforcing agent calcined kaolin, 15 parts of condensed bromoacenaphthene, 1.5 parts of antioxidant, 6 parts of resin, 27 parts of plasticizer, 4 parts of S, 2 parts of CBS, 0.8 part of DPTT, 6 parts of RC;

[0048] The middle rubber layer includes 110 parts of HNBR, 4 parts of zinc oxide, 2 parts of stearic acid, 70 parts of carbon black, 11 parts of condensed bromoacenaphthene, 2 parts of antioxidant, 6 parts of resin, 20 parts of plasticizer, 5 parts of S, 4 parts of CBS, 6 parts of RC;

[0049] The inner rubber layer includes 110 parts of HNBR, 6 parts of zinc oxide, 3 parts of stearic acid, 100 parts of carbon black, 12 parts of condensed bromoacenaphthene, 1.5 parts of antioxidant, 14 parts of plasticizer, 3.5 parts of vulcanizing agent, 1.5 parts of triallyl isocyanurate, 2 parts of S, 110 parts of CBS.

[0050] Example 3

[0051] Different from Example 1, a nuclear power hydraulic oil pipe includes an outer rubber layer, a middle rubber layer and an inner rubber layer; steel wire layers are provided between the outer rubber layer and the middle rubber layer, and between the middle rubber layer and the inner rubber layer;

[0052] The outer rubber layer includes 50 parts of HNBR, 50 parts of CSM, 5 parts of zinc oxide, 1.5 parts of stearic acid, 50 parts of carbon black, 3.5 parts of active magnesium oxide, 35 parts of reinforcing agent calcined kaolin, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 5 parts of resin, 26 parts of plasticizer, 2.5 parts of S, 1 part of CBS, 0.5 part of DPTT, 5 parts of RC;

[0053] The middle rubber layer includes 100 parts of HNBR, 3.5 parts of zinc oxide, 1.5 parts of stearic acid, 60 parts of carbon black, 10 parts of condensed bromoacenaphthylene, 1 part of antioxidant, 5 parts of resin, 18 parts of plasticizer, 3.5 parts of sulfur, 1.5 parts of CBS, and 5 parts of RC;

[0054] The inner rubber layer includes 100 parts of HNBR, 5 parts of zinc oxide, 1.5 parts of stearic acid, 90 parts of carbon black, 10 parts of condensed bromoacenaphthylene, 1 part of antioxidant, 12 parts of plasticizer, 2.5 parts of vulcanizing agent, 1 part of triallyl isocyanurate, 1 part of sulfur, and 105 parts of CBS;

[0055] The carbon black in the inner rubber layer is carbon black N660 and carbon black N330, among which, there are 60 parts of carbon black N660 and 30 parts of carbon black N330.

[0056] Among them, in this application, CSM is chlorosulfonated polyethylene;

[0057] CBS is accelerator N-cyclohexyl-2-benzothiazole sulfenamide, which is used in combination with sulfur to shorten the normal vulcanization time;

[0058] S is sulfur;

[0059] DPTT is accelerator tetrasulfide bis(pentamethylene thiuram) disulfide.

[0060] As Figure 1 shown, a forming process for a nuclear power hydraulic oil pipe includes the following steps:

[0061] Step 1. Raw rubber pretreatment: Place the HNBR raw rubber on an open mill (roll temperature 40 - 50 °C), adjust the roll gap to 0.5 - 0.8 mm, and thin pass for 3 - 4 minutes;

[0062] Addition of small ingredients: Widen the roll gap to 2 - 3 mm, and sequentially add small ingredients such as zinc oxide, stearic acid, antioxidant, and resin;

[0063] Mixing of reinforcing agent and softening agent: Add carbon black, calcined kaolin, and plasticizer alternately in 3 - 4 batches to ensure uniform infiltration of the filler, and the roll temperature ≤ 70 °C;

[0064] Addition of vulcanization system: Add vulcanizing agent (S), accelerators (CBS, DPTT), adjust the roll gap to 0.5 - 0.8 mm, thin pass 3 times, and the vulcanizing agent needs to be added at low temperature (< 60 °C);

[0065] Final mixing treatment: Adjust the roll gap to 2 - 3 mm, make 5 triangular bales + 3 rolls to eliminate air bubbles and improve uniformity, take off the sheet and cool, the thickness of the rubber sheet is 2 - 3 mm, and cool to below 30 °C at room temperature;

[0066] Step 2. Preheat the rubber compound: Heat the mixed rubber on an open mill (roll temperature 60 - 70 °C) for 5 - 8 minutes;

[0067] Inner rubber extrusion: Cold-feed extruder (L / D ratio 12:1, temperature gradient: barrel 50°C → head 80°C), inner rubber thickness 2.5 - 3.5 mm;

[0068] Calendering of intermediate rubber layer: Cover a 1.0 - 1.5 mm intermediate rubber layer on the surface of the braided layer through a four-roll calender (roll temperature 70 - 80°C);

[0069] Steel wire braiding: Use a braiding machine, braiding angle 54° - 56°, coverage rate ≥ 95%. Before braiding, the steel wire needs to be coated with nylon water (isocyanate adhesive);

[0070] Outer layer coating and winding: Extrusion coating of the outer rubber (HNBR / CSM blend rubber), thickness 2.0 - 2.5 mm, winding with a wet cloth (pressure 0.3 - 0.5 MPa), shaping and preventing vulcanization deformation;

[0071] Step 3. Vulcanization: Vulcanize in a vertical vulcanizing tank or a continuous vulcanization production line, with stepwise temperature increase, where the temperature increase is 50°C → 100°C → 151°C, 10 minutes for each stage; Removing the cloth and the core: Immediately remove the cloth after vulcanization and remove the core; Inspection and packaging: Performance test: Keep the pressure for 5 minutes at 2.5 times the working pressure, fill with nitrogen to the rated pressure, and detect the leakage rate; Appearance inspection: The surface has no bubbles, impurities, or exposed braided layer; Packaging: Lined with anti-static film, wrapped with woven bags, marked with the pressure resistance level and batch number.

[0072] The steel wire braided layer is treated with copper-plated steel wire + nylon water treatment, with a bonding strength ≥ 18 kN / m (ASTM D429), delaying the propagation of fatigue cracks.

[0073] According to the components of Example 1, Example 2, and Example 3, the nuclear power hydraulic oil pipe is formed and processed, all using stepwise temperature increase vulcanization (50°C → 100°C → 151°C), reducing the risk of interface delamination caused by thermal stress;

[0074] In Example 2, the content of CSM and acenaphthylene bromide in the outer rubber layer is the highest, and the flame retardancy (LOI ≥ 35%) is the best, but excessive CSM may lead to a decrease in oil resistance, and the volume expansion rate ≥ 15%;

[0075] Example 3 uses a balanced ratio of HNBR / CSM = 1:1, taking into account both oil resistance and flame retardancy, and at the same time, acenaphthylene bromide is within the regulatory limits;

[0076] Among them, the inner rubber layer is synergistic with the carbon black N330 peroxide vulcanization system, with a high crosslinking density (swelling degree ≤ 15%) and excellent anti-creep performance. The outer rubber layer forms a radiation shielding layer with acenaphthylene bromide + kaolin in the intermediate rubber layer, absorbing the energy of γ rays. CSM and acenaphthylene bromide are synergistic, and the combustion self-extinguishing time ≤ 10 seconds.

[0077] Perform performance tests on the finished nuclear power hydraulic oil pipes produced in Example 3. The test results are shown in Table 1.

[0078] Table 1 Performance Tests of Finished Nuclear Power Hydraulic Oil Pipes

[0079]

[0080] The nuclear power hydraulic oil pipe materials and forming processes adopted in this application have excellent anti-creep performance, stable pressure-bearing state, small changes in various deformations, stress changes, strain energy and strain energy density of the pipe body, etc. During forming, carbon black is added in batches to achieve a dispersion degree ≥ 95%, avoiding stress concentration, and the vulcanization temperature rise is controlled in sections to reduce the risk of interlayer peeling caused by thermal expansion differences.

[0081] The above are only preferred embodiments of the present invention, and are not limitations on the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A nuclear power hydraulic oil pipe, characterized in that: It includes an outer rubber layer, a middle rubber layer and an inner rubber layer, and steel wire layers are provided between the outer rubber layer and the middle rubber layer, and between the middle rubber layer and the inner rubber layer; Among them, the outer rubber layer includes 40-60 parts of HNBR, 40-55 parts of CSM, 2-6 parts of zinc oxide, 1-2 parts of stearic acid, 40-55 parts of carbon black, 2-4 parts of active magnesium oxide, 20-40 parts of reinforcing agent calcined kaolin, 6-15 parts of condensed bromoacenaphthene, 0.5-1.5 parts of antioxidant, 3-6 parts of resin, 24-27 parts of plasticizer, 2-4 parts of S, 0.5-2 parts of CBS, 0.1-0.8 parts of DPTT, 2-6 parts of RC; The middle rubber layer includes 90-110 parts of HNBR, 2-4 parts of zinc oxide, 1-2 parts of stearic acid, 50-70 parts of carbon black, 8-11 parts of condensed bromoacenaphthene, 0.5-2 parts of antioxidant, 3-6 parts of resin, 16-20 parts of plasticizer, 2-5 parts of S, 1-4 parts of CBS, 2-6 parts of RC; The inner rubber layer includes 90-110 parts of HNBR, 4-6 parts of zinc oxide, 1-3 parts of stearic acid, 80-100 parts of carbon black, 8-12 parts of condensed bromoacenaphthene, 0.5-1.5 parts of antioxidant, 10-14 parts of plasticizer, 1.5-3.5 parts of vulcanizing agent, 0.5-1.5 parts of triallyl isocyanurate, 0.5-2 parts of S, 100-110 parts of CBS.

2. The nuclear power hydraulic oil pipe according to claim 1, characterized in that: The outer rubber layer includes 50 parts of HNBR, 50 parts of CSM, 5 parts of zinc oxide, 1.5 parts of stearic acid, 50 parts of carbon black, 3.5 parts of active magnesium oxide, 35 parts of reinforcing agent calcined kaolin, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 5 parts of resin, 26 parts of plasticizer, 2.5 parts of S, 1 part of CBS, 0.5 part of DPTT, 5 parts of RC; The middle rubber layer includes 100 parts of HNBR, 3.5 parts of zinc oxide, 1.5 parts of stearic acid, 60 parts of carbon black, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 5 parts of resin, 18 parts of plasticizer, 3.5 parts of S, 1.5 parts of CBS, 5 parts of RC; The inner rubber layer includes 100 parts of HNBR, 5 parts of zinc oxide, 1.5 parts of stearic acid, 90 parts of carbon black, 10 parts of condensed bromoacenaphthene, 1 part of antioxidant, 12 parts of plasticizer, 2.5 parts of vulcanizing agent, 1 part of triallyl isocyanurate, 1 part of S, 105 parts of CBS.

3. The nuclear power hydraulic oil pipe according to claim 2, wherein: The HNBR in the outer rubber layer is hydrogenated nitrile butadiene rubber with an acrylonitrile content of 34%, and the hydrogenation degree: ≥90%; the carbon black is carbon black N660.

4. The nuclear power hydraulic oil pipe according to claim 2, characterized in that: The HNBR in the middle rubber layer is hydrogenated nitrile butadiene rubber with an acrylonitrile content of 34%, and the hydrogenation degree: ≥94%; the carbon black is carbon black N660.

5. The nuclear power hydraulic oil pipe according to claim 2, characterized in that: The carbon black in the inner rubber layer is carbon black N660 and carbon black N330. Among them, 60 parts of carbon black N660 and 30 parts of carbon black N330.

6. A nuclear power hydraulic oil pipe according to claim 1, characterized in that: The resin is phenolic resin or alkylphenolic tackifying resin, the plasticizer is polyester plasticizer, and the RC is a vulcanization retarder.

7. The forming process of the nuclear power hydraulic oil pipe according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1: Perform raw rubber pretreatment, small material addition, mixing of reinforcing agent and softening agent, addition of vulcanization system, and final mixing treatment in sequence; Step 2: Perform preheating of the rubber compound, extrusion of the inner rubber, calendering of the middle rubber layer, steel wire braiding, outer layer coating and winding in sequence; Step 3: Vulcanization: Vulcanize in a vertical autoclave or a continuous vulcanization production line, with stepwise temperature increase, where the temperature increases as 50°C → 100°C → 151°C, 10 minutes for each stage; Remove the water cloth and the core: Immediately remove the water cloth after vulcanization and remove the core; Inspection and packaging.

8. The forming process of a nuclear power hydraulic oil pipe according to claim 7, characterized in that: In the raw rubber pretreatment in Step 1: Place the HNBR raw rubber on an open mill, adjust the roll gap to 0.5 - 0.8 mm, and thin pass for 3 - 4 minutes. Addition of minor ingredients: Widen the roll gap to 2 - 3 mm, and sequentially add minor ingredients such as zinc oxide, stearic acid, anti-aging agent, resin, etc. Mixing of reinforcing agent and softening agent: Alternately add carbon black, calcined kaolin, and plasticizer in 3 - 4 batches to ensure uniform infiltration of the filler, with the roll temperature ≤ 70°C. Addition of vulcanization system: Add vulcanizing agent S, accelerator CBS, DPTT, adjust the roll gap to 0.5 - 0.8 mm, and thin pass 3 times. The vulcanizing agent needs to be added at a low temperature. Final treatment of mixing: Adjust the roll gap to 2 - 3 mm, make 5 triangular bales + 3 rolls to eliminate air bubbles and improve uniformity, take off the sheet and cool it. The thickness of the rubber sheet is 2 - 3 mm, and cool it to below 30°C at room temperature.

9. The forming process of a nuclear power hydraulic oil pipe according to claim 7, characterized in that In Step 2: Preheat the rubber compound: Heat the mixed rubber on an open mill for 5 - 8 minutes. Extrude the inner rubber: Use a cold feed extruder, with the thickness of the inner rubber being 2.5 - 3.5 mm. Calender the middle rubber layer: Cover a 1.0 - 1.5 mm middle rubber layer on the surface of the braided layer through a four-roll calender. Steel wire braiding: Use a braiding machine, with the braiding angle being 54° - 56°, the coverage rate ≥ 95%. The steel wire needs to be coated with isocyanate adhesive before braiding. Outer layer coating and winding: Extrude and coat the outer rubber, with the thickness being 2.0 - 2.5 mm, wind a wet water cloth, and shape it to prevent vulcanization deformation.

10. The forming process of a nuclear power hydraulic oil pipe as described in claim 9, characterized in that, In the inspection and packaging: Among them, it includes performance testing: Keep the pressure for 5 minutes at 2.5 times the working pressure, fill nitrogen to the rated pressure, and detect the leakage rate; Appearance inspection: There are no air bubbles, impurities, and the braided layer is not exposed on the surface; Packaging: Line with an anti-static film inside, wrap with a woven bag outside, and mark the pressure resistance level and batch number.

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