Hydrogenation valve butt end machining process

Abstract

The present application belongs to the hydrogen / hydrogen valve processing technology field, and specifically relates to a hydrogen / hydrogen valve butt joint end processing technology, comprising the following steps: step a, selecting a valve body material, and forming a valve body blank by integral die forging processing; step b, finishing the surface of the valve body blank to form a valve body; step c, processing the butt joint end of the valve body according to the prefabricated size; and step d, extruding the butt joint end of the valve body by an extrusion die. The integral die forging valve butt joint end extrusion variable diameter forming process adopted by the present application is a brand new valve manufacturing technology, and the integral valve extrusion variable diameter forming manufacturing process is adopted to overcome the traditional hydrogen / hydrogen valve butt joint welding joint process, to solve the problems of valve sealing leakage, hydrogen corrosion cracking of the welding seam and the like, and to improve the valve quality and avoid the hazards caused by hydrogen leakage.

Description

Technical Field

[0001] This invention belongs to the field of hydrogenation / hydrogenation valve processing technology, specifically relating to a processing technology for the mating end of a hydrogenation / hydrogenation valve. Background Technology

[0002] Hydrogenation / hydrotreating valves are crucial components of hydrogenation / hydrotreating units in petrochemical refineries. Their function is to connect or disconnect the flow of media in pipelines, change the direction of flow, and protect the safe operation of pipeline equipment. Hydrogenation / hydrotreating units operate under high temperature, high pressure, and hydrogen sulfide conditions. The presence of hydrogen and hydrogen sulfide media significantly impacts valve weld corrosion, cracking, and hydrogen embrittlement. Hydrogen is a flammable and explosive gas; any valve leakage will cause significant harm to the environment and the equipment.

[0003] Currently, hydrogenation / hydrogenation valves use a welded joint where the valve body and the weld seam are integrated (due to valve structure limitations, the inner diameter of the weld seam is smaller than the valve seat embedded in the valve body flow channel). This weld seam is prone to hydrogen corrosion cracking, leading to valve body leakage. Therefore, the existing technology suffers from the problem that the weld seam of hydrogenation / hydrogenation valves is formed by welding the valve body and the machined weld seam together. Due to the influence of welding quality and the heat generated during welding, hydrogen corrosion cracking occurs in the weld seam under conditions of hydrogen and hydrogen sulfide, causing hydrogen leakage and affecting the safety of the entire refinery. Therefore, domestic refineries desire higher-quality hydrogenation / hydrogenation valves and require improved technical levels, placing higher demands on the manufacturing of hydrogenation / hydrogenation valves. Summary of the Invention

[0004] In view of the defects of the existing technology, the purpose of this invention is to provide a processing technology for the mating end of a hydrogenation / hydrogenation valve. By forming the mating end of the valve body by extrusion and diameter reduction through integral die forging, the problem that the valve mating end cannot be manufactured with diameter reduction requirements for different sizes by machining and other methods is solved. It also avoids defects such as slag inclusions and porosity in the welding process of the mating end weld joint, as well as the impact of the heat generated during welding on the valve sealing performance, thereby improving the safety and reliability of the hydrogenation / hydrogenation valve during use.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: a processing technology for the docking end of a hydrogenation / hydrogenation valve, comprising the following steps:

[0006] Step a: Select valve body material and form valve body blank by integral die forging;

[0007] Step b: Trim the surface of the valve body blank to form the valve body;

[0008] Step c: Machin the mating end of the valve body according to the pre-made dimensions;

[0009] Step d: The mating end of the valve body is extruded and formed using an extrusion die.

[0010] Furthermore, in step a, the valve body blank formed by integral die forging is subjected to heat treatment and inspection.

[0011] Furthermore, the valve body material is carbon steel, stainless steel, or alloy steel.

[0012] Furthermore, in step c, after the valve body's mating end is machined, the valve seat of the hydrogen supply / hydrogenation valve is embedded in the valve body flow channel, and the gate and valve seat are assembled and the valve sealing test is performed.

[0013] Furthermore, in step d, the valve mating end is formed by diameter reduction after extrusion.

[0014] Furthermore, in step d, both the extrusion mold and the valve are mounted on a press, and the valve mating end is extruded and formed by the press to achieve the predetermined mating end diameter variation size.

[0015] Furthermore, after step d, step e is included, which involves stress-relieving the extruded valve.

[0016] Furthermore, after step e, step f is also included, which involves inspecting the valve mating dimensions and conducting a sealing test.

[0017] An extrusion die, employing the aforementioned extrusion die for extruding valve mating ends and forming them with a variable diameter.

[0018] Furthermore, the extrusion die is provided with a cavity that matches the valve docking end. The diameter of the cavity gradually increases from the bottom to the opening. An annular stress groove is formed on the outer edge of the bottom of the cavity, and the annular stress groove is continuous with the cavity.

[0019] The beneficial effects of this invention are as follows: The integral die-forged valve body end extrusion and diameter-changing forming process adopted in this invention is a brand-new valve manufacturing technology. By adopting the integral valve extrusion and diameter-changing forming manufacturing process, it overcomes the problems of valve sealing leakage and hydrogen corrosion cracking of weld seams caused by the traditional welding joint process of hydrogen-containing / hydrogenated valves, thereby improving valve quality and avoiding the hazards caused by hydrogen leakage. Attached Figure Description

[0020] Figure 1 Schematic diagram of the prefabricated structure for the valve body connection end;

[0021] Figure 2 A schematic diagram of the variable diameter extrusion molding of the valve body's mating end;

[0022] Figure 3 This is a schematic diagram of an extrusion die;

[0023] Figure 4 The heat treatment curve of the valve blank in step one;

[0024] In the diagram: 1. Valve body, 2. Prefabricated mating end, 3. Valve seat, 4. Extruded mating end, 5. Extrusion die, 6. Cavity, 7. Annular stress groove. Detailed Implementation

[0025] To make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0026] Because the flow channel holes at the valve's mating end gradually narrow from the inside out, they cannot be directly formed by machining on the valve body. The traditional process involves first machining a reducing hole on the weld joint at the mating end, and then welding the weld joint to the valve body to form a butt-welded valve. Due to the influence of welding quality and the heat generated during welding, the weld seam is prone to hydrogen corrosion cracking under conditions such as hydrogen and hydrogen sulfide, leading to hydrogen leakage within the valve body and potentially affecting the safety of the entire refinery. Therefore, this invention proposes a machining process for the mating end of a hydrogenation / hydrogenation valve. The valve body is formed through integral die forging and machining, and the mating end of the valve body is extruded using an extrusion molding die to achieve a reducing diameter.

[0027] Due to the variable diameter requirement of the flow channel hole at the valve body docking end, an extrusion molding process is used to make it an integral valve body structure. By pre-forming the extrusion dimensions at the valve body docking end, designing the extrusion molding die, setting the extrusion pressure, and performing stress relief treatment, the variable diameter forming of the docking end of the hydrogenation / hydrogenation valve is achieved.

[0028] The specific process includes the following steps:

[0029] Step 1: Prepare integral die-forged valve body blanks of different materials (carbon steel A105, stainless steel F316, alloy steel F22, etc.) according to the characteristic requirements of the valve body of the hydrogenation / hydrogenation valve. Use die forging technology to forge the raw materials into valve blanks, and perform heat treatment and testing according to the technical requirements of hydrogenation / hydrogenation valves, including blank performance, material internal and surface quality, and non-destructive testing such as ultrasonic and liquid penetration.

[0030] Taking A105 material as an example:

[0031] 1. The A105 blank for the hydrogenation / hydrogenation valve undergoes normalizing heat treatment, with the holding time being the minimum value (e.g., Figure 4 The minimum value is 30 minutes), and the heating rate above 400℃ should be controlled to be ≤220℃ / h. Figure 4 Testing instruments include thermocouples and timers.

[0032] 2. The performance of the blank is tested using equipment such as tensile, impact and Brinell hardness testers. The tensile strength is ≥485Mpa, the yield strength is ≥250Mpa, the elongation is ≥30%, the shrinkage is ≥22%, and the hardness is HB143~187.

[0033] 3. Use ultrasonic equipment to inspect the internal quality of the blank:

[0034] 1) Straight probe inspection: No cracks are allowed, and the size of a single defect should not exceed 2 mm of the equivalent diameter (for valve stems). φ 1 mm);

[0035] 2) Angle probe inspection: No cracks are allowed. The depth of the V-groove is 3% of the workpiece wall thickness, with a maximum value of 3mm; the maximum length of the V-groove is 25mm.

[0036] 3) No dense defects: Within a 50 mm acoustic path on the scanning line or within the same depth on a 50 mm × 50 mm detection surface, the equivalent diameter... φ 1.5 mm Less than 5 defect echoes are displayed.

[0037] 4. Liquid penetrant testing is used to inspect the outer surface and accessible inner surface of the blank:

[0038] 1) The blank has no cracks or white spots;

[0039] 2) The length of any linear display shall not exceed 2 mm;

[0040] 3) The size of a single circular defect shall not exceed 2 mm (1 mm for valve stem);

[0041] 4) The cumulative length of dense defects (referring to concentrated defects with a size of less than 0.5 mm) shall not exceed 4 mm in any 100 mm × 100 mm area.

[0042] Step 2: The valve body blank is surface-trimmed and processed into finished products. The valve body mating end is processed according to the pre-extruded dimensions.

[0043] The process and steps of machining valve body blanks into finished products:

[0044] 1) Clamp the blank, machine the three end faces flat with allowance, and the roughness should not exceed Ra6.3;

[0045] 2) Machin the end face and chamfer of the middle section, drill the middle cavity hole leaving allowance, and precision machine each part of the middle cavity to the dimensions;

[0046] 3) The flow holes and bezels at both ends of the valve body are to the specified dimensions;

[0047] 4) Punch square holes to the required dimensions;

[0048] 5) The valve body mating end is machined according to the pre-extruded dimensions.

[0049] Based on the above technical solution, it should be noted that the machining of the mating end according to the pre-made dimensions refers to machining the outer diameter surface, while the inner hole is not machined. The inner hole size remains unchanged during the machining process.

[0050] Step 3: The valve seat of the hydrogenation / hydrogenation valve is embedded in the valve body flow channel (see...) Figure 1 The assembly and sealing tests are carried out; the sealing test is a sealing test between the gate and the valve seat using a valve test bench.

[0051] Step 4: Design and manufacture extrusion dies according to the different dimensions and extrusion pressure requirements of the valve mating ends. (See attached image) Figure 3 .

[0052] Based on the above technical solution, the dimensions of the valve body connection end are as required by the contract pipe number, and the diameter is adjusted accordingly.

[0053] Step 5: Adjust the extrusion equipment to extrude and form the mating end of the hydrogenation / hydrogenation valve, see... Figure 2 .

[0054] Based on the above technical solution, both the extrusion mold and the valve are installed on a press. The valve mating end is extruded and formed by the press to achieve the predetermined diameter change of the mating end.

[0055] Step 6: The extruded valve undergoes stress relief treatment.

[0056] Taking A105 material as an example, after extrusion, the valve docking end of A105 material is heated to 200℃ and kept at that temperature for 20 minutes to perform stress relief treatment.

[0057] Step 7: Inspect the valve mating end dimensions and conduct a sealing test to ensure the performance meets the requirements of hydrogenation / hydrogenation valves, and achieve variable diameter forming of the valve mating end.

[0058] Based on the above technical solution, calipers, angle gauges, etc. are used to detect the dimensions of the valve mating end, and a sealing test between the gate and the valve seat is conducted through a valve test bench.

[0059] Furthermore, the extrusion die is provided with a cavity that matches the valve docking end. The diameter of the cavity gradually increases from the bottom to the opening. An annular stress groove is formed on the outer edge of the bottom of the cavity, and the annular stress groove is continuous with the cavity.

[0060] Furthermore, according to different materials such as carbon steel, stainless steel, and alloy steel, as well as different mating end sizes, pre-made extrusion dimensions and extrusion pressures are used; extrusion molding dies are designed according to different mating end sizes, shapes, and extrusion forces; the valve mating ends of the entire machine are extruded to achieve variable diameter forming of the mating ends of hydrogen-containing / hydrogenated valves.

[0061] Furthermore, stress relief treatment is applied to the extruded parts, with the hardness of alloy steel materials HB≤225 and the hardness of carbon steel materials HB≤200.

[0062] After the reducing diameter molding of the docking end of the hydrogenation / hydrogenation valve of the present invention, the valve sealing performance meets the requirements of hydrogenation / hydrogenation valve.

[0063] like Figure 1 The valve body of the integral forged hydrogenation / hydrogenation valve is machined and formed, with the pre-extrusion dimensions of the mating end being pre-fabricated. Different materials (A105, F316, F22, etc.) have different dimensions. The valve seat is embedded in the valve body flow channel. The entire machine is assembled and tested. Extrusion dies are designed and manufactured according to the different dimensional requirements of the mating end (see...). Figure 3 The valve and extrusion die are fixed on the press, and extrusion pressure is applied multiple times according to different sizes and materials to finally achieve the predetermined diameter change size of the mating end (see...). Figure 2 Stress relief treatment is applied to the extruded valves (stress relief temperature and holding time vary for different sizes and materials); the valves are cleaned and inspected (valve sealing performance, non-destructive testing of the mating end surface, etc.) to achieve variable diameter forming of the valve mating end.

[0064] This invention solves the problem of the valve body's flow channel size being smaller than the valve body's flow channel size when the valve seat is embedded in the valve body and then extruded with a variable diameter at the valve body's mating end. This avoids defects such as porosity and slag inclusions that occur during welding joints, as well as corrosion and cracking of the weld seam caused by hydrogen in hydrogenation / hydrogenation units, thus improving the safety of hydrogenation / hydrogenation units.

[0065] The above examples are merely preferred embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A process for machining a hydrogen / hydrogenation valve docking end, characterized in that, It comprises the following steps: Step a, taking valve body material, processing the material through integral die forging to form valve body blank; For step a, the valve body blank formed by integral die forging is heat treated and detected; Step b, the surface of the valve body blank is trimmed to form a valve body; Step c, the butt joint end of the valve body is processed according to the pre-prepared size; For step c, after the butt joint end of the valve body is processed, the valve seat of the hydrogen-containing / hydrogenation valve is inlaid on the valve body flow channel, the gate plate and the valve seat are assembled, and the valve sealing test is carried out; Step d, the butt joint end of the valve body is extruded by an extrusion die; the extrusion die is provided with a cavity matched with the butt joint end of the valve, the aperture of the cavity gradually increases from the hole bottom to the hole opening, the outer edge of the hole bottom of the cavity is formed with an annular stress groove, and the annular stress groove is continuous with the cavity; For step d, the extruded valve butt joint end is formed with variable diameter; For step d, the extrusion die and the valve body are installed on the press, and the valve butt joint end is extruded by the press to reach the predetermined variable diameter size of the butt joint end; It further comprises step e, stress relief treatment of the extruded valve; It further comprises step f, inspection of the valve butt joint end size and sealing test.

2. A process for machining a hydrogen / hydrogen compatible valve mating end as defined in claim 1, wherein: For step a, the valve body material is carbon steel, stainless steel or alloy steel.

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