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CN-121993480-A - Novel stud suitable for annular wire planting of medium-pressure steam generator outlet flange

CN121993480ACN 121993480 ACN121993480 ACN 121993480ACN-121993480-A

Abstract

The application relates to the technical field of fastening connection of high-temperature pressure equipment, in particular to a novel stud suitable for ring-planting wires of an outlet flange of a medium-pressure steam generator, which mainly comprises a stud body made of a high-temperature alloy material; the axial center hole penetrates through the stud body, the countersunk inner polygonal driving part is arranged at one end of the stud body and is used for being matched with a corresponding driving tool, and the threaded surface of the stud body is coated with a high-temperature anti-seizing lubricant layer. The application can keep high strength, low creep rate and excellent oxidation resistance of the stud at 480 ℃ or even higher by adopting high temperature alloys such as NiCr20TiAl and the like and combining a specific heat treatment process, can reduce the probability of adhesion from the root, allows an induction heating rod or a liquid nitrogen cooling conduit to be inserted through an axial center hole design, provides initial pretightening force or rapidly releases thread engagement by utilizing the heat expansion and cold contraction principle, realizes nondestructive disassembly of the stud, and further greatly reduces the disassembly time of a single stud.

Inventors

  • Jia Hangkong

Assignees

  • 国能新疆化工有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1. Novel double-screw bolt suitable for medium pressure steam generator outlet flange ring planting silk, the double-screw bolt is double-end double-screw bolt, its characterized in that includes: the stud body is made of a high-temperature alloy material; an axial center hole penetrating the stud body; the countersunk inner polygonal driving part is arranged at one end of the stud body and is used for being matched with a corresponding driving tool; the threaded surface of the stud body is coated with a high-temperature anti-seizing lubricant layer.
  2. 2. The novel stud suitable for annular wire planting of an outlet flange of a medium pressure steam generator according to claim 1, wherein the superalloy material is a NiCr20TiAl superalloy bar stock, and the chemical components thereof comprise, in mass percent: carbon (C) 0.04-0.10%; 18.00-21.00% of chromium (Cr); titanium (Ti) 1.80-2.70%; 1.00-1.80% of aluminum (Al); Silicon (Si) less than or equal to 1.00%, manganese (Mn) less than or equal to 1.00%, phosphorus (P) less than or equal to 0.020%, sulfur (S) less than or equal to 0.015%, nickel (Ni) less than or equal to 65.00%, copper (Cu) less than or equal to 2.00%, cobalt (Co) less than or equal to 2.00%, boron (B) less than or equal to 0.006%, and the balance of iron (Fe) and unavoidable impurities.
  3. 3. The novel stud suitable for use in medium pressure steam generator outlet flange ring planting according to claim 2, wherein the stud body is solution treated and precipitation hardened heat treated, wherein: The solution treatment is that heating the NiCr20TiAl bar stock to 1050-1080 ℃ and then carrying out air cooling; The precipitation hardening treatment is that when the NiCr20TiAl bar stock is cooled to 840-860 ℃ in the air, the air cooling is carried out after the heat preservation is carried out for 24 hours at the temperature of 840-860 ℃, and the air cooling is carried out after the heat preservation is carried out for 16 hours at the temperature of 690-710 ℃.
  4. 4. The novel stud for annular wire of an outlet flange of a medium pressure steam generator of claim 1, wherein the countersunk internal polygonal driver is any one of an internal triangle-internal octagon counterbore.
  5. 5. The novel stud suitable for annular wire planting of an outlet flange of a medium pressure steam generator according to claim 4, wherein the countersunk inner polygonal driving part is of a countersink inner hexagonal structure, the depth of the countersink inner hexagonal structure is 35-50% of the length of the stud body, and the depth of the countersink inner hexagonal structure is not less than 120mm.
  6. 6. The novel stud suitable for annular wire planting of an outlet flange of a medium pressure steam generator according to claim 1, wherein the surface roughness Ra of the wall of the axial center hole is less than or equal to 3.2 μm, and a smooth transition is formed at the intersection of the bottom of the sunk inner polygonal driving part and the axial center hole.
  7. 7. The novel stud for use in medium pressure steam generator outlet flange ring planting according to claim 6, wherein the axial center hole is a standard through hole, and the aperture of the axial center hole is 15-40% of the nominal diameter of the stud body.
  8. 8. The novel stud for annular wire planting at the outlet flange of a medium pressure steam generator according to claim 6, wherein the axial center through hole is a conical through hole with a large upper part and a small lower part, and one end of the axial center through hole far away from the countersunk inner polygonal driving part is a small diameter end; The diameter of the large diameter end of the axial center through hole is smaller than or equal to 40% of the nominal diameter of the stud body, and the diameter of the small diameter end is larger than or equal to 15% of the nominal diameter of the stud body.
  9. 9. The novel stud suitable for annular planting of an outlet flange of a medium pressure steam generator according to claim 8, wherein when the axial center through hole is a conical through hole with a large upper part and a small lower part, a filling piece matched with the axial center through hole is inserted into the axial center through hole, and the filling piece is in interference fit with the axial center through hole; The end of the filling piece, which is close to the sunk inner polygonal driving part, is also provided with a hook-shaped/annular piece.
  10. 10. The novel stud for use in medium pressure steam generator outlet flange ring planting according to claim 1 wherein the high temperature anti-seize lubricant is a silver based anti-seize agent.

Description

Novel stud suitable for annular wire planting of medium-pressure steam generator outlet flange Technical Field The application relates to the technical field of fastening connection of high-temperature pressure equipment, in particular to a novel stud suitable for ring-planting wires of an outlet flange of a medium-pressure steam generator. Background In the fields of coal chemical industry, petrochemical industry and the like, a key device in devices for preparing olefins (MTO) from methanol, and the like, namely a medium-pressure steam generator, an outlet flange of the medium-pressure steam generator is usually connected by adopting a wire-planting type double-end stud. The temperature of the tube side medium of the equipment is up to 480 ℃, and the equipment needs to continuously run for a long period. In the prior art, a standard solid stud made of common alloy steel is generally used for the connecting part, so that the obvious defect that the stud material is easy to creep under the continuous high-temperature and high-pressure working condition, and serious adhesion (commonly called "seizure") is generated between screw thread pairs due to oxidation, fretting wear and the like is generally caused. The vast majority of studs cannot be disassembled by conventional torque tools, such as hydraulic wrenches, each time scheduled for service, and are forced to employ destructive means such as drilling, flame cutting, and the like. The process is extremely long in time consumption, and the female threads on the flange body can be damaged, but the repeated tapping can lead to failure of the connecting pair, so that the intrinsic safety and long-period operation of equipment are seriously threatened, and huge maintenance cost and production delay are caused. Disclosure of Invention The application provides a novel stud suitable for annular wire planting of a flange at an outlet of a medium-pressure steam generator, which is used for solving the problems that in the prior art, under a continuous high-temperature working condition, the conventional stud for annular wire planting is easy to detach due to creep and oxidation, high in replacement cost, easy to cause secondary damage to an equipment body and the like. The application provides a novel stud suitable for ring-planting wires of an outlet flange of a medium-pressure steam generator, which is a double-end stud and comprises the following components: the stud body is made of a high-temperature alloy material; an axial center hole penetrating the stud body; the countersunk inner polygonal driving part is arranged at one end of the stud body and is used for being matched with a corresponding driving tool; the threaded surface of the stud body is coated with a high-temperature anti-seizing lubricant layer. Preferably, the high-temperature alloy material is a NiCr20TiAl high-temperature alloy bar stock, and the chemical components of the high-temperature alloy bar stock comprise the following components in percentage by mass: carbon (C) 0.04-0.10%; 18.00-21.00% of chromium (Cr); titanium (Ti) 1.80-2.70%; 1.00-1.80% of aluminum (Al); Silicon (Si) less than or equal to 1.00%, manganese (Mn) less than or equal to 1.00%, phosphorus (P) less than or equal to 0.020%, sulfur (S) less than or equal to 0.015%, nickel (Ni) less than or equal to 65.00%, copper (Cu) less than or equal to 2.00%, cobalt (Co) less than or equal to 2.00%, boron (B) less than or equal to 0.006%, and the balance of iron (Fe) and unavoidable impurities. Preferably, the stud body is solution treated and precipitation hardened heat treated, wherein: The solution treatment is that heating the NiCr20TiAl bar stock to 1050-1080 ℃ and then carrying out air cooling; The precipitation hardening treatment is that when the NiCr20TiAl bar stock is cooled to 840-860 ℃ in the air, the air cooling is carried out after the heat preservation is carried out for 24 hours at the temperature of 840-860 ℃, and the air cooling is carried out after the heat preservation is carried out for 16 hours at the temperature of 690-710 ℃. Preferably, the countersunk type inner polygonal driving part is any one of an inner triangle-inner octagonal counter bore. Preferably, the countersunk type inner polygonal driving part is of a countersunk type inner hexagonal structure, the depth of the countersunk type inner hexagonal structure is 35-50% of the length of the stud body, and the depth of the countersunk type inner hexagonal structure is not lower than 120mm. Preferably, the surface roughness Ra of the hole wall of the axial center hole is less than or equal to 3.2 mu m, and a smooth transition is formed at the junction of the bottom of the sunk inner polygonal driving part and the axial center hole. Preferably, the axial center hole is a standard through hole, and the aperture of the axial center hole is 15-40% of the nominal diameter of the stud body. Preferably, the axial center through hole is a conical through hole with