Search

CN-121976001-A - Induction quenching method and ring piece obtained by same

CN121976001ACN 121976001 ACN121976001 ACN 121976001ACN-121976001-A

Abstract

The invention relates to the technical field of ring heat treatment, in particular to an induction quenching method and an obtained ring. The ring is made by the method. The method comprises the steps of carrying out first induction quenching treatment on a target area of an outer circle of a ring, carrying out induction preheating treatment on an inner circle of the ring, heating the surface of the inner circle of the ring to 200-300 ℃ through the induction preheating treatment, keeping the temperature for 20-30 min, carrying out second induction quenching treatment on the inner circle of the ring, propping the outer circle by adopting a tool matched with the outer circle of the ring, and carrying out induction tempering treatment on the inner circle when the surface temperature of the inner circle is reduced to 30-50 ℃. The invention can not only avoid deformation of the ring member caused by uneven stress, but also control the increase of the surface temperature of the inner circle relative to the internal temperature of the inner circle to be smaller, and avoid unqualified surface tissues and surface cracks.

Inventors

  • Tian Kaiguo
  • Xu Wangrong
  • LU ZHIFANG
  • LIU QINGLONG
  • WANG XING

Assignees

  • 中国铁建重工集团股份有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (11)

  1. 1. An induction hardening method, comprising: S1, performing first induction quenching treatment on a target area of the outer circle of a ring piece; S2, carrying out induction preheating treatment on the inner circle of the ring, wherein the induction preheating treatment heats the surface of the inner circle of the ring to 200-300 ℃ and the heat preservation time is 20-30 min; S3, performing second induction quenching treatment on the inner circle of the ring piece; And S4, propping the outer circle by adopting a tool matched with the outer circle of the ring, and performing induction tempering treatment on the inner circle when the surface temperature of the inner circle is reduced to 30-50 ℃.
  2. 2. The induction quenching method according to claim 1, further comprising an ovality adjustment step for the ring after the induction tempering in the step S4, wherein the ovality adjustment step comprises measuring the ovality of the inner circle of the ring after the induction tempering, and if the ovality of the inner circle of the ring exceeds 1mm, adjusting the tool to prop against the outer circle so that the ovality of the inner circle of the ring is less than or equal to 1mm, and then, standing for 48-72 h, and removing the tool.
  3. 3. The induction hardening method of claim 1, wherein the target area is a machined area reserved on the outer circumference.
  4. 4. The induction quenching method according to claim 1, wherein the first induction quenching treatment is performed at an induction frequency of 6-8 khz, a rotational speed of 400-500 mm/min, a quenching liquid concentration of 15-20 mol/L, a voltage of 20-35 kv, and a coupling gap of 3-5 mm.
  5. 5. The induction hardening method according to claim 1, wherein the induction frequency used in the induction preheating treatment is 2-4 khz, the rotational speed used is 300-500 mm/min, the voltage used is 30-50 kv, and the coupling gap used is 2-5 mm.
  6. 6. The induction quenching method according to claim 1, wherein the second induction quenching treatment is performed at an induction frequency of 4-7 khz, a rotational speed of 120-200 mm/min, a quenching liquid concentration of 15-20 mol/L, a voltage of 60-90 kv, and a coupling gap of 2-5 mm.
  7. 7. The induction hardening method according to claim 1, wherein the induction tempering treatment is performed at an induction frequency of 2to 4khz, a rotational speed of 200 to 300mm/min, a voltage of 40 to 60kv, and a coupling gap of 2to 5mm, and the ring is air-cooled after the induction tempering treatment.
  8. 8. The induction hardening method of claim 4 or 6, wherein the quenching fluid comprises a PAG quenching fluid.
  9. 9. The induction hardening method according to any one of claims 1 to 7, further comprising a step S5 of turning the target area of the outer circle to obtain a finished ring.
  10. 10. A ring prepared by the induction hardening method of claim 9.
  11. 11. The ring of claim 10, wherein the ring has an inner circular ovality of less than or equal to 1mm, an inner circular quenched surface hardness of 56-62 hrc, an inner circular quenched layer depth of the ring of more than or equal to 9mm, and a critical hardness between the ring body and the maximum depth of the inner circular quenched layer of the ring of 48-50 hrc.

Description

Induction quenching method and ring piece obtained by same Technical Field The invention relates to the technical field of ring heat treatment, in particular to an induction quenching method and an obtained ring. Background The main bearing is a heart of the shield machine, a high-hardening and high-hardness martensitic structure is generally obtained on the surface by surface quenching, and excellent contact fatigue performance is obtained by matching with a tempering process. However, the main bearing ring piece is easy to generate deformation such as ellipse and warp in the induction quenching process, and basically, because the ring piece is heated and cooled unevenly or unsynchronized, expansion and contraction at different positions and tissue transformation are unsynchronized, so that the ring piece is macroscopically deformed due to uneven stress distribution, the deformation can reach 2-8 mm sometimes, and the ring piece which is severely deformed can even be further increased due to new stress introduced into the working procedures such as turning, drilling and the like in the subsequent machining process, and can be scrapped seriously. In addition, the induction quenching temperature rise speed is fast and can reach 200-500 ℃ per second in the induction quenching process, and the induction quenching temperature rise speed has a skin effect, namely that the whole area from the surface to the target depth (such as within 10 mm) is difficult to be heated to the quenching temperature in a short time. For this reason, it is necessary to greatly increase the operating voltage so that the region from the surface to the target depth (e.g., within 10 mm) is entirely reached to the quenching temperature (e.g., 830 to 880 ℃), at which time the surface quenching temperature can reach 1100 ℃, and the quenching temperature at the depth of 10mm has a large temperature gradient. At high temperature, the temperature gradient causes coarse austenite grains on the surface, which leads to unqualified structure after cooling, and also leads to easy formation of surface quenching cracks, which leads to rejection of ring pieces. Therefore, it is necessary to provide an induction quenching method and the obtained ring member to solve the problems that the ring member is scrapped due to serious deformation of the ring member, and the surface structure is unqualified and surface quenching cracks are generated after cooling due to excessive temperature gradient generated from the surface of the ring member to the target depth in the conventional induction quenching method. Disclosure of Invention The invention aims to provide an induction quenching method and an obtained ring piece, and the specific technical scheme is as follows: in a first aspect, the present invention provides an induction hardening method comprising: S1, performing first induction quenching treatment on a target area of the outer circle of a ring piece; S2, carrying out induction preheating treatment on the inner circle of the ring, wherein the induction preheating treatment heats the surface of the inner circle of the ring to 200-300 ℃ and the heat preservation time is 20-30 min; S3, performing second induction quenching treatment on the inner circle of the ring piece; And S4, propping the outer circle by adopting a tool matched with the outer circle of the ring, and performing induction tempering treatment on the inner circle when the surface temperature of the inner circle is reduced to 30-50 ℃. Optionally, the method further comprises an ovality adjustment step for the ring piece after the induction tempering treatment in the step S4, wherein the ovality adjustment step comprises the steps of measuring the ovality of the inner circle of the ring piece after the induction tempering treatment, adjusting the tool to prop against the outer circle if the ovality of the inner circle of the ring piece exceeds 1mm, enabling the ovality of the inner circle of the ring piece to be less than or equal to 1mm, and then, standing for 48-72 h and removing the tool. Optionally, the target area is a turning area reserved on the outer circle. Optionally, the first induction quenching treatment adopts an induction frequency of 6-8 KHz, a rotation speed of 400-500 mm/min, a concentration of quenching liquid of 15-20 mol/L, a voltage of 20-35 KV and a coupling gap of 3-5 mm. Optionally, the induction frequency adopted in the induction preheating treatment is 2-4 KHz, the adopted rotating speed is 300-500 mm/min, the adopted voltage is 30-50 KV, and the adopted coupling gap is 2-5 mm. Optionally, the second induction quenching treatment adopts an induction frequency of 4-7 KHz, a rotation speed of 120-200 mm/min, a quenching liquid concentration of 15-20 mol/L, a voltage of 60-90 KV and a coupling gap of 2-5 mm. Optionally, the induction tempering treatment adopts an induction frequency of 2-4 KHz, a rotation speed of 200-300 mm/min, a voltage of 40-60 KV and a coupling