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CN-121972916-A - Worm wheel slewing bearing for maritime lifting equipment and manufacturing method thereof

CN121972916ACN 121972916 ACN121972916 ACN 121972916ACN-121972916-A

Abstract

The invention discloses a worm wheel slewing bearing for maritime lifting equipment and a manufacturing method thereof, wherein the manufacturing method comprises the following steps of preprocessing raw materials, and carrying out quenching and tempering on a base material; the mechanical rough machining comprises the steps of turning and milling the base material to machine an inner ring and an outer ring structure, carrying out gas nitrocarburizing treatment and post-oxidation treatment on the outer ring, wherein the gas nitrocarburizing treatment comprises the steps of carrying out first heat treatment on the outer ring under inert mixed gas to generate a diffusion layer and a white bright layer on the surface of the outer ring, the post-oxidation treatment comprises the steps of introducing mixed gas consisting of water vapor and nitrogen, generating an Fe 3 O 4 oxide layer on the surface of the white bright layer after second heat treatment, and carrying out quenching treatment on the inner ring and the outer ring structure. The problems that the depth of a hardening layer of an existing slewing bearing for maritime hoisting equipment is difficult to ensure to reach the standard stably, the quenching deformation is controlled, the transmission precision of a product is improved, the severe use requirement of a maritime environment cannot be met, and the like are solved.

Inventors

  • CAO GUOLAN
  • HU CHUANG
  • Rui Ziyang
  • HU FEIYU
  • LIU SHUHUI
  • GAO QI
  • PAN SHUXIAN
  • LI XINLEI
  • WU FANG

Assignees

  • 马鞍山方圆精密机械有限公司

Dates

Publication Date
20260505
Application Date
20260326

Claims (10)

  1. 1. A manufacturing method of a worm wheel slewing bearing for marine lifting equipment, characterized by comprising the following steps: 1) Pretreatment of raw materials, namely quenching and tempering the matrix material; 2) Turning and milling the base material to obtain an inner ring and an outer ring structure; 3) Performing gas nitrocarburizing treatment and post-oxidation treatment on the outer ring; The gas nitrocarburizing treatment comprises performing a first heat treatment on the outer ring under inert mixed gas to generate a diffusion layer and a white-bright layer on the surface of the outer ring; The post-oxidation treatment comprises the steps of introducing mixed gas consisting of water vapor and nitrogen, and generating an Fe 3 O 4 oxide layer on the surface of the white bright layer after the second heat treatment; 4) And quenching the inner ring and outer ring structures.
  2. 2. The method according to claim 1, wherein in the step (1), the specific step of the heat-treatment comprises heating the base material to 840 to 860 ℃, maintaining the temperature for 1.2 to 2 hours, cooling with water, and tempering; The tempering condition includes heat preservation at 610-630 deg.c for 1.2-2 hr.
  3. 3. The method according to claim 1, wherein in the step (1), the hardness of the base material is controlled to 230 to 280HB after tempering and cooling.
  4. 4. The method according to claim 1, wherein in the step (3), the inert mixed gas is composed of NH 3 、N 2 and CO 2 .
  5. 5. The method according to claim 1, wherein in the step (3), the condition of the first heat treatment comprises heat-retaining at 560 to 580 ℃ for 4 to 6 hours.
  6. 6. The method according to claim 1, wherein in the step (3), the condition of the second heat treatment comprises heat-retaining at 460 to 510 ℃ for 2 to 3 hours.
  7. 7. The method according to claim 1, wherein in the step (4), the medium frequency induction hardening is performed at a medium frequency current frequency of 4000 to 7000HZ and a hardening temperature of 860 to 880 ℃.
  8. 8. The method according to claim 1, wherein in the step (4), after the quenching treatment, the raceway hardness of the inner ring and the outer ring is 56-63HRC, and the depth of the hardened layer is not less than 3.0mm.
  9. 9. The method according to claim 1, wherein the substrate is S48C.
  10. 10. A worm wheel slewing bearing for marine lifting equipment, characterized in that the worm wheel slewing bearing for marine lifting equipment is manufactured by the manufacturing method as set forth in any one of claims 1 to 9.

Description

Worm wheel slewing bearing for maritime lifting equipment and manufacturing method thereof Technical Field The invention relates to the field of slewing bearings, in particular to a worm wheel slewing bearing for marine lifting equipment and a manufacturing method thereof. Background The slewing bearing is used as a key core component of marine lifting equipment, bears the realization function of the slewing motion of the equipment, and simultaneously needs to bear axial force, radial force and overturning moment under complex working conditions for a long time. The performance of the marine crane directly determines the running stability, the safety and the service life of marine crane, and strict requirements are put on aspects of material selection, heat treatment process, precision control and the like. At present, 50Mn material is mostly adopted as a core matrix material for the slewing bearing for the domestic marine lifting equipment, and the material has uneven internal structure stress distribution after quenching due to the characteristic of material components, so that the depth of a hardening layer cannot be detected by a conventional nondestructive detection means, and potential safety hazards are easily caused. Meanwhile, the traditional slewing bearing outer ring mostly adopts a single heat treatment process, so that the surface hardness, the machining precision, the transmission precision and the high corrosion resistance are difficult to be considered. In terms of technology, the quenching deformation is difficult to control in the conventional gear intermediate frequency induction quenching technology of the slewing bearing, and the transmission precision is affected. In addition, the material selection and the heat treatment process in the traditional preparation method lack of cooperative design, so that the bearing capacity of the product is insufficient, the service life is short, and the long-term service requirement of high-end marine lifting equipment is difficult to meet. Disclosure of Invention The invention aims to provide a worm wheel slewing bearing for maritime lifting equipment and a manufacturing method thereof, which solve the problems that the existing slewing bearing for the maritime lifting equipment is difficult to ensure that the depth of a hardening layer is stable and reaches the standard, the quenching deformation is controlled, the transmission precision of a product is improved, and the severe use requirement of the maritime environment cannot be met. In order to achieve the above object, the present invention provides a method for manufacturing a worm wheel slewing bearing for a marine lifting device, the method comprising: 1) Pretreatment of raw materials, namely quenching and tempering the matrix material; 2) Turning and milling the base material to obtain an inner ring and an outer ring structure; 3) Performing gas nitrocarburizing treatment and post-oxidation treatment on the outer ring; The gas nitrocarburizing treatment comprises performing a first heat treatment on the outer ring under inert mixed gas to generate a diffusion layer and a white-bright layer on the surface of the outer ring; The post-oxidation treatment comprises the steps of introducing mixed gas consisting of water vapor and nitrogen, and generating an Fe 3O4 oxide layer on the surface of the white bright layer after the second heat treatment; 4) And quenching the inner ring and outer ring structures. Preferably, in the step (1), the specific steps of the thermal refining comprise heating the base material to 840-860 ℃, preserving heat for 1.2-2h, and tempering after water cooling; The tempering condition includes heat preservation at 610-630 deg.c for 1.2-2 hr. Preferably, in the step (1), after tempering and cooling, the hardness of the base material is controlled to 230 to 280HB. Preferably, in step (3), the inert mixed gas consists of NH 3、N2 and CO 2. Preferably, in step (3), the conditions of the first heat treatment include incubation at 560-580 ℃ for 4-6 hours. Preferably, in step (3), the conditions of the second heat treatment include incubation at 460-510 ℃ for 2-3 hours. Preferably, in the step (4), the intermediate frequency induction quenching mode is adopted, the intermediate frequency current frequency is 4000-7000HZ, and the quenching temperature is 860-880 ℃. Preferably, in the step (4), after quenching treatment, the raceway hardness of the inner ring and the outer ring structure is 56-63HRC, and the depth of a quenching layer is more than or equal to 3.0mm. Preferably, the substrate material is S48C material. The invention also provides a worm wheel slewing bearing for the marine lifting equipment, which is manufactured by the manufacturing method. Compared with the prior art, the worm wheel slewing bearing for maritime lifting equipment and the manufacturing method thereof have the advantages that 1, the material selection is scientific and reasonable, the internal stru