U-TRSM introduces you to the heat treatment process of slewing bearings

The slewing bearings need to go through multiple heat treatments during the production process, different heat treatments are carried out during the connection of each process to achieve the required heat treatment purpose. Heat treatment is the core part in the production of slewing bearings. Heat treatment determines the mechanical properties of the slewing bearing. It is an important link in slewing bearing load capacity and service life in actual use.

In the processing of the slewing bearing, the heat treatment is generally carried out in the stable order of normalizing (quenching and tempering), raceway quenching, tooth surface quenching.

Quenching and tempering can optimize the material and improve the overall mechanical performance; the raceway and rolling element are in direct contact, raceway bears load through the support of the rolling element. The rolling elements roll in raceway to realize the rotation of the slewing bearing, so the raceway must have sufficient hardness; Tooth surface quenching improves the load capacity and wear resistance of the tooth, it’s very important for the transmission of the slewing ring. Stability is an important means to eliminate the internal stress of the slewing ring, which is frequently used in the process of machining.

The commonly used materials of slewing bearings are mainly 50Mn and 42CrMo. The inner and outer rings of slewing bearings are generally forgings formed by rolling rings. For heat treatment of forgings, 50Mn is generally subjected to normalizing treatment, and 42CrMo is subjected to quenching and tempering treatment.

Normalizing treatment: The slewing bearing is heated to a certain temperature, after holding it for a period of time, then taken out of the furnace and naturally cooled in the air. The main purpose of slewing bearing normalizing is to refine the structure, improve the steel performance to make the organization close to the equilibrium state, the hardness of the slewing bearing after normalizing is generally HB187-241.

Quenching and tempering treatment: Quenching and tempering is a dual heat treatment method of quenching and high temperature tempering. First of all doing complete rings quenching of the slewing bearing, then doing high temperature tempering, the purpose is to make the slewing ring have good comprehensive mechanical properties. Generally, the quenching and tempering will be placed after the rough turning, in order to release most internal stress during the rough turning process and prevent large deformation or even cracks during the tempering process. The quenched and tempered hardness of the slewing bearing is generally HB229-269.

Raceway quenching and tooth quenching: In the production process of the slewing bearing, the slewing bearing ring raceway and tooth surface are surface quenched. Surface quenching is a combination of heating and immediate cooling, through rapid heating, the surface of the processed steel parts reaches the quenching temperature, before the heat is transferred to the center of the slewing ring, it is rapidly cooled, only the surface layer is hardened to martensite, the center is still the surface hardened layer of the unquenched original normalized or tempered structure. The general tooth surface quenching hardness is HRC45-55; the raceway quenching hardness is HRC50-60. Hardness is related to the level of heat treatment, which affects the service life.

Tempering stability: The hardness is high after the raceway and teeth are quenched, also the brittleness is large. Prone to cracks or brittle fractures in subsequent processing and use, the subsequent processing and use are prone to cracks or brittle fracture. The tempering stability can reduce the internal stress and prevent the post-processing deformation, reduce the brittleness and improve the toughness.

The heat treatment of the slewing ring is very important to the slewing ring. We recommended that when ordering the slewing ring, it’s necessary to clarify what heat treatment is required for the slewing ring. If you don’t know the heat treatment, you can consult the engineer of Unique Transmission to explain the working conditions. Unique Transmission’s engineers will provide you with professional advice and provide you with a detailed technical agreement, which will definitely bring you a different experience in the selection and purchase of slewing bearings and slewing drives.

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U-TRSM introduces you to the heat treatment process of slewing bearings

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Heat treatment is the core part in the production of slewing bearings. Heat treatment determines the mechanical properties of the slewing bearing.

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U-TRSM

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U-TRSM

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