Gear drive shaft vacuum heat treatment

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The gear drive shaft is an important transmission part in the rolling mill, which mainly bears the alternating load, the impact load, the shear stress and the contact stress. The shaft is prone to cracks and the teeth are prone to wear. Therefore, the core of the gear shaft is required to have a certain strength and toughness, a higher fatigue limit and the ability to resist multiple impacts. The surface should also have a certain hardness and wear resistance. In order to meet these performance requirements, the material must have good mechanical properties, and 42CrMo steel is often used after normalizing, quenching and tempering, induction heating quenching and low temperature tempering to achieve the required performance.

42CrMo is a medium carbon alloy steel. The preparatory heat treatment is normalizing. The main purpose is to obtain a certain hardness, facilitate the cutting of the billet, and prepare the structure for quenching and tempering. The purpose of quenching and tempering is to improve the comprehensive mechanical properties of the gear drive shaft of the rolling mill. Medium frequency induction heating surface vacuum quenching is to obtain high hardness and wear resistance on the surface of the part, while the core still maintains a certain strength and high plasticity and toughness.

Through the analysis of the vacuum heat treatment process of 42CrMo steel, it is through the correct vacuum heat treatment process to achieve the required performance and ensure the quality.

When the gear drive shaft rotates, it mainly bears shear stress, alternating bending stress, transmits dynamic load, etc., and is subjected to multiple impact stresses. During the working process, due to different stress, different failure forms are caused, mainly including fatigue wear, crack, surface pitting, bending fatigue fracture, impact fracture, etc.

performance requirements

(1) High fatigue limit (2) High flexural strength (3) High toughness (4) High wear resistance (5) Multiple impact resistance (6) High temperature resistance High strength (7) with certain precision

The selection of gear shaft materials is determined according to the working conditions, requirements and performance of the gear shaft.

According to the requirements, the performance of 42CrMo steel is very good. After normalizing, quenching and tempering, induction heating vacuum quenching and low temperature tempering, the surface hardness can reach a high hardness of HRC50, the surface wear resistance is good, and the core hardness can reach HRC35~ 45. 42CrMo steel has high strength and toughness, good hardenability, high fatigue limit and ability to resist multiple impacts after quenching and tempering. Small deformation during vacuum quenching, high creep strength and durable strength at high temperature, and no obvious temper brittleness.

Alloying elements Cr and Mo contained in 42CrMo steel. Among them, chromium can increase the hardenability of steel and has a secondary hardening effect. It can improve the hardness and wear resistance of carbon steel, and when the content exceeds 12%. The steel has good high temperature oxidation resistance and corrosion resistance of oxidative media. The main function of chromium in quenched and tempered structural steel is to improve the hardenability. The steel has better comprehensive mechanical properties after vacuum quenching and tempering, and chromium-containing carbides can also be formed in carburized steel, thereby improving the wear resistance of the material surface. Molybdenum can improve hardenability and thermal strength in steel. In quenched and tempered steel, molybdenum can harden and harden parts with larger sections, improve the tempering resistance or tempering stability of the steel, and enable the parts to be tempered at a higher temperature, thereby more effectively eliminating ( or reduce) residual stress and increase plasticity. Therefore, 42CrMo is often used as the material for the gear shaft of the rolling mill in production. Its comprehensive mechanical properties are excellent and meet the quality requirements.

Equipment selection: The RVT series vacuum tempering furnace produced by SIMUWU is a high-quality product for the vacuum tempering process of the tool and mold. The good temperature control accuracy and temperature control uniformity ensure the effective progress of the vacuum tempering process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.