Post-forging heat treatment method of alloy steel

Abstract

The invention relates to a heat treatment method of alloy steel after forging. The method comprises the steps of forming a decarburization-preventing and oxidation-resistant protective layer on a surface of an alloy steel workpiece; and then carrying out isothermal annealing on a to-be-treated alloy steel workpiece with the decarburization-preventing and oxidation-resistant protective layer. The heat treatment method of the alloy steel after forging can effectively prevent the surface of the to-be-treated alloy steel workpiece from decarburization and oxidation and shorten a heating period, thereby being beneficial to improve comprehensive mechanical performance of the to-be-treated alloy steel workpiece.

Description

technical field [0001] The invention relates to a heat treatment process, in particular to a post-forging heat treatment method of alloy steel. Background technique [0002] 34CrNi3Mo alloy steel is one of the high-strength alloy steels widely used in the machinery manufacturing industry. It has good comprehensive mechanical properties, good plasticity, toughness, wear resistance, corrosion resistance and certain heat resistance. Tempering stability and wide tempering temperature range, and good cold and hot processing performance. Therefore, 34CrNi3Mo alloy steel is mainly used for parts such as gear shafts, and is especially suitable for important forgings with large cross-sections, high loads and impact loads. [0003] The traditional manufacturing method of the gear shaft includes a forging process, a post-forging heat treatment process, a machining process, and a quenching and tempering process. However, in the actual production process, the traditional post-calcinati...

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Problems solved by technology

However, in the actual production process, the traditional post-calcination heat treatment process usually puts the workpiece directly into the annealing furnace for ordinary annealing. Due to the long heat treatment cycle of the workpiece in the annealing furnace, it is easy to cause oxidation and decarburization of the workpiece surface, thus affecting The effect of the subsequent quenching and tempering process

For example, the traditional post-calcination heat treatment process may lead to high hardness of the workpiece, which will have a certain impact on the mechanical properties of the workpiece and cannot meet the technical requirements for the use of the workpiece

In addition, in the traditional quenching and tempering process, oil cooling is usually used for tempering and cooling, which is not conducive to reducing the residual stress of the workpiece, thus affecting the comprehensive mechanical properties of the workpiece

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