Analysis of the Causes and Control of High Hardenability of Gear Steel 18CrNiMo7-6HL

The phenomenon of heat treatment deformation is inextricably linked to the hardenability of steel. The 18CrNiMo7-6HL steel exhibits a markedly high degree of hardenability. To more effectively regulate the deformation processes associated with the heat treatment of this steel, it is essential to investigate the factors that influence its hardenability. This paper presents a study of factory-produced heavy-duty gear steel, 18CrNiMo7-6HL. The steel is compared with SAE4320H steel, which is used for the same products in terms of its inclusions, chemical composition, grain size, martensitic transformation tendency, and heat treatment process. The high difficulty associated with the analytical research of 18CrNiMo7-6HL hardenability represents a significant challenge. This paper aims to provide a comprehensive overview of the factors influencing 18CrNiMo7-6HL steel hardenability and to present potential strategies for optimizing 18CrNiMo7-6HL hardenability.