Heiko is a melt pump manufacturer based in Henan Province, specializing in customized extrusion melt pumps for the domestic plastic extrusion industry. With years of experience in R&D and manufacturing, Heiko has grown into a leading supplier of melt gear pumps in the sector. The new-generation Haike melt pumps feature advantages such as low pulsation, high precision, and long service life. As gears are wearable components of melt pumps, Haike, as a professional melt pump manufacturer, analyzes and elaborates on common heat treatment processes for gears. Different processes are applied for conveying various types of materials.

Melt pumps for plastics mainly convey melts that are corrosive, highly acidic, etc. Therefore, the pump bodies and gears of melt pumps must be made of alloy steel or stainless steel, such as Cr12MoV, W18Cr4V, W9Cr4V2, and other grades. Surface hardening treatment, e.g., nitriding. It offers excellent torque transmission performance and is less likely to fracture under high loads. However, the large hardness difference between the metal surface and the core may cause the hard surface layer to be crushed and damaged by the softer core. Through-hardening treatment. Gears obtain good wear resistance and will not fail rapidly once the surface layer is damaged. The disadvantage is that harder gears are more brittle and sensitive to torque and vibration. When through-hardening is followed by surface hardening, the hardness difference between the surface and core is reduced, resulting in strong resistance to surface damage and excellent torque transmission performance.

Among gear heat treatment methods for melt pumps, domestic manufacturers commonly adopt full through-hardening with a hardness of HRC 54–58, combined with surface titanium–nitriding to achieve a hardness of HV 2500. This ensures core hardness, as well as corrosion resistance and wear resistance on the working surfaces, providing better pitting resistance than gears treated with only nitriding.