Comparison of the application of 38CrMoAIA and 42CrMo in bimetallic screws and barrels?

1. Comparison of material properties
38CrMoAIA
Nitriding performance: 38CrMoAIA steel is a commonly used nitriding steel with good nitriding performance and mechanical properties. After nitriding treatment, the surface can obtain high hardness and good wear resistance.
Mechanical properties: The steel has high hardenability and good cutting performance, but low cold deformation plasticity, poor welding performance, and a tendency to decarburization.
Chemical composition: Carbon C: 0.35-0.42%, Silicon Si: 0.20-0.45%, Manganese Mn: 0.30-0.60%, Chromium Cr: 1.35-1.65%, Molybdenum Mo: 0.15-0.25%.
Application characteristics: Mainly used to manufacture nitriding parts with precise dimensions, high wear resistance and fatigue strength, and no large impact loads, such as cylinder liners, bottom sleeves, gears, bolts, shafts and rotors.
42CrMo
High strength and toughness: 42CrMo steel is an ultra-high strength steel with high strength and toughness, good hardenability, and no obvious temper brittleness.
Fatigue limit and impact resistance: After quenching and tempering, it has a high fatigue limit and resistance to multiple impacts, and good low-temperature impact toughness.
Chemical composition: carbon C: 0.38-0.45%, silicon Si: 0.17-0.37%, manganese Mn: 0.50-0.80%, chromium Cr: 0.90-1.20%, molybdenum Mo: 0.15-0.25%.
Application characteristics: suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness, as well as important parts with higher strength requirements and larger cross-sectional dimensions than 35CrMo, such as shafts, gears, connecting rods, gearbox gears, etc.
2. Comparison of applicable scenarios
38CrMoAIA: More suitable for scenarios with high requirements for wear resistance and fatigue strength, but small impact loads. In bimetallic screw and barrel applications, it can be used as a substrate for parts that require a high wear-resistant surface, such as screws and barrels on injection molding machines.
42CrMo: Due to its high strength and toughness, as well as good impact resistance, 42CrMo is more suitable for scenes that need to withstand large impact loads. In the manufacture of bimetallic screws and barrels, it may be more used for parts that need to withstand high stress and impact, or as a reinforcement of the entire assembly.
Performance Comparison
Wear resistance: The surface of nitrided 38CrMoAIA steel has extremely high hardness and wear resistance, so in the application of bimetallic screws and barrels, its wear resistance may be better than 42CrMo. However, 42CrMo can also obtain good wear resistance through proper heat treatment.
Impact resistance: 42CrMo steel performs well in impact resistance, especially in low temperature environments. It can still maintain good toughness. This is crucial for bimetallic screw and barrel parts that need to withstand impact loads.