The quality of the gear material is related to the operation of the parts and the whole equipment machinery. When processing large gears, we must pay attention to the choice of materials.
Therefore, we must be cautious when selecting materials. Depending on the working conditions of the large gear (such as speed and load) and the form of failure (such as pitting, flaking or breaking), large gears are usually made of the following materials:
(1) Medium carbon structural steel tempered or surface shredded with 45 steel. After heat treatment, the comprehensive mechanical properties are good, but the cutting performance is poor, the tooth surface roughness is large, and it is suitable for manufacturing gears with low speed and small load.
(2) Medium carbon alloy nanostructured steel is tempered or surface quenched with 40cr. After heat treatment, the mechanical parts can be better than 45 steel, and the heat treatment deformation is small, and it is used for manufacturing gears with high speed, high precision and large load.
(3) Carburized steel Carburizing or carbonitriding is carried out using 20cr and 18crMnTi. After carburizing and quenching, the hardness of the tooth surface can reach HRc58-63. The core has high toughness, which is both wear-resistant and impact-resistant. It is suitable for manufacturing high-speed, medium-load or impact-bearing gears. After the carburizing treatment, the gear is deformed greatly, and it is still necessary to correct the grinding teeth, and the cost is high. The deformation by carbonitriding treatment is small, and the bearing capacity is not as good as the former due to the thinner layer.
(4) Nitrided steel The shape of the nitride is 38crMoAIA, the deformation is small, the tooth can be no longer ground, and the tooth surface wear resistance is high, which is suitable for manufacturing high-speed gears.