Most quenched and tempered parts work under relatively large dynamic loads, and they bear the effects of tension, compression, bending, torsion or shear. Some surfaces also have friction, requiring certain wear resistance, and so on. In short, the parts work under various composite stresses. These types of parts are mainly structural components of various machines and mechanisms, such as shafts, connecting rods, studs, gears, etc., and are widely used in manufacturing industries such as machine tools, automobiles, and tractors. Especially for large components in heavy machine manufacturing, quenching and tempering treatment is more commonly used. Therefore, quenching and tempering treatment plays a very important role in heat treatment.
In mechanical products, the performance requirements for quenched and tempered components are not entirely the same due to their different stress conditions. Generally speaking, various quenched and tempered parts should have excellent comprehensive mechanical properties, namely a suitable combination of high strength and high toughness, to ensure the long-term smooth operation of the parts.
