Tempering is a heat treatment method, aim to improve the comprehensive properties of steel, that is, high temperature tempering after quenching. The steel has both high strength and excellent toughness, plasticity, cutting performance and so on.
The seamless steel pipe needs to be heated during tempering. The heating temperature to be determined according to the material and specific composition of the steel. The selection of the quenching medium is based on the permeability of the steel and the size of the seamless steel pipe. The internal stress is very large and brittle, after the seamless steel pipe is quenched, so the seamless steel pipe must be tempered at a high temperature after quenching in order to eliminate the internal stress of the seamless steel pipe, to increase the toughness, and adjust the strength.
High temperature tempering is tempering between 500-650°C. Most quenched and tempered parts work with big dynamic loads. They have to bear the effects of stretching, compression, bending, torsion or shearing, and some may have friction surfaces, which require certain wear resistance and so on.
Here are tempering of seamless steel pipe, most of tempered seamless steel pipes for machining.