Heat treatment is a kind of industrial and metalworking processes , which is used to alter physical, and sometimes chemical properties of material. As we mentioned before, all raw material of ZFV valve be carried out proper heat treatment , as per international standard such as ASTM standard requirement.
Main heat treatment techniques include annealing, normalizing, tempering, quenching, solution treatment, case harden and precipitation strengther. We explain quenching this time.
Quenching is the way that heat a material to certain temperature, most materials are heated to between 815 and 900 degree C (1500 to 1650 degree F), then take material out and rapidly cool the material in water, oil or air to obtain certain material properties. The material is applied quenching to reduce the crystal grain size of both metallic and plastic materials, for increasing their hardness.
The purpose of quenching is harden raw material, make the material resistance to deformation.Before hardening, cast steels is of a uniform grain structure. This is a mixture of ferrite and cementite formed when steel is manufactured and cooled at a slow rate. Pearlite is not an ideal material for many common applications of steel alloys as it is quite soft. By heating pearlite past its eutectoid transition temperature of 727 °C and then rapidly cooling,the material’s crystal structure become harder known as martensite structure.
Quenching for material may also cause reducing impact toughness, so quenching is often used along with heat treatment tempering.
Zhejiang Zhengfeng Valve