Raw material of ZFV valve be carried out heat treatment , as per international standard such ASTM standard requirement. Heat treatment is a kind of industrial and metalworking processes , which is used to alter physical, and sometimes chemical properties of material.
Heat treatment for valve raw material involves the use of extreme high temperature, to achieve a purpose that harden or soften material. Heat treatment techniques include annealing, normalizing, tempering, quenching, solution treatment, case harden and precipitation strengther. Here we explain annealing.
Annealing is a generalized term, which consists of heating a metal to a specific temperature and then cooling ar a rate that will produce a refined microstructure, either fully or partially innealing separating the constituent. The rate of cooling is generally slow.
The advantages of annealing include :
soften raw material, for cooling machine work earlier.
remove material innerstress, reduce plastic deformation, to make dimension of valve part stable.
recrystallize refined microstructure, repaire poosible defects of raw material
The annealing heat treatment is used for alloy steel, carbon steel, forged steel, welded part.
The annealing heat treatment used to be applied to raw material, but not machined material.
Zhejiang Zhengfeng Valve