The technology of heating treatment process
The technology of steel strips's annealing,quenching,tempering.
1)The steel strip's annealing
It is heating the steel strips in the certain temperature and holding for a period of time.then made it cooling slowly,this is called annealing.the steel strips'annealing is to heat the steel up to phase change or phase transition temperature,after through keeping warm and colling slowly,the main purpose of annealing is to eliminate the defect structure,improve the organization that make the element uniformity and grain refining,increasing the steel strips' chemical properties and decreasing the remaining stress,and reducing the hardness,improving the plasticity,toughness and machinability at the same time.therefore,the annealing is not only to eliminate and improve the defect structure and internal stress which is remained by the last production,but also can make prepared well for the next process.so the annealing is the intermediate heat treatment,and also called pre-heat treatment
2)The steel strip's hardeneing or quenching
Hardening or Quenching process involves heating the steel strip to above the critical transofrmation temperature for the given grade and then rapidly,and it acquire the heating trement way by the martensite imbalance of the organization.Hardening or Quenching can increase the steel srip's strength and hardness,but it is need to reduce the plasticity.it is common used the water,oil on the hardening or quenching.
3)The steel strip's Tempering
After hardening or quenching,The problem here is that the steel strip in this condition is extremely brittle and therefore requires further treatment in the form of tempering. so the tempering consit of reheating the steel strip to a lower temperature and holding it at the given temperature for a given period of time. This process is done in an inert atmosphere to avoid oxidation.which is mainly to elimate the internal stress from the Quenching produced and reduce the hardness and brittleness,in order to get the desired mechanical properties, This type of steel strip has high degree of toughness and has excellent spring properties.
