Heat treatment process of hot formed spring

Heat treatment process of hot formed spring:
   Large spring parts with a diameter or plate thickness greater than 10-15mm are mostly made of steel wire or steel plate drawn by hot-rolled wire rod.
Processing and heat treatment are as follows: first heat the spring steel wire to 50-80°C higher than the normal quenching temperature and hot coil forming, then quenching + tempering at medium temperature to obtain tempered sorbite with excellent elastic limit and fatigue strength. Spring. Steel quenching and heating should use equipment with less oxygen or no oxidation, such as salt bath furnaces, protective atmosphere furnaces, etc., to prevent oxidative decarburization.
  After heat treatment, spring steel must be shot peened to strengthen the surface, generate residual compressive stress, and improve fatigue strength.
  The process flow of hot rolled spring steel is: after flat steel shearing, heating and bending, after heat quenching + medium temperature tempering + shot peening.