The simple annealing of zinc and aluminum alloy surface treatment is to soften the workpiece by casting, forging, rolling, welding or cutting, improving the plasticity and toughness, homogenizing the chemical composition, removing the residual stress, and getting the expected physical properties. At the same time, there will be a variety of types of use according to the different processing requirements.
Annealing type:
1. Zinc and aluminum alloy surface treatment manufacturers introduce complete annealing and isothermal annealing. Complete annealing and weighing crystallization annealing, generally referred to as annealing, is to heat the steel or steel to more than Ac3 20 to 30 degrees C, heat preservation for a long time, so that the tissue completely austenitizing after the slow cooling, in order to get close to the balance of the heat treatment process. This annealing is mainly used for casting, forging and hot rolled profiles of various kinds of carbon steel and alloy steel for hypoeutectoid composition, and sometimes for welding structures.
2. Spheroidizing annealing. Spheroidizing annealing is mainly used for hypereutectoid carbon steel and alloy tool steels, such as cutting tools, measuring tools and steel used for moulds. Its main purpose is to reduce hardness, improve machinability, and prepare for later quenching.
3. Stress annealing. Stress annealing is also called low temperature annealing (or high temperature tempering). This annealing is mainly used to eliminate the residual stresses of castings, forgings, weldments, hot rolled pieces, and cold drawn parts. If these stresses are not eliminated, deformation or cracks will occur in the steel parts after a certain period of time or in subsequent cutting processes.
4. The surface treatment of zinc aluminum alloy surface treatment is to heat the steel to Ac1 to Ac3 (subeutectoid steel) or Ac1 to ACcm (hypereutectoid steel), and then cooled slowly after heat preservation to obtain the heat treatment process of near equilibrium.