The metal component is heated to above or below the critical point, maintained for a certain time, and then cooled slowly, so as to obtain the metal heat treatment process close to the equilibrium state of structure and performance; annealing is a metal heat treatment process, which means that the metal is slowly heated to a certain temperature, maintained for a sufficient time, and then cooled at a suitable speed. The purpose is to reduce the hardness and improve the machinability, to eliminate the residual stress, to stabilize the size, to reduce the deformation and crack tendency, to refine the grain, to adjust the structure and to eliminate the defects.
Purpose of metal annealing:
(1) Reduce hardness and improve machinability;
(2) Eliminate residual stress, stabilize size, reduce deformation and crack tendency;
(3) Refine grains, adjust structure, eliminate defects,
In production, annealing process is widely used. According to the different purposes of workpiece annealing, there are many kinds of annealing process specifications, such as complete annealing, spheroidizing annealing, and stress relief annealing.
Metal annealing method:
One of the main technological parameters of annealing is high heating temperature (annealing temperature). The selection of annealing temperature of most alloys is based on the phase diagram of the alloy system, such as carbon steel based on the iron carbon balance diagram. The annealing temperature of various steels (including carbon steel and alloy steel) shall be at a temperature above AC3, above AC1 or below according to different annealing purposes. The annealing temperature of all kinds of non-ferrous alloys is below the solid line temperature of each alloy, above or below the solid solubility line temperature.
On 2018-08-08 11:45:46
