Spheroidizing_annealing

Spheroidizing annealing scope Spheroidizing mainly used in steel and eutectoid eutectoid steel, such as carbon tool steel, alloy tool steel, bearing steel. These steels are rolled, forged air cooling, the resulting organization is lamellar pearlite and cementite network, this organization is hard and brittle, not only difficult machining, and also easy to deformation and cracking after quenching process. Annealed and spheroidized pearlite is spherical, which takes the shape of a spherical cementite particles dispersed in the ferrite matrix and the lamellar pearlite compared not only low hardness, ease of machining, and quenching When heated, the austenite grain is not easy growing up, cooling the workpiece deformation and cracking tendencies small. In addition to some of the need to improve the cold plastic deformation (such as stamping, cold heading, etc.) of sub-eutectoid steel ball annealing can be sometimes. Ball annealing temperature Ac1 + (20 ~ 40) ℃ or Acm-(20 ~ 30) ℃, cooling or isothermal heat directly after slow cooling. When the ball annealing Albright is the "incomplete", but lamellar pearlite transformation into austenite, and a small amount of excess carbon dissolved. Therefore, it is impossible to eliminate network carbide, such as a mesh hypereutectoid steel carbide exists, before the ball annealing must first be normalized to eliminate it, in order to ensure the normal ball annealing.