What is the role of copper annealing? What are the methods of copper annealing?-Kehua
Annealing is a very important process in metal smelting. If a metal product is not annealed, it cannot be regarded as a qualified product. Different metals have different annealing methods. Next, Kehua will take you to understand the role of copper annealing, and what are the methods of copper annealing? What is the role of copper annealing copper annealing (1) Reduce hardness and improve machinability. (2) Eliminate residual stress, Stabilize the size and reduce the tendency of deformation and cracking; (3) Refine the grains, adjust the structure, and eliminate the structure defects. (4) Uniform material organization and composition, improve material properties or prepare organization for subsequent heat treatment. What are the methods of annealing copper parts? ①Complete annealing. It is used to refine the coarse superheated structure with poor mechanical properties after casting, forging and welding of medium and low carbon steel. The workpiece is heated to 30-50°C above the temperature at which all ferrite is transformed into austenite, kept for a period of time, and then slowly cooled with the furnace. Kehua believes that the austenite transforms again during the cooling process, which can make the steel structure finer. ②Spheroidizing annealing. It is used to reduce the high hardness of tool steel and bearing steel after forging. The workpiece is heated to 20-40°C above the temperature at which the steel begins to form austenite, and then slowly cooled after heat preservation. During the cooling process, the lamellar cementite in the pearlite becomes spherical, thereby reducing the hardness. ③Isothermal annealing. It is used to reduce the high hardness of some alloy structural steels with high nickel and chromium content for cutting. Generally, it is first cooled to the most unstable temperature of austenite at a relatively fast rate, and the austenite is transformed into trosteite or sorbite for an appropriate time, and the hardness can be reduced. ④ Recrystallization annealing. It is used to eliminate the hardening phenomenon (increase in hardness and decrease in plasticity) of metal wires and sheets during cold drawing and cold rolling. The heating temperature is generally 50 to 150 °C below the temperature at which the steel begins to form austenite. Only in this way can the work hardening effect be eliminated and the metal soften. Annealing copper parts can reduce the hardness and increase the toughness, which can prolong the service life of copper parts. Commonly used copper annealing methods include complete annealing, spheroidizing annealing and isothermal annealing.