Tempering, i.e., one of the metal heat treatment process, is reheated after hardening of the workpiece to below the lower critical temperature Ac1 (heating pearlite to austenite transformation start temperature) to the appropriate temperature, heat preservation for a period of time after cooling in air or water, oil and other medium of metal heat treatment process, heat treatment will temper the heat treatment process are commonly used with the following seven aspects.
(1) for low carbon steel, after normalizing the hardness is slightly higher than annealing, toughness is also better, can be used as the pretreatment of cutting.
(2) for medium carbon steel, can replace quenching treatment (quenching + high temperature tempering) as ^ post-heat treatment, can also be used as induction heating method for surface quenching preparation.
(3) for tool steel, bearing steel, carburizing steel, etc., can reduce or inhibit the formation of network carbide, so as to get the good structure required by spheroidizing annealing.
Used for steel castings, can refine the cast structure, improve the cutting performance.
(5) for large forging, can be used as ^ post-heat treatment, so as to avoid the quenching of a greater tendency to crack.
6, used in ductile iron, so that the hardness, strength, wear resistance to improve, such as used in the manufacture of automobiles, tractors, diesel engine crankshaft, connecting rod and other important parts.
Before spheroidization annealing of eutectoid steel, a normalizing process can eliminate the network secondary cementite, so as to ensure that all the cementite spheroidization during spheroidization annealing. Thermal insulation, high strength characteristics make it widely used in various categories.
On 2018-08-08 11:45:46
