Structure and application of linear motion ball bearings
Structure and application of linear motion ball bearings
PRODUCT
High carbon chromium bearing steel annealing
by：Waxing
2020-09-10
High carbon chromium bearing steel annealing of high carbon chromium bearing steel spheroidizing annealing is to obtain ferrite matrix uniformly distributed on the fine carbide particles, small, uniform, round, for cold working and final quenching tempering after tissue preparation.
Traditional spheroidizing annealing process is slightly higher than the temperature of Ac1 (
Such as GCr15 is 780 ~ 810 ℃)
Slow cooling after heat preservation with furnace (
25℃/小时)
Below 650 ℃ from air cooling.
The process of heat treatment time is long,
More than 20 h)
(
1]
, and the carbide particles are not uniform, after annealing effect after cold working and the microstructure and mechanical properties of the final quenching tempering.
Later, according to characteristics of supercooled austenite transformation, development of isothermal spheroidizing annealing process: in the cold heat, quick to Ar1 below a certain temperature range,
690～720℃）
Isothermal, completed in the process of isothermal austenite to ferrite and carbide, shift can be directly released after the completion of air cooling.
This process has the advantage of saving heat treatment time (
The whole process about 12 ~ 18 h)
, after processing the carbide tiny evenly in the organizations.
Another time saving process is repeated spheroidizing annealing: cooling after it was first heated to 810 ℃ to 650 ℃, cooling after heated to 790 ℃ to 650 ℃ from air cooling.
Although the process can save some time, but more complex operation.
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