Large forgings forging after heat treatment
Publish Time: 2016-11-09 Origin: Site
Immediately after forging, the heat treatment is called heat treatment after forging.Main aim of the large forging after heat treatment is to stress, recrystallization fine grains, and hydrogen at the same time.
(1) the recrystallization process of large forgings after many recrystallization processing, make the grain refinement, organization improvement, performance was improved.
(2) to the forging of hydrogen hydrogen annealing low limit of hydrogen content in the following, and make it uniform distribution, by removing the white dots, the risk of hydrogen embrittlement.
Due to hydrogen in the y phase, 6 c phase solubility and diffusion coefficient is different, in particular the hydrogen solubility in the phase is low, and the diffusion coefficient is big, this makes the outward unceasingly in hydrogen diffusion in the process of annealing.
Tend to hydrogen annealing merged with recrystallization.To hydrogen annealing temperature is usually at 650 ℃.Should as far as possible the slow cooling after annealing, to prevent to produce new internal stress.General cooling can be divided into two phases:
Above 400 ℃, due to steel plasticity is good, not easy to form internal stress, so the cooling can be faster;400 the following, cooling speed will slow down.
For more alloy elements and high performance requirements of forging, forging requirements for one or more recrystallization after heat treatment, in order to improve the organization and performance of forgings.