Views: 21 Author: Site Editor Publish Time: 2016-11-25 Origin: Site
After carburizing and heat treatment after forging to mechanical processing, get the requirements of high surface hardness and surface roughness, improving forgings of fatigue strength, to meet the needs of the forging work.Carburizing after machining is commonly the following.
(1) turning and grinding
Forging the surface of the carbon content is high, after carburizing heat treatment after surface exist a large amount of residual austenite, easy to form in the process of grinding grinding cracks, burns and crack, for example, if there is a thick carbide, carbide network or carbide film also can produce grinding crack, so the mechanical processing in this paper, based on the technical requirements of carburizing forgings, according to the characteristics of specific to choose the correct process parameters, such as analysis and predict possible defects will help improve the quality of the parts, and can guide the actual machining.
(2) the shot blast
After heat treatment of carburizing forgings in shot peening machine or shot blasting machine shot blast, pill granule with high speed of 50 ~ 70 m/s and forging the impact after a certain period of time, on the surface depth of 0.1 ~ 0. 25 mm range, won the uniform cold work hardening layer, improve the surface hardness.Its role and the effect of material on the surface of the original organization has a direct relationship, if the surface is redundant residual austenite after quenching organization, has the obvious hardening effect.Once appear on the surface of carbide network, will cause the emergence of surface crack, therefore the carburized parts surface quenching organization has more strict control and requirements.
(3) roll or polishing
Forging surface carburization in order to improve the fatigue life, improve the effect of surface strengthening, except for shot peening processing, also can be rolled or polishing processing, namely rolling or rolling friction polishing, is a kind of cold work hardening on the surface strengthening technology, has the following features:
(1) improve the surface hardness, changed the size and distribution of residual stress.
(2) improve the surface finish.
(3) improve the bending fatigue strength and contact fatigue strength.
Data is introduced in the forging of the groove, groove, roll or polishing, in areas such as the rounded corners compared with other parts, the effect is more obvious, so for rolling or polishing is the important measures for prolonging the service life of carburizing forgings, the class after forging part of automobile carburized process achieved good results.