sales@dropforging.netMechanical Processing after Carburizing Treatment of Drop Forging
In order to achieve high surface hardness and surface roughness, improve fatigue strength, and meet working performance of drop forgings, Mechanical processing will be operated after carburizing treatment. The mechanical processing after carburizing treatment is generally as follows:
1) Machining
The surface carbon content after carburizing is high, and after heat treatment, the surface of drop forged blanks will exsit a large amount of residual austenite, easy to form grinding cracks, such as burns and crack, in the process of grinding. Besides, grinding crack can also produce if there is thick carbide, carbide network or carbide film. So in the process of Mechanical Processing, we should refer to the technical requirements of carburizing forgings, choose the correct process parameters according to the specific characteristics. This will help improve the quality of the drop forgings, and can guide the actual machining.
2) Shot blasting
Shot blast the carburized drop forgings into shot blasting machines, pill granule will impact the products with high speed of 50 ~ 70 m/s after a certain period of time, on the surface depth range of 0.1 ~ 0. 25 mm, drop forgings will win the uniform cold work hardening layer, thus to improve the hardnss of forging surface. Its effect has a direct relationship with the original organization of material surface. There will be obvious hardening effect if the surface has redundant residual austenite organization after quenching. Once appear carbide network on the surface, it will cause the emergence of surface crack, therefore, there is a strict control and requirements on the quenching organization of carburized forging surface.
3) Rolling or polishing
To improve the fatigue life, and the strengthening effect of drop forging surface, except for shot blasting processing, drop forgings can also be rolled or polished processing, namely rolling or rolling friction polishing. It is a kind of cold work hardening and strengthening technologies on the surface, which has the following features:
a) Improving surface hardness, change the size and distribution of residual stresses.
b) Improve surface finish of drop forgings.
c) Increase bending fatigue strength and touching fatigue strength.
1) Machining
The surface carbon content after carburizing is high, and after heat treatment, the surface of drop forged blanks will exsit a large amount of residual austenite, easy to form grinding cracks, such as burns and crack, in the process of grinding. Besides, grinding crack can also produce if there is thick carbide, carbide network or carbide film. So in the process of Mechanical Processing, we should refer to the technical requirements of carburizing forgings, choose the correct process parameters according to the specific characteristics. This will help improve the quality of the drop forgings, and can guide the actual machining.
2) Shot blasting
Shot blast the carburized drop forgings into shot blasting machines, pill granule will impact the products with high speed of 50 ~ 70 m/s after a certain period of time, on the surface depth range of 0.1 ~ 0. 25 mm, drop forgings will win the uniform cold work hardening layer, thus to improve the hardnss of forging surface. Its effect has a direct relationship with the original organization of material surface. There will be obvious hardening effect if the surface has redundant residual austenite organization after quenching. Once appear carbide network on the surface, it will cause the emergence of surface crack, therefore, there is a strict control and requirements on the quenching organization of carburized forging surface.
3) Rolling or polishing
To improve the fatigue life, and the strengthening effect of drop forging surface, except for shot blasting processing, drop forgings can also be rolled or polished processing, namely rolling or rolling friction polishing. It is a kind of cold work hardening and strengthening technologies on the surface, which has the following features:
a) Improving surface hardness, change the size and distribution of residual stresses.
b) Improve surface finish of drop forgings.
c) Increase bending fatigue strength and touching fatigue strength.