Comparison of various carburizing methods

(1) Solid carburizing

Strengths:

(a) The equipment cost is cheap, the operation is simple and does not need high technology.

(b) Heat source for heating, electrical, gas and fuel oil can be used.

(c) It is suitable for large and small workpieces, especially for those with large shape or requiring original carburizing layer.

(d) Suitable for a variety of small production.

Disadvantages:

(a) The carburizing depth and surface carbon concentration are not easy to be adjusted correctly, and there is a tendency of excessive carburizing. The deformation of the processed parts is large.

(b) At the end of carburizing, it is not easy to directly quench, and it needs to be reheated.

(c) The working environment is poor and there are many workers.

(2) Liquid carburizing

Strengths:

(a) Moderate and small production. Equipment is cheap. No need for high technology.

(b) It is easy to homogenize and heat rapidly, and can be quenched directly.

(c) Suitable for small parts and thin carburizing layer treatment parts.

(d) Carburizing is uniform and the surface is bright.

Disadvantages:

(a) Not suitable for deep carburizing of large shaped parts.

(b) Salt bath composition is easy to change and management is troublesome.

(c) Countermeasures should be taken for toxic, exhaust or public hazard problems.

(d) After treatment, the surface attached with salt is not easy to clean, easy to rust.

(e) It is difficult to prevent carburization. Danger of splashing.

(3) Gas carburizing

Strengths:

(a) Suitable for mass production.

(b) The surface carbon concentration can be adjusted.

(c) Gas flow, temperature and time are easy to be automated and managed.

Disadvantages:

(a) Equipment is expensive.

(b) The cost is high when the processing capacity is small.

(c) Special operation knowledge is required.