The causes of fracture of the chipper knives made in China are analysed. A new process on gaseous Carbon-Nitrogen-Boron penetration is tested and better results have been achieved.

The series of disc chippers is made up of seat, cutter disc, feed inlet port, shell, electric control system, etc.

At present, the serial disc chippers adopt wear-resisting backing board plate coated with chromium. The flying knife, bottom knife and flying knife bolt adopt the special steel and are made specially.