Easily wearing position of draught fan case surface,made from A 3 steel,is forced to take build-up welding process of GTC wear resisting alloy,and the service life of it is increased by a factor of 9.

By analyzing the weldability of fan shell and run environment of fan, the reasonable welding procedure was put out.

The high precision and automatic machining equipment for manufacture of fan casting had a great development with the development of the coal and steel industry.