PURPOSE: To perform multilayer build up welding without cracks and with an arbitrary hardness and a required build up quantity, by performing welding, which uses welding materials which include metallic carbide and can obtain a high hardness, and welding, which uses welding materials superior in tenacity, alternately in the arc.
CONSTITUTION: The powder mixture of a high-hardness and high-melting point by metallic oxide and alloy powder as a binder is supplied from welding powder material supply device 4, and welding head 7 is used to perform build up welding on base metal 10 while jetting working gas 8, thereby forming high-hardness layer 11. Next, device 4 is switched to welding powder supply device 5 by changeover cock 6. Welding powder materials superior in tenacity are supplied from device 5 to perform build up welding, thereby forming thin buffer layer 112 to prevent cracks. By repeating these operations, a required hardened build up quantity (the height of layer 11) is obtained. In this case, power source 1, high frequency generating device 2, and pilot arc power source 3 are used properly according to the known method.
KONISHI MICHITOMO
HORIGUCHI MASUO
IZUMI HISATOSHI
