| 摘要 |
PROBLEM TO BE SOLVED: To provide the gas nozzle for a welding torch of low cost in which spatter is not stuck to the gas nozzle, a cylindrical body is not burned and not oxidized, further crack and degrading are not generated to the cylindrical body and by which welding work is efficiently is executed. SOLUTION: The gas nozzle 1 mounted to the tip of a welding torch of arc welding machine consists of the cylindrical body 2 made of graphite and a boron nitride coating film 3 coated on the outer face of the cylindrical body 2. Though a graphite or a material liable to oxidizing is used for the material of the gas nozzle 1, in the case arc welding is executed in the atmosphere of arc heat having a high temp. exceeding 5000-1000K (temperature by Kelvin), crack is not generated to the cylindrical body 2, degradation of the cylindrical body 2 is prevented, further, heat resistance and releasing property are excellent, spatter is not stuck to the gas nozzle 1 due to poor wettability of graphite. |
