| 摘要 |
PURPOSE:To join material of different kind metallurgically without giving influence of heat on base metal, by interposing metal of low melting point between adjoining faces of metallic material of different kind and applying current to melt the metal of low melting point and joining the metallic material. CONSTITUTION:An output pipe 2 having pressure resisting and heat resisting functions is used for an oil well pipe 1 made of steel, and a stainless steel pipe having corrosion resisting and wear resisting functions is used for an inner pipe 3. An intermediate pipe 4 made of silver solder, metal of low melting point, is fitted between the two metallic pipes. Rolling electrodes 6, 6' of an electric seal welding device 5 are pressed against the surface of the outer pipe 2 and inner pipe 3. The material pipe 1 is rotated and pushed forward at set speed. Welding current is applied to electrodes 6, 6' and rolled throughout whole circumference of the material pipe 1 from end to end. By applying current, the silver solder intermediate pipe 4 is molten by resistance heat at set low temperature to form a molten layer between the inner and outer pipes 2, 3, and joins the inner and outer pipes firmly and metallurgically. |
