To enhance a wear resistance and a seizure resistance of a squeeze roll of a welding machine for a resistance welded tube.
A squeeze roll is composed of a roll shaft 10, a roll body 14 and a caliber part 15. A rubber 16 for a shock absorption is provided between the roll body 14 and the caliber part 15. The caliber part 15 is composed of ceramic, while the roll body 14 and the roll shaft 10 are of alloy tool steel. Passages 6, 7, 8 for circulating cooling water are provided inside the roll body 14 and the roll shaft 10. As a result, the caliber part 15, being composed of ceramic, is unlikely to receive the influence of induction heating. The cooling water passages 6, 7, 8, being provided inside the roll body 14 and the roll shaft 10, contribute to superior cooling efficiency and high rigidity. With the rubber 16 for shock absorption provided between the roll body 14 and the caliber part 15, stress cracking in the caliber part 15 is prevented which is due to the thermal expansion of the roll body 14.
NAGAHAMA YUTAKA
SATO AKIO
