PURPOSE: To improve strength of a hearth roll and to eliminate creep deformation, by providing cooling flow path to inner part of the hearth roll for transferring a thick plate, etc., in a heat treating furnace, and passing fluid to be allowed to flow into the heat treating furnace to the cooling flow path.
CONSTITUTION: N2 to be supplied by a pipe line 15 is allowed to flow into the heat treating furnace 10, and the N2 is blown into the cooling flow path 14 from one end of the hearth roll 11 through a rotary joint 17. Therefor, the roll 11 for transferring the thick plate 12 is revolved in the furnace 10, but N2 can be blown into the path 14. The path 14 is formed by fixing a roll 18 and a core 19 with plural supports 20. Blown N2 is passed through the path 14 and released into the furnace 10 from plural blowing out holes 21 at the other end. In this way, temp. of the roll 11 is lowered and the creep strength is improved.
UESUGI YASUHIRO
TSUCHIYA SHIGEO
EDAHIRO NOBUYUKI
