JPS5591938A - Heat treatment apparatus for long sized material - Google Patents

Abstract

PURPOSE:To shorten heating time and also, to improve the operation efficiency, by heating the end part of steel pipe at the inlet of heating furnace previously and introducing in the heating furnace, at the time of heating long sized steel pipe having a thick wall or large diameter end part. CONSTITUTION:The long sized steel pipe (a) having the end part 6 of thick and large diameter is moved on the transferring line 2 from the inlet table 1 and is introduced to the heating furnace 3. The burner type or induction heating type preheating furnace 5, is arranged in front of the furnace 3 and the tip end (b) of end part of the pipe (a) is heated white it travels at the same moving speed as that of the pipe (a). When heated tip end (b) of fore end part entered the furnace 3, the preheating furnace 5 is brought back and the tip end (b) of rear end part is brought to the inlet of the furnace 3 with the pipe (a) heated at the above end part of the pipe (a). When the rear end part (b) entered the furnace 3, the pipe (a) is brought back quickly and is allowed to waite for the next end part of the pipe (a). Or, the tip end of rear end part of preceding pipe and that of fore end part of succeeding pipe, may be heated at the same time. Each end part is heated with the central thin part of the pipe a in the furnace 3 uniformly and the pipe (a) is taken out on the outlet table 4.