| 摘要 |
PURPOSE:To obtain fast heating speed as well as to enhance heat efficiency and attain to shorten a furnace length by a mechanism wherein a second preheating furnace for introducing a high temperature exhaust gas of a collision jet type direct firing furnace and a first preheating furnace for injecting and preheating low temperature exhaust gas from the said first preheating furnace are arranged. CONSTITUTION:A heat absorbing agent coating apparatus 3, a first preheating means 4, a second preheating means 5, a collision jet type direct firing furnace 6 are arranged at the back of an inlet side looper 2 of a fast heating zone of a continuous annealing apparatus. To a furnace 6, a pair of a burner 8 is arranged to an axial advancing direction at both sides of a front and a back surface of a steel band so as to form 4 firing zones to an upward and downward direction and constituted so as to collide a high temperature exhaust gas to a longitudinal direction of a steel band from an inclined direction. A second preheating furnace 5 introduces a high temperature exhaust gas from a furnace 6 and preheats a steel band to a fast heating initiation temperature by radiant heat. A first preheating furnace 4 introduces a low temperature exhaust gas from a furnace 5 and preheat a steel band by radiant and conductive heat. By above described constitution, heat efficiency is enhanced compared to a conventional radiant heating method and, moreover, energy saving is promoted by coating a heat absorbing agent and a required preheating furnace length can be shortened to 1/5 compared to a conventional length. |
