| 摘要 |
PURPOSE:To make effective use of the potential heat of a steel wire rod having been finish-rolled, the heat treatment in-line and accomplish the simplification and energy saving of plant by sending said wire material directly to a heat treatment apparatus including a holding furnace, a quick cooling cell, a heat retaining cover, and a cooling and cleaning device. CONSTITUTION:The hot-rolled wire material past a roughing mill 1, an intermediate rolling mill 2 and a finishing block 3 as a finish rolling mill is admitted into a direct heat treatment apparatus 4 by way of a laying cone 9. The front face moving carriage 15-1 of the direct heat treatment apparatus moves to make a holding furnace 5 in-line, and since the rear face carriage 15-2 does not move, a heat retaining cover 12 closes. An air cooling device 14-2 is not operated and a spray system of a cooling and washing device 8 operates. In this way, the wire material is held at a fixed temp. while it is passing the holding furnace 5 and heat retaining cover 12, whereby the formation of desired crystal grains is accelerated, after which it is quick-cooled down to outside the metal carbide deposition temp. at the time when it passes the cooling and cleaing device 8. |
