CONTINUOUS COOLING OF LOW CARBON STEEL WIRE ROD

摘要

Low carbon steel (C ? 0.4%) wire rod at 800-880.degree.C from a rolling mill is deposited in loose turns on a conveyor where it is slowly cooled until the austenite to ferrite transformation is at least 80% complete and the ferrite grain size is at least ASTM 9 and is then rapidly cooled to 350-560.degree.C. Thereafter, the wire rod, e.g. on the conveyor or in coils, is subjected to a slow-cooling stage functioning as an overaging stage. The rapid cooling speed is such that at least the major part of the carbon remaining in supersaturation at the end of the first slow cooling stage is still in supersaturation at the beginning of the second slow cooling stage.