MANUFACTURE OF NONNTEMPERED STEEL BAR HAVING EXCELLENT LINEARITY

摘要

PURPOSE:To obtain non-tempered steel bar having excellent linearity and good mechanical properties by subjecting steel wire to a rapid heating and cooling treatment while applying a specific streche to the steel wire. CONSTITUTION:The rolled steel 2 supplied from the supply stand I is stretched by the wire stretching die 3, whereupon wire-stretching tension is at the same time given to stretched wire as a stretching force. At this time, the stretching stress given at the die 3 and the caterpillar device 7 is regulated so as to be a stretching stress/ high temperature yield X 100% = more than 60%. The stetched wire 4 is rapidly heated to 450 to 600 deg.C at the heater 5 by using a resistance heat by direct electric energization and then cooled uniformly at the cooling tank 6. Then it is drawn by the caterpillar device 7 and then cut by the cutter 8 into a predetermined length of bars.