METHOD OF HEAT HARDENING OF REINFORCING RODS AND DEVICE FOR ITS EMBODIMENT Russian patent published in 2000 - IPC

FIELD: metallurgy, particularly, heat treatment of rolled products. SUBSTANCE: method is used in heat hardening of reinforcing rods made of carbon steel. Rate of controlled cooling is set to be equal to 200-300 C/s and cooling is continued down to intermediate temperature of 500-600 C with holding for 0.2-0.8 s at this temperature and ending of cooling is effected at arbitrary rate. Water is supplied to cooling chamber at velocity exceeding speed of reinforcing rod motion by a factor of 1.1-1.2, and at excessive pressure of 0.5-0.9 kgf/sq.mm. The device for method embodiment has direct flow jet nozzle with cooling chamber. Ratio of jet nozzle slot area to area of cooling chamber outlet section area is 1.5-1.15, and cross-section area of cooling chamber exceeds that of reinforcing rod by a factor of 9-15. EFFECT: improved quality of reinforcing rods due to increase of their strength, plastic and ductile properties. 3 cl, 4 dwg, 2 tbl, 3 ex