Patent ID: 9181610
Filing Date: 2015-11-10
Classification: C21D,C22C

Abstract:
1. An air cooling equipment for a heat treatment process for a martensitic stainless steel pipe or tube, comprising: a conveying device for intermittently conveying the steel pipe or tube in a direction substantially at right angles to a longitudinal direction of the steel pipe or tube; and an air cooling device provided with a first group of nozzles and a second group of nozzles for spraying air through an inner surface of the steel pipe or tube, the first group of nozzles and the second group of nozzles being arranged along the longitudinal direction of the steel pipe or tube at first stop positions and second stop positions of the steel pipe or tube intermittently conveyed by the conveying device so as to face to an end of the steel pipe or tube, wherein the first group of nozzles is arranged at the first stop positions of the steel pipe or tube at which the inner surface temperature is 400° C. or lower, and the second group of nozzles is arranged at the second stop positions of the steel pipe or tube at which the inner surface temperature exceeds 400° C., and a volumetric flow rate of the air sprayed from the first group of nozzles arranged at the first stop positions is higher than the volumetric flow rate of the air sprayed from the second group of nozzles arranged at the second stop positions.