MANUFACTURE OF STAINLESS STEEL STRIP FREE FROM DETERIORATION IN CORROSION RESISTANCE DUE TO GRAIN BOUNDARY PRECIPITATE

摘要

PROBLEM TO BE SOLVED: To prevent deterioration in corrosion resistance due to grain boundary precipitates by an easy method, in the manufacture of a strip of austenitic, martensitic or duplex stainless steel. ;SOLUTION: This steel strip can be manufactured by applying, in succession, hot rolling and annealing to a slab of austenitic, martensitic or ferrite + austenite duplex stainless steel. At this time, coiling temperature is regulated to 600°C in the hot rolling stage. In the annealing stage, the maximum ultimate material temperature Tm is regulated preferably to 800-1000°C; the average temperature rise rate from 600°C to Tm is regulated to ≥10°C/s; the soaking time at Tm is regulated preferably to 0-1 min; and the average cooling rate from Tm to 600°C is controlled to ≥10°C/s. By this procedure, the occupancy of precipitates in the grain boundaries of the annealed hot rolled steel strip can be reduced to ≤10%.;COPYRIGHT: (C)2000,JPO