Production method null of the alloy hot dip zincing steel sheet which is superior in resistance chipping characteristic and resistance powder ring

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a hot dip galvannealed steel sheet particularly excellent in chipping resistance as well as powdering resistance. ;SOLUTION: A base steel sheet is made to infiltrate into a hot dip galvanizing bath in which the concn. of Al is controlled to 0.07 to 0.2 wt.% to form a hot dip galvanizing layer on the surface of the base steel sheet, and thereafter, the hot dip galvanized steel sheet is heated to ≥550°C at a heating rate of ≥10°C/sec to alloy the plating layer and is subsequently cooled to 400°C at a cooling rate of ≥10°C/sec.;COPYRIGHT: (C)1999,JPO