Webb, Burden, Ziesenheim & Webb
Method for hot-dip coating chromium-bearing steel
 A method of pretreating and hot-dip coating aluminum or aluminum alloys on a chromium-containing steel strip to provide an improved coating comprising annealing final gauge steel strip in an oxygen excess atmosphere to produce a chromium-rich oxide on the surface and thereafter electrolytically descaling the strip in an aqueous salt solution to remove the oxide and to expose a chromium depleted surface of the strip. The strip is then transported to a coating line where it is heated to a temperature at or above the temperature of a bath of aluminum or aluminum alloy. A substantially hydrogen atmosphere is maintained over the bath while the dew point is maintained below minus 35.degree. C. The strip is then drawn through the bath to coat the strip. 
Allegheny Ludlum Corporation Wheeling-Nisshin, Inc.
C
C23C
inventional
Eisuke Donald R. John P. James B. Yoshio William A.
Otani Zaremski Ziemianski Hill Hayashi Bertol