CHROMATE-FREE TYPE PRECOATED STEEL SHEET EXCELLENT IN EDGE RED RUSTING RESISTANCE

摘要

A NEW TYPE OF CHROMATE-FREE TYPE PRECOATED STEEL SHEET EXCELLENT IN EDGE RED RUSTING RESISTANCE WHICH CAN BE USED WITHOUT THE WORRY OF THE OCCURRENCE OF RED RUST DETRACTING FROM THE AESTHETIC APPEARANCE EVEN IN AN OUTDOOR ENVIRONMENT IN WHICH IT IS EXPOSED TO RAINWATER ETC. IS PROVIDED. THE CHROMATE-FREE TYPE PRECOATED STEEL SHEET EXCELLENT IN EDGE RED RUSTING RESISTANCE OF THE PRESENT INVENTION IS COMPRISED OF A ZINC-BASED PLATED STEEL SHEET ON THE TWO SURFACES OF WHICH ARE PROVIDED A CHROMATE-FREE TYPE CONVERSION TREATMENT LAYER AND AT LEAST ONE LAYER OF A COATING FORMED ON TOP OF THE SAME, THE OUTERMOST LAYER OF COATING AMONG AT LEAST THE COATINGS OF THE BACK SURFACE OF THE PRECOATED STEEL SHEET COMPRISING A TUNGSTATE OR SILICATE WITH A HIGH EDGE RESIDENCE.