PRETREATMENT OF GALVANIZED STEEL SHEET BEFORE CHEMICAL CONVERSION TREATMENT

摘要

PURPOSE:To obtain a surface having superior suitability to chemical conversion treatment by continuously passing a galvanized steel sheet through cleaning, polishing and grinding stages in a wet state before chemical conversion treatment so as to activate the surface of the steel sheet. CONSTITUTION:A galvanized steel sheet is cleaned by spraying washing water, polished with a polishing roll in a wet state and ground with a grinding brush roll in a wet state before the steel sheet is subjected to chemical conversion treatment. Thus, the surface of the steel sheet is activated and a surface having superior suitability to chemical conversion treatment is both.