INVAR ALLOY STEEL SHEET FOR SHADOW MASK, METHOD FOR PRODUCING SAME, SHADOW MASK, AND COLOR PICTURE TUBE

摘要

THE OBJECT OF THE PRESENT INVENTION IS TO PROVIDE AN INVAR ALLOY STEEL SHEET FOR SHADOW MASK WHICH HAS IMPROVED ETCHABILITY, AN ECONOMICAL PRODUCING METHOD FOR THE SAID INVAR ALLOY STEEL SHEET, A SHADOW MASK MADE OF THE INVAR ALLOY STEEL SHEET, AND A COLOR PICTURE TUBE WHICH INCORPORATES THE SHADOW MASK.AN ALLOY SLAB CONSISTING ESSENTIALLY OF 33 TO 40 WT℅ NI AND THE BALANCE BEING FE IS HOT WORKED AND THEN THE HOT WORKED ALLOY SLAB IS SUBJECTED TO A PRIMARY COLD ROLLING AT A ROLLING REDUCTION RATIO OF NOT MORE THAN 80℅, ANNEALING AT A TEMPERATURE OF 550° C OR HIGHER, AND A SECONDARY COLD ROLLING AT A ROLLING REDUCTION RATIO OF NOT MORE THAN 50℅ IN THIS ORDER TO PRODUCE AN INVAR ALLOY STEEL SHEET HAVING A PERCENTAGE OF <100> TEXTURE BEING 60 TO 80℅.