Optimization of hot rolling process of gravity cast AZ31-xCa (x = 0-∼2.0 mass%) alloys

Abstract

In this study, the effects of Ca content and processing variables on the external surfaces and tensile properties of hot-rolled AZ31-xCa sheets were evaluated systematically. The number and length of side crack were decreased with increasing preheating temperature and decreasing reduction ratio per pass and Ca content. The UTS and YS were not strongly dependent on the Ca content but the elongation decrease with increasing Ca content. The amount of decrease in elongation due to increase in Ca content was least when the sheets were fabricated under preheating temperature of 400°C and reduction ratio per pass of 15%. The sheets had the sound external features with little side cracks by homogenization of gravity cast AZ31-xCa alloys before hot rolling. In the cases of AZ31-xCa alloys containing under 1 mass% Ca. the annealed sheets after homogenization and hot rolling had the similar tensile properties to those of AZ31 sheet.