加熱鋳型式連続鋳造法によって得られたＡｌ‐４．５ｍａｓｓ％Ｍｇ合金鋳塊の曲げ加工による変形能と強度特性

Abstract

Al-4.5 mass% Mg alloy billets were cast by the heated mold continuous casting (Ohno Continuous Casting) method developed by the authors. The billets were cold worked by 90° bending and cyclic bending. The relationships between the bending workability, crack initiation, mechanical properties and structures of the billets were examined and compared with those of billets produced by the conventional method. The specimens bent from conventional billets tend to exhibit crack initiation at the grain boundary and fracture easily, but the specimens from the OCC billets were free from such defects. The bending fatigue life of the OCC billets was five times that of the conventional billets, and the OCC billets moved through the cyclic bender easily but the conventional billets did not. Mechanical properties of the OCC billets such as hardness, tensile strength, elongation and fatigue strength were superior to those of the conventional billets. Mechanical properties of the OCC billets were improved by cyclic bending.