Makoto Morishita

DC鋳造におけるAl–Mn系およびAl–Mg系アルミニウム合金の割れ感受性予測方法

A new prediction method based on a relation between calculated solid fraction and temperature was developed concerning Al-Mn and Al-Mg series aluminum alloys. Two crack modes were considered in order to understand that the surface crack is located at ingot surface. The one is based on “the difference in strain between water chilling surface and mushy surface (crack mode Z)” and the other is on “the difference in strain rate between surface and just inner surface (crack mode Y)”. It was assumed that the high solid fraction region was from 0.75 to 0.95 (Region II) and two indexes were set up which are calculated from temperature difference (ΔTII) and difference in a temperature drop per unit solid fraction (ΔRII/ΔTII) within the Region II. By using the both indexes, which were called “Brittle temperature range” and “Parameter of the strain rate difference” respectively, the crack sensitivities through DC casting experiments were suitably represented.