An accurate and reproducible mechanical Hat-channel test for evaluating flaking performance of Galvanneal sheet products has been implemented at Dofasco. Effective test conditions have been established and a flaking performance rating system has been set up. Good correlation between Hat-channel and production press performance has been achieved. The flaking mechanism of Galvanneal with good and poor adhesion was examined. The effect of lubricant on flaking has also been investigated.