Abstract: A superplasticity of casting brass(ZHAlMn52-2-5)is studied.A result shows that average grain size of casting brass is 140μmunder industrial production condition.The brass without any pretreatment has excellent superplastcity .Fracture elongation and flow stress can beattened 160% and 72MPa at initial strain rate of 3.3×10-3s-1at strain temperature of 400℃.When superplastic forming test of sliding valve used casting brass ,it has excellent formability and weldability of a cavity.The sleding valve after superplastic forming used casting stock go through recovering heat treatment(500℃×2h),mechanical property and abrasion resistance are better than it used forged stock.

Key words: Brass, Forming, Large grain superplasticty, Sliding valve