FORGING OF MG-ZN-ZR ALLOY

PURPOSE:To obtain a forged product of Mg-Zn-Zr alloy excellent in strength and toughness by setting strictly condition of forging in the first step, rolling reduction in the second and subsequent steps and forging temperature in the final step. CONSTITUTION:An alloy composed of 1.5-6.5wt% Zn, 0.45% or more Zr, the balance substantially Mg is forged by two or more times of processes. In forging of the first step, temperature is set to 360-450 deg.C, and when roll down parallel to metal flow of the material, rolling reduction is made to above 80%, and when roll down vertically, rolling reduction is set to above 50%. In forging of the second and later steps, rolling down is made vertical to metal flow and making total rolling reduction above 30%. Further, forging temperature in the final step is set to 212-290 deg.C. By this method of forging, a forged product of Mg-Zn-Zr alloy excellent in mechanical properties both in L direction and LT direction can be obtained.