Abstract
The correlations between hardness masurements and tensile as well asyield strengthes were studied for two types of Al-Zn-Mg alloys. Theinappropriateness of Tabor's equations for calculating tensile strengthand uniform strain were discussed in details. Under the condition that the flow curve can be expressed by σ＝Ｋεｎ,equation for calcu-iating yield strength and tensile strength fromhardness data were given. A good agree-ment of calculated and observedvalues were obtained.