First, ASTM A 681 is a standard that covers a wide range of tool steel grades, not one specific alloy. Second, as Jay mentioned, mechanical properties are highly dependent upon composition (including uniformity/homogeneity), heat treatment, etc. And third, there is not much information available regarding yield and tensile strengths of tool steels, because they are predominantly quenched and tempered to very high hardness levels, which gives them excellent wear resistance and high resistance to compression, but poor tensile ductility. Hence, tensile testing is not performed often. If you can provide an alloy, product form, condition (heat treated, normalized, etc.), and a description of your problem, perhaps we can assist you further.