This part of ISO2566 specifies a method of converting room temperature percentage elongations after fracture obtained on various proportional and non-proportional gauge lengths to other gauge lengths. The formula (see clause4) on which conversions are based is considered to be reliable when applied to austenitic stainless steels within the tensile strength range 450 to 750N/mm2 and in the solution treated condition. These conversions are not applicable to cold reduced steels; quenched and tempered steels; non-austenitic steels. Neither should they be used where the gauge length exceeds or where the width to thickness ratio of the test piece exceeds 20. Care should be exercised in the case of strip under 3mm thickness, as the index in the formula given in clause4 increases with decreasing thickness; the value to be used shall be the subject of agreement between the customer and the supplier.