ASTM B221-14, AMS-QQ-A200/8, EN 10204-3.1, AMS 4129 O - Soft T4 - Solution heat treated and naturaly aged to a substantially stable condition T42 - Solution heat treated and naturaly aged to a substantially stable condition T451 - Solution heat treated then stress relieved by stretching. Equivalent to T4. T6 - Solution heat treated and artificially aged T62 - Solution heat treated then artificia..
