標準AAR M-107/M-208
*If the manufacturer chooses to vary from the above limits for nickel, chromium, molybdenum,and vanadium, the following formula must be met:
930?–?[570?×?%?carbon]?–?[80?×?%?manganese]?–?[20?×?%?silicon]?–?50?×?%?chromium]?–?[30?×?%?nickel]?–?[20?×?%?molybdenum?+?%?vanadium]?>?390