Age hardening manganese-containing maraging steel

Claim 1

A MARTENSITIC STEEL CHARACTERIZED IN THAT IT TRANSFORMS SUBSTANTIALLY TO MARTENSITE AT ROOM TEMPERATURE OR ABOVE AND FURTHER CHARACTERIZED IN THE AGED CONDITION BY A COMBINATION OF RELATIVELY HIGH YIELD STRENGTH TOGETHER WITH A SATISFACTORY LEVEL OF THOUGHNESS, AND STELL CONSISTING ESSENTIALLY OF ABOUT 10% TO 20% NICKEL, FROM 1.2% TO 3.9% MANGANESE, UP TO 5% CHROMIUM, THE SUM OF THE NICKEL PLUS MANGANESE PLUS CHROMIUM CONTENTS BEING ABOUT 14% TO 23%, CARBON IN AN AMOUNT UP TO 0.03%, UP TO 1% TITANIUM, UP TO 1% ALUMINUM, UP TO 1% SILICON, UP TO 2% COBALT, UP TO 2% MOLYBDENUM, UP TO 2% VANADIUM, UP TO 2% TUNGESTEN, UP TO 0.4% BERYLLIUM, UP TO 2% COLUMBIUM, UP TO 2% TANTALUM, UP TO 2% COPPER, WITH THE PROVISO THAT THE TOTAT SUMMATION OF COBLAT, MOLYBDENUM, VANADIUM, TUNGSTEN, BERYLLIUM, COLUMBIUM, TANTALUM AND COPPER IS NOT GREATER THAN 2%, AND THE BALANCE ESSENTIALLY IRON.