Stainless steel

Claim 1

A STAINLESS STEEL SUITABLE FOR KNIFE BLADES CONSISTING BY WEIGHT OF FROM ABOUT 11.5 TO 15 PERCENT CHROMIUM, FROM ABOUT 0.15 TO 2.00 PERCENT OF MANGANESE, FROM ABOUT 0.15 TO 1.00 PERCENT SILICON, FROM ABOUT 1 TO 6 PERCENT COBALT, FROM ABOUT 0.001 TO 0.005 PERCENT BORON AND THE BALANCE IRON AND CARBON EXCEPT FOR IMPURITIES INCLUDING NOT MORE THAN ABOUT 0.04 PERCENT OF EACH OF SULFUR AND PHOSPHORUS, SAID CARBON BEING NOT GREATER THAN 1.00 PERCENT BUT IN AN AMOUNT CORRESPONDING TO THAT WHICH IS EFFECTIVE TO INCREASE SUBSTANTIALLY THE HARDNESS OF A STEEL OF SUBSTANTIALLY THE SAME COMPOSITION BUT WITHOUT SAID CONTENTS OF CHROMIUM, COBALT AND BORON WHEN THE STEEL IS HEATED ABOVE ITS CRITICAL TEMPERATURE AND QUENCHED, SAID CONTENTS OF COBALT AND BORON RENDERING THE STEEL SUFFICIENTLY SOFT WHEN HEATED TO A TEMPERATURE BETWEEN 1010*C. AND 1149*C. TO PERMIT AN INGOT THEREOF TO BE SUBJECTED TO A ROLLING OPERATION TO REDUCE IT TO A SHEET OF SUBSTANTIALLY THE THICKNESS OF KNIFE BLADES WITHOUT REQUIRING EXCESSIVE POWER TO DRIVE THE ROLLING MILL OR CAUSING THE ROLLS THEMSELVES TO HAVE A SHORT LIFE OR PRODUCING EDGE CRACKING, THE STEEL BEING CAPABLE OF BEING HARDENED TO A HARDNESS EQUAL SUBSTANTIALLY TO THAT OF A STEEL OF THE SAME CARBON CONTENT BUT WITHOUT SAID CONTENTS OF CHROMIUM, COBALT AND BORON BY HEATING ABOVE THE CRITICAL TEMPERATURE OF THE STEEL AND QUENCHING.