<P> The separators between the tools have been made from aluminium alloy since 1951 . This makes the knives lighter . Previously these separating layers were made of nickel - silver . </P> <P> The martensitic stainless steel alloy used for the cutting blades is optimized for high toughness and corrosion resistance and has a composition of 15% chromium, 0.60% silicon, 0.52% carbon, 0.50% molybdenum, and 0.45% manganese and is designated X55CrMo14 or DIN 1.4110 according to Victorinox . After a hardening process at 1040 ° C and annealing at 160 ° C the blades achieve an average hardness of 56 HRC . This steel hardness is suitable for practical use and easy resharpening, but less than achieved in stainless steel alloys used for blades optimized for high wear resistance . According to Victorinox the martensitic stainless steel alloy used for the other parts is X39Cr13 (aka DIN 1.4031, AISI / ASTM 420) and for the springs X20Cr13 (aka DIN 1.4021, but still within AISI / ASTM 420). </P> <P> The steel used for the wood saws, scissors and nail files has a steel hardness of HRC 53, the screwdrivers, tin openers and awls have a hardness of HRC 52, and the corkscrew and springs have a hardness of HRC 49 . </P> <P> The metal saws and files, in addition to the special case hardening, are also subjected to a hard chromium plating process so that iron and steel can also be filed and cut . </P>

What are the swiss army knife tools for