The tempering colors are used for judgment regarding tempered steels` final properties. Steel that is very hard is normally tempered within the light-to-dark straw range. Spring steels are often tempered towards blue color. There is variance regarding the final-hardness of tempered steel, which depends upon composition of steel. Thickness of oxide film also increases over […]

Iron is naturally occurring and a second most abundant element on earth. It is comprised of up to 80 % earth’s core and up to 30 % of earth’s crust. It cannot be found on earth in its native form under normal conditions. It is normally found in sulfide and oxide with lot of impurities. […]