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As more steel is produced than is scrapped, the amount of recycled raw materials is about 40% of the total of steel produced – in 2016, 1,628,000,000 tonnes (1.602 × 10 9 long tons; 1.795 × 10 9 short tons) of crude steel was produced globally, with 630,000,000 tonnes (620,000,000 long tons; 690,000,000 short tons) recycled.
Corrosion – Steel, when in contact with water, can corrode, creating a potentially dangerous structure. Measures must be taken in structural steel construction to prevent any lifetime corrosion. The steel can be painted, providing water resistance. Also, the fire resistance material used to envelope steel is commonly water resistant. [11]
Steel is made from iron and carbon. Cast iron is a hard, brittle material that is difficult to work, whereas steel is malleable, relatively easily formed and versatile. On its own, iron is not strong, but a low concentration of carbon – less than 1 percent, depending on the kind of steel – gives steel strength and other important properties.
Carbon steel is heated to approximately 550 °C (1,000 °F) for 1 hour; this ensures the steel completely transforms to austenite. The steel is then air-cooled, which is a cooling rate of approximately 38 °C (100 °F) per minute. This results in a fine pearlitic structure, and a more-uniform structure.
Sheet metal of iron and other materials with high magnetic permeability, also known as laminated steel cores, has applications in transformers and electric machines. Historically, an important use of sheet metal was in plate armor worn by cavalry , and sheet metal continues to have many decorative uses, including in horse tack .
Where x is the material type (only 1 is specified so far), yy is the steel group number (specified in EN10027-2) and zz(zz) is a sequential number designated by the certifying body, the number in brackets being unused but reserved for later use.
Mill scale is a complex oxide that contains around 70% iron with traces of nonferrous metals and alkaline compounds. Reduced iron powder may be obtained by conversion of mill scale into a single highest oxide i.e. hematite (Fe 2 O 3) followed by reduction with hydrogen.
Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy containing a minimum level of chromium that is resistant to rusting and corrosion. Stainless steel's resistance to corrosion results from the 10.5% or more chromium content, which forms a passive film that can protect the material ...