Effect of Alloying on Material Properties

Co is used in high grade permanent magnets for steels

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Unformatted text preview: in high-grade permanent magnets. For steels in nuclear reactors, the lowest Co content should be used. D:\Private\Article\Material\Alloying.doc Farid 11:16 PM Page 2 21/08/2009 EFFECT of THE INDIVIDUAL ALLOYING ELEMENT ON THE MATERIAL PROPERTIES By : Farid Moch. Zamil (f). Copper ( Cu ) (Trace element). Should not be recovered from remelting scrap, since it constantly builds up. < 0.15 % in construction steels for improved weather resistance and tensile strengh. > 1.00 % in age harderning steels as precipitation harderning element. > 2.00 % in corrosion resistant steels, to improve resistance to acids. Cu builds up below the oxide layer and in hot forming operations can cause high surface sensivity. Magnesium ( Mg ) (Trace element). Strong de oxidation medium, and used in cast iron for formation of graphite from Carbon. Molybdenum ( Mo ) (Alloying element). Lower the critical cooling rate,forms carbide, increases tensile strength (primarily heat) resistance, creep rupture strength) ; increases cutting efficiency and corrosion resistance, limit temper brittlenes. < 1.50 % in low alloy constructional and tool steels. < 2.50 % in corrosion resistant steels. > 6.00 % in high speed tool steels. Nickel ( Ni ) (Important alloying element). Increase tensile strength properties (40 N/mm2 per 1 % Ni), greatly increased impact strength (also at low temperature) ; decreases critical cooling rate, not carbide forming ( air and oil harderning ). < 2.00 % in low alloyed contruction and tool steels (heat treatable steels) < 8.00 % in low temperature steels. > 8.00 % in corrosion resistant steel (with Cr min. 18 %). 36.00 % especially low thermal expansion. Tantalum ( TA ) and Niobium (Nb) (Trace element). Strong carbide and nitride forming elements, increase high temperature strength combines C and N in corrosion resistance steels, thus improving resistance to intercrystalline corrosion. Titanium (Ti) (Trace element). Strong de oxidation, denitriding and decarburisation element (oxide, nitride and carbide forming) ; refines grain in fine grained steels ; increase creep rupture properties ; additional element for case hardening steels ; permanent...
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This note was uploaded on 03/17/2010 for the course ME ME78212 taught by Professor Prof.sulis during the Spring '10 term at Institut Teknologi Bandung.

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