Manganese (Mn)

Manganese (Mn)
Manganese is good as deoxidizer and desulfurization agent. Steel in the general contain a certain amount of manganese, it can remove or reduced because of the sulfur caused by the hot steel brittle, so as to improve the performance of steel heating.

Manganese and iron to form the crystallology, improving steel iron ferrite and austenitic hardness and strength; And at the same time, carbide form elements, into the cementite replace part of iron atoms. Manganese steel due to a decrease in the critical transition temperature. Play the role of pearlite thinning. Also indirectly play improve pearlite steel the intensity of the role; Austenitic manganese stability ability of organization is second only to nickel, and also a strong increase steel its quench-hardening ability. Already use no more than 2% of manganese content with other elements with a variety of steel/" target="_blank" class="keylink">alloy steel made.
Manganese has rich resources, and the characteristic of diversity of efficiency, won a wide range of applications, such as with manganese higher carbon steels, spring steel.
In the high carbon high manganese steel wear-resisting. Manganese content of up to 10% a 14%, the solid solution treatment has good toughness, when impact and deformation, the surface layer of deformation and strengthening, high wear resistance.
Manganese and sulfur melting point higher MnS form. Can prevent for FeS in hot fragile phenomenon. Manganese have increase steel grain coarsening tendency of brittleness and sensitivity. If smelting casting and forging rolled cooling improper, easy to make steel produce white point.

(1) for the organization and show do steel heat treatment effect
A, manganese is good as deoxidizer and desulfurizer, industrial steel in the general all contains A certain amount of manganese
B, manganese solid soluble in ferrite and austenitic. Expand the austenitic area, make the critical temperature A4 point increases, the A3 points lower, (α + γ) the area move down. When manganese content of more than 12%, the critical point drop to room temperature below, make steel at room temperature to form single austenitic organization. In the lower GongXi temperature at the same time, make GongXi body the carbon content decrease
C, manganese strong steel Ar1 and reduce the martensite transformation temperature (its role after carbon) and the speed of the phase change in steel, improving steel its quench-hardening ability, increase the austenite content
D, make steel conditioning organization of uniform, refining, to avoid the carburizing layer of carbide together as piece, but the increase of steel overheating brittleness sensitivity and tendency
E, manganese is weak carbide form elements
(2) for the role of the mechanical properties of the steel
A, manganese and iron fortified ferrite or austenitic role than carbon, phosphorus, silicon, increase the strength in the same time, to ductility no effect
B, because detailed the pearlite, improve low carbon steel and carbon steel strength, make the ductility is reduced
C, by improving its quench-hardening ability and raise the quenching and tempering treatment saxhlet body mechanics performance of the steel
D, in the strict control of heat treatment process, avoid overheating of the grain size when grew up and brittleness, under the premise of manganese steel does not reduce the toughness
(3) of steel of physical, chemical and process performance role
A, along with the increase of the content of manganese steel heat conductivity fell sharply, linear expansion coefficient rise, make rapid heating or cooling form A larger stress, the tendency to craze increase
B, make steel of electrical conductivity sharply reduced, resistivity increases accordingly, resistance temperature coefficient decline
C, make coercive force increases, saturation magnetic feeling, remaining magnetic feeling and magnetic conductance decreased, thus manganese on permanent magnet alloy favorable, magnetic alloys harmful
D, manganese content high, steel antioxidant properties fall
E, make steel of sulfur formed higher melting point of MnS, avoid the FeS-phase film, eliminate the hot steel brittle, improve the hot working performance
F, high manganese austenitic steel deformation resistance is bigger, and the columnar crystal clear ingot, forged are easy to crack
G, due to improve its quench-hardening ability and reduce the martensite transformation temperature, have an adverse effect on the welding performance. In scope shall reduce carbon content
(4) in the application of steel
A free cutting steel, often have A moderate amount of manganese and phosphorus, MnS inclusion of scraps to break easily broken
B, the common low steel/" target="_blank" class="keylink">alloy steel of manganese to strengthen iron of ferrite and pearlite, improve the strength of steel, manganese content is commonly 1% 2%
C, carburizing and conditioning of steel/" target="_blank" class="keylink">alloy steel and many series contains no more than 2% of the manganese
D, spring steel, bearing steel and steel used in its quench-hardening ability raise the role of manganese strong, can use oil quenching and air cooling of quenching process, reduce the craze, and twisted and deformation
E, wear-resisting steel, no magnets, stainless steel, heat-resistant steels, including high carbon high manganese wear-resisting cast steel (C: 1.0% 1.4%, Mn: 10%-14%), carbon high manganese no magnets (C: 0.3% 0.6%, Mn: 18% 19%), low carbon high manganese steel (a Cr, no Ni or less Ni), high manganese steel heat (to Mn generation of heat resistant steel not peeling Ni, or contain Al, Mo, V, etc)