The application of manganese in the iron and steel industry

Aug 31
07:34

2012

David Yvon

David Yvon

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Manganese and oxygen, sulfur affinity is larger, the manganese is liquid steel as deoxidizer and desulfurization agent. Manganese can strengthen ferrite and refining pearlite, so can improve the strength of steel and hardenability, so it can be used as steel alloy element.

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Steel strength limit with increase with the content of manganese,The application of manganese in the iron and steel industry Articles every 1% increase in the manganese content, ultimate strength improve 98066.5 kPa, and at the same time, steel plastic limit also corresponding improvement.

When the steel manganese content is more than 10%, the steel of corrosion resistance increases greatly in the atmosphere, manganese can also reduce the oxygen and sulfur on the harm of steel, so as to improve steel malleability and rolling resistance.

Although manganese element was found in 1774, but, in the iron and steel industry manganese play an important role until 1856 invention of bottom blowing Bessemer converter, and 1864 invention open hearth furnace process after, to be recognized. Now manganese is an important raw material become indispensable to the iron and steel industry.

Steelmaking process, in order to improve the quality of steel, need to get rid of the molten iron carbon, sulfur and other harmful impurity, the most simple process is to use oxidation method, but some iron and impurity element with oxidation to produce ferrous oxide (FeO), while FeO in solubility in liquid steel, so that in liquid steel increased oxygen, can achieve 0.25% ~ 0.45%. Oxygen content increased, the performance of the steel adverse effects, so steel to oxygen levels have strict requirements, generally no more than 0.02%, and even more strict. Therefore, steelmaking process must take off exceeds the oxygen. Manganese is active good metal powder, the chemical performance is lively than iron, manganese will join steel liquid when can and FeO reaction formation insoluble in molten steel of oxide slag, floating YuGangShui level, reducing oxygen in steel.

Compared with other elements (such as calcium, aluminum, silicon), the ability of deoxidization of manganese in the molten steel is low, but because of its easy to production, the price is low, so still deeply iron and steel enterprise's welcome, especially for refined rimming steel speaking, using ferromanganese alloy deoxidizing is ideal deoxidizer, for manganese of deoxidizing ability is weak, it can adjust the steel oxygen content, and unapt make oxygen off too much and not boiling. At the same time the existence of manganese can also make the ability of silicon and aluminum’s deoxidization strengthens, because MnO of deoxidizing products with other oxide (such as Si02) can form low melting point compound and benefit from the liquid steel out.

Sulfur exist in iron statistics (FeS) in steel liquid, steel containing sulfur high easy to produce heat brittle, reduce the mechanical properties of the steel, therefore, steelmaking process must control the content of sulfur. Manganese and sulfur binding force greater than iron and sulfur binding force. When adding manganese alloy after the steel [FeS] is very easy and manganese generation high melting point [MnS] and turn people slag, so as to reduce the sulfur content in the steel.

Manganese can strengthen the ferrite and refining pearlite, thereby enhancing the strength of steel, still can improve steel hardenability, steel hardness and wear resistance. Therefore, manganese powder is an important alloy elements.

Ordinary carbon structural steel generally contain Mn0.25 % ~ 0.8%; High quality carbon structural steel generally contain Mn0.7 % ~ 1.2%; In low alloy steel adding 0.8% ~ 1.7% of Mn can make the strength of the steel than the ordinary carbon steel is increased by 20% ~ 30%; Spring steel including Mn0.4 % ~ 1.3%; Bearing steel including Mn0.3 % ~ 1.6%; Tool steel including Mn0.4 % ~ 2%; Wear resistant steel including Mn11 % ~ 15%; Heat resistant steel including Mn17 % ~ 21%; Electrical steel including Mn17 % to 19%.

Source:http://www.mhcmp.com