Manganese Alloys LCSiMn : Low carbon silicomanganese

Manganese Alloys
Manganese alloys are mostly used in steelmaking and foundry activities.
Some 30 % of the manganese used today in steelmaking is still used for its properties as a deoxidant and a sulphide former. In this last case it combines with sulphur avoiding the formation of iron sulphides, which sulphides are low melting point phases which become liquid at hot rolling temperatures and which, consequently, generate surface cracking.
The other 70% of the manganese is used purely as an alloying element. Steels usually contain from 0,2% to 2% manganese depending on grades as manganese is the cheapest alloying element among those which enhance some key mechanical properties like strength and toughness. In the specific case of stainless steel it can substitute expensive nickel in some austenitic grades called 200 series.
There are two families of manganese alloys called ferro-manganese (FeMn) and silico-manganese (SiMn). Silicomanganese adds additional silicon which is a stronger deoxidant. Nitrogen, boron, titanium, phosphorus are elements which can be controlled depending on requested specification. A very specific application of refined manganese alloys is a constituent in the coating of welding electrodes.

Chemical composition
Typical grades available. Other grades are on request. Valid for sizes > 10 mm.
Sizing
Standard sizing :
20 – 80 mm – maximum 10 % undersize
10 – 50 mm – maximum 10 % undersize
3 – 25 mm – maximum 5 % undersize
All sizes:
Maximum 10 % oversize.
Physical data
Density: 5.9 – 6.5 g/cm3
Bulk density: approx. 3000 kg/m3
Angle of repose: 40° - 60° - depending on size of material
Melting range: 1075°c – 1240°c
Packing
LCSiMn is usually delivered as bulk. Packing in big bags and other packaging is on request.
Origin of product
Norway.

It is lumpy material with a silvery metallic surface.
Low carbon silicomanganese is used in the production of stainless steel in AOD, VOD and CLU processes with the following advantages:
- Use of LCSiMn during slag reduction instead of HCFeMn during decarburization reduces the total treatment time. This reduces the amount of oxidized Mn, and hence the quantity of Si needed in the slag reduction period. At the same time, this reduces lining attack due to less fluid slag (less MnO).
- Computer model calculations at KTH, Sweden, show impro- vements in productivity of 4% to 6% during decarburization process of steel, by changing from the use of HCFeMn to the LCSiMn practice.
LCSiMn can replace Mn-metal and FeSi in the production of some carbon steel grades.
The LCSiMn manganese to phosphorus ratio (% Mn / % P) can be twice to four times higher than standard HCFeMn. Phosphorus input is significantly lowered when using LCSiMn.