Meltstock Mo Products
The following table shows the meltstock Mo products used for alloying the individual material categories.
| Super- alloys |
Stainless Steel |
Alloy Steel |
Tool Steel & High Speed Steel |
Cast Iron |
|
|---|---|---|---|---|---|
| Roasted Molybdenite Concentrate (Technical Mo Oxide) | x | x | x | ||
| Ferromolybdenum | x | x | x | x | |
| Mo Metal Pellets | x |
The alloyed steels above are typically melted in an electric arc furnace. The raw materials base is usually alloy steel scrap and pig iron. That way an important share of the total alloy quantity required to make a specific grade is covered by recycling, both from in house scrap and alloy steel scrap collected from steel fabricators and recycling units. Depending on the steel grade and market factors the share of molybdenum from recycled material can vary between 10 and 50%.
New molybdenum in the form of Technical Mo Oxide is added with the scrap charge to approach the specified Mo content of the steel grade.
After meltdown, the liquid metal is usually transferred into a refining unit such as an AOD vessel or a ladle furnace for further metallurgical treatment. This includes the addition of Ferromolybdenum (FeMo) for final adjustment to the specified Mo content.
Exclusively FeMo is used as the product to add molybdenum to cast iron; similarly FeMo is the product used when only small amounts of new molybdenum are added to the steel.
Roasted molybdenite concentrate (Technical Mo oxide)
Roasted molybdenite concentrate (Technical Mo oxide) is the principal product for adding molybdenum to alloy and stainless steels.
Technical Mo oxide typically contains:
Mo: 56 - 58%
Cu: 0.5% max
Technical Mo oxide is available as:
- powder (max 400 mesh) packaged in:
- cans with 10 kg or 20 lbs Mo content,
- steel drums (250 kg or 500 lbs)
- bulk bags ( 1000 kg or 1500 kg)
- pillow shaped briquettes, packaged in:
- steel drums (250 kg or 500 lbs)
- or bulk bags (1000 kg or 1500 kg).
Roasted molybdenum concentrate (Technical Mo oxide) powder (left) and briquettes.
(Courtesy of Molymet, Chile)
Ferromolybdenum
(Courtesy of Treibacher, Austria)
Ferromolybdenum (FeMo)
FeMo can be used in any melting or refining unit to produce Mo containing steel or cast iron. It is especially used as ladle addition to achieve accurate final analysis adjustment. In steels with low Mo content such as High Strength Low Alloy (HSLA) steel with usually no more than 0.2% Mo 100% of the Mo is added as FeMo.
FeMo typically contains:
Mo: 65 – 75%
Cu: 0.5% max.
Size ranges are usually falling between:
- 0 and 10 mm, and
- 10 mm on the low side and several maximum size limits between 20 and 100 mm
FeMo is also available as powder for special applications such as welding electrodes.
FeMO is packaged in steel drums or big bags.
FeMo standards:
- ASTM A132-04 Standard Specification for Ferromolybdenum
- DIN 17561, 2004-02, Ferromolybdän
Mo Metal Pellets
Pure Mo metal (Mo min. 99.9%) is used for Superalloys to avoid contamination with trace elements.
The molybdenum powder is pressed into pellets for ease of handling in the melt shop.