Ferrochrome
Ferrochrome is a master alloy made from iron , chromium and occasionally carbon or nitrogen ; in the case of ferrochrome silicon or ferrosilicon chrome additionally with silicon . It is produced by reduction of chromium ore with coal in electric arc furnace . In ferrochrome the chromium content is between 45 and 95%, in ferrochrome silicon between 28% and 40%. Ferrochrome is mainly used as an alloy additive in the manufacture of chrome- alloyed steels .
use
Over 80% of the ferrochrome produced worldwide is used to manufacture stainless steel . In 2006, 28 million tons of stainless steel were produced. The corrosion resistance and appearance of stainless steel depends on the chromium content. The average chromium content in stainless steel is around 18%. Ferrochrome from southern Africa, known as charge chrome, is made from a chrome ore with a low chrome content.
Names and composition
Ferrochrome and ferrochrome silicon , material numbers 0.40xx, are usually divided into five groups based on their composition:
| designation | Cr content [%] | C content [%] | Si content [%] | N content [%] |
|---|---|---|---|---|
| Ferrochrome suraffiné | 55 to 95 | <0.5 | <1.5 | <0.05 or 3 to 10 |
| Ferrochrome affiné | 55 to 75 | 0.5 to 2.0 | <1.5 | --- |
| Ferrochrome carburé | 45 to 70 | 4 to 10 | until 5 | --- |
| Ferrochrome silicon (Si low) | 35 to 40 | <0.1 | 35 to 40 | --- |
| Ferrochrome silicon (Si high) | 28 to 35 | <1.5 | 45 to 55 | --- |
Individual evidence
- ↑ icdacr.com - International Chromium Development Association
- ↑ USGS 2006 Minerals Yearbook July 2008 (PDF; 93 kB)
- ↑ DIN 17565 (2004-02)