The selection of a recarburiser always depends on the produced iron alloy. Ductile graphite iron (GGG / GJS), cast iron with vermicular graphite (CGI) and special steel grades require a low sulfur content.
For grey iron (GG / GJL) normally a recarburiser with a medium sulphur content is fully sufficient (see enclosed table). To determine the carbon content, at least one sample should be extracted from the molten iron for chemical analysis.
Chemical composition (typical values)
| Type of recarburiser | Field of application | Properties / Advantages / Disadvantages | Solubility 1 – 6 |
|---|---|---|---|
| Graphite – crystalline carbon | |||
| High purity, synthetic raphite (i.e. Ultra High Power-E-Graphite) | all iron alloys | High C content, very good solubility, low N and H content | 1 |
| Synthetic graphite E-graphite graphitised Petroleum coke | all iron alloys | High C content, very good solubility, low S, N, ash content | 1 |
| Natural graphite | iron alloys with an elevated tapping temperature | The higher ash content results in a slower solubility, S and N content is generally low, varying analysis (depending on the storage facility) | 4 |
| Coke – amorphous carbon | |||
| Acetylene coke Granular and pellets | all iron alloys | High C content, slower solubility, low S, N content | 5 |
| Low sulphur petroleum coke (Needle coke) | all iron alloys | High C content, good solubility, low S, N, ash content | 1 |
| Medium sulphur petroleum coke | grey iron, steel casting and steel production | High C content, acceptable solubility | 2 |
| High sulphur and nitrogen petroleum coke | grey iron and steel production | High C, S, N content, slower solubility with higher saturation levels | 3 |
| Metallurgical Coke Breeze | steel production | High ash content, requires high melting temperatures and a low C saturation of the molten metal | 6 |
| Pellets | |||
| Carbon pellets | all iron alloys | High C content, with an elevated content of volatile matter, ideally suited for the base iron carburisation. Also suitable for rotary furnaces. Pellets are available with different chemical compositions | 4 |
| Anthracite – amorphous carbon | |||
| Electrically calcined anthracite | iron alloys with a high tapping temperature | The higher ash content results in a slower solubility, S and N content depends on the storage facility | 5 |
| Gas-calcined anthracite | iron alloys with a high tapping temperature | The higher ash content leeds to a slower solubility. S and N content depends mainly on the geological deposit. | 5 |
| Dried Anthracite | iron alloys with a high tapping temperature | Similar to ECA and GCA, but with higher volatile components | 5 |