The cost-effective use of the blow bars is influenced by many factors (e.g. feed material, rotor speed, moisture content, feed size, crushing ratio). Use the following guideline to identify the optimum blow bar for your particular application. If this leads you to choose various blow bars, start with the most cost-effective choice for your application.
Questions on selecting blow bars appropriate to the application:
- Which material will be crushed? (broken-up concrete, for example)
- How can the feed size be classified? (e.g. largest grain size 600 mm)
- Is the material cubic or plate-like?
- What is the abrasiveness class of the material?
Determining the possible blow bars:
See diagram: Feed material classification
Verification of the determined blow bar version with regard to the availability of the crusher type:
- Manganese steel
- Martensitic steel
- Martensitic steel with ceramic insert
- Chrome steel
- Chrome steel with ceramic insert
Recommendations for blow bar application
| Version | Properties | Recommended application |
|---|---|---|
| Manganese steel | Manganese steel is used when increased impact resistance or elongation is required. When the impact force is sufficient, the manganese steel of the blow bar consolidates (cold consolidation) and therefore reduces the wear. | ◇ Mild abrasiveness, e.g. limestone ◇ In case of very large feed size ◇ When there is a very high proportion of unbreakable objects in the feed material e.g. iron◇ |
| Martensitic steel | This steel combines hardness and impact resistance where using chromium steel would lead to breakage. Furthermore, martensite blow bars have a longer service life than manganese blow bars for applications with abrasive materials. | ◇ Building rubble ◇ Blasted limestone ◇ In case of large feed material (depends on the geometry of the crusher inlet) |
| Martensitic steel with ceramic insert (MartComp / MartXpert) | The blow bar comprises a martensite body which is reinforced on the inside with ceramic inlays. This composite material combines the hardness of a ceramic with the mechanical characteristics of steel and has a 2 to 4 times longer service life when compared to blow bars made of single alloys. | ◇ Recycling of building rubble with little to medium iron content ◇ Concrete ◇ Natural stone |
| Martensitic steel with ceramic insert (MartXtra / MartPower) | The ceramic inlay is cast in deeper and more elongated. The impact edge therefore is preserved until the end of the wear period, increasing the service life compared to the MartComp/ MartXpert blow bar for abrasive applications. | ◇ Recycling of building rubble with little to medium iron content ◇ Concrete ◇ Natural stone ◇ Asphalt |
| Chrome steel | Chrome steel is characterised in particular by its increased hardness and has the advantage of being particularly wear resistant in applications where manganese and martensitic steels wear down more quickly. | ◇ Secondary crushing level with natural stone or river gravel ◇ In case of smaller feed sizes |
| Chrome steel with ceramic insert (ChromComp / ChromXpert) | The bond between chrome body and ceramic inlays ensures a constant wear profile with very abrasive pre-crushed materials which are encountered especially in gravel pits and quarries. | ◇ Secondary crushing level with very abrasive natural stone or river gravel ◇ Asphalt in case of smaller feed size ◇ Milled material without any iron content |