2026-10-09
Typical working condition
This is a typical working condition, not a single site: the second crushing stage of a granite aggregate production line. The material has already passed the primary crusher, and this stage reduces it further. The machine is an impact crusher. The finished product is used as high-grade concrete aggregate.
Blow bar material is selected to match the material being crushed
Blow bar material is selected according to the material being crushed. High-chromium alloy blow bars have a hardness of HRC 56–58 and a service life 3–5 times that of conventional materials. HRC is the Rockwell C hardness scale.
The lost foam casting process is covered by our own patent. It makes the casting denser inside, and internal density directly affects the actual service life of the wear part. Casting quality is part of wear life, not separate from it.
High manganese chromium alloy steel is one of our standard materials.
Parts to review together on a secondary impact crusher
A secondary impact crusher has to be reviewed as a set of parts, not one part at a time. The list below covers the wear parts, the rotor assembly, the adjustment hardware and the drive:
- Blow bars
- Impact plate liners
- Rotor assembly
- Tension rods
- Adjusting bolts
- Springs
- Flywheel
- Bearings
- Motor
- V-belts
Early blow bar failure: the feed, not the material
In field experience, the first thing to look at when a blow bar fails early is not the material grade. It is the feed.
Oversize blocks and uncrushable objects crack the blow bars. Feed that arrives on one side of the rotor wears the blow bars through on one side first.
The fix belongs upstream of the crusher. We recommend iron removal and oversize control ahead of the impact crusher, so that oversized blocks and uncrushable metal do not reach the chamber.
The number one cause of early blow bar failure is not the material, it is the feed.
Replacement points and matched spare parts
On a granite line running three shifts, the replacement point is judged from production records.
Order spare parts in sets. When the blow bars and the impact plate liners are replaced together, the crushing curve does not drift.