Choosing the right blow bar material is one of the most impactful decisions you can make for your HSI crusher. The wrong alloy wastes money — either through premature wear or unnecessary over-specification. This guide breaks down the two most widely used blow bar materials: high chrome white iron and martensitic steel, along with a brief look at manganese and composite upgrade options. For the complete 9-material comparison including ceramic and TiC composites, lead times, and rotation schedules, see our comprehensive blow bars material guide.
Complete 9-Material Blow Bar Guide
Compare all materials including ceramic and TiC composites, with lead times and rotation schedules.
High Chrome White Iron (ASTM A532 Class III)
High chrome iron is the maximum abrasion resistance option for blow bars. Its dense chromium carbide microstructure delivers hardness of 60–64 HRC, making it the top performer in clean, abrasive secondary and tertiary crushing applications.
- Hardness: 60–64 HRC
- ASTM A532 Class III Type A equivalent
- Maximum wear resistance from chromium carbide microstructure
- Impact tolerance: brittle — unsuitable for tramp metal or large uncrushables
- Clean limestone and basalt in secondary/tertiary circuits
- River gravel and natural aggregate
- Manufactured sand production
- Any application with rigorous steel removal upstream
Tempered High Chrome Variant (55–58 HRC)
For operations with variable quarry conditions and occasional unexpected impacts, a tempered version reduces hardness to 55–58 HRC. This controlled trade-off sacrifices 10–15% wear life but significantly reduces brittleness. It is a practical choice when feed cleanliness cannot be guaranteed 100% of the time.
Martensitic Steel
Martensitic steel is a quench-and-temper alloy that arrives already hard at 48–54 HRC. Unlike manganese steel, it does not rely on work-hardening — it is effective from the first pass. This makes it the go-to material for concrete recycling and demolition, where impact energy is high but abrasion is moderate.
- Hardness: 48–54 HRC as-delivered
- No work-hardening required — effective immediately
- Medium-high impact tolerance — handles rebar strikes without catastrophic fracture
- Lower cost than high chrome
- Concrete recycling with rebar content
- Mixed demolition waste
- Moderate-abrasion feeds with variable impact loading
- Applications where tramp metal cannot be reliably removed
Martensitic steel bridges the gap between manganese's toughness and high chrome's abrasion resistance. When your feed is too abrasive for manganese but contains too much tramp metal for high chrome, martensitic is usually the correct choice.
What About Manganese Steel?
Manganese steel (Mn18Cr2) is the third major blow bar material and deserves mention in any material comparison. It is the classic work-hardening alloy: starting at 200–240 HB, the surface work-hardens to 500+ HB under repeated impact while the core stays tough.
Manganese is best suited for primary crushing and heavy demolition where impact energy is extremely high. However, it requires sufficient impact force to activate — in low-impact secondary applications, the surface "glazes" rather than hardens, leading to rapid, premature wear.
For a detailed comparison of all three base alloys plus six composite upgrade options, visit our complete blow bars material guide.
Material Hardness Comparison
Rockwell C (HRC) equivalent scale — higher values indicate greater hardness and abrasion resistance
Material Selection Guide
| Application | Recommended Material | Why |
|---|---|---|
| Granite / Basalt (clean) | High Chrome (60–64 HRC) | Maximum abrasion resistance for clean, hard rock |
| Limestone (secondary) | High Chrome or Martensitic | Chrome for abrasion; martensitic if impacts occur |
| River Gravel | High Chrome (60–64 HRC) | Abrasive natural aggregate, typically clean feed |
| Concrete Recycling | Martensitic (48–54 HRC) | Tolerates rebar strikes without fracture |
| Mixed Demolition | Martensitic (48–54 HRC) | Handles variable feed and tramp metal |
| Primary Crushing | Manganese (Mn18Cr2) | Work-hardens under heavy impact |
| Variable Quarry | Tempered High Chrome (55–58 HRC) | Compromise between wear life and impact tolerance |
Ceramic & TiC Composite Upgrades
All three base alloys — high chrome, martensitic, and manganese — are available with ceramic insert (MMC) or TiC insert upgrades. These composites embed extremely hard particles (1600 HV ceramic or 3200 HV titanium carbide) into the base metal, extending wear life by 30–50% in suitable applications.
However, composite blow bars require functioning magnetic separation and metal detection upstream. The inserts fracture under point-load impact from tramp iron or undetected rebar. They are strictly for operations with controlled, clean feed.
Learn more about ceramic insert technology and TiC insert technology, or see the full material comparison with lead times.
Free Technical Consultation
Our application engineers help you choose the right blow bar material for your specific crusher model and feed conditions.
Need Help Choosing?
Material selection depends on your specific crusher model, feed characteristics, and operational constraints. ATF application engineers provide free technical consultations — contact us with your crusher model and feed material for a recommendation, or explore our complete blow bars material guide for detailed specifications across all 9 material options.
