Impact Crusher Wear Parts: A Complete Guide to Blow Bars, Impact Plate

Impact crushers are workhorses in quarries, recycling yards, and mining operations. They use high-speed impact to fracture material — and the components that take the heaviest punishment are the impact crusher wear parts: the blow bars (also called hammers), impact plates, and liners.

Unlike jaw or cone crushers that rely on compression, impact crushers use kinetic energy. A spinning rotor throws material against impact plates, fracturing it on contact. This means impact crusher wear parts experience extremely high impact forces, sliding abrasion, and thermal stress — a punishing combination.

The wrong choice of impact crusher wear parts can lead to:

• Premature blow bar breakage — catastrophic failure that damages the rotor

• Rapid wear — blow bars lasting only days instead of weeks

• Poor product shape — too many flats or elongated pieces

• Frequent downtime — replacing parts too often

The right choice? You can extend blow bar life by 2–3x, reduce cost per ton significantly, and keep your impact crusher running reliably.

In this guide, we cover everything you need to know about impact crusher wear parts — blow bars, impact plates, and liners. We’ll explain material options (high chrome, manganese, ceramic composite), how to match them to your application, how to identify wear patterns, and how to maximize service life. Whether you run a horizontal shaft impactor (HSI) or a vertical shaft impactor (VSI), this guide will help you make better decisions.

 

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What Are Impact Crusher Wear Parts and How Do They Work?

Impact crusher wear parts consist of three main component groups:

How an impact crusher works

1. Material enters the top of the crusher through the feed opening.

2. The rotor spins at high speed (typically 400–800 RPM). Attached to the rotor are the blow bars.

3. Material hits the blow bars and is fractured on impact. The blow bars also throw the material toward the impact plates.

4. Material strikes the impact plates, fracturing further. It rebounds back toward the blow bars.

5. This cycle repeats — material bounces between blow bars and impact plates — until it is small enough to exit through the bottom discharge opening.

Because impact crusher wear parts are subjected to repeated high-velocity impacts and sliding abrasion, they wear faster than wear parts in compression crushers. A set of blow bars in a hard rock application might last only 200–500 hours, while jaw plates in the same application could last 2,000 hours.

⚠️ Key takeaway: Impact crusher wear parts require more frequent replacement than jaw or cone crusher wear parts. Choosing the right material is critical to minimizing replacement frequency.

 

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Blow Bars – The Most Critical Impact Crusher Wear Part

Blow bars (also called hammers or impact hammers) are the most heavily stressed impact crusher wear parts. They attach directly to the rotor and take the initial impact of incoming material.

Blow bar attachment methods

 

When blow bars wear down, the gap between the blow bar tip and the impact plate increases, reducing crushing efficiency. Most operators reverse or rotate blow bars (end-for-end) once to extend life before replacement.

 

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Material Selection for Blow Bars – High Chrome, Manganese, or Ceramic Composite?

The material of your blow bars determines wear life, resistance to breakage, and cost per ton. Three main material families exist for impact crusher wear parts.

1. High Chrome Iron (15–25% Chromium)

Best for: Highly abrasive materials (river gravel, quartzite, iron ore, hard basalt, recycled asphalt)

Characteristics:

• Very high hardness (650–800 HB)

• Excellent abrasion resistance

• Relatively brittle — poor impact toughness

• Not suitable for materials with tramp iron (rebar, bolts)

 

When to choose high chrome blow bars:

• Your feed material is highly abrasive (silica content >15%)

• There is no tramp iron risk (clean feed, no rebar or bolts)

• You want maximum wear life (2–3x longer than manganese in abrasive conditions)

2. Manganese Steel (Mn14, Mn18, Mn22)

Best for: Materials with tramp iron risk (recycled concrete with rebar, demolition debris, material from previous crusher with possible metal contamination)

Characteristics:

• Work-hardens under impact (surface hardness increases with use)

• Very tough — resists breakage from tramp iron

• Lower abrasion resistance than high chrome

• Can be welded or repaired more easily

 

When to choose manganese blow bars:

• Your feed may contain tramp iron (recycling applications)

• You prioritize toughness (no breakage) over maximum wear life

• Your material is less abrasive (limestone, soft rock)

3. Ceramic Composite (Chromium-Ceramic)

Best for: Extremely abrasive materials where maximum wear life is the priority

Characteristics:

• Ceramic particles (alumina) embedded in a high chrome matrix

• Highest abrasion resistance available for impact crusher wear parts

• 1.5–2x longer wear life than standard high chrome

• Higher upfront cost (15–30% more than high chrome)

• Brittle — not for tramp iron applications

When to choose ceramic composite blow bars:

• Your material is extremely abrasive (silica >25%, iron ore, copper ore)

• You want the longest possible wear life between changes

• You have a high-tonnage operation where downtime is very expensive

• There is no tramp iron risk

Material comparison summary

⚠️ Critical warning: Never use high chrome or ceramic composite blow bars in applications that may contain tramp iron (rebar, bolts, large metal pieces). The blow bars will crack or shatter, potentially damaging the rotor — a very expensive repair.

 

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Impact Plates and Liners – The Supporting Cast

While blow bars get most of the attention, impact plates and liners are also important impact crusher wear parts.

Impact plates (apron plates)

Function: Stationary plates that absorb the impact of material thrown by the blow bars. Impact plates are typically adjustable — moving closer to or farther from the blow bar tips to control product size.

Wear pattern: Impact plates wear most in the center zone, where material strikes directly. As they wear, the crushing action becomes less efficient.

 

When to replace impact plates: When the wear surface has lost >50% of original thickness, or when the plate has developed deep grooves or holes.

Liners

Function: Protect the crusher housing (upper and lower housing, side liners) from wear. Liners are typically the longest-lasting impact crusher wear parts.

Wear pattern: Liners wear most in areas where material ricochets — usually on the lower housing near the discharge opening.

Material: Most liners are made of wear-resistant steel (400–500 Brinell hardness) or manganese steel.

 

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How to Match Impact Crusher Wear Parts to Your Application

Application matching is the single most important factor in maximizing impact crusher wear parts life.

Decision flow: Which blow bar material should you choose?

Feed size considerations for impact crusher wear parts

 

Rule of thumb: Maximum feed size should not exceed 60–70% of the rotor diameter for HSI crushers, and should never exceed the blow bar height.

 

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How to Extend the Service Life of Your Impact Crusher Wear Parts

Even with the right material choice, proper operation practices will extend impact crusher wear parts life.

1. Check feed material for tramp iron

Before feeding material into an impact crusher with high chrome or ceramic composite blow bars, remove tramp iron using magnets or manual picking. A single piece of rebar can crack a high chrome blow bar, requiring immediate shutdown.

2. Maintain consistent feed rate

Inconsistent feed (surges and gaps) causes:

• Uneven blow bar wear

• Impact plate hammering

• Reduced wear life

Solution: Use a feeder (vibrating or belt) to maintain a consistent, continuous feed rate.

3. Rotate or reverse blow bars at half life

Most blow bars are reversible (end-for-end) or rotatable (top to bottom). At approximately 50% wear:

• Reverse blow bars end-for-end to expose the unworn end

• If blow bars are symmetrical, rotate them to place the worn side away from the impact zone

This can double blow bar life with no additional cost.

4. Adjust impact plate position as blow bars wear

As blow bars wear, the gap between blow bar tips and impact plates increases. Most impact crushers allow hydraulic or mechanical adjustment of impact plates.

Best practice: Adjust impact plates weekly to maintain the optimal gap. This keeps product size consistent and prevents efficiency loss.

5. Avoid feeding wet, sticky material

Moist, sticky material can:

• Pack between blow bars and rotor, causing unbalanced rotor

• Accelerate abrasive wear on impact plates

• Reduce throughput and increase wear part stress

Maximum recommended moisture: 8–10% for most impact crushers. For wetter material, use a jaw or cone crusher instead.

 

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How to Know When to Replace Your Impact Crusher Wear Parts

Blow bar replacement indicators

Impact plate replacement indicators

Typical wear life ranges by application

Note: These are estimates. Actual wear life varies significantly with feed size, rotor speed, and crusher settings.

 

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BDI Wear Parts – Your Source for Impact Crusher Wear Parts

At BDI Wear Parts, we supply a complete range of impact crusher wear parts for most major brands, including:

• HSI crushers: Sandvik, Metso, Terex, Hazemag, Kleemann, Powerscreen, Eagle, and more

• VSI crushers: Parts for most vertical shaft impactor models

 

What makes BDI impact crusher wear parts different:

 

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Frequently Asked Questions (FAQ)

Q1: What is the difference between high chrome and manganese blow bars? Which one should I choose?

A: The choice depends entirely on your feed material and tramp iron risk.

 

Quick rule:

• If your feed is clean (no metal risk) and abrasive → High chrome or ceramic composite

• If your feed may contain tramp iron (rebar, bolts) → Manganese (Mn18 or Mn22)

 

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Q2: How can I extend the life of my blow bars without changing material?

A: Three practical methods:

1. Rotate or reverse blow bars at 50% wear – Most blow bars are reversible end-for-end or rotatable top-to-bottom. This can double blow bar life with no extra cost.

2. Adjust impact plates as blow bars wear – As blow bars wear, the gap to the impact plates increases. Adjust impact plates weekly to maintain the optimal gap. This keeps crushing efficiency high and prevents uneven wear.

3. Maintain consistent feed rate and remove fines – Inconsistent feed (surges and gaps) accelerates wear. Pre-screening to remove fines before the impact crusher also reduces unnecessary wear on blow bars and impact plates.

If you are already doing all of these and still have short blow bar life, consider upgrading to a higher-performance material (e.g., from standard high chrome to ceramic composite, or from Mn14 to Mn18).

 

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Q3: Can I use aftermarket impact crusher wear parts from BDI on my OEM crusher?

A: Yes. BDI Wear Parts blow bars, impact plates, and liners are designed as direct replacements for OEM parts on most major impact crusher brands (Sandvik, Metso, Hazemag, Kleemann, Terex, Powerscreen, and others).

We use a verification process — including crusher model, rotor type, and critical dimensions — to ensure every part fits exactly as intended. For older or uncommon crusher models, we can reverse-engineer blow bars from your worn samples or drawings.

Thousands of Canadian operations use aftermarket impact crusher wear parts from reputable suppliers like BDI to save 30–50% compared to OEM pricing without sacrificing quality or fitment. We provide material certifications with every shipment so you can verify quality before installation.

 

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Conclusion: Choose the Right Impact Crusher Wear Parts and Reduce Your Cost Per Ton

Impact crusher wear parts — blow bars, impact plates, and liners — are replaced more frequently than any other crusher wear parts. But that doesn’t mean you have to accept high costs.

The right combination of:

• Material selection (high chrome for clean abrasive rock, manganese for tramp iron risk, ceramic composite for extreme abrasion)

• Proper operation (consistent feed, remove tramp iron, adjust impact plates regularly)

• Rotation/reversal (double blow bar life at no cost)

…can reduce your impact crusher operating cost per ton by 25–40% compared to using generic or mismatched parts.

Whether you need standard high chrome blow bars for river gravel or manganese blow bars for recycled concrete with rebar, BDI Wear Parts delivers quality, fitment, and value — with Canada-focused logistics and competitive pricing.

 

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