Crusher Wear Parts: Manganese, Martensitic, Chrome and Ceramic

Crusher wear parts are parts such as jaw plates, mantles and concaves, blow bars, apron liners, VSI rotor tips, screen media and housing liners, which wear over time through direct contact with the material and are replaced periodically. Together with energy, wear parts are one of the largest items in the operating cost of a crushing and screening plant. The right choice of material can multiply part life in the same crusher; the wrong choice means early breakage, unplanned stoppages and high costs.

In this guide we cover in detail wear mechanisms, the main wear part materials (manganese steels, martensitic steels, high chrome white irons, ceramic-reinforced composites, wear plates, polyurethane and rubber), material selection by crusher type, quality control, ways to extend wear part life and supplier selection.

Wear Mechanisms

To choose the right wear part material, you need to understand what kind of wear the part is exposed to:

• Impact: Rock striking the part at high speed or force. Important in jaw crushers, impact crushers and VSIs. Resisting impact requires toughness.
• Abrasion (sliding wear): Hard particles sliding over the surface and removing material. The lower areas of cone crushers, chutes, troughs and screens are typical examples. Resisting abrasion requires hardness.
• Gouging: Large, hard rocks gouging the surface; seen in primary crushers.
• Corrosion: Accelerates wear in wet and chemical environments.

The basic dilemma is: as hardness increases, wear resistance increases but toughness (impact resistance) decreases. The right balance between these two properties must be found for each application.

Main Wear Part Materials

Austenitic Manganese Steels (Hadfield Steel)

Manganese steels are the most common wear material in the crushing industry. As cast they are relatively soft; however, under impact and pressure the surface hardens (work hardening) while the core remains tough. This property is ideal for jaw plates, mantles and concaves that work under constant impact and pressure.

Important: Manganese steel only hardens when there is enough impact and pressure. If impact is insufficient (e.g. very fine, abrasive feed, soft rock), the surface does not harden and the part wears quickly. In addition, manganese steel can become brittle if overheated (incorrect welding or cutting).

Martensitic Steels

Martensitic steels are harder than manganese steel and tougher than high chrome cast iron. They are a good middle way for blow bars, especially in impact crushers where there is metal and coarse feed but wear is also important (recycling, primary impact crushing, moderately abrasive rock).

High Chrome White Irons

Thanks to the hard chromium carbides in their structure, they have very high abrasion resistance; however, they are brittle. They are preferred for blow bars in secondary and tertiary crushing in impact crushers, with controlled feed size and metal-free material. They are also used in mill liners, pump parts and wear liners. An uncrushable metal object can break a high chrome blow bar.

Ceramic- and Carbide-Reinforced Composites

Composite parts in which very hard particles such as ceramics (e.g. alumina–zirconia) or titanium carbide (TiC) are embedded in a manganese or martensitic steel matrix. There is hard reinforcement in the areas of heaviest wear and a tough matrix in the rest. In suitable applications they can offer markedly longer life than standard materials; their unit prices are higher and they should be assessed according to the application.

Wear Plates and Hardfacing

Wear plates in the 400–500 HB hardness class are usually used for chutes, troughs, bins, crusher housings and buckets. At very abrasive points, chromium carbide overlay (hardfaced) plates may be preferred. For bin and chute liners, see our bin guide, and for crusher housing liners, our housing liners guide.

Polyurethane and Rubber

For sliding wear by fine, wet material, polyurethane and rubber can last longer than metal. Screen panels, hydrocyclone liners, pump parts, chute liners and mill liners are typical applications. Rubber also offers impact damping and noise reduction.

Material Selection by Crusher Type

For the effect of rock properties on material selection, see our rock crushability guide.

Quality Control: How Can You Tell a Good Wear Part?

• Chemical analysis: The composition of the material must match the declared grade. A spectral analysis report can be requested.
• Heat treatment: If quenching (solution annealing) of manganese steels is not done correctly, carbides precipitate at the grain boundaries and the part becomes brittle. In martensitic and chrome materials, heat treatment determines hardness.
• Hardness: Hardness values appropriate to the material grade should be measured.
• Casting quality: There should be no porosity, cracks, shrinkage cavities or mould defects. Ultrasonic or dye penetrant testing can be applied to critical parts.
• Dimensions and tolerances: The part’s seating surfaces and bolt holes must fit the crusher exactly. A part that does not seat, if forced in with backing and shims, can break early.
• Certificates and traceability: Heat numbers, material certificates and production records should be requested.

Ways to Extend Wear Part Life

1. Correct feeding: Feeding the crusher continuously and evenly, and choke feeding cone crushers, ensures wear is distributed evenly.
2. Removing fines: Scalping before the crusher reduces unnecessary abrasive wear.
3. Metal protection: A magnetic separator and metal detector prevent breakage of blow bars and liners (magnetic separator guide).
4. Turning and rotating: Symmetrical jaw plates and blow bars can be turned at the right time to increase usable life.
5. Profile selection: A crushing chamber profile suited to the feed size evens out the wear profile.
6. Backing compound: Correctly applied backing behind mantles and concaves ensures the parts seat properly and do not crack (backing compound guide; for CSP’s own brand, see Aurox crusher backing).
7. Tonnage-based tracking: The tonnage processed by each part should be recorded so that the effect of material changes can be measured.
8. Replacement at the right time: Thinning a part too far can damage the supporting parts (housing, rotor, pitman).

How Is a Replacement Schedule Created?

Wear part replacement should be scheduled to avoid unplanned stoppages:

• An average life by tonnage is established for each part.
• Remaining life is estimated by regular wear measurements (thickness, profile).
• Replacements falling in the same period are grouped and done at planned shutdowns.
• Order timing is set taking part lead times into account.
• At least one set of critical parts is kept in stock.

Choosing a Supplier

Looking only at unit price when choosing a wear part supplier is misleading. The right basis of comparison is wear cost per tonne (part cost + replacement labour + downtime cost, divided by tonnes processed). It is important that the supplier:

• Can provide material certificates and quality control records,
• Can offer different metallurgy options and application advice,
• Can guarantee dimensional compatibility,
• Is reliable in terms of stock and lead time,
• Can provide field experience and technical support.

A new supplier or material should first be trialled with a limited number of parts and compared on a per-tonne basis.

A Field Example

Suppose cone crusher mantles at a granite quarry are lasting less than expected. The investigation shows that the feed distribution is very fine and the crusher is running half empty; the manganese surface is not hardening sufficiently and wear is concentrated in the lower area. When fines are removed by scalping, the crusher is choke fed with feed level control and Mn18Cr2 alloyed mantles and concaves are used, the wear profile improves and part life increases. This example shows that wear part life depends not only on the material but also on operating conditions.

Frequently Asked Questions

Should Mn18 or Mn22 be chosen?

In most applications Mn18 is a good balance. In very hard, coarse and high-impact applications Mn22 can give better results. If impact is insufficient, higher manganese gives no advantage.

Why do high chrome blow bars break?

High chrome materials are brittle; coarse feed or uncrushable metal can lead to breakage. In these conditions martensitic or manganese bars should be preferred.

Are ceramic-reinforced parts always more economical?

No. In suitable applications, the increase in life can cover the price difference; however, impact conditions and crusher type must be assessed.

Can manganese parts be repaired by welding?

Limited repairs can be made with suitable electrodes and low heat input; overheating makes the material brittle.

How should wear part costs be compared?

By total cost per tonne (part + labour + downtime) rather than unit price.

Wear Part Catalogue by Crusher Type

For cone crusher mantle and concave selection, see our mantle and concave replacement guide; for VSI wear parts, our rotor tips and anvil ring guides; and for jaw crushers, our toggle plate guide.

Information Needed to Order Wear Parts

• Crusher make, model and serial number,
• Part number (if known) or technical drawing / dimensions,
• Type of rock processed and abrasiveness information,
• Feed size and target product,
• Material of the current part and the life achieved (tonnes or hours),
• Preferred crushing chamber profile or jaw tooth type,
• Quantity required and delivery date.

This information allows the right material and profile to be recommended and compatible parts to be supplied first time.

Wear Part Life Record Table

Glossary

• Work hardening: The hardening of the surface of manganese steel under impact and pressure.
• Hadfield steel: The classic name for austenitic manganese steel.
• Martensitic steel: Steel given a hard martensite structure by heat treatment.
• High chrome cast iron: A very wear-resistant but brittle material containing hard chromium carbides.
• HB: Brinell hardness value.
• Concave (bowl liner): The fixed crushing surface of a cone crusher.

Support from CSP Mühendislik

CSP Mühendislik supplies wear parts in different metallurgy options for jaw, cone, impact and vertical shaft crushers, and supports application-specific material recommendations and replacement planning. For your parts requirements, see our jaw crusher spare parts, cone crusher spare parts, impact crusher spare parts and VSI crusher spare parts pages, and find out about our service, maintenance and repair.