Manganese Steel | Mn13-Mn22 Work Hardening | ATF

Material Technology

Manganese Steel | Mn13-Mn22 Work Hardening | ATF

Mn13-Mn22 manganese steel: work hardening 200-500+ BHN. Impact toughness carbon optimization. Grade selection by duty. Industry standard.

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Key Specifications

Grade Range
Mn13 to Mn22Cr3
As-Cast Hardness
180–290 HB (grade-dependent)
Work-Hardened Hardness
350–550+ BHN (impact-dependent)
Carbon Range
1.0–1.4% (controls work-hardening response)
Chromium Range
0–3.5% (grain refinement, yield strength)
Impact Toughness
> 100 J/cm2 (fully austenitic structure)
Heat Treatment
Solution anneal 1,050–1,100 C + water quench
Standard
ASTM A128 (all grades)

Key Properties of Manganese Steel for Crusher Parts

Work-Hardening Mechanism

Austenitic manganese steel work-hardens under compressive impact. Repeated deformation introduces strain-induced martensite and mechanical twinning at the surface, raising hardness from approximately 200 HB as-cast to 450-550+ BHN in service while the interior remains tough and ductile.

Exceptional Impact Toughness

The fully austenitic structure provides impact toughness values exceeding 100 J/cm2 at ambient temperatures. This resistance to brittle fracture is critical in primary crushers where tramp iron or uncrushable objects can enter the chamber.

Non-Magnetic Austenitic Structure

Properly heat-treated manganese steel is non-magnetic in the as-supplied condition. The stable austenite phase only transforms locally at the wear surface under impact, preserving bulk ductility throughout the service life of the part.

Self-Renewing Wear Surface

As the hardened surface layer wears away, the fresh austenite beneath is exposed and work-hardens in turn. This self-renewing mechanism provides consistent crushing performance from installation to end of life.

Broad Grade Selection

Grades from Mn13 to Mn22 with optional chromium modifications allow precise matching of material properties to service conditions. Low-impact applications use standard Mn13, while high-energy primary crushers benefit from Mn18Cr2 or Mn22Cr2.

Weldability for Field Repair

Manganese steel accepts hard-facing and buildup welding using appropriate electrodes (typically E-FeMn type). Field welding repairs can extend part life, though interpass temperatures must be controlled below 260 C to prevent embrittlement.

Manganese

Manganese Steel: The Foundation of Crusher Wear Parts

Austenitic manganese steel, first developed by Sir Robert Hadfield in 1882, remains the most widely used material for crusher wear parts worldwide, with global consumption exceeding one million tonnes annually across mining, aggregate, and recycling industries. The defining characteristic of manganese steel is its work-hardening response: the fully austenitic microstructure transforms under repeated compressive impact through mechanical twinning and strain-induced martensitic transformation, raising the surface hardness from an as-cast 180–290 HB (grade-dependent) to 350–550+ BHN in service while the core retains its original toughness exceeding 100 J/cm2 Charpy impact energy. This combination of a hard, wear-resistant surface backed by a tough, shock-absorbing interior is unmatched for high-impact crushing applications where tramp metal, uncrushable objects, or variable feed conditions make brittle alloys such as high-chrome white iron unsuitable. All grades are supplied in the solution-annealed and water-quenched condition per ASTM A128 to dissolve grain-boundary carbides and achieve the fully austenitic microstructure essential for service performance.

Modern manganese steels have evolved well beyond the original Hadfield Mn13 composition. Grades ranging from Mn13 through Mn22, often modified with chromium additions of 1.5–3.5%, are engineered to match specific crusher duties across the full spectrum of impact and abrasion severity. Higher manganese content (17–23%) increases work-hardening capacity, work-hardening depth, and ultimate achievable surface hardness, while controlled carbon levels (typically 1.0–1.4%) balance work-hardening response against the risk of grain-boundary carbide precipitation during heat treatment. Chromium additions refine the as-cast grain structure, increase the initial yield strength (improving resistance to plastic flow before work hardening is fully activated), and enhance abrasion resistance in the pre-hardened condition. Selecting the correct grade for a given application—considering crusher type, feed material hardness and abrasiveness (Bond Work Index, SiO2 content), impact energy, and required product size—directly impacts liner life, crusher throughput, maintenance cost, and total cost of ownership per tonne of processed material.

Mn13 to Mn22 Grades
Work Hardening to 500+ BHN
ISO Certified

Grade Selection by Equipment Type

The correct manganese grade depends on the type of crusher, the impact energy generated, and the feed material characteristics. Below are typical grade recommendations by equipment category. Actual selection should consider specific operating conditions including feed size, closed-side setting, and ore hardness.

Primary Jaw Crushers

  • Mn18Cr2 recommended for standard primary duty (limestone, granite, basalt)
  • Mn22Cr2 for large-format jaws (1200mm+ feed opening) processing hard ore
  • Mn13Cr2 or Mn14 acceptable for soft rock and recycling applications
  • Cheek plates typically one grade lower than jaw plates (e.g., Mn14 cheeks with Mn18Cr2 jaws)

Secondary Cone Crushers

  • Mn14 or Mn18Cr2 for mantles and concaves in standard aggregate production
  • Mn13Cr2 for fine-crushing cones with lower impact energy
  • Mn22Cr2 for high-performance cone crushers in hard-rock mining
  • Higher grades provide longer life where feed is consistently abrasive

Gyratory Crushers

  • Mn18Cr2 as the standard grade for primary gyratory mantles and concaves
  • Mn22Cr2 or Mn22Cr3 for large mining-class gyratories (60x89, 54x75, etc.)
  • Upper concave rows may use higher grades due to greater impact exposure
  • Spider caps and arm guards typically Mn13 or Mn13Cr2

Impact Crushers

  • Mn14 or Mn18Cr2 for horizontal shaft impactor blow bars (high impact energy)
  • Mn13 for apron liners and side plates in HSI applications
  • Mn22Cr2 seldom used in impactors; high-chrome white iron or martensitic steel often preferred for abrasion-dominant wear
  • Impact crusher selection depends heavily on rotor speed and feed hardness

Grinding Mills

  • Mn13 or Mn14 for mill liners in AG/SAG and ball mills
  • Mn18Cr2 for high-lift lifter bars exposed to direct ball impact
  • Composite Mn/Cr-Mo designs increasingly replacing straight manganese in large mills
  • Shell liners and grate plates may combine manganese with rubber backing

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Manganese Steel Grade Comparison

The table below compares the principal manganese steel grades used in crusher wear parts. All grades are solution-annealed and water-quenched to achieve a fully austenitic microstructure before installation. Carbon content is maintained within 1.0-1.4% across all grades to balance work-hardening response with resistance to grain-boundary carbide precipitation.

Mn13 (Standard Hadfield)

Hardness:180-220 HB as-cast / 350-400 BHN work-hardened
Application:Secondary and tertiary crushers, low to moderate impact, standard aggregate applications
Notes:C 1.0-1.3%, Mn 11.5-14%. The baseline grade. Economical for moderate-duty service where impact energy is sufficient to activate work hardening.

Mn13Cr2

Hardness:200-230 HB as-cast / 400-450 BHN work-hardened
Application:Medium-duty jaw crushers, cone crushers, secondary gyratory crushers
Notes:C 1.0-1.3%, Mn 11.5-14%, Cr 1.5-2.5%. Chromium refines grain structure and improves initial yield strength. Better performance than standard Mn13 in abrasive feeds.

Mn14

Hardness:200-230 HB as-cast / 400-450 BHN work-hardened
Application:Medium to heavy-duty jaw and cone crushers, general-purpose primary crushing
Notes:C 1.0-1.35%, Mn 13-15%. Slightly higher manganese than Mn13 increases work-hardening depth. Widely specified as a cost-effective upgrade from standard Hadfield.

Mn18Cr2

Hardness:220-260 HB as-cast / 450-500+ BHN work-hardened
Application:Primary jaw crushers, heavy-duty gyratory crushers, high-impact cone crushers
Notes:C 1.1-1.4%, Mn 17-19%, Cr 1.5-2.5%. The most popular premium grade. High manganese content gives superior work hardening and longer life under heavy impact.

Mn22Cr2

Hardness:240-280 HB as-cast / 500-550+ BHN work-hardened
Application:Extra-heavy-duty primary crushers, large gyratory crushers, mining-class jaw crushers
Notes:C 1.1-1.4%, Mn 20-23%, Cr 1.5-2.5%. Maximum work-hardening capacity. Specified for the largest crushers processing hard, abrasive ores at high throughput.

Mn22Cr3

Hardness:250-290 HB as-cast / 500-550+ BHN work-hardened
Application:Extreme-duty primary gyratory and jaw crushers, ultra-hard ore processing
Notes:C 1.15-1.4%, Mn 20-23%, Cr 2.5-3.5%. Highest Cr addition for maximum as-cast hardness and abrasion resistance. Used where both high impact and severe abrasion are present.

All grades are supplied in the solution-annealed and water-quenched condition per ASTM A128. Actual work-hardened surface hardness depends on impact energy, feed material, and operating conditions. Values shown are typical ranges based on field measurements.

FAQ

Manganese FAQs

Find answers to common questions about manganese materials, selection, maintenance, and ordering. Can't find what you're looking for?

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How does work hardening occur in manganese steel?
Work hardening in austenitic manganese steel occurs through two principal mechanisms: mechanical twinning and strain-induced martensitic transformation. When the austenite is subjected to compressive impact, deformation twins form within the grains and localized regions transform from austenite to martensite. Both mechanisms impede dislocation movement, progressively raising the surface hardness. The process is cumulative with each impact cycle, and hardness increases until the deformation energy is insufficient to produce further transformation. This is why higher-impact applications achieve greater work-hardened hardness values.
What is glazing and how is it prevented?
Glazing occurs when manganese steel is subjected to abrasion without sufficient impact energy to activate work hardening. The surface remains at its as-cast hardness of approximately 200 HB and wears rapidly by abrasive gouging. Glazed liners appear smooth and polished rather than work-hardened. Prevention requires matching the manganese grade to the duty: use lower grades (Mn13) in low-impact applications so the available energy can still activate hardening, or switch to a different alloy system (high-chrome iron, martensitic steel) where impact energy is inherently low.
Why is solution annealing and water quenching required?
As-cast manganese steel contains grain-boundary carbides that severely reduce toughness. Solution annealing (heating to 1050-1100 C) dissolves these carbides back into the austenite matrix. Rapid water quenching then prevents the carbides from re-precipitating during cooling. Without this heat treatment, the material is brittle and unsuitable for service. Slow cooling or reheating above approximately 260 C allows carbide precipitation and must be avoided, which is also why welding interpass temperatures must be carefully controlled.
How does carbon content affect performance?
Carbon is the primary element controlling the work-hardening response and as-cast hardness of manganese steel. Higher carbon (1.3-1.4%) produces greater as-cast hardness and a stronger work-hardening effect, but increases the risk of grain-boundary carbide precipitation if heat treatment is not precisely controlled. Lower carbon (1.0-1.1%) improves weldability and reduces carbide risk but lowers maximum achievable hardness. The optimal carbon content for a given grade balances wear performance against casting quality and heat-treatment reliability.
What role does chromium play in modified manganese grades?
Chromium additions of 1.5-3.5% in modified grades such as Mn13Cr2 and Mn18Cr2 serve multiple functions. Chromium refines the as-cast grain size, increases the initial yield strength (improving resistance to plastic deformation before full work hardening), and improves abrasion resistance in the pre-hardened condition. Chromium also stabilises certain carbide types that can improve wear resistance. However, excessive chromium can reduce impact toughness, which is why additions are typically limited to 3.5% maximum.
How does grain size affect manganese steel performance?
Finer grain size in manganese steel improves both yield strength and work-hardening rate. Grain refinement is achieved through controlled pouring temperatures, inoculation practices during casting, and alloying additions (chromium, titanium, or vanadium in small amounts). Coarse-grained castings require more impact energy to initiate work hardening and are more susceptible to intergranular cracking. ATF controls grain size through process parameters and composition management to ensure consistent field performance.
When should I choose manganese steel over high-chrome white iron?
Manganese steel is the preferred choice when the dominant wear mechanism is impact or combined impact-abrasion, because its toughness prevents catastrophic fracture. High-chrome white iron is preferred when abrasion is dominant and impact loads are moderate to low, because its high carbide volume fraction provides superior abrasion resistance. As a general rule, primary crushers and jaw crushers almost always use manganese, while tertiary and fine-crushing applications may benefit from high-chrome alternatives. Many operators use manganese in the impact zone and chrome in the abrasion zone within the same machine.

Technical content reviewed by ATF Engineering Team | Metallurgical specifications verified against ASTM/ISO standards

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Manganese Grades Available
500+
BHN Work-Hardened Surface
60+
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