Skip to main content

Heat Treatment for Crusher Liners, Jaw Plates, and Cone Components

Crusher liners, jaw plates, mantles, concaves, and cone components operate in one of the most aggressive wear environments in industrial service — compressive and abrasive contact with rock at loads measured in hundreds of thousands of pounds, delivered in cyclic impacts thousands of times per hour. UTEC Industrial provides in-house induction hardening, through-hardening, and quench-and-temper heat treating services for industrial components in the Pacific Northwest, with integrated CNC machining and reverse-engineering capability. The two dominant liner-material families each depend on heat treatment to deliver service life, but the required heat treatment looks entirely different: austenitic manganese (Hadfield) steel requires a solution-anneal-and-water-quench cycle to produce an initially-soft austenitic structure that work-hardens in service, while Cr-Mo and high-alloy wear-plate liners require a conventional austenitize-quench-temper cycle that ships the part already at its working hardness. Getting the heat treatment right for each material family is the difference between a liner that lasts a rated service interval and one that fails prematurely through brittle fracture, inadequate work-hardening, or premature edge spalling. This article covers the heat treatment requirements, hardness expectations, and process considerations for the principal liner and jaw materials used in mining and aggregate processing.

What heat treatment does austenitic manganese (Hadfield) steel require, and why is it counterintuitive?​

Austenitic manganese steel — the 12–14% Mn / 1.0–1.4% C composition known as Hadfield steel (ASTM A128) — is the dominant liner material for jaw crusher jaw plates, gyratory crusher concaves and mantles, impact crusher blow bars in certain service classes, and ball mill liners in many applications. Its heat treatment is counterintuitive because the objective is to produce a relatively soft as-shipped hardness (around 200 HB, or roughly 18–20 HRC), not a hard one. The cycle is a solution anneal in the range of 1,850–1,950 °F (1,010–1,065 °C) for 1 hour per inch of section thickness, followed immediately by a severe water quench. The high-temperature soak dissolves the coarse carbides that formed during casting solidification into a uniform austenitic solid solution; the rapid quench freezes the austenite in place at room temperature and prevents carbide re-precipitation during cooling. The resulting microstructure is fully austenitic, work-hardening capable, and relatively ductile. In service, the impact of rock on the liner surface deforms the austenite and induces strain-induced martensitic transformation and twinning in the near-surface layer — the surface work-hardens progressively to 500+ HB (roughly 50+ HRC) during the first hours or days of crushing service, while the underlying bulk material remains tough austenite. A Hadfield liner shipped in the wrong condition — un-solution-annealed, or solution-annealed but air-cooled rather than water-quenched — contains coarse carbides that embrittle the material; it will crack under the first impact rather than work-hardening in place (ASM Handbook, Vol. 4D, ASM International, 2014; ASTM A128; Heat Treater's Guide: Irons and Steels, 2nd ed., ASM International, 1995).

What are the typical dimensions and weights of crusher liners, and what does that mean for furnace selection?​

Jaw plates for primary jaw crushers range from under 1,000 lb for small quarry equipment up to 10,000–15,000 lb for large primary jaws on 60-inch or 72-inch gapped crushers. Gyratory crusher concaves are segmented rings that can exceed 4,000 lb per segment, with a full concave set assembled from 10–16 segments around the crusher chamber. Mantles for large gyratory and cone crushers are cast as monolithic pieces and can reach 20,000 lb or more for large gyratory units. The physical envelope of these parts — 5 to 10 feet across for primary jaw plates, 6 to 10 feet in diameter for large mantles — places the majority of them inside the working envelope of a 6-foot × 10-foot × 17-foot car-bottom furnace, which is sized specifically to accept components in this class. Smaller commercial heat treaters with 4-foot-class furnaces must decline the larger pieces. The 50-ton load capacity of UTEC Industrial's car-bottom furnace accommodates either one large mantle, a stacked load of jaw plates, or a concave-segment set processed as a single cycle, depending on load geometry and fixturing. Water-quench capacity is a separate consideration from furnace capacity — the thermal mass of a 10,000-lb Hadfield casting at 1,900 °F releases significant heat into the quench bath, and the quench tank must be sized to absorb that heat without rising above a temperature that would compromise quench severity. Large-casting heat treaters typically specify minimum quench-bath volume per pound of load, with agitation and cooling provisions to hold bath temperature during the quench (ASM Handbook, Vol. 4B, ASM International, 2014).

How does the heat treatment of Cr-Mo and high-alloy wear plate liners differ from Hadfield manganese?​

Chromium-molybdenum cast steels (typically 1.5–3 Cr, 0.3–0.7 Mo compositions covered by ASTM A128 is not applicable — these are separate alloy classes such as ASTM A1035 cast steel or proprietary high-chromium alloys), martensitic stainless steels, and wrought alloy steel wear plates (400-series Brinell through-hardened plate) are heat-treated by a conventional austenitize-quench-temper cycle, not the Hadfield solution anneal. A typical 2 Cr–0.5 Mo liner casting is austenitized at 1,550–1,650 °F for 1 hour per inch, oil- or polymer-quenched, and tempered at 400–600 °F to produce a tempered martensitic structure with as-shipped hardness of 45–55 HRC (approximately 421–514 HB). Unlike Hadfield steel, these liners ship at their final working hardness — there is no work-hardening phase in service, because the material is already at the target hardness on day one. The trade-off is that Cr-Mo and high-chromium liners are less impact-tolerant than work-hardened Hadfield — they excel in abrasion-dominated service (ball mill liners in a dry grinding circuit, cone crusher parallel zones, sand-and-gravel crushing) and perform poorly in high-impact primary-crushing service where Hadfield would be specified. High-chromium white irons (ASTM A532) are a third family — these are cast in the "as-cast" austenitic-plus-carbide condition and heat-treated by a 1,850–1,950 °F austenitize cycle followed by air cooling and a 400–600 °F temper to transform the austenite to martensite; the resulting microstructure of martensite plus primary chromium carbides produces as-shipped hardness of 600+ HB (58–65 HRC) with exceptional abrasion resistance but essentially no impact tolerance (ASM Handbook, Vol. 4D, ASM International, 2014; ASTM A532; Heat Treater's Guide: Irons and Steels, 2nd ed., ASM International, 1995).

What hardness ranges should be specified on drawings for each liner type, and how is hardness verified?​

As-shipped hardness specification depends on the liner material and service class. For Hadfield manganese (ASTM A128 Grade B-2 or C), the as-shipped target is typically 200–220 HB (18–20 HRC), not because this is the working hardness but because it is the indicator that the solution anneal and quench produced a fully austenitic structure free of re-precipitated carbides — a higher reading suggests incomplete solution, a lower reading suggests excessive decarburization. The specification should state "as-shipped hardness 180–225 HB per ASTM A128," not an arbitrary hardness target. For Cr-Mo and high-alloy wear liners, the specification is the working hardness: 45–55 HRC for 2 Cr–0.5 Mo cast steel, 55–60 HRC for 400-series wrought wear plate (AR400, AR500), 58–65 HRC for high-chromium white iron. Hardness is verified on the liner body (not at chill corners or riser-proximate regions, which may show non-representative values due to local solidification conditions) using either Brinell testing per ASTM E10 with a 3,000-kgf load on a flat prepared surface, or Rockwell C per ASTM E18 on a ground test pad. For Hadfield castings, hardness testing must be performed before any service-induced work hardening can contaminate the result — a hardness check taken from a chipped corner on a used jaw plate will read 500+ HB from work hardening, completely obscuring the original as-shipped condition. The hardness verification record, along with the chemistry record and the furnace cycle chart, is part of the heat treatment documentation package delivered with each liner (ASTM A128, A532; ASTM E10, E18, E140; ASM Handbook, Vol. 4D, ASM International, 2014).

How does distortion during heat treatment affect crusher liner fit and clamping?​

A jaw plate or concave segment that distorts during heat treatment — from asymmetric section thickness, from non-uniform quench, or from inadequate blocking during the cycle — may fail to seat properly against the crusher backing, leaving voids that concentrate stress at liner bolt holes and reduce effective bearing area. Mantle distortion on a gyratory or cone crusher is particularly troublesome because the mantle must interface concentrically with the main shaft and with the surrounding concaves; a mantle that warps out of round during quench cannot be installed without either machining the out-of-round surface true (removing material from the working face and reducing liner thickness) or scrapping the piece. Heat-treatment-induced distortion is controlled by three practices: (1) fixturing the casting in the furnace on blocks or fixtures that support it in its final service orientation, minimizing sag during the soak; (2) orienting the casting for uniform quench media contact, so no surface experiences a dramatically slower cooling rate than the opposite face; and (3) for cone-crusher mantles and large concaves, performing a post-quench straightening or machining correction before the temper, with the temper then stabilizing the corrected geometry. For monolithic mantles exceeding 10 feet in diameter, the combination of thermal mass, quench severity requirement, and geometric complexity pushes the heat treatment into the specialty-casting domain; UTEC Industrial's programmable ramp-and-soak control and 50-ton load capacity handle the vast majority of jaw-plate, concave-segment, and small-to-mid-size mantle loads delivered for processing (ASM Handbook, Vol. 4D, ASM International, 2014; Totten, Steel Heat Treatment Handbook, 2nd ed., CRC Press, 2006).

What is the effect of re-heat-treating a used crusher liner, and when is it worthwhile?​

Used Hadfield liners that have not yet reached the minimum wear threshold can sometimes be re-heat-treated to restore the initial work-hardenable condition — the cycle is the same solution anneal and water quench as the original processing, which dissolves the strain-induced martensite and carbides accumulated during service back into a fresh austenite structure. The practical case for re-heat-treating is narrow: the liner must be essentially free of cracks, the residual thickness must remain above the minimum service dimension, and the cost of rehandling, shipping, and re-heat-treatment must be competitive against a new replacement liner. For primary jaw plates that have reached end of service through smooth wear across most of their surface but still carry significant residual thickness, re-heat-treatment can extend service life by 20–40% of the original interval. For liners that have cracked or that have reached minimum thickness in any local region, re-heat-treatment is not appropriate — the crack will propagate through the re-heat-treated austenite just as it did through the work-hardened original, and a below-minimum section cannot be restored to dimensional service. Cr-Mo and high-chromium liners are not typically re-heat-treated; the cost of the austenitize-quench-temper cycle is high enough, and the wear-life extension small enough, that new-liner replacement is almost always more economic (ASM Handbook, Vol. 4D, ASM International, 2014; Heat Treater's Guide: Irons and Steels, 2nd ed., ASM International, 1995).

How should heat treatment be specified on a crusher liner drawing?​

A complete heat treatment specification for a crusher liner should state the target microstructure or heat-treated condition, not just a hardness number — the hardness alone is ambiguous. For Hadfield manganese castings, the specification should reference the applicable ASTM grade (A128 Grade B-2, for example) and state "solution anneal and water quench per ASTM A128," with the as-shipped hardness range (typically 180–225 HB) cited as the acceptance criterion. For Cr-Mo and high-alloy castings or wear-plate fabrications, the specification should state the cycle — austenitize temperature, quench medium, and temper temperature — along with the target working hardness. Critical callouts that should appear on every heat-treated liner drawing include: hardness test location (specify a designated test pad away from chilled corners and risers); the documentation deliverables required (furnace cycle chart, hardness test results, chemistry certificate); and any restrictions on local hardness variation across the liner face (e.g., "hardness shall be within ±30 HB across the working face"). The heat treater does not specify the heat treatment — the engineer of record does — and ambiguous specifications lead to parts that pass the hardness test but do not perform in service because the underlying microstructure was wrong. UTEC Industrial's standard documentation package for heat-treated mining components includes the programmed cycle record, the actual temperature profile from the load thermocouples, the quench medium used, and the hardness verification record, so the customer can match the as-shipped condition against the drawing requirement before putting the part into service (ASTM A128; ASM Handbook, Vol. 4D, ASM International, 2014; ASTM E10, E18).

Related Articles

References​

  • ASM International. (2014). ASM Handbook, Volume 4D: Heat Treating of Irons and Steels. ASM International.
  • ASM International. (2014). ASM Handbook, Volume 4B: Steel Heat Treating Technologies. ASM International.
  • ASM International. (1995). Heat Treater's Guide: Practices and Procedures for Irons and Steels (2nd ed.). ASM International.
  • ASTM A128 / A128M: Standard Specification for Steel Castings, Austenitic Manganese. ASTM International.
  • ASTM A532 / A532M: Standard Specification for Abrasion-Resistant Cast Irons. ASTM International.
  • ASTM E10: Standard Test Method for Brinell Hardness of Metallic Materials. ASTM International.
  • ASTM E18: Standard Test Methods for Rockwell Hardness of Metallic Materials. ASTM International.
  • ASTM E140: Standard Hardness Conversion Tables for Metals. ASTM International.
  • Totten, G.E. (ed.). (2006). Steel Heat Treatment Handbook (2nd ed.). CRC Press / Taylor & Francis.

Need In-House Heat Treating for Heavy Industrial Parts?​

UTEC Industrial operates a 6' × 10' × 17' car-bottom furnace (1,800 °F, 50-ton capacity), in-house induction hardening with per-part hardness verification, and automated vibratory stress relief at our Spokane, WA facility. Weldment stress relief, annealing, quench and temper, and induction hardening — all under one roof, with full documentation on every job.

Request a Quote →

Questions? Call (509) 922-1832 or email sales@utec.co

Last updated on