C-Cr-Mo AS2074 L2B Cast Steel Chute Liner Plates (Cr-Mo Alloy Composition)

Product scope and identity

This page covers custom AS2074 L2B or an explicitly approved L2B-modified cast-steel liner. It is intended for replacement or new-design chute positions where cast shape and a heat-treated strength, hardness and toughness balance are required. Manufacture is to drawing, not a universal stock dimension.

The AS2074 name identifies a material family; it does not automatically specify every casting tolerance, NDT method, repair rule, document or guaranteed service result. Those requirements belong in the quotation, approved drawing and purchase order.

L2B screening chemical composition

The following public EB group capability range is shown in mass percent for preliminary RFQ discussion. It is not a substitute for the current purchased AS2074 text. Public third-party tables may use different editions or residual limits, so contractual documents must identify the exact standard and any modification.

Heat analysis should report actual results for the ordered elements and link them to the casting heat. If product analysis or residual-element limits are needed, define sampling, method and permissible variation before production.

Carbon controls hardness potential

At 0.55-0.65% C in the screening range, L2B has meaningful hardening potential. Carbon also raises welding and cracking sensitivity and changes the amount of toughness available at a selected hardness. The best target is not automatically the upper chemistry or highest HRC.

Carbon must be measured with a suitable laboratory method. Portable XRF can screen many alloy elements but does not directly determine carbon. Grade verification should therefore combine traceable heat chemistry with the approved testing basis.

Chromium and molybdenum work as a system

Chromium supports hardenability and wear response; molybdenum can increase depth of response and resistance to softening during tempering. Their effect depends on carbon, manganese, silicon, austenitizing and the actual quench path. A thick boss cannot be made equivalent to a thin coupon merely by adding Mo.

Both Cr and Mo should appear on the certificate when required. The quotation should state whether the base grade or a modified chemistry is supplied, because an informal “Cr-Mo steel” description is too broad for acceptance.

Hardness is not hardenability

Hardness describes resistance to indentation at a tested location. Hardenability describes the depth through which the desired structure can form under a defined quench. Buyers often confuse a hard surface result with proof that a heavy casting is uniformly treated.

Specify the scale, prepared locations, reading count and acceptable range. If the core or a bolt boss must meet a criterion, show the depth or representative section on the drawing and agree how it will be tested.

Casting route and tooling

Resin-sand or sodium-silicate-sand processes may be selected according to geometry, size, quantity and foundry plan. Pattern allowances must cover solidification shrinkage, heat-treatment movement and machining. Cores, parting, gating and risers should be reviewed before tooling release.

A cast liner can integrate curvature, ribs, bolt recesses and bosses, but design freedom is not unlimited. Abrupt thickness changes and isolated heavy junctions create feeding and thermal risks. EB China reviews manufacturability against the approved drawing.

Section transitions determine casting risk

A thick boss next to a thin wall freezes and cools differently, which can promote shrinkage, segregation, distortion or a different heat-treated structure. Generous fillets and gradual transitions reduce stress concentration and help process control.

Before copying a worn sample, restore original thickness and review whether the old geometry caused failure. A material upgrade without correcting an exposed edge, thin ligament or rocking backing often repeats the same problem at higher cost.

Austenitizing prepares the matrix

Austenitizing temperature and time are selected for the grade, prior structure and section. The process must prepare the intended transformation without excessive grain growth, oxidation or decarburization. Furnace uniformity, load arrangement and actual casting temperature matter.

No universal set point is stated on this product page. The supplier process and qualification evidence govern, while the buyer specifies final condition and contractual records rather than copying an internet recipe.

Quenching develops the section response

Quench medium, temperature, agitation, transfer delay, load spacing and geometry control cooling. The Cr-Mo system helps hardenability, but heavy sections still respond differently from thin edges. Excessive severity increases crack and distortion risk; insufficient severity can leave an unintended soft structure.

The production plan should connect casting support, safe transfer and thermal-lot identity. If distortion affects fit, define post-treatment dimensional checks and permitted correction methods.

Tempering makes the condition usable

A freshly hardened medium-carbon steel can be too stressed and brittle for a bolted impact liner. Tempering adjusts hardness, toughness and stability. Chromium and molybdenum influence softening and carbide reactions, so time and temperature must be matched to the complete chemistry.

Final hardness and required mechanical evidence are measured after the last specified thermal cycle. Do not require maximum hardness without considering impact, edges, bolts and maintenance handling.

Microstructure and mechanical evidence

The delivery structure may be described using pearlitic, bainitic or tempered-martensitic concepts depending on the approved condition. Those labels need sampled evidence and cannot be inferred from chemistry. Metallography should define location, preparation, etchant, magnification and acceptance description.

Impact or tensile requirements need specimen type, orientation, temperature and relationship to the production casting. Separately cast coupons are convenient but may not represent a heavy liner. Use an agreed representative block or sacrificial casting when section equivalence is important.

Credible chute applications

L2B cast steel can be evaluated in crusher-discharge transitions, receiving or impact zones, ore/clinker chutes, transfer-point components and other positions combining abrasion with impact or gouging. Cast geometry may be helpful when a flat fabricated plate cannot reproduce ribs, bosses or curvature.

Suitability requires duty data. Fine low-stress sliding may favor high-Cr white iron or Ni-Hard; very high contact stress may favor work-hardening manganese steel; straightforward fabricated panels may favor NM plate. Select by wear mechanism rather than brand name.

L2B versus L2A and L2C

L2A uses a lower published carbon range and no listed Mo in the common screening table. L2C uses higher C and Cr with Mo. L2B sits between them chemically, but that does not make it a universal compromise. Heat treatment, section and required toughness can move the best decision.

If a buyer requests an alternative, the quotation should compare chemistry, delivery condition, properties and risks. Do not substitute L2C merely because it looks higher on a table.

L2B versus high-Cr white iron

High-Cr white iron uses a carbide-dominant strategy and substantially higher carbon/chromium families. It can excel in supported sliding abrasion but is more sensitive to impact and unsupported edges. L2B is a heat-treated alloy steel with a different matrix and fracture response.

Compare by duty, not just HRC. White iron may show higher hardness while L2B provides more usable impact tolerance. The wrong support or joint can defeat either material.

L2B versus high-manganese steel

High-manganese steel relies on an austenitic matrix and service-induced work hardening under sufficient contact stress. L2B develops its delivered properties primarily through its C-Cr-Mo chemistry and heat treatment.

Use manganese steel where repeated severe impact can activate a hardened surface while retaining a tough core. Use L2B where a pre-engineered heat-treated matrix and cast shape better match combined wear. Confirm with comparable field data.

L2B versus Si-Cr-Mn-Mo cast steel

ZG42Cr2Si2MnMo uses lower carbon than the L2B screening range but deliberately elevated silicon and a broader public Mo range. The two families have different transformation and tempering behavior. They are not equivalents despite both containing Cr and Mo.

A technical comparison should include chemistry, section, thermal route, hardness/toughness targets, manufacturing history and field failure. EB China can review both against the same liner map.

Fixing, backing and joint design

The liner must bear against the intended support without rocking. Bolt holes and recesses need adequate ligament and radii. Flow-facing joints should avoid exposed edges and uncontrolled packing. Lifting features must be approved for declared mass.

Provide the full liner map and installation method. Chemistry cannot compensate for a damaged shell, loose bolts, an unsupported span or an incorrect overlap. Record backing and fixing condition during field trials.

Dimensional, visual and NDT inspection

Inspect outline, thickness, datums, profile, bolt features, bearing surfaces, flatness and mass against the approved drawing. Visual examination addresses cracks, hot tears, fins, adhering material and specified surface conditions.

NDT requires a suitable method, defined zones, sensitivity and acceptance criteria. Generic “100% UT” is not a complete requirement. Agree the plan before production, when geometry and process can still be adjusted.

Traceability and document package

Permanent or durable marking should connect part number, drawing revision and heat/batch to chemistry, thermal and inspection records. The packing list should map each crate and quantity. Electronic files should use the same identifiers as the physical casting.

A typical agreed package may include heat analysis, heat-treatment confirmation, hardness and mechanical reports, dimensions, NDT, marking and packing photographs. Only documents required by the quotation are contractual.

Field validation plan

Record baseline ID, thickness, mass where practical, hardness points, backing and photographs. During service, track tonnes or hours, feed size, trajectory, abnormal impacts, fixing condition and thickness on a numbered grid. Compare the same position and duty.

At removal, classify wear, gouging, fracture, bolt damage, deformation or support failure. Evaluate cost per processed tonne, replacement exposure and downtime—not calendar life alone. Feed the result into the next alloy and geometry decision.

Common RFQ mistakes

Avoid ordering “Cr-Mo steel” without grade and edition, copying a generic chemistry table, demanding maximum hardness, ignoring the heavy section, treating L2B as white iron, assuming welding is routine or specifying NDT without acceptance. Do not reproduce a worn sample without restoring intended geometry.

The remedy is to connect application, drawing, composition, casting route, heat treatment, properties, inspection, installation and field evidence in one approved package.

RFQ checklist

Send the AS2074 edition, L2B or approved modification, chemistry, delivery condition, hardness and required mechanical evidence. Provide 2D/3D drawing, revision, liner map, quantity, mass, sections, fixing, machining and marking.

Describe material handled, maximum lump, impact/drop, abrasion, throughput, moisture, temperature, present material, wear map and failure mode. State inspection, witness, documentation, packing and delivery requirements.

Engineering and safety boundary

Final material, geometry, structure, support, fixing and installation require customer and qualified-engineer approval. EB China manufactures to the approved drawing and purchase specification. Chemistry and hardness do not guarantee service life.

Inspection and replacement require isolation/lockout, stored-energy control, lifting, working-at-height and confined-space procedures as applicable. Welding, heating or modification needs an approved grade-specific method.

Technical basis and disclosure

Composition ranges are public EB group capability screening data. Standards must be verified from the current authorized full text before contractual use. Images disclose EB ownership or third-party license and do not prove the alloy of a pictured part.

The paired technical article provides deeper grade comparison; this product page is the procurement path for drawing-based L2B review, manufacture and quotation.