2.4879 G-NiCr28W Heat Treatment Trays

Description

Custom 2.4879 heat treatment trays for drawing-based RFQs

EB Castworld supplies custom cast heat treatment trays specified as 2.4879 / G-NiCr28W for selected high-temperature furnace duties. This is a drawing-and-service review product, not a stocked retail tray. The purchaser provides the approved geometry, furnace arrangement, load case, atmosphere, temperature cycle and acceptance requirements; EB Castworld then reviews casting route, section design, machining, inspection and documentation for quotation.

Material 2.4879 is a cast nickel-chromium-tungsten alloy designation associated with G-NiCr28W. Its high nickel and chromium concept, together with tungsten and carbon, can support elevated-temperature strength and oxidation-related performance in appropriate furnace environments. That description is not a universal service-temperature or lifetime guarantee. Tray behavior depends on metal temperature, atmosphere, load distribution, rail spacing, section transitions, thermal cycling, handling and retirement criteria.

Product scope and equipment boundary

RFQ item	What EB Castworld can review	What the purchaser must approve
Tray geometry	Castability, feeding access, rib and junction transitions, machining allowance and handling features.	Envelope, workpiece pattern, interfaces, datums, clearances and allowable distortion.
Material	2.4879 / G-NiCr28W chemistry requirement and traceability plan.	Governing standard edition, permitted alternatives and service suitability.
Furnace duty	Manufacturing implications of the stated atmosphere, temperature cycle and loading.	Furnace safety, load rating, operating limits and retirement criteria.
Manufacturing	Suitable casting route, finishing, machining and approved weld controls.	Drawing revision, critical characteristics and deviation approval.
Inspection	Chemistry, visual, dimensional, PT and other agreed inspection planning.	Methods, coverage, sampling, acceptance criteria and document package.

The scope can include a single tray, a repeat tray family, or a tray assembly with purchaser-defined mating features. Rails, baskets, pins, spacers, fasteners, fabricated members and lifting devices are included only when they appear in the approved supply scope. A tray should not be assumed interchangeable merely because its outside dimensions resemble an existing unit.

Material identity: 2.4879 / G-NiCr28W

The order should identify the cast designation, material number and governing specification. Published supplier data for G-NiCr28W commonly describe a high-nickel alloy with approximately 27–30% chromium and 4.0–5.5% tungsten, together with controlled carbon, silicon, manganese, phosphorus and sulfur. Those figures are a reference to the alloy concept, not an acceptance table for every order. The current purchased standard and customer specification control the certified limits.

Element or feature	General metallurgical role	Procurement caution
Nickel	Supports an austenitic matrix and high-temperature structural stability.	High nickel content alone does not establish creep strength or atmosphere compatibility.
Chromium	Supports oxidation resistance through chromium-rich surface-scale behavior.	Scale performance changes with sulfur, carbon activity, oxygen potential and cycling.
Tungsten	Contributes solid-solution and carbide-related elevated-temperature strength.	Nominal tungsten is not a substitute for verified heat chemistry and microstructure control.
Carbon	Influences castability, carbide population and hot-strength response.	More carbide is not automatically better where thermal shock, welding or stress concentration dominates.
Silicon and minor elements	Influence deoxidation, oxidation behavior and casting response.	Use the complete specified limits; do not approve material from Cr/Ni values alone.

2.4879 must not be represented as automatically equivalent to ASTM A297 HK, HP, 310S, 1.4848, 1.4849 or a proprietary furnace alloy. Similar descriptions such as “heat resistant” do not establish equal chemistry, product form, creep response, weldability or service performance. Any substitution requires purchaser engineering approval.

Temperature, atmosphere and load must be evaluated together

Some alloy producers publish maximum-use-temperature values for their own G-NiCr28W products. Such values are conditional reference data rather than a tray design rating. A loaded tray can distort through creep at a metal temperature below a published oxidation limit. Conversely, a lightly loaded component may be limited by carburization, sulfidation, thermal fatigue, local overheating or interaction with process deposits.

Service input	Why it changes tray selection	Evidence to send
Metal temperature	The tray can be hotter or colder than the furnace setpoint; local gradients drive stress.	Measured or estimated tray temperature, setpoint, soak and excursion history.
Atmosphere	Air, carburizing, nitriding, reducing and contaminated atmospheres affect scale and internal attack differently.	Gas composition, dew point or carbon potential where controlled, and known contaminants.
Static load	Workpiece mass and contact pattern determine bending and creep demand.	Part mass, quantity, footprint, stacking pattern and center of gravity.
Support condition	Rail spacing, flatness and contact points set the structural span and restraint.	Furnace hearth/rail drawing, support spacing and insertion direction.
Cycle	Heating and cooling rates, quench exposure and handling create thermal fatigue and shock.	Complete time-temperature sequence, transfer time and cooling method.

Final allowable load, operating temperature and retirement condition remain the responsibility of the furnace owner and responsible engineer. EB Castworld does not assign a load rating or service-life multiplier without an approved design basis and controlled validation.

Tray geometry and castability review

A useful RFQ drawing defines outside dimensions, grid opening, rib width and depth, wall thickness, bosses, feet, rail contacts, locating features, lifting points, machining, datums and inspection zones. Uniform nominal thickness does not by itself create uniform solidification: heavy rib intersections, abrupt bosses and isolated masses can become hot spots. The foundry review should address feeding, shrinkage, distortion and access for cleaning and inspection.

Geometry also affects service behavior. Long unsupported spans increase bending; sharp stiffness changes concentrate thermal stress; constrained corners can resist free thermal expansion; and small local bearing areas can create high contact stress. A redesign proposal is a deviation until the purchaser approves the revised drawing. Tooling, pattern or model revision should remain traceable to that approval.

Casting route and manufacturing plan

The suitable casting process depends on size, section, detail, quantity, tolerance and surface requirements. Investment casting can provide detail for appropriate envelopes, while sand or other approved moulding routes may be more suitable for large tray geometries. EB Castworld reviews the route against the drawing rather than promising every process for every part.

1. Review drawing, service data, critical characteristics and acceptance documents.
2. Freeze approved material designation and permitted returns or additions under the applicable procedure.
3. Plan tooling, gating, feeding, shrinkage allowance and identification.
4. Control melting, heat identity, pouring and representative chemistry sampling.
5. Remove gates and feeders without reducing minimum wall or damaging critical surfaces.
6. Perform approved heat treatment, straightening, machining or production welding only when specified.
7. Complete ordered visual, dimensional, NDT and document checks.
8. Protect identification and critical surfaces through packaging and shipment.

Welding, straightening and repair controls

High-alloy castings require material- and geometry-specific welding controls. The RFQ should state whether production welds or repair welding are prohibited, conditionally permitted or subject to purchaser approval. Where welding is allowed, define procedure qualification, filler, preparation, preheat/interpass or controlled cooling as applicable, welder qualification, repair mapping, post-weld inspection and traceability.

Hot or cold straightening can alter residual stress and geometry. It should be performed only under an approved route with measurable dimensional acceptance. A visually flat tray at room temperature is not proof that it will remain flat under service load; service validation belongs to the approved furnace program.

Dimensions, tolerances and machining

Do not place a generic “CT grade” on the order without defining the applicable standard, process and datum system. ISO 8062-3:2023 addresses general dimensional and geometrical tolerances and machining allowances for castings using plus/minus tolerances; ISO 8062-4:2023 addresses profile tolerancing in a general datum system. The drawing should identify which rules apply and specify individual tolerances for functional interfaces.

Feature	Drawing input	Typical verification approach
Overall envelope	Length, width, height and free-state condition.	Calibrated dimensional layout on an agreed support condition.
Rail or hearth contacts	Datums, spacing, flatness/profile and machining status.	Fixture, CMM or documented gauge/layout as appropriate.
Grid and ribs	Minimum wall, opening, draft and transition requirements.	Section and accessible feature measurements at defined points.
Locating/lifting features	Position, bore/slot size, load direction and finish.	Gauge and dimensional report; lifting approval remains with purchaser.
Machined surfaces	Stock allowance, final dimensions, finish and post-machining NDT.	Final inspection linked to drawing revision.

Inspection and quality-document options

The inspection plan should be risk-based and written into the order. Chemistry verification supports grade identity, but cannot alone validate feeding, dimensions, crack acceptance or hot-load performance. Visual inspection, dimensional checks and penetrant testing are commonly considered for open-to-surface conditions; radiography or other methods require agreed technique, coverage and acceptance suited to the section and risk.

Document or test	Define in the RFQ	Possible deliverable
Material	Standard/edition, chemistry limits, heat/lot traceability.	Material certificate linked to part marking.
Dimensions	CTQs, datums, sampling and measuring condition.	Dimensional report or first-article layout.
Visual/surface	Reference standard, surface condition and acceptance.	Inspection record and deviation disposition.
Penetrant testing	Method, stage, coverage, acceptance and personnel qualification.	PT report and repair/retest map where applicable.
Other NDT	Method, feasibility, technique, zone and acceptance.	Signed report with traceable indications.
Welding	Whether allowed; WPS/PQR, filler, map and NDT.	Approved procedure and production/repair records.

Typical failure evidence to provide

If the RFQ replaces a distorted or cracked tray, send the failed component drawing and preserve evidence. Record furnace position, load, cycle count or operating time, measured temperature, atmosphere, rail spacing and prior repairs. Photograph the tray in position before cleaning, mark orientation and measure distortion on a defined support plane.

• Progressive sag can indicate creep demand, overload, support change, metal-temperature increase or loss of section.
• Corner or rib-junction cracks can involve thermal fatigue, stiffness transition, casting condition or handling damage.
• Heavy scale, internal attack or section loss requires atmosphere and contaminant review, not only a higher nominal alloy.
• Broken lifting or locating features require review of handling direction, restraint, geometry and inspection.

These observations guide investigation; they do not establish root cause without material, microstructural, dimensional and operating evidence.

What to include in a 2.4879 tray RFQ

First-article and trial expectations

For new tooling, changed geometry or a new operating duty, state whether the order begins with one first article or a controlled trial lot. Define the dimensional report, inspection hold points and customer approval needed before repeat production. A first article verifies the ordered manufacturing and inspection route at room temperature; it does not establish hot-load life unless the purchaser conducts a controlled furnace trial.

Change control after approval

Identify changes that require renewed purchaser review, such as alloy source or specification, casting route, tooling revision, critical section, repair-welding rule, heat-treatment route or inspection plan. Marking and documentation should connect each delivered tray to the applicable drawing and heat/lot. This prevents a successful qualification from being treated as blanket approval for an undocumented process change.

1. Approved 2D drawing and, when available, 3D model with revision status.
2. Material number 2.4879, G-NiCr28W designation and governing standard edition.
3. Furnace type, hearth/rail arrangement, transfer and handling method.
4. Setpoint and estimated/measured tray-metal temperature, soak and cycle.
5. Atmosphere, carbon potential/dew point where applicable, and contaminants.
6. Workpiece mass, distribution, contact points and stacking arrangement.
7. Critical dimensions, datums, tolerances, machining and surface requirements.
8. Chemistry, visual, dimensional, NDT, welding and documentation requirements.
9. Current-part service evidence, distortion/crack photographs and retirement rule.
10. Quantity, trial/first-article plan, marking, packaging and destination.

Related engineering and product pages

Use the heat treatment fixture selection guide to distinguish trays, baskets, racks and specialty fixtures. Read the 2.4879 G-NiCr28W engineering guide for material and service boundaries. For another specific product intent, review the ASTM A297 HK base tray. General manufacturing and inspection context is available on the factory capability and quality assurance pages.

Send drawings for quote

Send Drawings for Quote, or email sales@ebcastworld.com with the drawing, material specification, furnace duty, load, inspection requirements, quantity and destination. EB Castworld will review manufacturability and clarify missing inputs before quotation. Final material, structure, thickness, dimensions, welding, installation and operating limits must follow purchaser-approved documents.

Technical references and safety boundary

• Saint-Gobain SEVA, alloy designations and reference data including G-NiCr28W / 2.4879.
• ISO 8062-3:2023, dimensional/geometrical tolerances and machining allowances for castings.
• ISO 8062-4:2023, profile tolerancing for castings in a general datum system.
• ISO 13577-1:2016, general safety requirements for industrial furnaces and associated equipment.

Boundary: This product page is not a furnace design calculation, safe-work procedure, lifting approval, material-equivalence statement or service-life guarantee. The furnace owner and responsible engineer approve the load, design, alloy, atmosphere, operating window, inspection and retirement criteria.