ASTM A297 HK Heat Treatment Cast Basket

Description

Custom ASTM A297 HK heat treatment cast baskets for drawing-based RFQs

EB Castworld supplies custom cast heat treatment baskets for industrial furnace loading systems using customer-approved drawings, service data and acceptance requirements. This page is an engineering and procurement reference for quotation; it is not an online retail listing and does not imply stock, a standard safe load, a fixed service temperature or a guaranteed number of cycles.

The product title uses ASTM A297 Grade HK because ASTM A297/A297M includes HK among its general-purpose heat-resistant casting grades. “HK40” is also used as industry shorthand, but shorthand must not replace the exact grade, standard edition and chemistry limits stated on the purchase order. Final material selection remains the purchaser’s engineering responsibility and must consider furnace atmosphere, actual basket-metal temperature, load distribution, support geometry, cycle severity, handling and previous failure evidence.

Cast heat treatment basket with open grid and load-supporting ribs — Existing EB Castworld media-library image illustrating cast basket geometry. It is not evidence of a particular customer project, certified alloy, safe load or service life.

Product scope and equipment boundary

RFQ subject	EB Castworld review scope	Purchaser approval
Basket geometry	Castability, section transitions, grid and rib arrangement, machining allowance, cleaning access and identification.	Envelope, workpiece pattern, interfaces, clearances, handling method and approved drawing.
Material	Ordered designation, heat traceability, chemistry verification and agreed material documents.	ASTM edition, Grade HK or approved alternative, atmosphere compatibility and service suitability.
Furnace duty	Manufacturing implications of the stated temperature cycle, atmosphere, support and loading.	Furnace safety, operating window, permissible load, transfer method and retirement criteria.
Manufacturing route	Pattern/tooling review, casting route, finishing, machining and approved weld controls.	Drawing changes, critical characteristics, repair permissions and deviation disposition.
Inspection	Chemistry, visual, dimensional, penetrant and other agreed inspection planning.	Methods, coverage, sampling, acceptance criteria and required dossier.

The quoted scope may include one basket, a repeat basket family, or an assembly whose removable grids, dividers, pins, feet or locating features are defined by the drawing. Fixtures, rails, lifting devices, fasteners and installation services are not automatically included. A basket that fits the furnace opening is not necessarily interchangeable with an existing unit unless its support, load path, thermal expansion and handling interfaces are also approved.

ASTM A297 Grade HK and the “HK40” shorthand

ASTM A297/A297M covers iron-chromium and iron-chromium-nickel alloy castings for heat-resistant service. The standard includes multiple general-purpose grades and identifies chemical requirements, manufacturing provisions and repair-welding considerations. The current purchased standard controls acceptance. A web page, supplier brochure or historical certificate cannot replace the ordered edition.

Grade HK is commonly associated with a heat-resistant austenitic cast-alloy concept containing substantial chromium and nickel with controlled carbon. Exact limits must be taken from the applicable ASTM edition and customer specification. The following table describes metallurgical roles without turning a nominal composition into a performance guarantee.

Element or feature	General role	Procurement boundary
Chromium	Supports oxidation-related resistance and participates in carbide formation.	Performance changes with scale damage, atmosphere chemistry, deposits and thermal cycling.
Nickel	Supports an austenitic matrix and structural stability at elevated temperature.	Nickel content alone does not establish creep strength, thermal-fatigue resistance or life.
Carbon	Influences castability, carbide population and elevated-temperature strength response.	Higher carbon or hardness is not universally better where impact, welding or thermal shock controls failure.
Silicon and manganese	Influence deoxidation, castability and oxidation-related behavior.	Use the complete ordered chemistry; simplified “25Cr-20Ni” labels are insufficient.
Residual elements	Can affect cleanliness, hot cracking and weld response.	Heat analysis and any supplementary limits must be agreed before production.

Grade HK is not automatically equivalent to HP, HH, HU, 310, 1.4848, 1.4849, 2.4879 or a proprietary micro-alloyed grade. Similar chromium and nickel values do not establish equal carbide structure, creep response, weldability or atmosphere resistance. Any substitution or chemistry modification requires purchaser approval.

Temperature, atmosphere, load and support form one design case

Basket selection cannot be based on furnace setpoint alone. The metal can experience local temperatures and gradients that differ from the controller value because of burner location, circulation, shielding by the load, door opening, transfer and quenching. Provide the complete time-temperature cycle and, where available, measured basket or workpiece temperature.

Service input	Why it matters	Evidence for quotation
Temperature cycle	Heating, soaking, cooling and excursions influence creep, oxidation and thermal fatigue.	Setpoint, measured metal temperature if known, soak time, ramp, cooling and transfers.
Atmosphere	Air, carburizing, nitriding, reducing and contaminated environments attack alloys differently.	Gas composition, carbon potential or dew point where controlled, and known contaminants.
Workpiece load	Total mass does not describe concentrated contacts, eccentric loading or blocked gas flow.	Part mass, quantity, footprint, stacking, center of gravity and dividers.
Support condition	Rail spacing and contact points determine span, restraint and local bearing stress.	Hearth/rail drawing, contact width, insertion direction and mating-fixture details.
Handling	Forks, hooks, manipulators and impacts can control damage independently of furnace exposure.	Handling drawing, engagement points, accelerations and approved lifting procedure.

The furnace owner and responsible engineer approve the operating load, temperature, atmosphere, lifting method and retirement rule. EB Castworld does not assign a safe working load or cycle-life promise without an approved design basis and controlled validation.

Basket geometry and castability review

A useful basket drawing defines overall envelope, grid opening, rib width and depth, wall thickness, base contacts, side walls, feet, locating features, lifting interfaces, removable members, machining, datums and inspection zones. Long unsupported spans increase bending demand. Heavy rib intersections and abrupt bosses can form solidification hot spots. Sharp stiffness changes and restrained corners can concentrate thermal stress.

During design-for-casting review, a foundry may propose fillet, junction, draft, feeding-access or local-thickness changes. Such proposals are deviations until the purchaser approves a revised drawing. The objective is to improve manufacturability while preserving functional interfaces, load paths and thermal clearances—not to make undocumented geometry changes.

Casting route and manufacturing controls

The suitable route depends on basket size, section, detail, quantity, tolerance, surface and inspection requirements. Large open-grid baskets may require a different moulding and feeding strategy from small precision fixtures. Investment casting, sand casting or another approved route should be selected against the actual drawing rather than promised generically.

Review drawing revision, service duty, critical characteristics and document requirements.
Freeze the ordered grade and permitted material practices under the applicable specification.
Plan tooling, contraction allowance, gating, feeding, identification and accessible inspection surfaces.
Control melting, heat identity, chemistry sampling and pouring under approved procedures.
Remove gates and feeders without reducing the specified minimum section.
Perform agreed heat treatment, straightening, machining or welding only under approved controls.
Complete visual, dimensional, NDT and documentation checks before release.
Protect identification, machined interfaces and basket geometry during packing and shipment.

Welding, repair and straightening boundaries

The purchase order should state whether production welding or repair welding is prohibited, permitted within a qualified procedure, or subject to purchaser approval. Where welding is allowed, define procedure qualification, filler, preparation, welder qualification, repair mapping, inspection and traceability. A repair must not conceal a systematic feeding or geometry problem.

Straightening can change residual stress and room-temperature geometry. It should follow an approved method with measurable acceptance. A basket that is flat when cold is not thereby proven stable at temperature under load; hot performance remains part of the purchaser’s controlled qualification and operating program.

Dimensions, tolerances and first-article control

Define functional datums and individual tolerances for interfaces. ISO 8062-3:2023 addresses general dimensional and geometrical tolerances and machining allowances for castings using plus/minus tolerancing, while ISO 8062-4:2023 addresses profile tolerancing in a general datum system. The drawing must state the applicable approach and should not rely on an unexplained generic casting-tolerance grade.

Characteristic	Drawing requirement	Verification approach
Overall envelope	Length, width, height and free-state support condition.	Calibrated layout on defined supports.
Rail/base contacts	Datums, spacing, profile/flatness and machining status.	Gauge, CMM or documented layout as appropriate.
Grid and ribs	Minimum wall, openings, transitions and permitted draft.	Measurements at defined points and accessible sections.
Locating/handling features	Position, size, finish and approved load direction.	Dimensional report; lifting approval remains with purchaser.
Replaceable members	Fit, clearance, orientation and retention method.	Assembly trial or gauges defined by the drawing.

For new tooling, a source change or a major revision, specify whether the order begins with a first article or controlled trial lot. Define the report, hold points and customer approval needed before repeat production. First-article acceptance verifies the ordered manufacturing and room-temperature inspection route; it does not establish furnace life.

Inspection and quality-document options

Chemical analysis supports grade identity but cannot alone validate feeding, dimensions, crack acceptance or hot-load performance. Inspection should be risk-based and written into the order.

Requirement	Define in the RFQ	Possible evidence
Material	ASTM edition, grade, supplementary limits and heat/lot traceability.	Material certificate linked to part marking.
Visual examination	Surface condition, reference and acceptance criteria.	Inspection record and deviation disposition.
Dimensions	CTQs, datums, setup, sampling and first-article requirement.	Dimensional layout or inspection report.
Penetrant testing	Method, stage, coverage, acceptance and personnel qualification.	PT report and repair/retest map where applicable.
Other NDT	Feasible method, technique, zone, timing and acceptance.	Signed report traceable to the basket and drawing.
Welding	Whether allowed; procedure, filler, map and post-repair inspection.	Approved procedure and production/repair records.

Failure evidence for a replacement basket

Before cleaning or cutting a failed basket, photograph it in the furnace or as-received condition, mark orientation and rail contacts, and record load, cycle and atmosphere. Measure sag, twist and dimensional change on an agreed support plane. Preserve a representative sample if chemistry, hardness or metallography may be required.

Progressive sag can involve creep demand, overload, changed supports, higher metal temperature or section loss.
Cracks at grid or wall junctions can involve thermal fatigue, stiffness transitions, casting condition or impact.
Scale loss, carburization or local section reduction requires atmosphere and contaminant review.
Broken lifting features require review of engagement direction, restraint, geometry and operating practice.

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

Qualification, repeat orders and change control

First production lot

A new basket design or transferred tool should normally have a defined qualification route. The order can identify a first article, trial lot, dimensional hold point and document review before repeat production. Qualification should specify the support condition used for measurement, the approved drawing revision and the characteristics that must be reported. A room-temperature inspection does not qualify hot-load life; the purchaser must define any controlled furnace trial and its acceptance criteria.

Repeat manufacture

After approval, identify changes that require renewed review: alloy specification or source, casting route, tooling revision, critical section, repair-welding rule, heat treatment, machining datum or inspection plan. Part marking and the release dossier should connect each delivered basket to its heat/lot and drawing. This prevents an accepted first lot from becoming blanket approval for undocumented process changes.

Heat treatment basket assembly with open sections for furnace loading — Existing site media retained from a consolidated basket page. It illustrates a basket form only and is not represented as a named customer project or proof of material grade.

RFQ checklist for a heat treatment cast basket

Approved 2D drawing and, where available, 3D model with revision status.
ASTM A297/A297M Grade HK, standard edition and permitted alternatives.
Furnace type, rail/hearth arrangement, transfer and handling method.
Setpoint, estimated or measured basket-metal temperature, soak and complete cycle.
Atmosphere, carbon potential/dew point where applicable, deposits and contaminants.
Workpiece mass, quantity, distribution, stacking and contact pattern.
Critical dimensions, datums, tolerances, machining and surface requirements.
Welding permissions, visual, dimensional, NDT and document requirements.
Existing failure history, distortion/crack photographs and retirement rule.
Quantity, first-article plan, marking, packaging and destination.

Related engineering pages

Use the heat treatment fixture selection guide to distinguish baskets, trays, racks and base fixtures. Compare the 2.4879 G-NiCr28W heat treatment tray and ASTM A297 HK base tray where those geometries match the drawing. Review quality assurance and factory capability for general manufacturing context.

Send drawings for quote

Send Drawings for Quote, or email sales@ebcastworld.com with the drawing, standard edition, furnace duty, atmosphere, support and load arrangement, inspection requirements, quantity and destination. Final material, geometry, thickness, dimensions, welding, handling and operating limits follow purchaser-approved documents.

References and engineering boundary

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