Key takeaways
- Name one required grade and standard; list any alternative separately.
- State the section, delivery condition, test location and properties required after heat treatment.
- Link each result to the shipped heat and treatment lot.
Use condition language before process assumptions
Identify the material state needed at delivery: stock for further treatment, annealed or normalized bar for machining, or quenched-and-tempered bar accepted to specified properties. State the governing product standard and diameter beside that condition. Ask the supplier to describe the proposed sequence where the drawing leaves it open.
QT requires more than the abbreviation
For QT supply, state the required mechanical or hardness values, applicable section, sample source and location, and inspection lot. Show any peeling, grinding, or machining after treatment and the stage at which dimensions will be accepted. Confirm whether test material is treated with the production bars or by another permitted route.
Annealed and normalized routes need context
For annealed or normalized supply, identify the downstream machining or hardening operation and any incoming hardness requirement. Separate the condition needed for processing from the properties required after final treatment. Confirm who specifies and verifies the finished component's treatment response.
Certificate wording should match the route
List the inspection-document type, actual test results, and treatment records required by the order. Connect the steel heat, treated section, treatment batch, and specimen identity with the shipped bar markings. Request any deviation in sampling or record availability during quotation, while the inspection plan can still be agreed.
Keep the ISO and SAE routes distinct
42CrMo4 in ISO 683-2 and SAE 4140 in SAE J404 belong to different designation and specification systems. ISO 683-2 provides a product and condition framework for covered alloy steels. SAE J404 defines alloy-steel chemistry; it is not a complete quenched-and-tempered bar property contract. A buyer who allows both should name one required route and demand a clause-level alternative rather than writing a slash designation that leaves precedence unresolved.
Where the ISO and SAE orders differ
| Decision | Required-route field | Alternative-offer evidence | What the buyer does |
|---|---|---|---|
| Specification identity | Exact grade, product standard, edition, product form, and precedence | Separate ISO-to-SAE clause map and named ASTM product basis | Engineering accepts or rejects the alternative in writing |
| Treatment representation | Condition, ordered and ruling section, furnace-lot definition, and straightening sequence | Proposed processor, lot model, sample representation, and route deviations | Quality confirms the evidence represents production material |
| Testing and inspection | Ordered properties, methods, locations, frequency, NDT if justified, and retest | Comparable test plan without transferred values from another standard | Approve one acceptance schedule before processing |
| Documents and release | Inspection-document type, actual fields, traceability map, hold points, and deviations | Sample dossier, subcontract reports, price, and schedule effects | Release only the accepted route and closed deviation status |
Link test results to the actual treated section and lot
Avoid asking for a generic QT certificate. Define the material state being accepted and the unit represented by each sample. Require heat, diameter or section, treatment batch, specimen source and location, test method, actual result, and disposition to reconcile. If the supplier uses a prolongation or separately prepared test piece, its representation must be authorized by the controlling product route and accepted schedule rather than inferred after testing.
ISO 10474 classifies inspection documents according to order requirements. List the actual fields and linked reports needed, including treatment-lot identity, process record where ordered, test locations, deviations, re-treatment or retest, bar or bundle marks, and final packing link. Make document review timing clear so the certificate cannot arrive after the shipment decision.
Simunovic and co-authors measured surface and core hardness in quenched 42CrMo4 after two tempering durations. Both location and treatment mattered. This is why a QT order needs a test location and material state alongside its hardness requirement. The experimental cycle is not a production recipe for another section. [5]
RFQ example
Item: Alloy-steel round bars for [shaft drawing and revision], [size and quantity]
Required route: 42CrMo4 to ISO 683-2:2016, [condition and surface], with ordered and ruling section stated
Alternative: SAE 4140 to SAE J404_200901 plus ASTM A29/A29M-23 and the attached purchaser property schedule; quote separately
Heat treatment: Supplier to declare processor, treatment-lot definition, cycle-record fields, straightening sequence, and sample representation
Inspection: Approved methods, locations, frequency, judgment, retest, dimensions, surface, marking, and separately specified NDT
Documents: ISO 10474 type [state], actual results, heat-treatment-lot-bundle map, process and subcontract reports, and deviations
Approval: No alternative manufacture or route change without written purchaser authorizationQuestions buyers ask
When should 42CrMo4 / 4140 buyers request QT condition?
Buyers should request QT condition when the application requires reviewed strength, toughness, or hardness targets after quenching and tempering. Include diameter, target values, certificate wording, and inspection requirements.
What is the difference between annealed, normalized, and QT RFQ wording?
Annealed wording usually supports machinability review, normalized wording supports structure and condition review, and QT wording supports strength or hardness target review. Connect each condition to the application and standard.
What heat-treatment documents should buyers request?
Buyers may request MTC, heat-treatment record or certificate wording where applicable, hardness or mechanical test results, heat number traceability, dimensional inspection, and third-party inspection records if specified by the order.
RFQ checklist
- Required delivery condition: annealed, normalized, QT, or other wording
- Grade standard and acceptable cross-reference names
- Diameter, length, quantity, and section-size information
- Target hardness, tensile strength, yield strength, or impact requirement if specified
- Downstream processing route such as peeling, grinding, or machining
- MTC, heat-treatment record, and certificate wording requirements
- Hardness inspection, mechanical testing, UT, or third-party inspection needs
- Application, drawing, destination, and packing requirements
- Required grade route, product standard, edition, product form, and precedence
- Alternative product basis, clause map, price, schedule, exclusions, and deviations
- Ordered and ruling section, delivery condition, surface, and downstream work
- Treatment processor, lot definition, straightening sequence, and sample representation
- Test methods, locations, frequency, judgment, retest, NDT, and actual results
- Inspection document, process records, traceability map, approval points, and release
References
- ISO 683-2:2016 Alloy steels for quenching and tempering
- SAE J404_200901 Chemical Compositions of SAE Alloy Steels
- ASTM A29/A29M-23 General Requirements for Steel Bars
- ISO 10474:2013 Steel and steel products — Inspection documents
- Simunovic et al.: quenching, tempering and cross-sectional hardness of 42CrMo4
Inquiry support
Unsure which processing route to quote?
Send the drawing or RFQ with the grade, size, condition, processing, inspection, quantity, and destination. We can flag open points before quotation.