The component manufacturing route
List the operations from supplied bar to finished teeth or splines: blanking, rough machining, tooth or spline cutting, heat treatment, and final finishing as applicable. Identify the responsible party and acceptance stage for each. Show where treatment or stock removal changes the critical section or surface.
Grade and delivery condition
Name the required grade, product standard and edition, and thermal delivery condition. State any hardness needed for machining and the properties required after final treatment separately. If 40Cr, 42CrMo, 42CrMo4, or SAE 4140 is proposed as an alternative, obtain review against the drawing and approved process.
Rough size and machining allowance
Show the supplied stock envelope beside the finished outside diameter, bore, face width, shoulders, roots, and spline features. Assign allowance to the operations that need it and check the minimum clean-up at the critical surfaces. Record the drawing revision and any reserved material for tests.
Inspection points to settle early
Specify required chemistry, mechanical and hardness tests, surface examination, dimensions, and UT with their methods, locations, coverage, and acceptance criteria. Keep the heat and treatment lot traceable through cutting and machining. Identify which final tooth or spline checks fall outside the bar supplier's delivery scope.
Write the bar requirement around the actual gear route
A gear or spline bar RFQ begins with the approved drawing and process plan, not a generic alloy grade. State the supplied stock envelope, finished section, tooth or spline manufacturing route, machining stock, critical transition zones, heat-treatment responsibility, surface finishing, and final inspection owner. ISO 683-2 supplies product and condition context for covered alloy steels but cannot confirm tooth geometry, case response, distortion, contact behavior, or component performance.
Details that affect the bar order
| Decision | RFQ definition | Evidence required | Stage boundary |
|---|---|---|---|
| Incoming material | Grade, product standard, edition, product form, section, condition, surface, and alternatives | Inspection document with actual ordered results and heat or lot traceability | Evidence applies to the stated incoming or delivered bar state |
| Stock and geometry | Supplied and finished envelopes, datums, machining stock, straightness or form controls, and sample extent | Dimensional report using the controlled drawing and inspection stage | ISO 1101 language cannot choose tolerances or finished tooth acceptance |
| Surface and decarburization | Process state, functional zones, method, locations, frequency, permitted result, and disposition | ISO 3887 report where specifically ordered plus identity link | The method cannot add an allowable depth or guarantee treatment response |
| Downstream release | Tooth manufacture, treatment, finishing, NDT, deviations, final validation, and release approvers | Separate downstream records under the accepted process plan | Bar conformity does not certify the completed gear or spline |
Stock removal, decarburization, and traceability
Show the supplied bar envelope and finished root, bore, shoulder, or spline zones on the drawing. Define minimum cleanup stock using approved geometry and tolerance analysis rather than a generic allowance. If straightness or other geometrical control affects machining yield, state the datum and verification stage. ISO 1101 provides geometrical-tolerancing language; the drawing and inspection plan must select the actual requirements and measurement approach.
RFQ example
Item: Alloy-steel bars or blanks for [gear or spline drawing and revision], [size and quantity]
Material: [grade] to [product standard and edition], [section, delivery condition, and surface]; alternatives by written clause comparison only
Geometry: Supplied and finished envelopes, datums, machining stock, straightness or form controls, end zones, and inspection stage per attached schedule
Process responsibility: [party] performs tooth or spline machining, heat treatment, finishing, NDT, and final validation; supplier lists every subcontractor
Surface control: Decarburization or other surface checks only to the named method, material state, locations, frequency, acceptance, and disposition
Documents: ISO 10474 type [state], actual results, heat-to-process-lot-to-blank-or-bundle map, dimensional and surface reports, and deviations
Release: Drawing conflicts and exceptions closed in writing before manufacture and shipment hold point cleared before dispatchQuestions buyers ask
What should buyers include in a gear or spline steel bar RFQ?
Buyers should include intended component route, grade standard, delivery condition, rough bar size, final drawing size if available, machining allowance, heat-treatment expectation, inspection coverage, certificate requirement, quantity, and destination.
Is grade name enough for gear and spline bar quotation?
No. Grade name should be paired with condition, size, machining route, drawing or final dimensions, inspection requirements, and document expectations so the supplier can review the bar route properly.
Which JOTAIN grades are often reviewed for gear or spline routes?
Depending on application requirements, buyers may review 40Cr, 42CrMo, 42CrMo4 / 4140, or 34CrNiMo6 routes. Final selection should be confirmed around load, size, condition, machining, and inspection needs.
RFQ checklist
- Component type such as gear blank, spline shaft, keyed shaft, sleeve, or machined rotating part
- Controlling grade standard and acceptable equivalent names if cross-reference is allowed
- Delivery condition such as annealed, normalized, QT, or buyer-reviewed heat-treatment route
- Rough bar diameter, length, machining allowance, and final drawing size where available
- Drawing revision, controlled dimensions, and mandatory notes that affect the quotation
- Hardness, mechanical property, or heat-treatment certificate requirement if applicable
- UT, dimensional, surface, or third-party inspection requirement before shipment
- Packing, marking, heat-number traceability, destination, and shipment document needs
- Gear or spline drawing revision, supplied and finished envelopes, critical zones, and duty concern
- Grade, product standard, edition, section, delivery condition, surface, and alternatives
- Datums, machining stock, geometry controls, end zones, measurement stage, and sample extent
- Tooth or spline machining, heat treatment, finishing, NDT, and validation responsibilities
- Decarburization need, method, material state, locations, frequency, acceptance, and disposition
- Heat and process-lot identity, actual-result documents, deviations, packing, and release
References
Inquiry support
Working from a part drawing?
Send the drawing or RFQ with the grade, size, condition, processing, inspection, quantity, and destination. We can flag open points before quotation.