Duty inputs
What controls the part
- Load direction
- Fatigue exposure
- Toughness
- Section size
Component route 02
Shaft Bars & Rotating Parts
Round bars for motor shafts, transmission shafts, gear shafts, pins, spindles and rotating mechanical parts.
Round bar supply built around shaft applications where load, rotation, fatigue resistance, and downstream machining must be considered together.
Supply requirements
Five details to agree before ordering.
Specify the part, material, delivery condition, inspection requirements and quotation details together.
- 01ComponentShafts & pins
- 02Grade40Cr
- 03ConditionHot rolled or forged
- 04InspectionUT
- 05RFQDrawing + destination
Candidate grades
Material routes to review
- 40CrCommon alloy route for shaft and pin requirements.
- 42CrMo4 / 4140Higher-strength alloy route for demanding sections.
- 34CrNiMo6Alternative for high-load, toughness-led review.
- 35CrMoAlternative alloy route after size and duty review.
- Project-specific routeConfirm load, section and fatigue conditions.
Supply and release
Condition before quotation
- Supply stages
- Hot rolled or forged · Q&T · Peeled or turned
- Inspection
- UT · Straightness and dimensions · Mechanical properties
Production handoff
Connect bar condition to the next operation.
The order should state who is responsible for heat treatment, bar preparation, machining allowance, finishing and release inspection.
- Forging route review
- Heat treatment
- Peeling or turning
- Rough machining
Source imagery
See the component context.
Material supply for shaft and rotating component production.
Semi-finished shaft forms can support downstream machining routes.
RFQ checks
Questions buyers ask first.
When does a shaft buyer need QT or forged-route review?
QT or forged-route review may be needed when the shaft has higher load, larger diameter, fatigue exposure, toughness requirement, or drawing-based mechanical properties. The RFQ should state the required condition and inspection scope.
Why does machining allowance matter for shaft bars?
Machining allowance affects starting diameter, surface route, cutting plan, and dimensional inspection. Buyers should share rough size and final size when available so the material route can be reviewed clearly.
Which inspection documents are useful for shaft bar orders?
Useful documents may include MTC, heat number traceability, mechanical test records, UT records if specified, dimensional inspection, surface inspection, packing list, and third-party inspection records when requested.
Technical references
Go deeper only where needed.
40Cr / 41Cr4 / SCr440 round bar for shaft routesReview the 40Cr grade, delivery condition, machining, and inspection route for shafts, gears, and rotating parts.34CrNiMo6 product pageReview Ni-Cr-Mo alloy steel where shaft toughness, section size, and fatigue exposure need closer discussion.Fatigue and toughness inspectionPrepare fatigue, toughness, UT, mechanical testing, and traceability wording before RFQ.Gear and spline steel bar RFQ checklistTranslate tooth and spline routing, machining allowance, heat treatment, inspection, and drawing revision into the bar RFQ.Pin, bushing, and coupling steel selectionReview load, wear, alignment, section size, surface condition, and machining route before fixing the bar grade.Crankshaft and connecting-rod bar RFQ reviewConnect fatigue-critical geometry, forging or machining route, heat treatment, inspection stage, and traceability to the stock requirement.
Component RFQLock the route before quotation.
Send the part, grade or acceptable alternatives, size, condition, inspection scope, quantity and destination.