Common 4340 Alloy Steel Specifications & Heat Treatment
| Grade | 4340 Alloy Steel |
|---|---|
| Common bar standards | ASTM A29 / A322 for 4340 alloy bar; AMS 6414 only for certified aerospace-quality product when specified. |
| Heat-treatment condition | Common annealed or normalized starting condition, or quenched-and-tempered high-strength state. |
| Rod dimensions | Finished OD and upper/lower limits; length, quantity, straightness, surface roughness and certs as required. |
Grinding high-hardness bar can require burn/finish inspection and distortion allowance.
These are common references, not automatic certification/availability or an in-house heat-treatment claim. The order’s material specification, condition, outside processing if any, and acceptance requirements govern.
CARBON & ALLOY STEEL / PRECISION ROD BUYING GUIDE
Nickel-chromium-molybdenum alloy used for demanding strength/toughness combinations.
4340 Alloy Steel Rod Purchasing Specifications
SAE/AISI 4340; order the specified AMS/ASTM product form and certificate. A purchasing description must also identify whether the order is for raw stock, finished ground bar, or grinding of customer-owned stock. Finished outside diameter is separate from the material grade and is verified by an agreed inspection method.
Condition, Machining and Finishing
Define annealed, normalized or quenched-and-tempered condition and mechanical acceptance.
Grinding allowance and wheel selection depend on incoming bar diameter, condition, length and straightness. If the bar will undergo subsequent heat treatment or plating, coordinate processing sequence and the final diameter acceptance with your engineer.
Typical 4340 Alloy Steel Applications
Engineered shafts, power-transmission hardware and qualified aerospace parts.
End-use suitability depends on the component design, not merely a material name or a polished surface. Drawings should identify functional dimensional limits and related mechanical-property requirements.
Material Selection and Substitution Cautions
Fatigue performance, hydrogen embrittlement or plating effects must be considered by engineering where applicable.
Precision Rod RFQ Checklist
4340 Alloy Steel Centerless Ground & TG&P Bar Options
4340 Alloy Steel Centerless Ground Bar
For 4340 Alloy Steel centerless ground rod or bar, high-strength 4340 components often have heat-treatment sequencing constraints; quote final hardness and OD together. Review precision centerless grinding when specifying your finished outside diameter.
4340 Alloy Steel TG&P / Turned, Ground & Polished
When a drawing calls for 4340 Alloy Steel TG&P (TGP) or turned, ground and polished rod, a 4340 turned-ground-polished shaft inquiry should define post-heat-treat finishing and straightness needs. Explore bar supply and surface finishing.
Centerless-ground bar and TG&P shafting are not synonymous. Verify material condition, full route, OD tolerance, straightness, surface finish and available lengths against the RFQ. Request pricing →
- Material: grade, applicable ASTM/AMS or mill specification, supply condition and certifications.
- Size: finished outside diameter, explicit upper/lower tolerance limits and incoming OD if grinding supplied stock.
- Length and volume: full-bar or cut lengths, cut tolerance, pieces/bars/pounds and shipping destination.
- Acceptance: straightness span/method, roughness, roundness, hardness and lot traceability if required.
Quote Finished Rod Stock or Your Existing Bars
Precision Ground Rods coordinates sourcing and finishing inquiries on a quotation basis. Material supply and processing through centerless OD grinding, straightening, polishing, cutting and packaging are reviewed against your order. We do not guarantee every grade is stocked or that every tolerance is achievable for all diameters and lengths.
Request 4340 Alloy Steel Rod Pricing → · Browse all materials
General purchasing guide only. The written quotation and mill documentation govern grade, condition and acceptance; this page is not a material certificate.
