SAE 9315 – AMS 6263
High-hardenability Ni-Cr-Mo carburizing steel
Low-carbon 3.25% Ni-1.2% Cr-Mo carburizing steel, with a high-strength, tough core under a hard case (≈ 58–62 HRC). A slightly higher-carbon version of 9310, used in heavy-duty and aircraft gears; today it is specified mainly by AMS 6263.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | G93150 (former SAE) |
| W.Nr./EN | ≈ 15NiCr13 (1.5752) / 14NiCrMo13-4 (1.6657), approximate |
| DIN | ≈ 14NiCrMo13-4 |
| JIS | ≈ SNCM815 (approximate) |
| Trade names | 9315, AMS 6263 |
| Others | 9310 family (AMS 6260/6265) |
Standards by product form
| Form | Standard |
|---|---|
| Bar / forging / tubing (aerospace) | AMS 6263 |
| Bar (SAE composition) | SAE 9315 (historical SAE/AISI grade) |
| Bar – commercial alternative | SAE 9310 – ASTM A29 / SAE J404 |
| Gears | AGMA 2001 / ISO 6336 (material classes) |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7228.40.00 | 7228.40 | 7228.40.0000 | 7228 40 90 |
| Hot-rolled bar | 7228.30.00 | 7228.30 | 7228.30.8041 | 7228 30 61 |
| Seamless pipe | 7304.19.00 | 7304.19 | 7304.19.5050 | 7304 19 10 |
| Welded pipe | 7306.19.00 | 7306.19 | 7306.19.5150 | 7306 19 00 |
| Flange and fitting | 7307.91.00 | 7307.91 | 7307.91.5030 | 7307 91 00 |
Tariff class: alloy steel (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
Pipe: 7304.19 and 7306.19 are line pipe for oil and gas pipelines; boiler, heat exchanger or process tubes go under 7304.39/7304.59 (seamless) and 7306.30/7306.50 (welded).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
SAE 9315 (AMS 6263 limits C to 0.11 – 0.17)
| Element | Range (%) |
|---|---|
| C | 0.13 – 0.18 |
| Mn | 0.45 – 0.65 |
| P | ≤ 0.025 |
| S | ≤ 0.025 |
| Si | 0.20 – 0.35 |
| Ni | 3.00 – 3.50 |
| Cr | 1.00 – 1.40 |
| Mo | 0.08 – 0.15 |
Mechanical properties
Carburized, oil quenched and tempered at 150 °C – core properties, Ø ≈ 25 mm (typical)
| Property | Value |
|---|---|
| Yield strength (core) | ≈ 960 MPa (typical) |
| Tensile strength (core) | ≈ 1,200 MPa (typical) |
| Elongation (core) | ≈ 15% (typical) |
| Core hardness | ≈ 35 – 40 HRC (typical) |
| Surface hardness | ≈ 58 – 62 HRC |
| Case depth | ≈ 1.0 – 1.5 mm (per cycle) |
Typical physical properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Modulus of elasticity | ≈ 205 GPa |
| Thermal conductivity (20 °C) | ≈ 36 W/m·K (typical) |
| Thermal expansion (20–100 °C) | ≈ 11.5 µm/m·K (typical) |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Carburized gears operate up to ≈ 150–175 °C (case tempering temperature). |
| Heat treatment | Annealing/subcritical ≈ 650 °C for machining. Carburizing ≈ 925 °C (e.g. 8 h), cooling, reheating to ≈ 790–800 °C and quenching in agitated oil; optional sub-zero treatment to reduce retained austenite; tempering 150–175 °C. |
| Welding | Not usual on carburized parts. In the annealed condition: preheat ≈ 150–250 °C, low-H consumable (AWS E10018-M / ER100S-1) and stress relief; never weld the carburized case. |
| Machining | Fair in the annealed or normalized and tempered condition; final finishing by grinding after carburizing. |
Filler metal for welding
The wire composition is usually not identical to the material: each page explains why.
Typical applications
- Aircraft and helicopter transmission gears
- Heavy gearbox and mining gears
- Truck and tractor pinions and crown wheels
- Carburized splined shafts
- Large bearings and races
- Machine tool components
Alternatives: SAE 9310 (AMS 6265, VAR) for aerospace with lower C; SAE 8620 for less demanding, lower-cost gears; 4320 as an intermediate; 18CrNiMo7-6 (EN) for European industrial gearboxes.
Frequently asked questions
What is the chemical composition of SAE 9315?
Per SAE 9315 (AMS 6263 limits C to 0.11 – 0.17): C 0.13 – 0.18; Mn 0.45 – 0.65; P ≤ 0.025; S ≤ 0.025; Si 0.20 – 0.35; Ni 3.00 – 3.50.
Which standards cover SAE 9315?
Bar / forging / tubing (aerospace): AMS 6263. Bar (SAE composition): SAE 9315 (historical SAE/AISI grade). Bar – commercial alternative: SAE 9310 – ASTM A29 / SAE J404. Gears: AGMA 2001 / ISO 6336 (material classes).
Up to what temperature can SAE 9315 be used?
Carburized gears operate up to ≈ 150–175 °C (case tempering temperature).
Which materials can replace SAE 9315?
SAE 9310 (AMS 6265, VAR) for aerospace with lower C; SAE 8620 for less demanding, lower-cost gears; 4320 as an intermediate; 18CrNiMo7-6 (EN) for European industrial gearboxes.
