Tolerances for Titanium and Titanium Alloy Forgings
AMS 2249 is a SAE Aerospace Material Specification that defines dimensional tolerances, straightness, flatness, and machining allowances for titanium and titanium alloy forgings. It applies to closed-die, open-die, and ring forgings used in aerospace and other high-performance industries.
This standard ensures uniformity and interchangeability across forgings supplied by various manufacturers.
What AMS 2249 Covers
AMS 2249 defines tolerances for:
Feature |
Description |
Dimensional Tolerances |
Max deviations on thickness, width, length, OD, ID |
Straightness |
Permissible bow or deviation over a length (typically per mm or inch) |
Flatness |
Tolerances for flat areas of parts |
Machining Allowance |
Minimum stock left for machining after forging |
Flash Tolerances |
Limits for flash width and thickness |
Parting Line Displacement |
Allowable misalignment at the die parting line |
Draft Angles |
Minimum draft required for forging removal from dies |
Weight Tolerances |
Acceptable weight variation on finished forgings |
These tolerances vary depending on part size, forging method, and whether the forging is rough, finish-machined, or net-shape.
Applicability
Category |
Detail |
Material Types |
Pure titanium and titanium alloys (e.g., Ti-6Al-4V, CP grades) |
Forging Types |
Open-die, closed-die, seamless rings |
Product Forms |
Aircraft components, engine parts, structural forgings |
Examples of Typical Tolerances (Illustrative Only)
Feature |
Size Range |
Tolerance (Typical) |
Thickness |
25–50 mm (1–2 in) |
±0.8 mm (±0.031 in) |
OD (ring forgings) |
100–300 mm |
±1.0 mm to ±2.0 mm |
Straightness |
L/1000 or 0.5 mm max |
Varies by shape and size |
Flash (height) |
Typically ≤ 3 mm |
Dependent on die configuration |
Machining Allowance |
1.5–3 mm (min) |
Depends on part geometry |
Note: Always refer to the current AMS 2249 document for exact tolerance tables.
Related Specifications
AMS 4928 Ti-6Al-4V forgings and bar
AMS 4925 Ti-6Al-4V ELI bar and forgings
AMS 2241 General tolerances for titanium bars/wire/plate
ASTM B381 Titanium forgings for general industrial use