Materials & coatings lookup
Legacy drawings cite specs that no longer exist under that name — a print calling for QQ-A-250/4 is asking for what is now AMS-QQ-A-250/4 (2024 aluminum sheet and plate), and certifying material against the wrong revision is a routine FAIR finding. This page looks up common aerospace material callouts — aluminum, steel, and titanium AMS/ASTM specs — alongside coating and plating specs, and resolves superseded designations to their current equivalents.
Use it when a drawing note names a spec you don’t recognize, or when your mill cert cites a different-but-equivalent designation than the print.
Hardness by material
Steels from one scale to another: the hardness conversion.
All 19 materials in the table.
Brinell: from 90 HB (6061) to 240 HB (Inconel 625).
Rockwell C: from 28 HRC (4130, 15-5PH, 17-4PH and Ti-6Al-4V ELI) to 56 HRC (300M).
4340, 15-5PH, 17-4PH, Waspaloy and Inconel 718 span HRC 40, the base-metal hardness that splits the legacy QQ-C-320 hard-chrome classes (2b/2c below, 2d/2e at or above): which one applies follows the part's measured hardness.
7175 has no hardness range recorded.
- Materials shown
- 19of 19
| Common name | Alloy | Group | Hardness range | Specifications |
|---|---|---|---|---|
| Aluminum 2024 | 2024 | Aluminum | 120–150 HB (temper-dependent) | AMS 4037 (Sheet (T3) / Plate (T351)); AMS 4035 (Sheet/Plate (O, annealed)); AMS 4120 (Bar/Rod/Wire (T4/T351)); |
| Aluminum 6061 | 6061 | Aluminum | 90–105 HB (T6/T651) | AMS 4027 (Sheet (T6) / Plate (T651)); AMS 4117 (Bar/Rod (T6/T651)); AMS 4150 (Extrusion/Rings (T6)); AMS-QQ-A-250/11 (Sheet/Plate) |
| Aluminum 7050 | 7050 | Aluminum | 135–160 HB | AMS 4050 (Plate (T7451)); AMS 4108 (Hand Forging (T7452)); AMS 4342 (Extrusion (T74511)) |
| Aluminum 7075 | 7075 | Aluminum | 135–160 HB | AMS 4078 (Plate (T7351)); AMS 4045 (Sheet (T6) / Plate (T651)); AMS 4154 (Extrusion (T6/T6510/T6511)); AMS 4124 (Bar/Rod/Wire (T7351, cold-finished)); AMS-QQ-A-250/12 (Sheet/Plate) |
| Aluminum 7175 (UNS A97175) | 7175 | Aluminum | — | AMS 4149 (Die & Hand Forging (T74, formerly T736)); |
| AISI 4130 Chrome-Moly Steel | 4130 | Steel | 28–34 HRC (Q&T) | AMS 6350 (Sheet/Strip/Plate (annealed)); AMS 6351 (Sheet/Strip/Plate (spheroidized annealed)); AMS 6345 (Sheet/Strip/Plate (normalized)); AMS 6370 (Bar/Forging/Ring (annealed)); AMS 6371 (Seamless Mechanical Tubing (normalized or stress-relieved)); AMS 6348 (Bar (normalized)) |
| AISI 4340 Nickel-Chrome-Moly Steel | 4340 | Steel | 38–44 HRC (Q&T) | AMS 6414 (Bar/Forging (VAR)); AMS 6359 (Sheet/Strip/Plate (air melt)); AMS 6415 (Bar (AQ)); AMS 6454 (Sheet/Strip/Plate (VAR)) |
| 300M Ultra-High-Strength Steel | 300M | Steel | 52–56 HRC | AMS 6417 (Bar/Forging); AMS 6419 (Bar (consumable electrode melted)) |
| 15-5PH Precipitation Hardening Stainless | 15-5PH | Stainless Steel | 28–47 HRC (H900–H1150) | AMS 5659 (Bar/Forging/Ring); AMS 5862 (Sheet/Strip/Plate) |
| 17-4PH Precipitation Hardening Stainless | 17-4PH | Stainless Steel | 28–47 HRC (H900–H1150) | AMS 5643 (Bar/Forging/Ring); AMS 5604 (Sheet/Strip/Plate) |
| 303 Free-Machining Stainless Steel | 303 | Stainless Steel | 150–212 HB | AMS 5640 (Bar); ASTM A582 (Bar) |
| 304 Austenitic Stainless Steel | 304 | Stainless Steel | 123–201 HB | AMS 5639 (Bar); AMS 5513 (Sheet/Strip/Plate); ASTM A240 (Plate/Sheet/Strip) |
| 316 Austenitic Stainless Steel | 316 | Stainless Steel | 130–217 HB | AMS 5524 (Sheet/Strip/Plate); AMS 5648 (Bar/Wire); ASTM A240 (Plate/Sheet/Strip) |
| Ti-6Al-4V Grade 5 | Ti-6Al-4V | Titanium | 30–39 HRC | AMS 4911 (Sheet/Strip/Plate); AMS 4928 (Bar/Wire/Forging); AMS 4967 (Bar/Wire/Forging (annealed, heat treatable)); AMS 4935 (Extrusion/Flash-Welded Ring (annealed, beta processed)) |
| Ti-6Al-4V ELI Grade 23 (Extra Low Interstitial) | Ti-6Al-4V ELI | Titanium | 28–37 HRC | AMS 4930 (Bar/Wire); AMS 4931 (Bar/Forging/Ring (duplex annealed)) |
| Commercially Pure Titanium Grade 2 | CP Ti Grade 2 | Titanium | 145–200 HB | AMS 4902 (Sheet/Strip/Plate); AMS 4941 (Welded Tubing (annealed)) |
| Inconel 625 (UNS N06625) | Inconel 625 | Nickel | 145–240 HB | AMS 5666 (Bar/Forging); AMS 5599 (Sheet/Plate); ASTM B446 (Bar/Rod) |
| Inconel 718 (UNS N07718) | Inconel 718 | Nickel | 34–44 HRC (aged) | AMS 5662 (Bar/Forging (solution treated 1775 deg F, precipitation-hardenable)); AMS 5663 (Bar/Forging (solution treated + aged)); AMS 5596 (Sheet/Strip/Plate); AMS 5664 (Bar/Forging (solution treated 1950 deg F, precipitation-hardenable)) |
| Waspaloy (UNS N07001) | Waspaloy | Nickel | 31–43 HRC | AMS 5707 (Bar/Forging); AMS 5544 (Sheet/Strip/Plate) |
Where legacy specifications went
Federal (QQ-) and military (MIL-) specifications were cancelled, adopted by SAE as AMS documents, or split into one AMS specification per alloy. Each row is the resolver's own answer; the one the Superseded spec field resolves is lit, and picking a row resolves it.
Materials
Coatings
QQ-A-250/11 → AMS-QQ-A-250/11
How far a coating moves the surface
Every coating in the table on one scale, then the one you pick in section on its substrate. A fit is dimensioned on the finished part, so whatever the coating adds, and how much it varies, comes out of the tolerance unless the feature is sized after coating.
Anodise MIL-PRF-8625 · Type III · Class 1, 2
Thickness used: None on the drawing: 50.8 µm (0.002 in) ±20%, MIL-PRF-8625 3.7.2.1.
The factor is 2 because a diameter has two surfaces.
- Diameter change
- +40.6…+61.0µm
- Coating thickness
- 40.6–61.0µm
- Surface moves out, per surface
- 20.3–30.5µm
- Grown into the metal
- 20.3–30.5µm
- Coating variation uses
- 81% of T (20.3 of 25.0 µm)
- Machine undersize before coating
- 50.8µm, to centre the coated size
Coatings
| Spec | Type | Common name | Thickness | Notes |
|---|---|---|---|---|
| MIL-PRF-8625formerly MIL-A-8625 | Type I · Class 1 | Chromic Acid Anodize | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type I · Class 2 | Chromic Acid Anodize (Dyed) | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IB · Class 1 | Low-Voltage Chromic Acid Anodize | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IB · Class 2 | Low-Voltage Chromic Acid Anodize (Dyed) | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IC · Class 1 | Non-Chromic Acid Anodize | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IC · Class 2 | Non-Chromic Acid Anodize (Dyed) | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type II · Class 1 | Sulfuric Acid Anodize | 1.8–25.4 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type II · Class 2 | Sulfuric Acid Anodize (Dyed) | 1.8–25.4 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IIB · Class 1 | Thin Sulfuric Acid Anodize | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type IIB · Class 2 | Thin Sulfuric Acid Anodize (Dyed) | 0.5–17.8 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type III · Class 1 | Hard Anodize (Hardcoat) | 12.7–114.3 µm typical | |
| MIL-PRF-8625formerly MIL-A-8625 | Type III · Class 2 | Hard Anodize (Hardcoat, Dyed) | 12.7–114.3 µm typical | |
| MIL-DTL-5541 | Type I · Class 1A | Hexavalent Chromate Conversion (Corrosion Protection) | — | |
| MIL-DTL-5541 | Type I · Class 3 | Hexavalent Chromate Conversion (Low Resistance) | — | |
| MIL-DTL-5541 | Type II · Class 1A | Non-Hexavalent Conversion Coating (Corrosion Protection) | — | |
| MIL-DTL-5541 | Type II · Class 3 | Non-Hexavalent Conversion Coating (Low Resistance) | — | |
| AMS-QQ-P-416formerly QQ-P-416 | Type I · Class 1 | Cadmium Plate (As Plated, 0.0005 in min) | ≥ 12.7 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type I · Class 2 | Cadmium Plate (As Plated, 0.0003 in min) | ≥ 7.6 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type I · Class 3 | Cadmium Plate (As Plated, 0.0002 in min) | ≥ 5.1 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type II · Class 1 | Cadmium Plate + Chromate (0.0005 in min) | ≥ 12.7 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type II · Class 2 | Cadmium Plate + Chromate (0.0003 in min) | ≥ 7.6 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type II · Class 3 | Cadmium Plate + Chromate (0.0002 in min) | ≥ 5.1 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type III · Class 1 | Cadmium Plate + Phosphate (0.0005 in min) | ≥ 12.7 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type III · Class 2 | Cadmium Plate + Phosphate (0.0003 in min) | ≥ 7.6 µm | |
| AMS-QQ-P-416formerly QQ-P-416 | Type III · Class 3 | Cadmium Plate + Phosphate (0.0002 in min) | ≥ 5.1 µm | |
| AMS 2700 | Method 1, Type 1 | Nitric Passivation, Method 1 Type 1 (Low Temp + Dichromate) | — | |
| AMS 2700 | Method 1, Type 2 | Nitric Passivation, Method 1 Type 2 (Medium Temp + Dichromate) | — | |
| AMS 2700 | Method 1, Type 3 | Nitric Passivation, Method 1 Type 3 (High Temp + Dichromate) | — | |
| AMS 2700 | Method 1, Type 4 | Nitric Passivation, Method 1 Type 4 (Free-Machining Grades) | — | |
| AMS 2700 | Method 1, Type 5 | Anodic Passivation, Method 1 Type 5 (High-Carbon Martensitic) | — | |
| AMS 2700 | Method 1, Type 6 | Nitric Passivation, Method 1 Type 6 (Low Temp) | — | |
| AMS 2700 | Method 1, Type 7 | Nitric Passivation, Method 1 Type 7 (Medium Temp) | — | |
| AMS 2700 | Method 1, Type 8 | Nitric Passivation, Method 1 Type 8 (Medium Temp, High Concentration) | — | |
| AMS 2700 | Method 2 (Citric) | Citric Acid Passivation, Method 2 | — | |
| AMS 2404 | Electroless Nickel · Class 1 | Electroless Nickel, As-Plated (AMS 2404 Class 1) | — | |
| AMS 2404 | Electroless Nickel · Class 2 | Electroless Nickel, Heat-Treated for Hardness (AMS 2404 Class 2) | — | |
| AMS 2404 | Electroless Nickel · Class 3 | Electroless Nickel, Adhesion Bake for Non-Heat-Treatable Al/Be (AMS 2404 Class 3) | — | |
| AMS 2404 | Electroless Nickel · Class 4 | Electroless Nickel, Adhesion Bake for Heat-Treatable Al (AMS 2404 Class 4) | — | |
| AMS 2405 | Electroless Nickel | Electroless Nickel, Low Phosphorus (AMS 2405) | — | |
| AMS 2460formerly QQ-C-320, AMS-QQ-C-320 | Chromium · Class 1 | Decorative Chromium (Class 1) | — | |
| AMS 2460formerly QQ-C-320, AMS-QQ-C-320 | Hard Chrome · Class 2 | Engineering (Hard) Chromium (Class 2) | ≥ 50.8 µm | |
| Hard Chrome · Class 2a | Hard Chromium 2a (Per Procuring Activity) | — | ||
| Hard Chrome · Class 2b | Hard Chromium 2b (Below HRC 40, Static/Limited Life) | — | ||
| Hard Chrome · Class 2c | Hard Chromium 2c (Below HRC 40, Dynamic/Unlimited Life) | — | ||
| Hard Chrome · Class 2d | Hard Chromium 2d (HRC 40+, Static/Limited Life) | — | ||
| Hard Chrome · Class 2e | Hard Chromium 2e (HRC 40+, Dynamic/Unlimited Life) | — |
Why do drawings cite superseded specs?
Aerospace part definitions outlive their standards. Federal and military specifications (QQ-, MIL-) were progressively cancelled or handed to SAE as AMS documents, but drawings are rarely revised just to refresh a material note — the old callout stays legally on the print for decades. The FAIR still has to certify conformance, so the practical question is always “what is the active successor spec, and does my cert satisfy it?” That mapping is what the resolver answers; the buying decision (accept successor vs. demand the exact cited spec) belongs to your customer’s flow-down.