Aug 2025
ASTM A449
ASTM A449 covers headed bolts, rods, and anchor bolts with diameters ranging from 1/4" to 3" inclusive. These medium-strength bolts are manufactured from medium carbon or alloy steel and achieve their mechanical properties through a heat treatment process. They are widely used in general engineering and construction applications.
ASTM A449 bolts are chemically and mechanically similar to ASTM A325 and SAE J429 Grade 5. However, ASTM A449 offers greater flexibility, as it covers a broader diameter range and is not limited to a specific configuration. This makes it a preferred choice for projects requiring versatility and reliable performance.
A449 Types
| Type 1 |
Plain carbon steel, carbon boron steel, alloy steel, or alloy boron steel. |
| Type 2 |
Withdrawn (2003) |
| Type 3 |
Weathering steel, offering improved resistance to atmospheric corrosion. |
A449 Chemical Properties| ASTM A449 – Type 1 Chemical Composition |
|---|
| Element | Carbon Steel | Carbon-Boron Steel | Alloy Steel | Alloy-Boron Steel |
|---|
| Carbon | 0.30 – 0.52% | 0.30 – 0.52% | 0.30 – 0.52% | 0.30 – 0.52% |
| Manganese (min) | 0.60% | 0.60% | 0.60% | 0.60% |
| Phosphorus (max) | 0.040% | 0.040% | 0.035% | 0.035% |
| Sulfur (max) | 0.050% | 0.050% | 0.040% | 0.040% |
| Silicon | 0.15 – 0.30% | 0.10 – 0.30% | 0.15 – 0.35% | 0.15 – 0.35% |
| Boron | — | 0.0005 – 0.003% | — | 0.0005 – 0.003% |
| Alloying Elements | — | — | * | * |
|
* Steel is considered an alloy if the maximum specified range for elements exceeds:
Manganese (1.65%), Silicon (0.60%), Copper (0.60%),
or if it contains minimum quantities of alloying elements such as Aluminum, Chromium (= 3.99%),
Cobalt, Columbium, Molybdenum, Nickel, Titanium, Tungsten, Vanadium, Zirconium, or others
intentionally added to achieve desired properties. |
| Type 3 Bolts — Class * |
| Element |
Class A |
Class B |
Class C |
Class D |
Class E |
Class F |
| Carbon |
0.33 – 0.40% |
0.38 – 0.48% |
0.15 – 0.25% |
0.15 – 0.25% |
0.20 – 0.25% |
0.20 – 0.25% |
| Manganese |
0.90 – 1.20% |
0.70 – 0.90% |
0.80 – 1.35% |
0.40 – 1.20% |
0.60 – 1.00% |
0.90 – 1.20% |
| Phosphorus |
0.035% max |
0.06 – 0.12% |
0.035% max |
0.035% max |
0.035% |
0.035% |
| Sulfur |
0.040% max |
0.040% max |
0.040% max |
0.040% max |
0.040% max |
0.040% max |
| Silicon | 0.15-0.35% | 0.30-0.50% | 0.15-0.35% | 0.25-0.50% |
|
|
| Copper | 0.25-0.45% | 0.20-0.40% | 0.20-0.50% | 0.30-0.50% |
|
|
| Nickel | 0.25-0.45% | 0.50-0.80% | 0.25-0.50% | 0.50-0.80% |
|
|
| Chromium | 0.45-0.65% | 0.50-0.75% | 0.30-0.50% | 0.50-1.00% |
|
|
| Vanadium |
|
| 0.020% min |
|
|
|
| Molybdenum |
| 0.06% max |
| 0.10% max |
|
|
| Titanium |
|
|
| 0.05% max |
|
|
| * Selection of a class shall be at the option of the manufacturer |