What is the difference between A514 grade E and A514 grade F?
A514 Grade E is a high-strength, quenched and tempered alloy steel within the ASTM A514 specification, offering a minimum yield strength of 100 ksi (690 MPa). Its defining feature is enhanced atmospheric corrosion resistance (approximately twice that of carbon steel), achieved through a controlled chemistry with elevated Molybdenum content. This grade is designed for applications like unpainted outdoor machinery or structural components where both extreme strength and moderate environmental durability are required, bridging the gap between standard high-strength steel and full weathering grades.
A514 Grade F is the most common and widely available grade in the ASTM A514 family, also providing a 100 ksi (690 MPa) minimum yield strength through quenching and tempering. Distinguished by its boron-treated chemistry for optimal hardenability, it serves as the general-purpose ultra-high-strength structural steel for critical, weight-sensitive components such as crane booms, mining shovel dippers, and high-stress connections, where maximum load capacity and toughness are essential and corrosion protection is managed through paint systems.
The primary difference between A514 Grade E and A514 Grade F lies in their chemical composition, which leads to distinct corrosion resistance properties and slightly different optimal applications, while both maintain identical 100 ksi (690 MPa) minimum yield strength and quenched & tempered microstructure.
1. Chemical Composition Comparison (Weight %)
The defining difference is in the Molybdenum (Mo) content, which gives Grade E its enhanced corrosion resistance.
Chemical Summary: The sole intentional compositional difference is the higher Molybdenum range in Grade E (0.20–0.30% vs. 0.15–0.25%). This makes Grade E a "corrosion-enhanced" variant of the standard Grade F chemistry.
2. Mechanical Properties Comparison
Both grades undergo quenching and tempering and must meet identical mechanical property requirements.
| Property | A514 Grade E | A514 Grade F | Standard / Note |
|---|---|---|---|
| Yield Strength (min) | 100 ksi (690 MPa) | 100 ksi (690 MPa) | Identical. The defining 100 ksi minimum. |
| Tensile Strength | 115 – 135 ksi (790 – 930 MPa) | 115 – 135 ksi (790 – 930 MPa) | Identical. Typical as-rolled range. |
| Elongation (min, in 2 in.) | ≥ 18% | ≥ 18% | Identical. Minimum ductility requirement. |
| Reduction of Area (min) | ≥ 40% | ≥ 40% | Identical. |
| Charpy V-Notch Impact (min) | ≥ 40 ft·lb (54 J) @ -40°F (-40°C) | ≥ 40 ft·lb (54 J) @ -40°F (-40°C) | Identical. Mandatory low-temperature toughness. |
| Hardness (typical) | 235 – 293 HB | 235 – 293 HB | Similar Brinell hardness range. |
Mechanical Summary: There is no difference in guaranteed mechanical properties. Both grades are specified to the same minimum strength, ductility, and toughness values.
Why This Distinction Matters
The choice is not about strength-it's about environmental durability versus cost/availability.
Grade E is for when you want a "bonus" of corrosion resistance without stepping down to 50 ksi weathering steel (A588) or up to 100 ksi weathering steel (A709 Grade 100W).
Grade F is for when strength and toughness are the only drivers, and corrosion protection will be handled by coatings.
1. What is the key chemical difference that defines A514 Grade E?
A514 Grade E is distinguished by its elevated Molybdenum (Mo) content (0.20-0.30%), which provides enhanced atmospheric corrosion resistance (approximately 2× that of carbon steel) while maintaining the 100 ksi yield strength of the A514 family.
2. Is A514 Grade E considered a true weathering steel like A588?
No, it is not a full weathering steel. While it offers improved corrosion resistance (~2× carbon steel), true weathering steels like A588 or A709W provide 4–6× resistance and form a stable, self-protecting patina for fully unpainted exposure.
3. What is the primary application niche for A514 Grade E?
It is used for high-strength structural components exposed to outdoor environments but not requiring a painted or full weathering system, such as heavy equipment booms, frames, and industrial structures subject to moderate atmospheric conditions.
4. How does A514 Grade E compare to A514 Grade F in terms of availability?
A514 Grade E is less common and more specialized than Grade F. Grade F is the standard, widely available 100 ksi Q&T steel, while Grade E is specified only when its enhanced corrosion resistance is a required design feature.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
