What Is ASTM A517?
ASTM A517 is the standard specification for high-yield quenched-and-tempered alloy steel plates intended for welded pressure vessels and structural parts under high stress. Grades ASTM A517Gr.A/B/E/F/H are among the most commonly specified, offering excellent strength-toughness balance after controlled heat treatment.
Key Grades Overview
- Grade A & B — widely used for moderate thicknesses
- Grade E — improved low-temperature toughness
- Grade F — higher strength with good hardenability
- Grade H — optimized for through-thickness properties
All grades are quenched and tempered to develop a fine microstructure that supports both high strength and acceptable ductility.
Chemical Composition
Heat analysis limits (weight %)
| Element | Gr.A | Gr.B | Gr.E | Gr.F | Gr.H |
|---|---|---|---|---|---|
| C | 0.15–0.21 | 0.15–0.21 | 0.12–0.20 | 0.10–0.20 | 0.12–0.21 |
| Mn | 0.80–1.10 | 0.70–1.00 | 0.40–0.70 | 0.60–1.00 | 0.95–1.40 |
| P, S | ≤0.035 | ≤0.035 | ≤0.035 | ≤0.035 | ≤0.035 |
| Si | 0.40–0.80 | 0.15–0.35 | 0.10–0.40 | 0.15–0.35 | 0.15–0.35 |
| Cr | 0.50–0.80 | 0.40–0.65 | 1.40–2.00 | 0.65–1.00 | 0.40–0.65 |
| Mo | 0.18–0.28 | 0.15–0.25 | 0.40–0.60 | 0.20–0.35 | 0.20–0.35 |
| B | ≤0.0025 | 0.0005–0.005 | 0.001–0.005 | 0.0005–0.006 | 0.0005–0.005 |
| V | — | 0.03–0.08 | — | 0.03–0.08 | 0.03–0.08 |
Boron is the critical micro-alloying addition that greatly enhances hardenability.
Mechanical Properties (Room Temperature)
Minimum values after quenching and tempering
| Grade | Thickness (mm) | Yield min. (MPa) | Tensile (MPa) | Elong. 50 mm (%) | CVN typical |
|---|---|---|---|---|---|
| A | ≤65 | 690 | 760–895 | 16 | — |
| B | ≤65 | 690 | 760–895 | 16 | — |
| E | ≤65 | 690 | 760–895 | 16 | 27 @ –40°C |
| F | ≤65 | 690 | 795–930 | 16 | 27 @ –40°C |
| H | ≤50 | 760 | 825–930 | 16 | 27 @ –40°C |
Engineers select ASTM A517 because it allows thinner sections for the same design pressure compared with lower-strength normalized steels (e.g. A516), reducing weight, cost, and welding heat input. Procurement teams appreciate that multiple grades can often be supplied from similar base chemistries, simplifying sourcing.
Common Applications
- Cryogenic and high-pressure gas trailers
- Mobile crane booms
- Mining equipment bodies
- Offshore platform components
- Heavy bridge girders
These applications benefit from the combination of high yield strength and reasonable sub-zero toughness (especially Grades E, F, H).
Welding Notes
ASTM A517 is weldable with precautions:
- Preheat 100–200 °C (grade & thickness dependent)
- Low-hydrogen electrodes (H4/H5)
- Interpass ≤250 °C
- PWHT usually not required for typical thicknesses
Follow qualified procedures per ASME Section IX or AWS D1.1. More guidance is available from the American Welding Society.
Conclusion
ASTM A517Gr.A/B/E/F/H remains a reliable high-strength choice for pressure vessels and heavy structures where weight efficiency and performance under stress are priorities. Understanding the small chemistry differences among grades helps engineers and buyers select the optimal variant for each project.
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