ASTM SA517 Grade E Pressure Vessel Steel Plate Chemical Composition & Mechanical Properties

Note: ASTM A517 Grade E is a Cr-Mo-B grade with no nickel addition. Its chromium content (1.40-2.00%) provides good corrosion resistance and hardenability. Grade E, along with Grade Q, has the highest maximum thickness capability of 150mm (6 in.) among all A517 grades [citation:4][citation:19]. Grade E is chemically identical to A514 Grade E, differing only in the specification (A517 for pressure vessels, A514 for structural applications) [citation:3][citation:15].

Carbon Equivalent (CE)

Typical value: ~0.65% (Grade E has moderate carbon equivalent)

Note: High-strength quenched and tempered steel requires controlled welding procedures; low hydrogen practice is mandatory. Preheat and interpass temperature control are critical for Grade E [citation:16].

• SA517 must be supplied in quenched + tempered condition
• Austenitizing temperature: not less than 900°C (1650°F)
• Quench in water or oil
• Tempering temperature: not less than 620°C (1150°F)
• Tempering temperature must be carefully controlled to achieve required strength and toughness balance

• A517 Grade E requires controlled welding procedures with preheat (150°C) and interpass temperature control [citation:16]
• Use only low hydrogen type electrodes; E11018 is commonly specified for matching strength [citation:13]
• Control heat input (8-23 kJ/cm range tested) to avoid HAZ softening [citation:16]
• Post-weld heat treatment at 550°C for 2h is commonly applied [citation:16]

Maximum thickness for Grade E: 6 in. [150 mm] [citation:4][citation:7][citation:19]

Grade E, along with Grade Q, has the highest thickness capability among A517 grades. Other grades have lower limits: Grade F (65mm), Grade H (50mm), Grade P (100mm), Grade S (50mm).

• Grade E: Cr-Mo-B, no Ni, highest thickness capability (150mm) [citation:4]
• Grade Q: Ni-Cr-Mo-V, highest thickness capability (150mm) [citation:4]
• Grade F: Ni-Cr-Mo-B, good low-temp toughness, 65mm max
• Grade P: Ni-Cr-Mo-B, high Ni for excellent low-temp toughness, 100mm max
• Grade S: Mn-Mo-Ti-Cb, optimized weldability, 50mm max

Design Considerations

• High strength: Grade E provides yield strength of 690 MPa for thickness up to 65mm
• Thickness capability: Maximum thickness for Grade E is 150mm (6 in.) [citation:4]
• Cr-Mo-B composition: Provides excellent hardenability and corrosion resistance
• Impact requirements: Transverse Charpy V-notch with lateral expansion ≥0.38mm [citation:4]

Fabrication Considerations

• Cold forming: May require stress relief after forming depending on strain level
• Hot forming: Forming temperature 900-960°C, re-quenching and tempering required after forming
• Welding: Low hydrogen practice mandatory; preheat 150°C minimum; interpass temperature control 150-200°C [citation:16]
• Machining: High strength requires proper tooling and cutting parameters
• PWHT: 550°C for 2h is commonly applied for stress relief [citation:16]

Common Failure Mode Prevention

• Hydrogen-induced cold cracking: Strict low-hydrogen practice, preheat, control diffusible hydrogen <=5 mL/100g
• HAZ softening: Control heat input during welding to avoid excessive softening [citation:16]
• Lamellar tearing: Consider through-thickness properties for critical joints
• Stress corrosion cracking: Consider environment and use appropriate protective measures