Product List
Gangsteel Material Solution
Email: admin@gangsteel.com
Sales: jack@gangsteel.com
ASME SA 516 Gr 70 and SA 516 Gr 70N are both carbon steel plates specified under ASME Section II (equivalent to ASTM A516 Grade 70), primarily used for moderate- and lower-temperature pressure vessels in industries like oil, gas, petrochemicals, boilers, and power generation.
The primary difference lies in the heat treatment process: SA 516 Gr 70 is typically supplied in the as-rolled condition (hot-rolled without additional treatment), while the "N" designation indicates a normalized condition (heated above the critical temperature and air-cooled for grain refinement). This results in subtle but important variations in performance, particularly toughness and suitability for low-temperature service.
The table below summarizes the main differences based on standard specifications and industry discussions:
|
Aspect |
SA 516 Gr 70 (As-Rolled) |
SA 516 Gr 70N (Normalized) |
|---|---|---|
|
Heat Treatment |
Hot-rolled only; no additional post-rolling treatment unless specified. |
Hot-rolled followed by normalizing (heated to ~900–950°C and air-cooled) to refine grain structure, relieve internal stresses, and homogenize carbides. Required for plates >1.5 inches (38 mm) thick per ASME Section VIII Div. 1. |
|
Chemical Composition |
Identical: C ≤0.27%, Mn 0.85–1.20%, P ≤0.025%, S ≤0.025%, Si 0.15–0.40% (with optional alloying elements like Nb or V for enhanced properties). No differences. |
Same as ASME SA516 Gr 70. |
|
Mechanical Properties |
- Tensile Strength: 485–620 MPa (70–90 ksi) - Yield Strength: ≥260 MPa (38 ksi) - Elongation: ≥17–21% (depending on thickness) - Standard toughness, but higher ductile-brittle transition temperature (DBTT), e.g., impact exemption at ~ -1°C for 25 mm thickness. |
- Same nominal tensile and yield strengths. - Improved Charpy V-notch toughness (better impact absorption at low temperatures). - Lower DBTT (e.g., exemption down to ~ -34°C for 25 mm thickness, a ~33°C improvement). - Slightly higher hardness but enhanced ductility and fatigue resistance post-heat treatment. |
|
Advantages |
- Lower cost due to simpler processing. - Adequate for ambient or moderate-temperature applications without stringent low-temp requirements. |
- Superior low-temperature performance and notch toughness. - Better resistance to corrosion (e.g., stress corrosion cracking, hydrogen-induced cracking) and internal stress relief. - More stable properties after welding, forming, or post-weld heat treatment (PWHT). |
|
Limitations |
- Poorer low-temp toughness; may require impact testing for cold service. - Potential for residual stresses if not controlled during rolling. |
- Higher cost due to additional heat treatment. - May lose some benefits if reheated above normalizing temperature during forming (recommend re-normalizing if needed). |
|
Applications |
- General pressure vessels, boilers, and storage tanks at ambient temperatures. - Cost-sensitive projects where low-temp impact isn't critical. |
- Low-temperature service (e.g., LNG tanks, cryogenic vessels). - Thicker plates (>38 mm) or high-stress environments like reactors, heat exchangers, and nuclear components. - Preferred for welding qualification and harsh conditions (e.g., sour service per NACE). |
|
Thickness Range |
Up to 204 mm (8 inches), but normalization often mandatory beyond 38 mm. |
Same, but explicitly normalized for thicker sections. |
Additional Notes
For precise procurement, refer to the latest ASME/ASTM standards or supplier data sheets.
https://gangsteel.net/product/boiler/ASME/SA516/grade/70/steel/plate.html
ASME SA 516 Gr 70 and SA 516 Gr 70N are both carbon steel plates specified under ASME Section II (equivalent to
