How to Choose Between SA516 Gr.60 and Gr.70 for Your LPG Tank
Selecting the correct pressure vessel steel plate for an LPG (liquefied petroleum gas) storage tank is a critical decision. It directly impacts safety, regulatory compliance, manufacturing costs, and the tank's service life.
Two of the most common material grades specified under the ASME Boiler and Pressure Vessel Code are SA516 Gr.60 and SA516 Gr.70. While both are excellent carbon steel plates for moderate and lower-temperature service, they are not interchangeable.
This guide breaks down the key differences-mechanical properties, cost implications, design pressure requirements, and welding considerations-to help you make an informed choice for your next LPG tank project.
Quick Comparison: SA516 Gr.60 vs. SA516 Gr.70
| Parameter | SA516 Gr.60 | SA516 Gr.70 |
|---|---|---|
| Minimum Tensile Strength | 60 ksi (415 MPa) | 70 ksi (483 MPa) – 16% stronger |
| Minimum Yield Strength | 32 ksi (220 MPa) | 38 ksi (262 MPa) – 19% higher |
| Typical Operating Pressure | Lower to medium | Medium to high |
| Relative Cost per Ton | Baseline | Slightly higher (approx. 5-8%) |
| Common LPG Tank Type | Small domestic tanks, bulk storage at moderate pressure | Large ASME-stamped tanks, transport vessels, high-pressure bullet tanks |
Design Pressure and Tank Size
SA516 Gr.70
SA516 Gr.70 has a higher allowable stress value in the ASME Code (Section VIII, Division 1). This means for the same wall thickness, a Gr.70 tank can safely withstand higher internal pressure. Conversely, for the same pressure rating, you can use a thinner Gr.70 plate, reducing overall tank weight.
SA516 Gr.60
SA516 Gr.60 is suitable for lower-pressure applications or larger, bulk storage tanks where internal pressure is relatively modest and weight reduction is less critical.
Practical example
A large, bullet-style LPG storage vessel operating at 250 psi will almost certainly require SA516 Gr.70 to meet code-required stress calculations without excessive wall thickness. For a smaller, domestically rated tank at 100 psi, Gr.60 may be perfectly adequate and more economical.
Low-Temperature Toughness (LPG Service)
LPG is stored under pressure as a liquid, which boils at around -43°C (-45°F) at atmospheric pressure. While operating tanks are under pressure, they must remain tough and ductile even at low ambient temperatures or during sudden pressure drops.
Both Gr.60 and Gr.70 are designed for moderate and lower-temperature service. Typically, both grades can meet Charpy V-notch impact test requirements at -40°C (-40°F) when specified with a normalized heat treatment.
Our recommendation: For any LPG tank in cold climates (e.g., Northern USA, Canada, Europe), always specify normalized SA516 Gr.70. The higher strength combined with certified low-temperature impact toughness provides an extra margin of safety against brittle fracture.
Weldability and Fabrication
Both grades have excellent weldability due to their low carbon content (≤0.30%) and low carbon equivalent (CE).
No major differences: You can weld both Gr.60 and Gr.70 using standard low-hydrogen processes (SMAW, GMAW, FCAW, SAW) with preheating typically not required for thinner plates (below 25mm) under normal shop conditions.
Thicker plates: For sections over 38mm, both grades may benefit from moderate preheat (50-100°C) and post-weld heat treatment (PWHT) as required by ASME.
Bottom line: Fabrication difficulty is nearly identical. Your choice will not be driven by weldability.
Which Grade Should You Choose?
| If your LPG tank project requires... | Recommended Grade |
|---|---|
| ASME Code stamp (most commercial LPG vessels) | SA516 Gr.70 (preferred for higher allowable stress) |
| High design pressure (>200 psi) or large diameter | SA516 Gr.70 (to reduce wall thickness) |
| Certified low-temperature toughness to -40°C | Both, with Normalized (Gr.70 offers higher strength) |
| Minimal initial material cost, low pressure, non-code tank | SA516 Gr.60 |
| Transportable LPG tank (road/rail) – weight is critical | SA516 Gr.70 (lighter vessel) |
| Project in a region with strict inspection (e.g., EU, North America) | SA516 Gr.70 with EN10204 3.2 |
why choose us?
At YUXIN steel group , we stock a full range of ASME SA516 Gr.70 pressure vessel plates from 6mm to 200mm thick, with normalized heat treatment and EN10204 Type 3.2 certification available.
✅ In stock for fast delivery
✅ Custom plasma/laser cutting to your dimensions
✅ Full mill test reports (MTC) with every order
✅ Technical support for material selection
👉 [Request a Quote for SA516 Gr.70 Now]
👉 [Compare with SA516 Gr.60 Plate]
one-stop solution
professional team
high quality
Choose YUXIN steel group, and what you purchase is not merely the steel plates, but also a complete warranty system and a sense of responsibility.
Our address
Tianjin, China
Phone Number
(86)-15937221771(WeChat)
(86)-15837212056(WhatsApp)
info@chinasteelcompany.com
FAQ
01.What is the minimum design temperature for ASME SA516 Gr.70 pressure vessel steel plate?
SA516 Gr.70 is specifically designed for moderate and lower-temperature service. The standard allows for impact testing down to -40°C (-40°F) when the material is ordered in the normalized condition.
For LPG tanks and other pressure vessels operating in cold climates, we strongly recommend specifying normalized SA516 Gr.70 with Charpy V-notch impact testing at -40°C. This ensures the plate maintains excellent toughness and prevents brittle fracture under sudden temperature drops or pressure fluctuations. For applications below -40°C, other low-carbon or nickel-alloy steels may be required.
02.Is preheating required when welding SA516 Gr.70 steel plate?
Yes, SA516 Gr.70 has excellent weldability due to its low carbon content (≤0.30%) and low carbon equivalent (CE). For thinner plates (typically under 25mm / 1 inch), preheating is not required under normal shop conditions when using low-hydrogen welding processes (SMAW, GMAW, FCAW, SAW).
However, for thicker plates (over 38mm) , or when the ambient temperature is low (below 5°C / 41°F), a moderate preheat of 50-100°C (120-210°F) is recommended to reduce the risk of hydrogen-induced cracking. Always follow the qualified welding procedure specification (WPS) and ASME Code requirements. Post-weld heat treatment (PWHT) may be required for thicker sections or specific service conditions.
03.Are SA516 Gr.70 and A516 Gr.70 the same? What's the difference?
They are essentially identical in terms of chemical composition and mechanical properties. The difference is purely in the naming convention:
SA516 refers to the ASME specification (Section II, Part A) – used for pressure vessels built to the ASME Boiler and Pressure Vessel Code.
A516 refers to the ASTM specification – the original standard developed by ASTM International.
In practice, most pressure vessel manufacturers specify SA516 Gr.70 because ASME Code requires the "SA" designation for code-stamped vessels. However, the material is the same. Many suppliers (including Yuxin Steel) produce plates that meet both ASME SA516 and ASTM A516 requirements simultaneously.
04.Do you offer EN 10204 Type 3.2 certification for SA516 Gr.70 plates? What is the cost and lead time?
Yes, absolutely. We can provide EN 10204 Type 3.2 inspection certificates for SA516 Gr.70 plates upon request. This certificate is issued by an independent third-party inspection body (such as TÜV, BV, SGS, DNV, or Lloyds) and is often required for international projects, insurance purposes, or when the end user demands full material traceability.
Standard (included): EN 10204 Type 3.1 – manufacturer's inspection, verified by an independent authorized representative.
Upon request (additional cost): EN 10204 Type 3.2 – third-party witnessed testing and certification.
Lead time for Type 3.2: Typically adds 3-7 days to the production schedule depending on the inspection body's availability.
China one-stop steel processing procurement
Through years of understanding and precipitation of steel, Yuxin Group has now become a mature steel processing and manufacturer, providing various products for many construction companies and steel structure companies around the world. Thanks to Yuxin Group's professionalism and integrity, it has become a world-renowned enterprise.
