ASTM A516 Grade 70 and the European EN 10028 System
ASTM A516 Grade 70 is one of the most widely used carbon steel plate grades for pressure vessels, storage tanks and heat exchangers operating in moderate and lower temperature service. European projects normally specify the equivalent EN designation, and for A516 Grade 70 that designation is EN 10028-2 P355GH.
P355GH is a weldable pressure vessel steel intended for elevated temperature service. It carries a minimum yield strength of 355 MPa and a tensile range of about 510-630 MPa, so it brackets the 485 MPa tensile level of A516 Grade 70 while adding the higher yield strength that European design codes expect when wall thickness is calculated.
Equivalent Grades of A516 Grade 70
Several regional grades can stand in for A516 Grade 70, but they are not interchangeable in every case, because their strength levels, impact test temperatures and allowable stress values differ.
| Region | Standard | Equivalent grade | Notes |
|---|---|---|---|
| Europe | EN 10028-2 | P355GH | Closest European match for Grade 70 |
| Europe | EN 10028-2 | P265GH | Suits lower A516 grades such as Grade 60 |
| Japan | JIS G3103 | SB450 | Boiler and pressure vessel plate |
| China | GB 713 | Q345R | Pressure vessel steel for moderate temperature |
| United States | ASTM A516/A516M | Grade 70 | Base specification |
When a European fabricator substitutes P355GH for A516 Grade 70, the designer has to check the allowable stress, the impact test temperature and the maximum permitted thickness in the applicable code. The two grades are close in tensile strength, but their yield strengths differ by roughly 90 MPa, and that difference changes the calculated wall thickness of a vessel.
Thickness Range and Plate Tolerance
A516 Grade 70 plate is produced from 3 mm up to 600 mm in thickness, which covers everything from thin heat exchanger shells to heavy storage vessel sections. Tolerances depend on the width of the plate and on the gauge that is ordered.
| Nominal gauge | Nominal thickness (in) | Gauge tolerance, 72 in wide plate (in) |
|---|---|---|
| 1/4 in | 0.2500 | +0.045 / -0.010 |
| 5/16 in | 0.3125 | Width class of the ordered plate |
| 3/8 in | 0.3750 | +0.055 / -0.010 |
Because the permitted under-thickness is much smaller than the permitted over-thickness, plate is normally rolled slightly above nominal so that the delivered thickness stays inside the design minimum. Tolerance widens as plate width increases, so a 72 in wide plate is ordered against the width-specific column of the specification rather than against a single figure. Thickness is verified at the plate corners and at mid-width, and the results are recorded on the mill certificate.
A516 Grade 70 Chemistry and Mechanical Properties
A516 Grade 70 is a carbon steel rather than an alloy steel. Carbon, manganese and silicon are the deliberate additions; phosphorus and sulphur are kept low so that the plate retains toughness and welds without cracking.
| Element | Limit |
|---|---|
| Carbon, max | 0.28 % |
| Manganese | 0.85-1.20 % |
| Silicon | 0.15-0.40 % |
| Phosphorus, max | 0.035 % |
| Sulphur, max | 0.035 % |
| Property | ASTM A516 Grade 70 | EN 10028-2 P355GH |
|---|---|---|
| Minimum yield strength | 260 MPa | 355 MPa |
| Tensile strength | 485-620 MPa | 510-630 MPa |
| Typical service window | Moderate and lower temperature | Elevated temperature |
| Heat treatment | As-rolled, normalized, or normalized and stress relieved | Normalized |
A516 Grade 70 versus A515, and Typical Applications
A515 is primarily used for the manufacture of intermediate-temperature pressure vessels, while A516 is used for the manufacture of low to intermediate-temperature pressure vessels. A515 plate is a carbon-silicon steel supplied normalized, and A516 is a carbon steel whose lower carbon and controlled manganese give it better impact energy at low temperature. Where a vessel sees a cold start-up or low ambient conditions, A516 Grade 70 is normally the safer choice; where the governing condition is a sustained elevated temperature, A515 Grade 70 is preferred. Typical applications are listed below.
Oil and gas processing equipment, separators and line components
Power plant pressure parts and boiler components
Chemical storage tanks and process vessels
Storage vessels and cryogenic-adjacent moderate temperature service
Heat exchanger shells, channels and covers
General fabrication of welded pressure equipment
A516 Grade 70 is supplied as hot rolled plate, shot blasted plate or normalized plate, and can be delivered with ultrasonic testing, charpy impact testing at the specified temperature, and third-party inspection for project documentation. Plates used in hydrogen or wet sour service are ordered with additional hardness and cracking tests to suit the service conditions.
Frequently Asked Questions
Q: What is the equivalent of ASTM A516 Grade 70 in Europe?
A: The European equivalent is EN 10028-2 P355GH, a normalized pressure vessel steel with a minimum yield strength of 355 MPa and a tensile range of about 510-630 MPa.
Q: What is the equivalent grade of A516?
A: Common equivalents include SB450 in JIS G3103, P265GH in EN 10028-2 and Q345R in GB 713. For A516 Grade 70 in particular, the closest European designation is P355GH.
Q: How thick is ASTM A516 Grade 70 plate?
A: A516 Grade 70 plate is produced in thicknesses from 3 mm to 600 mm, which allows it to be used for thin heat exchanger shells as well as heavy vessel sections.
Q: What is the thickness tolerance for A516 plate?
A: On 72 in wide plate the 1/4 in gauge (0.2500 in) is rolled to +0.045 / -0.010 in and the 3/8 in gauge (0.3750 in) to +0.055 / -0.010 in. Intermediate gauges follow the width class of the plate that is ordered.
Q: What is the difference between A516 and A515?
A: A515 is used mainly for intermediate-temperature pressure vessels, while A516 is used for low to intermediate-temperature pressure vessels. A515 is a normalized carbon-silicon steel and A516 is a carbon steel with better low-temperature toughness.
Q: What are the mechanical properties of A516 Grade 70?
A: The grade has a minimum yield strength of 260 MPa, a tensile range of 485-620 MPa, and a minimum elongation of 21 percent in a 50 mm gauge length.
Q: Does P355GH replace A516 Grade 70 directly?
A: The two grades are close in tensile strength, but P355GH has a higher yield strength. A direct replacement therefore requires a check of allowable stress, impact test temperature and the maximum thickness permitted by the design code.
Q: Where is A516 Grade 70 plate used?
A: Typical applications are oil and gas equipment, power plants, chemical storage tanks and storage vessels, heat exchangers and other welded pressure equipment that operates in moderate or lower temperature service.
