ASTM A516 Grade 60/70 dual certified plate is a pressure vessel quality (PVQ) carbon steel plate supplied with documentation demonstrating compliance to both ASTM A516 Grade 60 and ASTM A516 Grade 70. In industry usage, this does not mean a separate ASTM material grade exists. It means the same plate lot has been manufactured, tested, and reported so that the mill test certificate (MTC) supports both grade references, typically by meeting the higher mechanical threshold associated with Grade 70.
This is particularly relevant for EPC contractors, pressure vessel fabricators, inspection agencies, and project procurement teams working with mixed documentation. Drawings may call up Grade 60, legacy datasheets may mention SA/ASTM A516 Gr 60, while newer vessel calculations or client standards may reference Grade 70. In such cases, ASTM A516 Grade 60/70 dual can reduce procurement mismatch, provided the ordered plate, certified values, and applicable code requirements are reviewed together.
What ASTM A516 Grade 60/70 Dual Means
Dual certification indicates that one plate heat or lot has been tested and documented to satisfy the requirements of both grades within the ASTM A516 specification family for moderate- and lower-temperature pressure vessel service. Since Grade 70 has higher minimum strength requirements than Grade 60, dual certified material is commonly supplied with mechanical properties meeting Grade 70 minimum tensile and yield strength, while remaining orderable where Grade 60 is also referenced.
From a technical and commercial standpoint, the benefit is straightforward: one plate can often be accepted across multiple project references without changing to a different specification family. However, acceptance should always be based on the actual certified test results, specification edition, thickness range, supplementary requirements if any, and the governing design code such as ASME Section VIII where applicable.
Typical Applications of ASTM A516 Grade 60/70 Dual Plate
ASTM A516 plate is widely used where good notch toughness, weldability, and pressure vessel service suitability are required for carbon steel equipment. Dual certified plate is commonly considered where procurement flexibility is useful across mixed project documents.
- Boilers and steam drums
- Pressure vessels and separators
- Heat exchangers and channel covers
- Columns, towers, and reactors
- Storage vessels and process tanks
- Refinery and petrochemical equipment
- Fertilizer, chemical, and power plant fabrication
- Shop-fabricated and field-erected vessel components
ASTM A516 Grade 60 vs Grade 70 vs Dual Certified Plate
The principal distinction between Grade 60 and Grade 70 is strength level. Grade 70 has higher minimum tensile and yield requirements, which may influence thickness selection and design calculations, subject to code rules, corrosion allowance, joint efficiency, service conditions, and mandatory impact or supplementary testing. Dual certified plate is generally supplied so the reported mechanical values satisfy the Grade 70 threshold while the certificate also supports Grade 60 reference.
| Property | ASTM A516 Grade 60 | ASTM A516 Grade 70 | Typical Dual Certified Plate |
|---|---|---|---|
| Product form | PVQ carbon steel plate | PVQ carbon steel plate | PVQ carbon steel plate |
| Minimum tensile strength | 60 ksi (415 MPa) | 70 ksi (485 MPa) | Typically meets Grade 70 minimum |
| Minimum yield strength | 32 ksi (220 MPa) | 38 ksi (260 MPa) | Typically meets Grade 70 minimum |
| Ordering basis | Single-grade order | Single-grade order | One plate certified to both grades |
| Documentation scope | Grade 60 only | Grade 70 only | MTC references both grades |
| Procurement advantage | Suitable where Gr 60 only is specified | Suitable where Gr 70 only is specified | Useful where project documents reference both |
| Design implication | Lower minimum strength basis | Higher minimum strength basis | Use actual certified values and governing code |
Values above are general reference figures commonly associated with the grades. Actual supplied values remain subject to plate thickness, heat treatment condition, ASTM edition, and the mill's certified results. Purchasers and fabricators should rely on the MTC and approved calculations rather than catalogue summaries alone.
Chemical Composition and Mechanical Property Considerations
ASTM A516 is intended for pressure vessel service and is typically selected for its balance of strength, formability, and weldability. For dual certification, the chemistry and mechanical test results must align with the specification requirements applicable to the supplied plate. In practice, procurement teams should verify the following on the MTC:
- Heat number and plate identification traceability
- ASTM A516 grade references shown on the certificate
- Tensile and yield test results meeting the stated grade requirements
- Chemical analysis within specification limits
- Plate thickness and dimensions matching the purchase order
- Heat treatment condition, if specified
- Supplementary requirements such as impact testing, ultrasonic testing, or HIC/NACE-related conditions where project-specific
It is also important to distinguish between base ASTM compliance and additional client or code requirements. A plate may be dual certified to Grade 60/70, but a project may still require normalized condition, low-temperature impact properties, ultrasonic examination, or supplementary documentation beyond the basic ASTM scope.
Mill Test Certificate Requirements for ASTM A516 Grade 60/70 Dual
For most buyers, the practical meaning of ASTM A516 Grade 60/70 dual is established on the MTC. The certificate should clearly identify the material specification and the grade designation(s) covered by the test report. If the project requires dual acceptance, the documentation should not be ambiguous. The MTC is typically reviewed for:
- Specification listed as ASTM A516 or ASME SA-516, as ordered
- Grade designation showing 60/70 dual or equivalent dual compliance wording
- Actual mechanical test values, not only minimum requirements
- Chemical composition by heat analysis
- Quantity, dimensions, and plate numbers
- Any supplementary tests required by purchase order or code
Where ASME construction is involved, buyers should also ensure the ordered material designation, code stamping requirements, and documentation format are aligned with the vessel manufacturer's quality system and the authorized inspector's expectations.
Ordering and Inspection Points for Buyers
When ordering ASTM A516 Grade 60/70 dual certified plate, technical clarity at purchase stage helps avoid downstream NCRs, re-documentation requests, or fabrication hold points. A concise purchase order should define the exact specification basis, certification requirement, plate dimensions, testing scope, and any supplementary clauses.
Common review points include:
- Whether the project requires ASTM A516 or ASME SA-516 nomenclature
- Whether dual certification must be explicitly stated on the MTC
- Required thickness range and rolling tolerance standard
- Normalized, as-rolled, or other supply condition as applicable
- Impact test temperature and acceptance criteria, if required
- Third-party inspection, witnessing, and document review requirements
- UT testing level or additional NDT requirements
- Traceability from plate marking to final dossier
For vessel fabricators, it is good practice to verify that the material received matches not only the grade callout but also the approved design assumptions used in fabrication drawings and code calculations.
ASTM A516 Grade 60/70 Dual in Project Procurement
In many projects, dual certified plate is used to simplify stockholding and reduce conflicts between older and newer specifications. For example, one client standard may continue to reference Grade 60 while another package within the same project references Grade 70. Dual certification can support material rationalization, but only where the engineering basis permits it. It should not be treated as an automatic substitute without checking design temperature, code case assumptions, impact requirements, and purchaser specifications.
Accordingly, the most accurate way to understand this material is as dual documented ASTM A516 PVQ plate, not as a new standalone grade. The technical acceptability always depends on the certified results and the governing project documents.
FAQ
Is ASTM A516 Grade 60/70 dual a separate ASTM grade?
No. It is not a separate ASTM grade. The term usually means the plate is supplied with mill documentation showing compliance to both ASTM A516 Grade 60 and Grade 70 requirements, typically by meeting the higher Grade 70 mechanical threshold.
Does dual certified plate always mean the material can replace Grade 70 in design?
Not automatically. The MTC may show compliance to Grade 70 minimum properties, but substitution in design must still follow the governing code, approved calculations, service conditions, and project specification. Engineering review is required before any substitution is accepted.
What should be checked on the MTC for ASTM A516 Grade 60/70 dual?
Key checks include the specification and grade wording, heat number traceability, actual tensile and yield results, chemical analysis, plate dimensions, supply condition, and any supplementary testing such as impact testing or ultrasonic examination required by the purchase order.