ASTM A516 Grade 60 NACE HIC plate refers to pressure vessel quality carbon steel plate supplied to ASTM A516 / ASME SA516 Grade 60 with additional controls for sour service and verified resistance to hydrogen induced cracking (HIC). In practice, buyers typically specify this material for separators, drums, towers, heat exchangers, and storage equipment operating in wet H2S environments found in oil & gas, refinery, petrochemical, and process plants.
While ASTM A516 Grade 60 defines the base pressure vessel plate grade, the terms NACE and HIC indicate supplementary requirements beyond the base standard. These usually include restricted sulfur and phosphorus, calcium treatment or inclusion shape control where applicable, improved steel cleanliness, ultrasonic examination, and HIC/SWC testing to recognized sour service test methods. For procurement, the exact purchase order wording matters because "A516 Grade 60 NACE HIC" is not a single standalone ASTM grade; it is a base grade with added project-specific sour service requirements.
What A516 Grade 60 NACE HIC Means
A516 Grade 60 is a carbon steel plate for moderate and lower temperature pressure vessel service. It is selected where dependable notch toughness, weldability, and pressure vessel performance are required. When the plate is ordered for NACE HIC service, the material is intended for environments where atomic hydrogen generated by corrosion in wet hydrogen sulfide can diffuse into the steel and cause internal cracking.
In industry usage, buyers often reference NACE MR0175 / ISO 15156 for material suitability in H2S-containing production environments, while HIC resistance is commonly demonstrated by laboratory testing such as NACE TM0284. Sulfide stress cracking considerations may also involve NACE TM0177 depending on the component design, hardness limits, and service severity.
Typical Technical Requirements for Sour Service Plate
Project specifications vary by end user, EPC, and operating conditions, but A516 Grade 60 NACE HIC plate is commonly ordered with the following technical controls:
- ASTM A516 / ASME SA516 Grade 60 base specification
- Normalized or controlled rolled condition, as required
- Low sulfur and low phosphorus chemistry for improved resistance to crack initiation
- HIC testing as per NACE TM0284 on representative samples
- Through-thickness ultrasonic testing, often to ASTM A578
- Hardness control where project specifications require it
- Mill test certificate with heat-wise traceability and test reports
- Optional impact testing, PWHT simulation, or Z-quality requirements if specified
Because sour service performance depends on steelmaking route and cleanliness, buyers should verify not only the plate grade but also the acceptance criteria for HIC test results, specimen orientation, solution pH, exposure duration, and reporting format.
Chemical Composition and Mechanical Properties
The exact chemistry of A516 Grade 60 plate is controlled by the producing mill within ASTM/ASME limits and any tighter sour service restrictions imposed by the purchase order. For NACE HIC service, lower residuals and cleaner steel are generally preferred. Mechanical properties must meet the base grade requirements, while supplementary sour service testing demonstrates suitability for wet H2S exposure.
| Property | Typical Requirement / Reference | Procurement Note |
|---|---|---|
| Base grade | ASTM A516 / ASME SA516 Grade 60 | Confirm whether ASTM or ASME stamping route is required |
| Tensile strength | Approx. 415–550 MPa (60–80 ksi) | Verify against current edition of the governing standard |
| Yield strength | Minimum approx. 220 MPa (32 ksi) | Check thickness-related requirements if applicable |
| Elongation | As per ASTM/ASME requirement | Review test specimen basis in MTC |
| Sulfur | Often restricted below standard maximum for HIC service | Commonly project-specific, not identical for all orders |
| Phosphorus | Often restricted below standard maximum for sour service | Lower P supports improved resistance and weldability |
| HIC test | NACE TM0284 | Acceptance criteria must be stated in the PO |
| UT examination | ASTM A578, level as specified | Common for critical pressure vessel applications |
Difference Between Standard A516 Grade 60 and NACE HIC Plate
A standard A516 Grade 60 plate may satisfy mechanical and chemical requirements of the base pressure vessel specification, but that alone does not automatically qualify it for sour service. NACE HIC plate is produced and tested with additional emphasis on internal cleanliness, segregation control, inclusion morphology, and crack resistance under wet H2S test conditions.
This distinction is important during vendor evaluation. A supplier may list "SA516 Gr.60" and "SA516 Gr.60 NACE + HIC" together, but the latter should be backed by heat-wise documentation, supplementary test reports, and clear reference to the applicable acceptance criteria. For critical service, end users often require third-party inspection and review of original mill records.
Applications of A516 Grade 60 NACE HIC Plate
This material is widely used where pressure containment equipment is exposed to sour hydrocarbons, produced water, or wet H2S-bearing process streams. Typical applications include:
- Pressure vessels and separator shells
- Absorber and stripper columns
- Refinery drums and reactors with non-clad carbon steel sections
- Heat exchanger channels, covers, and formed components
- Storage tanks and process equipment in upstream and downstream facilities
- Fabricated dished ends, cones, and transition sections
Material selection should still be checked against actual partial pressure of H2S, pH, chloride content, temperature, hardness after fabrication, and any post weld heat treatment requirements. In severe sour environments, corrosion allowance, internal coating, or clad construction may also be considered.
Available Forms, Sizes, and Supply Condition
A516 Grade 60 NACE HIC is generally supplied as plate in a range of thicknesses suitable for vessel fabrication. Availability depends on mill route, width capability, and whether the order requires normalized rolling, HIC testing, or special ultrasonic acceptance levels. Plates may be supplied as full-size mother plates or cut to required dimensions for fabrication planning.
When requesting quotations, it is good practice to include thickness, width, length, quantity by heat if relevant, delivery condition, HIC test standard, UT standard, impact testing requirements, and whether original mill test certificates are mandatory. This reduces the risk of receiving standard pressure vessel plate without the sour service controls actually needed for the project.
Inspection and Documentation Checklist
For industrial buyers, documentation quality is as important as nominal grade designation. Before approval, review the following points:
- Heat number traceability on each plate
- ASTM/ASME compliance on MTC
- Actual ladle and product chemistry values
- Tensile test results and, where specified, impact test results
- HIC test report with CLR, CTR, and CSR values if required by project specification
- UT report with acceptance level clearly stated
- Statement of heat treatment or rolling condition
- Third-party inspection release, if applicable
These checks help distinguish compliant sour service plate from generic commodity stock. For fabricated equipment, downstream welding procedures and hardness control after welding should also align with the project sour service requirements.
Ordering Guidance for A516 Grade 60 NACE HIC
A robust purchase description should identify the base standard and every supplementary requirement. A typical order line may include the grade, dimensions, quantity, normalized condition, HIC test method, UT standard, and documentation level. If the project specification defines maximum sulfur, phosphorus, carbon equivalent, hardness, or acceptance limits for HIC indices, those values should be written directly into the order rather than assumed.
For example, buyers often request: SA516 Gr.60 plate, normalized, sour service, HIC tested as per NACE TM0284, UT as per ASTM A578, original MTC EN 10204 3.1, with third-party inspection. Exact wording should follow the governing project specification and approved vendor list requirements.
FAQ
Is A516 Grade 60 NACE HIC a separate ASTM grade?
No. ASTM A516 Grade 60 is the base pressure vessel plate grade. The terms NACE and HIC indicate additional sour service and cracking-resistance requirements that must be specified, tested, and documented separately.
Which NACE standard is usually referenced for HIC testing?
HIC resistance is commonly evaluated using NACE TM0284. Material suitability for H2S-containing oil and gas environments is often considered alongside NACE MR0175 / ISO 15156, depending on the service conditions and equipment design.
What should be checked before buying A516 Grade 60 NACE HIC plate?
Check the base ASTM/ASME compliance, actual chemistry, rolling or heat treatment condition, HIC test reports, UT reports, traceability, and the exact project acceptance criteria. Do not rely on the grade description alone without supporting mill documentation.