Why the Difference Between HIC Tested and Standard SA 516 GR 70 Plates Matters
Both plate types share the same ASTM A516 Grade 70 specification same base chemistry, same tensile minimums. The split is testing the protocol and service environment. HIC plates in clean boiler service wastes budget; standard plates in sour gas service create a hydrogen damage risk that inspection rarely catches before failure. SA 516 GR 70 Plates are available in both types with full mill certification and heat traceability.
What Is HIC Testing in SA 516 GR 70 Plates?
Hydrogen Induced Cracking starts when atomic hydrogen generated by wet H₂S corrosion reactions diffuses into steel and recombines at inclusion sites, initiating step-wise cracks parallel to the rolling plane. Standard plates carry no protection against this. HIC plates do.
NACE TM0284 puts test samples into acidic H₂S solution for 96 hours, then measures cross-sections for Crack Sensitivity Ratio, Crack Length Ratio, and Crack Thickness Ratio. Passing plates also require sulfur below 0.003%, calcium inclusion treatment, and through-thickness ultrasonic inspection before dispatch. Refineries specify these plates because NACE TM0284 results directly predict field performance in H₂S-containing streams.
HIC Tested vs Standard SA 516 GR 70 Plates – Key Differences
| Parameter | HIC Tested | Standard |
| Base specification | ASTM A516 Gr 70 | ASTM A516 Gr 70 |
| Hydrogen damage resistance | NACE TM0284 tested | Not rated |
| Sulfur content | Max 0.003% | Max 0.035% |
| Inclusion control | Calcium treatment | None |
| Certification | NACE + UT + MTC | MTC only |
| Service environment | H₂S, sour service, wet CO₂ | Clean steam, dry service |
| Price premium | 15–30% above standard | Baseline |
HIC-tested plates carry documented hydrogen damage resistance. Standard plates don’t. In clean service the documentation adds nothing; in sour service it’s mandatory.
Manufacturing and Testing Requirements
Additional Quality Control for HIC Plates
Ladle sulfur reduction below 0.003% 10× tighter than standard A516 eliminates the manganese sulfide inclusions where hydrogen preferentially traps. Calcium treatment converts remaining inclusions into spherical morphology, cutting available crack initiation sites dramatically.
HIC and NACE Testing Procedures
NACE TM0284 specimens run in saturated H₂S at pH 2.7–3.3 for exactly 96 hours. Passing criteria per NACE SP0472: Crack Sensitivity Ratio below 6%, Crack Length Ratio below 15%, Crack Thickness Ratio below 5%.
Certification and Traceability
Every HIC plate ships with an original mill test certificate covering chemistry, mechanical results, NACE TM0284 data, ultrasonic records, and heat number traceability. EPC contractors and refinery inspection teams require original documents not copies for weld procedure qualification and procurement sign-off.
SA 516 GR 70 Plate Thickness and Standard Plate Sizes
| Parameter | Range |
| Thickness | 5 mm – 150 mm |
| Width | 1,000 mm – 3,500 mm |
| Length | 3,000 mm – 12,000 mm |
| Custom cutting | Saw cut, plasma, waterjet |
SA 516 GR 70 plate thickness from 5 mm to 150 mm covers heat exchanger shell plate through heavy-wall pressure vessel applications. SA 516 GR 70 standard plate sizes follow ASTM dimensional tolerances. SA 516 GR 70 plate sizes outside standard ranges are available cut-to-order with 2–4 week lead time based on thickness.
Applications of HIC Tested SA 516 GR 70 Plates
Refineries fabricating sour water strippers, amine contactors, and distillation columns specify HIC-tested plates for every vessel in wet H₂S service. Sour gas units above 50 ppm H₂S and offshore pressure vessels in dissolved H₂S environments carry the same requirement. Standard plates in these applications develop step-wise cracking within 3–7 years a failure mode that voids vessel certification.
Applications of Standard SA 516 GR 70 Plates
Clean steam boilers, non-sour heat exchangers, atmospheric storage tanks, and general industrial pressure vessels below 260°C run standard SA 516 Gr 70 without issue. No H₂S means no hydrogen uptake the HIC testing premium adds cost with zero protective benefit in these conditions.
How to Choose the Right Plate for Your Project
Two questions determine the answer: does the process stream contain H₂S above 0.0003 MPa partial pressure, and does the project specification cite NACE MR0175, MR0103, or ISO 15156? Yes to either specify HIC plates. Clean steam, fresh water, dry hydrocarbon, and air service run standard. Ambiguous specs need clarification from the client’s materials engineer before procurement, not after plates arrive on site.
FAQs
What is an HIC tested SA 516 GR 70 plate?
An SA 516 Gr 70 plate that passes NACE TM0284 hydrogen cracking testing, with sulfur below 0.003% and calcium inclusion control confirmed in the original mill test certificate.
What is the difference between HIC tested and standard SA 516 GR 70 plates?
HIC plates carry NACE TM0284 test data, sulfur below 0.003%, and calcium treatment records. Standard plates meet only ASTM A516 Gr 70 mechanical requirements no hydrogen damage testing, no sulfur restriction beyond 0.035%.
What are the standard SA 516 GR 70 plate sizes?
Widths 1,000–3,500 mm, lengths 3,000–12,000 mm. Custom dimensions cut to drawing on request.
What SA 516 GR 70 plate thickness range is available?
5 mm through 150 mm. Plates above 100 mm are produced as discrete heavy plates with longer lead times.
When is HIC testing required?
When H₂S partial pressure exceeds 0.0003 MPa, or when the project specification references NACE MR0175, MR0103, or ISO 15156.
Conclusion
HIC-tested and standard SA 516 GR 70 share a base grade but serve different service conditions. Sour environments require the tested grade; clean service runs standard plate without penalty. Match the specification to actual operating conditions it protects against hydrogen damage where the risk is real and avoids unnecessary cost where it isn’t.
Contact us with your thickness, width, length, and certification requirements for a quote and lead time.
