ASTM A516 Grade 70 Pressure Vessel Steel vs ASTM A283 Grade C: Low-Tensile Structural Carbon Steel
Side-by-side engineering comparison of ASTM A516 Grade 70 Pressure Vessel Steel (ASTM A516/A516M) and ASTM A283 Grade C: Low-Tensile Structural Carbon Steel (ASTM A283/A283M). Compare mechanical properties, chemical composition, density, yield strength, international equivalents, and typical applications to select the right material for your project.
Quick Verdict
The decision comes down to one question: is the plate going into a pressure-retaining application governed by ASME Section VIII, API, or a boiler code? If yes, specify A516 Grade 70 — it is the pressure vessel carbon steel with certified elevated-temperature properties and guaranteed Charpy impact toughness....
Pressure vessel service with certified elevated-temperature properties
General structural plate for cost-sensitive fabrication
Quick Comparison
| Property | ASTM A516 Grade 70 Pressu | ASTM A283 Grade C: Low-Te |
|---|---|---|
| Standard | ASTM A516/A516M | ASTM A283/A283M |
| Category | Carbon Steel | Carbon Steel |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Yield Strength | 260 MPa (38 ksi) | 205 MPa (30 ksi) |
| Tensile Strength | 485-620 MPa (70-90 ksi) | 380-515 MPa (55-75 ksi) |
| Key Applications | ASTM A516 Grade 70 is the most widely used carbon steel for pressure vessels, boilers, and storage tanks operating at mo... | ASTM A283 Grade C is a low-to-intermediate tensile strength carbon steel for general structural applications where highe... |
International Equivalents
| ASTM A516 Grade 70 P Equivalents | ASTM A283 Grade C: L Equivalents |
|---|---|
| SA-516 Gr70 | S235JR |
| P355GH | Q215 |
| P295GH | SS330 |
| SPV355 | St33 |
| SGV480 | E235 |
How to Choose
| Choose ASTM A516 Grade 70 Pressu when... | A516 Grade 70 is the ASME pressure vessel carbon steel plate, certified for elevated-temperature service (up to 650°C) with guaranteed Charpy impact toughness and killed steel practice — required for boilers, pressure vessels, and storage tanks per ASME Section VIII. |
| Choose ASTM A283 Grade C: Low-Te when... | A283 Grade C is a low-cost general structural carbon steel plate for buildings, bridges, and machinery frames where pressure certification is not required. |
Decision Checklist: Which Is Right for You?
| Criterion | ASTM A516 Grade 70 P | ASTM A283 Grade C: L |
|---|---|---|
| Pressure Vessel Service With Certified Elevated-Temperature Properties | ✓ | |
| General Structural Plate For Cost-Sensitive Fabrication | ✓ | |
| Higher yield strength | ✓ | |
| Governing code — ASME Section VIII / API pressure service requires A51... | ✓ | |
| Certification & traceability — A516 requires MTRs and killed/fully-kil... | ✓ | |
| Impact toughness — A516 Gr 70 offers guaranteed Charpy options; A283 t... | ✓ |
Selection Guide
The decision comes down to one question: is the plate going into a pressure-retaining application governed by ASME Section VIII, API, or a boiler code? If yes, specify A516 Grade 70 — it is the pressure vessel carbon steel with certified elevated-temperature properties and guaranteed Charpy impact toughness. If the plate is for ordinary structural fabrication — buildings, bridges, machinery frames, ship general structure — A283 Grade C provides adequate strength at lower cost. Never substitute A283 for a pressure vessel spec; the certification, killed steel practice, and impact requirements do not match.
Key Decision Factors
- Governing code — ASME Section VIII / API pressure service requires A516 (or equivalent pressure vessel grade); structural codes (AISC) accept A283
- Certification & traceability — A516 requires MTRs and killed/fully-killed steel practice; A283 has relaxed certification
- Impact toughness — A516 Gr 70 offers guaranteed Charpy options; A283 typically has no impact requirement
- Cost — A283 Gr C is typically 5-15% cheaper than A516 Gr 70, but the savings never justify using it in pressure service
When to Use Each
Use ASTM A516 Grade 70 P for:
A516 Gr 70 is the default ASME Section VIII pressure vessel plate for ambient to 650°C service, covering both fired and unfired pressure vessels, air receivers, and storage tanks.
Certified to API 650 for large aboveground storage tanks; also standard for shell and tube heat exchanger shells and heads where guaranteed elevated-temperature strength is required.
A516 Gr 70 offers a range of Charpy options (including -20°F / -45°F) for cold-service applications where A283's un-tested notches would be a liability.
Use ASTM A283 Grade C: L for:
A283 Grade C is a low-cost structural carbon steel plate (yield 205 MPa) suitable for building frames, columns, and non-ASME structural members where pressure certification is not required.
For machine base plates, brackets, and non-classified weldments, A283 Gr C provides good weldability and machining at a lower price point than A516.
A283 Gr C is commonly stocked for maintenance, repair, and secondary structural members where the tighter requirement of A516 is unnecessary overhead.
Frequently Asked Questions
What is the main difference between ASTM A516 Grade 70 Pressure Ve and ASTM A283 Grade C: Low-Tensile?
ASTM A516 Grade 70 Pressure Vessel Steel (ASTM A516/A516M) provides 260 MPa (38 ksi) yield strength at 7.85 g/cm³ density, while ASTM A283 Grade C: Low-Tensile Structural Carbon Steel (ASTM A283/A283M) delivers 205 MPa (30 ksi) at 7.85 g/cm³. The choice depends on whether your application prioritizes pressure vessel service with certified elevated-temperature properties or general structural plate for cost-sensitive fabrication.
Can ASTM A516 Grade 70 Pressure Ve be substituted for ASTM A283 Grade C: Low-Tensile?
In many applications, these materials can be cross-referenced, but direct substitution should always be verified against specific project specifications, especially for pressure vessel service with certified elevated-temperature properties, general structural plate for cost-sensitive fabrication, and operating environment. Consult your engineer of record.
Can A283 Gr C be used to build a pressure vessel?
No. A283 Grade C is not listed in ASME Section VIII Div 1 for pressure vessel construction — it lacks the certified elevated-temperature allowables and impact toughness requirements that A516 Gr 70 provides. Using A283 in pressure service would not only fail inspection but violate ASME code. Always specify an approved pressure vessel grade (A516, A515, A285) for anything pressure-retaining.
What is the key difference between A283 and A516?
The manufacturing practice and certification. A516 Grade 70 is produced as killed steel (deoxidized) with specified tensile/elevated-temperature properties and Charpy impact options — required for pressure vessels. A283 Grade C is a lower-strength general structural plate with simplified testing and no pressure certification. Compositionally both are carbon-manganese steels, but A516 is designed, tested, and certified for pressure service.
What are the yield strengths of each?
A516 Grade 70 has a minimum yield strength of 260 MPa (38 ksi) with a tensile range of 485-620 MPa. A283 Grade C has a lower minimum yield of 205 MPa (30 ksi) with a tensile range of 380-515 MPa. For any load-bearing or pressure application, A516 Gr 70 provides significantly more design margin.