ASTM A612 / ASME SA612 is a high-strength carbon-manganese-silicon steel plate specifically developed for welded pressure vessels and boilers operating at moderate to low temperatures.
What Is ASTM A612 / ASME SA612?
ASTM A612: ASTM material specification
ASME SA612: The same material adopted into the ASME Boiler & Pressure Vessel Code
Both refer to the same steel grade, with identical chemical and mechanical requirements. The ASME designation is used when the plate is applied to code-stamped pressure vessels.
Key Characteristics of SA612 Steel Plate
High strength pressure vessel quality (PVQ) steel
Carbon–manganese–silicon alloy design
Good weldability with proper procedures
Suitable for moderate and low-temperature service
Enables thinner plate design compared with conventional carbon steels
Typical Mechanical Properties
| Property | Typical Requirement |
|---|---|
| Minimum Yield Strength | ~260 MPa (38 ksi) |
| Tensile Strength | 485–620 MPa (70–90 ksi) |
| Elongation | Good ductility (varies by thickness) |
Chemical Composition (Maximum Values, unless specified)
| Element | Content (%) | Role in Performance |
|---|---|---|
| Carbon (C) | ≤0.25 | Balances strength and weldability |
| Manganese (Mn) | 1.00-1.50 | Enhances tensile strength and toughness |
| Silicon (Si) | 0.15-0.50 | Aids deoxidation and improves strength |
| Phosphorus (P) | ≤0.025 | Reduces brittleness and improves notch toughness |
| Sulfur (S) | ≤0.025 | Minimizes hot cracking during welding |
| Nickel (Ni) | ≤0.25 | Enhances low-temperature toughness |
| Chromium (Cr) | ≤0.25 | Improves corrosion resistance |
| Carbon Equivalent (CE) | ≤0.48 | Ensures excellent weldability |
Primary Applications
Critical Industrial Equipment:
LNG/Cryogenic Storage Tanks (-40°C to -196°C)
High-Pressure Reactors (15-20 MPa) in petrochemical and refining
Hydrogenation Vessels requiring strength and toughness
Sour Gas Treatment Units (resistant to H₂S corrosion)
Nuclear Power Plant Auxiliary Vessels (ASME NQA-1 compliant)
General Pressure Vessels:
Heat exchangers operating at moderate temperatures
High-pressure piping systems
Storage tanks for hazardous liquids and gases
Heat Treatment Condition
Supplied as-rolled as standard
Normalizing can be provided by agreement
Stress relieving is typically applied after fabrication if required by code or service conditions
Heat treatment requirements should be clearly stated in the purchase order.
Weldability and Fabrication
SA612 offers good weldability when standard pressure-vessel welding practices are followed:
Low-hydrogen welding consumables
Controlled heat input
Preheating for thicker plates if required
PWHT according to ASME code and vessel thickness
Comparison with Common PVQ Steels
| Grade | Yield Strength | Tensile Strength | Impact Temp. | Max Service Temp. | Typical Use |
|---|---|---|---|---|---|
| SA612 | 345 MPa | 570-725 MPa | -40°C | 425°C | High-pressure, low-temp, critical applications |
| SA516 Gr.70 | 230-207 MPa | 485-620 MPa | -30°C | 454°C | General-purpose pressure vessels (80% market share) |
| SA515 Gr.60 | 172-159 MPa | 414-552 MPa | -29°C | 345°C | Low-pressure, ambient-temp applications |
Key Distinction:
SA612 vs SA516 Gr.70: Similar strength; SA612 favors reduced thickness, SA516 Gr.70 favors toughness
SA612 vs SA515 Gr.60: SA612 provides significantly higher strength
SA612 vs SA537: SA612 is more cost-effective for moderate low-temperature service
Selection Considerations
When to Choose SA612:
Pressure >10 MPa and temperature < -30°C
Weight reduction is critical (e.g., mobile or offshore applications)
Sour service conditions (H₂S present)
Project specifications demand premium quality and long service life
When to Consider Alternatives:
Budget constraints with minimal pressure requirements (<10 MPa)
Service temperature exceeds 425°C (use SA516 Gr.70)
Thickness requirements >25mm (some producers offer extended thicknesses)
Conclusion
ASTM A612 / ASME SA612 is a cost-effective, high-strength pressure vessel steel that supports modern vessel design by reducing thickness without compromising safety or weldability. It is an excellent choice for boilers and pressure vessels operating at moderate and low temperatures.
GNEE STEEL supplies certified ASTM A612 / ASME SA612 steel plates with full MTC, optional impact testing, and global project experience.
GNEE Steel also supplies a variety of boilers and pressure vessel steel plates, such as A204 Grade B,A515 Grade 70,A537 Class 1,SA387 Grade 11 Class 1,P265GH,S537 Class 2,P355Q,P275N,P355N,P690Q,Q345R, etc. If you want to know more about other types of steel plates, you can call the consultation hotline at +8615824687445 or send an email to ru@gneesteelgroup.com. You are welcome to consult us, and we are very willing to answer your questions.
FAQ
What is SA 612 material?
carbon-manganese-silicon steel plate
SA612 is killed carbon-manganese-silicon steel plate made for welded pressure vessels. Its fine grain makes it suitable for use in moderate and lower temperature service where impact resistance is important.
What is the composition of ASTM A612?
ASTM A612 steel plate is a high-strength low-alloy (HSLA) steel plate designed for welded pressure vessels. It has a nominal composition of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, and copper.
What is A612 steel?
ASTM A612 specification is the Standard Specification for Pressure Vessel Plates, Carbon Steel, High Strength, for Moderate and Lower Temperature Service. ASTM A612 encompasses carbon-manganese-silicon steel plates intended for use in welded pressure vessels for moderate and low temperature service.
Are SA612 and A612 Steel Plates the Same Product? What Are the Core Differences?
They are the same type of steel plate. ASTM A612 is the material standard, while ASME SA612 is the designation assigned after ASTM A612 was incorporated into the ASME Boiler & Pressure Vessel Code, specifically for the fabrication of pressure-bearing equipment.
What Are the Executive Standards for SA612/A612 Steel Plates? Are There Any Differences Between the ASTM and ASME Versions?
The executive standards are ASTM A612/A612M and ASME SA612. There are no substantial differences in chemical composition and mechanical properties between the two versions; the only variance lies in their applicable code systems.
What Are the Equivalent Grades of SA612/A612 in Chinese and European Standards? Can They Be Used as Direct Substitutes?
Common approximate equivalent grades include EN P355GH, DIN 1.0473, and GB Q345R. However, they cannot be used as direct equivalents. Their suitability must be confirmed in accordance with design specifications and approval requirements.
What Are the Yield Strength and Tensile Strength of SA612/A612? Do They Vary with Different Thicknesses?
The minimum yield strength of SA612 is approximately 260 MPa, and its tensile strength ranges from 485–620 MPa. As the thickness increases, the allowable minimum yield strength may decrease slightly.
What Are the Low-Temperature Impact Energy Requirements for SA612/A612? Are the Requirements at -40℃ and -45℃ Consistent?
Standards typically require impact testing at -40℃, while testing at -45℃ is not mandatory. If a project specifies -45℃ testing, additional impact tests must be conducted and clearly defined in the technical agreement.
What Are the Minimum and Maximum Service Temperatures for SA612/A612?
The recommended minimum service temperature is approximately -40℃, and the maximum operating temperature is generally around 400℃, depending on the design specifications and service medium.
What Is the Carbon Equivalent of ASME SA612? Is Preheating Required for Welding?
The carbon equivalent is usually around 0.42–0.45. Preheating at 50–120℃ is recommended for welding medium and thick plates. Commonly used welding materials include low-hydrogen electrodes such as E7018 and E7016.
What Is the Routine Thickness Range of SA612/A612, and What Is the Maximum Customizable Thickness?
The routine thickness range is 6–100 mm. Some steel mills can provide customized thicknesses up to 150 mm, subject to confirmation of their rolling and heat treatment capabilities.
What Are the Common Delivery Conditions for SA612/A612?
Common delivery conditions include As-Rolled (AR), Normalized (N), and Normalized + Tempered (N+T), with the normalized condition being the most widely used.
What Is the Machinability of SA612? Is It Prone to Cracking?
SA612 exhibits excellent cutting and bending performance. When processed with proper techniques and preheating, it is not prone to cracking.
Which Is More Suitable for Low-Temperature Applications: SA612 or SA516 Gr.70?
SA612 delivers more stable comprehensive performance in thick plate and high-stress working conditions, whereas SA516 Gr.70 offers better cost-effectiveness in conventional operating conditions.
Can Q345R Be Used as a Substitute for SA612?
Q345R can be used as a substitute in some working conditions for non-ASME projects. However, substitution is not recommended for export projects or scenarios where SA612 is explicitly required by specifications.
What Are the Differences Between SA612 and SA537 Cl.2?
SA537 Cl.2 boasts higher strength and low-temperature performance but comes with a significantly higher cost than SA612. It is suitable for more severe operating conditions.
Is SA612 Vessel Plate Suitable for LNG Storage Tanks?
SA612 is not recommended for primary LNG storage tanks operating at -162℃, but it can be used in LNG auxiliary systems or medium-to-low temperature vessels.
What Is the Hydrogen-Induced Cracking (HIC) Resistance of SA612 Steel Plates?
Standard SA612 does not mandate HIC resistance requirements. For applications involving sulfur-containing media, customized low-sulfur and low-phosphorus SA612 plates must be used, accompanied by HIC testing.
| Other steel plate by GNEE | ||||
| Name | Material | Specification (mm) | Tons | Remark |
| Clad steel plate | P265GH+410,S355JR+410,A516Gr70+316, A537CL1+304L,Q235B+304L,Q345B+304, A516Gr70(NACE)+410,A537CL1+904L, A537CL1+316L,A516Gr70+304L,A537CL1+304 ,A516Gr70+410,A516Gr70+904L |
2-300mm(Based plate),1-50mm(Composited plate) | / | UT, AR, TMCP.Normalized, Quenched and Tempered,Z Direction Test, Charpy V-Notch impact TestThe Third Party Test , Coated or Shot Blasting and Painting. |
| Low Alloy | Q345A, Q345B, Q345C, Q345D, Q345E, Q390, Q420, Q460C, ST52-3, S355J2+N, SS400, SA302GrC, S275NL, 35CrMo | 6 - 350 | 5788.56 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| Pressure Vessel Plate | A204 Grade B,A515 Grade 70,A537 Class 1,SA387 Grade 11 Class 1,P265GH,S537 Class 2,P355Q,P275N,P355N,P690Q,Q345R, | 3 - 300 | 8650 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| High-Strength Plate | A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E | 8 - 120 | 3086.352 | Quenched and tempered |
| Wear-Resistant Plate | NM360, NM400, NM450, NM500 | 6 - 150 | 3866.297 | Quenched and tempered |
| Ship Plate | ABS AH32,ABS DH32,ABS EH32,ABS FH36,ASTM A131 A, ASTM A131 EH32,ASTM A131 AH36,CCS A,CCS AH32,LR AH32, DNV A36,BV AH32 |
8 - 200 | 2853.621 | Hot rolling, normalized ,hot rolling controlled rolling, quenched and tempered + toughness and brittleness |