ASTM A612 / A612M is a high-strength, killed carbon-manganese-silicon steel specification specifically designed for welded pressure vessels and boilers operating at moderate and lower temperatures.For global pressure vessel projects, engineers and procurement teams often need to identify equivalent steel grades across different standards such as EN, DIN, JIS, GB, and others.
Understanding the equivalent grades of ASTM S612 / A612M steel plate helps ensure material compatibility, smooth project approval, and optimized sourcing strategies.
This specification covers hardened carbon-manganese-silicon steel plates for use in medium- and low-temperature welded pressure vessels. The maximum thickness of steel plates covered by this specification is 1 inch (25 mm).
For steel plates manufactured from carbon steel that have not been heat treated or have undergone only stress-relief treatment, the additional requirements of Specification A20/A20M shall be followed, including additional testing requirements and reporting of additional test results.
Chemical Properties of ASTM S612 / A612M Steel Plate
| Carbon, max:ᴬ | Manganeseᴬ | Phosphorus, maxᴮ (Composition) | Sulfur, maxᴮ (Composition) | Silicon | Carbon, max:ᶜ | Nickel, max:ᶜ | Chromium, max:ᶜ | Molybdenum, max:ᶜ | Vanadium, max:ᶜ |
|---|---|---|---|---|---|---|---|---|---|
| 0.29 | 0.92-1.62 | 0.025 | 0.025 | 0.13–0.55 | 0.38 | 0.28 | 0.29 | 0.08 | 0.08 |
Note A: For each reduction of 001 percentage point below the specifed carbon maximum, an increase of 06 percentage point manganeseabove the specified maximum is permitted up to a maximum of 1.65 % for heat analysis (1.70 % for product analysis)
Note B: Applies to both heat and product analyses.
Note C: When analysis shows that the amount of an element is 0.02 % or lower, the value may be reported as 0.02 %
Mechanical Properties of ASTM S612 / A612M Steel Plate
| Thickness | Tensile strength ksi [MPa] | Yield strength, min,ᴬ ksi [MPa] | Elongation in 8 in. [200 mm], min, %ᴮ | Elongation in 2 in. [50 mm], min, %ᴮ |
|---|---|---|---|---|
| 0.5 in [12.5 mm] and Under | 83-105 [570-725] | 50 [345] | 16 | 22 |
| Over 0.5 in. to 1 in. [Over 12.5 to 25mm] | 81-101 [560-695] | 50 [345] | 16 | 22 |
ASTM A612/A612M Size Specifications
| Parameter | Standard Certified Scope | Extended Supply Scope |
|---|---|---|
| Thickness | 9.52–25 mm (0.375–1.00 in) | 6–120 mm |
| Width | 1900–3050 mm (75–120 in) | 1500–4000 mm |
| Length | 6100–15240 mm (240–600 in, normalized) | 4000–25910 mm |
Confirm Delivery Condition:A612 typically requires normalizing treatment. When selecting equivalent materials, explicitly require the supplier to provide steel plates in the normalized condition.
ASTM S612 / A612M Steel Plate:Equivalent Grades by International Standards
| Standard / Region | Approximate Equivalent Grade | Key Features & Description |
|---|---|---|
| China (GB) | Q345R | The most commonly used medium and low temperature pressure vessel plate in Chinese standards, with yield strength similar to A612. |
| Europe (EN) | P355GH, P355NL | High-quality vessel steel under European EN 10028-2 standard, with good medium temperature strength and weldability. |
| Japan (JIS) | SPV355, SPV450 | Pressure vessel steel plate in JIS standard, specially designed for medium and low temperature equipment. |
| United States (ASME) | ASME SA-612 | ASME's equivalent adoption version of ASTM A612, which falls under the scope of boiler and pressure vessel specifications. |
How to Select an Equivalent Grade?
1. Preferred Design Code:
- If the project is designed according to ASME (American Society of Mechanical Engineers) codes, ASME SA-612 is the preferred choice.
- If the project is located within China and designed according to GB 150, Q345R is the preferred choice.
- If the project complies with the EU Pressure Equipment Directive, select P355GH or P355NL.
2. Verify Key Performance Indicators:
- Yield Strength: The yield strength of A612 is typically around 345 MPa. The Q345R and P355 series offer the best match in terms of strength.
- Operating temperature:
- For medium-temperature applications, select P355GH or Q345R.
- For low-temperature applications (below -20°C), P355NL or Q345R that has passed low-temperature impact testing must be selected.
- Thickness Limitations: A612 is typically limited to thinner gauges (e.g., 25 mm or 50 mm, depending on the specific standard). When selecting alternatives, verify that the mechanical properties of the substitute grade meet the required standards at these thicknesses.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Low-Temperature Impact | Key Difference |
|---|---|---|---|---|
| A612 | ≥ 345 | 570–725 | ≥ 27 J at -40°C | Best low-temperature toughness |
| Q345R | ≥ 345 | 470–630 | ≥ 27 J at -20°C | Lower tensile strength; higher impact test temperature |
| P355N | ≥ 355 | 470–630 | ≥ 27 J at -20°C | Slightly higher yield strength; weaker low-temperature performance |
| SPV355 | ≥ 355 | 490–610 | ≥ 27 J at 0°C | Lowest low-temperature performance |
3.Cost & Lead Time
Adequate budget, certification priority: For projects in Europe and the U.S., purchase local SA-612 / P355GH directly; no cost concerns.
Cost-sensitive, no mandatory standards: Overseas engineering firms will prioritize Q345R, which is mass-produced by domestic steel mills. Prices are 20%–40% lower than imported SA-612 and SPV355, and lead times are shorter.
Maintenance and Replacement of Imported Equipment: Replacement parts for damaged original equipment must use the original manufacturer's grade (e.g., SA-612 for U.S. equipment, SPV355 for Japanese equipment); substitution with Q345R is not permitted.
If you are seeking grade conversion or procurement advice:
For applications requiring only 345 MPa-grade medium-to-low-temperature pressure resistance with no regional certification: Q345R offers the best value for money;
For exports to the EU requiring PED certification: P355GH/P355NL1;
For exports to the U.S. requiring ASME inspection: SA-612;
For exports to Japan or Japanese-made complete equipment: SPV355;
Low-temperature storage tank equipment: Prefer P355NL1 and SA-612;
- High-pressure thick-walled equipment: SPV450 and thickened SA-612.
ASTM A612/A612M Application Scenarios
Petrochemical sector: Fabrication of reactors, heat exchangers, separators, spherical tanks, oil & gas storage tanks, liquefied gas tanks.
Power generation sector: Utility boiler steam drums, nuclear reactor pressure vessels.
Cryogenic storage & transportation: LNG storage tanks, LPG storage tanks and other cryogenic liquid containment equipment.
Hydraulic engineering: High-pressure penstocks for hydropower stations, turbine spiral casings and related structural components.
Why Choose GNEE Group?
With 20 years of experience in steel exports, we not only provide expert interpretation of standards but also offer one-stop customized supply, comprehensive third-party inspection, and global distribution services for A612/A612M steel plates. We help pressure vessel manufacturers worldwide resolve common issues related to material selection, welding, and quality.
Full-size stock available: hot-rolled/normalized A612 steel plates. We support custom cutting, surface treatment, and edge finishing. Flexible minimum order quantities for small batches worldwide.
We collaborate directly with top domestic steel mills. Stable monthly production ensures reliable delivery times. We support various trade terms including FOB, CFR, CIF, and DDP, with global shipping.
Prior to shipment, we conduct 100% visual inspection, dimensional checks, and random mechanical retesting. All documentation is issued in English to facilitate customs clearance and project acceptance.
Ultrasonic testing: Conducted in accordance with GB/T 2970 or NB/T 47013.3-2015 to detect internal defects in steel, such as cracks, inclusions, and delamination (acceptance grade: Grade I);
1.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.
2.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.
3.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.
4.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.
5.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.