ASTM A612 / A612M steel plate is a fully killed high-strength carbon-manganese-silicon steel plate, engineered exclusively for welded fabrication of medium & low-temperature pressure vessels.Widely adopted for manufacturing industrial pressure vessels and industrial boilers operating under medium and low temperature service environments across heavy-duty process industries.
ASTM A612/A612M pressure vessel steel plate
What is the difference between ASTM A612 and ASTM A612M?
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A612M: Suffix M denotes metric unit system (SI international standard metric units).
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ASTM A612 (No M Suffix): Adopts imperial US customary unit system (inch-pound unit framework).
Three Core Advantages of ASTM A612 Plate：
1. Excellent Low-Temperature Toughness
Minimum Charpy V-notch impact energy reaches 27 J at -40 °C. It fits equipment for cold regions and cryogenic storage service.
2. Higher Strength-to-Weight Ratio
Its yield strength is 10–15% higher than SA516 Gr 70. Thinner wall thickness can be adopted under identical design pressure, cutting total equipment weight and material expense. For storage tanks designed for 1.6 MPa, A612 reduces wall thickness by 8–12% vs SA516.
3. Good HIC Resistance
Low carbon equivalent (CEV ≤ 0.40%) minimizes cold cracking risk during welding. Applicable to oil & gas processing units with wet hydrogen sulfide (H₂S) media. HIC testing can be performed in compliance with NACE TM0284 standard.
ASTM A612 steel plate and Charpy V-notch test specimens
Note A: For each reduction of o01 percentage point below the specified carbon maximum. an increase of o .06 percentage point manganese
above 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 %.
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 |
ASTM A612/A612M Dimensional Tolerance
| Nominal Thickness Range | Thickness Tolerance (Width ≤1500mm) | Thickness Tolerance (Width 1500~2500mm) | Thickness Tolerance (Width >2500mm) | Corresponding Width Tolerance | Corresponding Length Tolerance | Flatness Tolerance | Camber Tolerance |
|---|---|---|---|---|---|---|---|
| 6 ~ 10 | -0.3 / +0.7 | -0.3 / +0.8 | -0.4 / +0.9 | ±3 | ±5 | ≤3mm/m | ≤2mm/m |
| 10 ~ 20 | -0.3 / +0.8 | -0.4 / +0.9 | -0.4 / +1.0 | ±5 | ±5 | ≤3mm/m | ≤2mm/m |
| 20 ~ 30 | -0.4 / +0.9 | -0.4 / +1.0 | -0.5 / +1.1 | ±5 | ±10 | ≤3mm/m | ≤2mm/m |
| 30 ~ 50 | -0.4 / +1.0 | -0.5 / +1.1 | -0.5 / +1.2 | ±8 | ±10 | ≤3mm/m | ≤2mm/m |
| 50 ~ 100 | -0.5 / +1.1 | -0.5 / +1.2 | -0.6 / +1.3 | ±8 | ±15 | ≤3mm/m | ≤2mm/m |
| 100 ~ 150 | -0.6 / +1.3 | -0.6 / +1.4 | -0.7 / +1.5 | ±8 | ±15 | ≤3mm/m | ≤2mm/m |
ASTM A612 / A612M Dimensional Measurement
ASTM A612/A612M Equivalent Grades
| Grade | Standard | Minimum Yield Strength (MPa) | Minimum Service Temperature | HIC Resistance | Typical Applications |
|---|---|---|---|---|---|
| A612 | ASTM | ≥ 290 | -40°C | Good | LNG storage tanks, low-temperature vessels |
| SA516 Gr70 | ASTM | ≥ 260 | -29°C | Fair | Ambient-temperature boilers, storage tanks |
| Q345R | GB | ≥ 345 | -20°C | Fair | Domestic pressure vessels (China) |
| P355NL1 | EN | ≥ 355 | -50°C | Excellent | Low-temperature vessels to European standards |
Although the unit price of ASTM A612 plate is slightly higher, its superior yield strength enables thinner shell wall designs under low-temperature service conditions, cutting total material consumption and welding workload. For large-scale LNG storage tanks and cryogenic equipment, A612 generally delivers better overall cost efficiency than SA516 Gr70 alongside enhanced operational safety.
ASTM A612/A612M Welding Procedure and PWHT Guidelines：
1. Welding Preheat Requirements
- Thickness ≤ 16 mm: Preheating is generally unnecessary when ambient temperature ≥ 0 °C
- Thickness 16–32 mm: Preheat to 50–100 °C
- Thickness 32–50 mm: Preheat to 100–150 °C
- Thickness > 50 mm: Preheat to 125–175 °C
Note: Preheat temperatures are calculated based on carbon equivalent and restraint degree; values above are general recommendations.
2. Recommended Filler Metals
- SMAW (Shielded Metal Arc Welding): E7018-G (low-temperature toughness electrodes)
- SAW (Submerged Arc Welding): F7P4-EM12K (matched flux & wire combination)
- GMAW (Gas Metal Arc Welding): ER70S-G (solid wire)
Important: Consumables must satisfy the base metal's low-temperature impact property requirements.
3. Post-Weld Heat Treatment (PWHT)
- Mandatory PWHT Conditions：Structures with thickness over 38 mm or high restraint levels
- Recommended Temperature：580–620 °C
- Soaking Time：Approx. 1 hour per 25 mm of plate thickness
Precautions：Control heating and cooling rates to prevent thermal stress cracking.
ASTM A612/A612M Performance characteristics
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Yield strength at 345 MPa grade. Yield strength is 25–30% higher than SA516 Gr70. It allows wall thickness reduction and equipment weight cutdown.
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Charpy impact energy ≥ 27 J at -40 ℃. Suitable for LNG service at -45 ℃ and high-pressure vessels operating in cold regions.
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Low carbon equivalent. No preheating required for plate thickness ≤ 20 mm. Preheating at 50–100 ℃ is applied for thickness above 20 mm to restrict hot cracking.
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Low phosphorus and sulfur content with trace copper and nickel addition. Resistance to Hydrogen Induced Cracking (HIC) doubles that of SA516 Gr70. Applicable to wet H₂S service environments.
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Elongation ≥ 22%. The material supports rolling, stamping and forming for complex vessel structures.
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Fully killed steel with homogeneous fine grain microstructure. Consistent properties across plate thickness. Delivers resistance to fatigue and brittle fracture.
Internal Welding of Vessel Shell
ASTM A612/A612M Application scenarios
ASTM A612/A612M Processing services
| Fabrication Type | Service Scope | Tolerance & Compliance Standard |
|---|---|---|
| Cutting Fabrication | Flame cutting, plasma cutting, laser cutting; blanking to any dimension per client drawings | ±1 mm |
| Bevel Machining | V-type, X-type, U-type welding bevels; grinding to remove hardened cutting layer | ±0.5° |
| Surface Treatment | Shot blasting & sandblasting, rust removal, anti-rust oil coating, temporary primer, anti-corrosion coating | Sa2.5 cleanliness grade |
| Inspection Service | Ultrasonic Testing (UT), Magnetic Particle Testing (MT), Penetrant Testing (PT), Hydrogen Induced Cracking (HIC) test, Charpy impact test | Produced to ASTM specifications |
| Marking Service | Stamping of heat number, material grade, standard code and mill logo; custom marking per client requirements | Permanent, legible marking with no peeling |
ASTM A612/A612M Cutting Processes Ultrasonic Testing
ASTM A612 Export Cases
5,000 m³ Medium & Low Temperature Auxiliary LNG Storage Tank Project, Russia
- Client: Far East Russian LNG Equipment Manufacturer
- Total Order Volume: 192 tons normalized ASTM A612 steel plate
- Plate Sizes: 28 mm, 36 mm, 42 mm thickness
- Service Conditions: Design temperature -42°C, operating pressure 0.8–1.2 MPa, outdoor exposure under frigid winter climate
Client Pain Points
- Extremely low ambient temperatures in local winters;
- Charpy V-notch impact energy ≥27 J at -40°C is mandatory.
- Thinner wall thickness is required vs SA516 Gr70 to cut tank dead weight.
Customized Technical Solution
- Delivery condition: Normalized (N) finish, grain refinement for guaranteed low-temperature toughness.
- 100% full-plate ultrasonic testing to SEP 1921 Level 2 standard.
- Independent third-party Charpy V-notch impact test at -40°C for every single plate.
Delivery & Project Outcomes
- Trade term: FOB Tianjin; 28-day production cycle plus 7-day direct sea freight to Vladivostok.
- Tank wall thickness reduced by 10% compared with SA516 Gr70, saving 12 tons of total steel consumption.
- Complete set of MTC 3.2 material test certificates plus third-party test reports accepted by Russian customs.
High Pressure Vessel Units for Peru Mining Site
GNEE has exported ASTM A612/A612M steel plates to Russia, Germany, Thailand, Brazil, Middle East and Peru, supporting low-temperature LNG tanks, hydrogen reactors, petrochemical separators and mining pressure vessels with full inspection certificates and one-stop processing service.
Why Choose GNEE Group?
With 20 years steel export experience, we not only interpret the standard professionally, but also provide one-stop customized supply, full third-party inspection and global delivery service for A612/A612M plates. We solve common selection, welding and quality problems for pressure vessel manufacturers worldwide.
Direct cooperation with top domestic steel mills. Stable monthly output, lead time guaranteed. Support FOB, CFR, CIF, DDP worldwide delivery.
Before shipment, we conduct 100% visual inspection, dimensional check and random mechanical re-test. All documents are issued in English version for easy customs clearance & project acceptance.
- Mill Test Certificate (MTC 3.1 / 3.2)
- Third-party inspection: SGS / BV / TUV on request
- Full compliance with ASTM, ASME standards for pressure vessel industry.
All standard stock plates are delivered in normalized + tempered (N+T) condition. Original mill MTC 3.1 certificates are supplied with each batch; third-party re-inspection is acceptable upon request.
Standard Stock Inventory List
| Thickness (mm) | Standard Width (mm) | Standard Length (mm) | Minimum Stock Tonnage |
|---|---|---|---|
| 8 | 1500 / 1800 | 6000 / 8000 | ≥ 50 MT |
| 10 | 1500 / 1800 | 6000 / 8000 | ≥ 80 MT |
| 12 | 1500 / 2000 | 6000 / 9000 | ≥ 100 MT |
| 14 | 1500 / 2000 | 6000 / 9000 | ≥ 60 MT |
| 16 | 1500 / 2000 | 6000 / 10000 | ≥ 120 MT |
| 20 | 1800 / 2200 | 6000 / 10000 | ≥ 150 MT |
| 25 | 1800 / 2200 | 6000 / 10000 | ≥ 80 MT |
| 30~50 | 2000 / 2500 | 6000 / 12000 | Stock availability to be confirmed per order |
Contact us now for a quote on ASTM A612/A612M.
FAQ：
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.
