ASTM A204 Grade B Steel Plate
ASTM A204 Grade B is a fully killed molybdenum alloy steel plate specified under standard ASTM A204/A204M-17(R2022), engineered for fabricated welded boilers, pressure vessels and industrial heat exchangers. This standard covers three strength grades (Grade A, Grade B and Grade C). Grade B achieves an optimal balance of intermediate-temperature tensile strength, weldability and overall cost. Accordingly, it has become the dominant material for shell-and-tube heat exchangers, tube sheets and high-temperature cooling equipment deployed in petroleum, natural gas, chemical and power generation sectors.
Why is ASTM A204 Grade B Plate Ideal for Heat Exchanger Fabrication?
By precisely regulating molybdenum (Mo) content within 0.45%~0.65%, A204 Grade B maintains stable metallic microstructure under long-term service at 300℃~450℃ and effectively prevents permanent creep deformation. Heat exchangers are subject to recurring thermal cycling during regular operation. A204 Gr.B avoids sagging or distortion after years of continuous heat exchange service, delivering far superior performance compared to plain carbon steel.
Heat exchangers endure frequent temperature fluctuations between cold process fluids and high-temperature media. Our A204 Grade B retains stable toughness across the temperature range from -30℃ to 450℃, resisting thermal shock and inhibiting weld cracking induced by repeated heating-cooling cycles, which significantly extends the service life of equipment.
As a fully killed low-carbon alloy steel, A204 Gr.B features ultra-low levels of phosphorus (P), sulfur (S) and other tramp elements. It is suitable for full penetration welding of heat exchanger shells and tube sheets. Uniform crack-free weld joints can be achieved without complicated preheating procedures, cutting processing costs for equipment manufacturers.
Process media in petrochemical heat exchange systems often contain hydrogen sulfide and weakly acidic substances. Molybdenum forms a dense passive film on the steel surface to retard medium erosion and reduce the risk of stress corrosion leakage for heat exchange equipment.
A204 Grade B has an ultimate tensile strength of 485~620 MPa and a minimum yield strength of 275 MPa, fully meeting internal pressure load requirements for medium-pressure heat exchangers. This characteristic enables thinner plate design to enhance heat transfer efficiency while guaranteeing pressure containment safety.
ASTM A204 Grade B Steel Plate for Heat Exchanger Specification
| Item | Specification |
|---|---|
| Product Name | ASTM A204 Grade B Steel Plate for Heat Exchanger |
| Standard | ASTM A204 / ASME SA204 |
| Product Type | Molybdenum Alloy Pressure Vessel Steel Plate |
| Supply Thickness | 6–150 mm |
| Supply Width | 1,500–4,000 mm |
| Supply Length | 3,000–18,000 mm |
| Heat Treatment | Normalized (N); Normalized + Stress Relieved (Optional) |
| Surface Condition | As Rolled, Shot Blasted & Painted, Pickled, or according to customer requirements |
| Edge Condition | Mill Edge (ME), Trimmed Edge (TE) |
| Inspection Standard | EN 10160, ASTM A578, or Customer Specification |
| Third-Party Inspection | SGS, TÜV, BV, DNV, ABS, Lloyd's Register (LR), Moody, or Customer Designated Agency |
| Mill Test Certificate | EN 10204 3.1 / 3.2 |
ASTM A204 Grade B steel plate chemical composition
| Element | A204 Grade A | A204 Grade B | A204 Grade C |
|---|---|---|---|
| Carbon (C) Max | ≤0.18 (≤0.25 for thickness＞100mm) | ≤0.20 (≤0.27 for thickness＞100mm) | ≤0.23 (≤0.28 for thickness＞100mm) |
| Manganese (Mn) Max | 0.90 | 0.90 | 0.90 |
| Silicon (Si) | 0.15~0.40 | 0.15~0.40 | 0.15~0.40 |
| Phosphorus (P) Max | 0.035 | 0.035 | 0.035 |
| Sulfur (S) Max | 0.035 | 0.035 | 0.035 |
| Molybdenum (Mo) | 0.45~0.60 | 0.45~0.65 | 0.45~0.60 |
ASTM A204 Grade B steel plate Mechanical properties
| Mechanical Index | A204 Grade A | A204 Grade B | A204 Grade C |
|---|---|---|---|
| Tensile Strength, ksi [MPa] | 65–85 [450–585] | 70–90 [485–620] | 75–95 [515–655] |
| Minimum Yield Strength, ksi [MPa] | 37 [255] | 40 [275] | 43 [295] |
| Min Elongation (200mm/8in), % | 19 | 17 | 16 |
| Min Elongation (50mm/2in), % | 23 | 21 | 20 |
ASTM A204 Equivalent steel grade
| ASTM Grade | Chinese GB | JIS | DIN | EN Standard |
|---|---|---|---|---|
| A204-Gr.A/B | 16Mo | 16Mo (G3103) | 15 Mo3 (1.5414, DIN17155) | 16Mo3 (1.5415, EN 10028-2) |
What is the difference between A204 Grade B and A36?
Production Standard & Product Positioning
ASTM A204 Grade B is a dedicated molybdenum alloy pressure vessel steel plate complying with ASTM A204 specification, engineered exclusively for high-temperature pressure-containing equipment. ASTM A36 is a conventional carbon structural steel only applicable to ambient-temperature building frames, machinery bases and non-pressure-bearing structural components.
Difference in Alloy Composition
ASTM A204 Gr.B contains 0.45%~0.65% molybdenum alloying element to enhance high-temperature mechanical properties. ASTM A36 is plain carbon steel without any alloy additions, consisting merely of basic carbon (C), manganese (Mn) and silicon (Si).
Strength & Temperature Resistance Performance
ASTM A204 Grade B features tensile strength of 485~620 MPa and minimum yield strength of 275 MPa. It maintains stable mechanical performance without strength degradation within the service temperature range from -30°C to 450°C. ASTM A36 delivers tensile strength of 400~550 MPa and minimum yield strength of 250 MPa. The steel will suffer softening, permanent deformation and loss of load-bearing capacity when operating above 200°C, making it unsuitable for continuous high-temperature heat exchange service conditions.
Core Application Fields
ASTM A204 Gr.B is specially utilized for heat exchangers, boilers, chemical high-pressure vessels and high-temperature process equipment for oil & gas industry. ASTM A36 is restricted to ambient-temperature construction works, bridges, general mechanical supports and non-pressure-bearing metallic structures.
Application Scenarios For A204 Grade B Heat Exchanger Steel Plate
- Petrochemical Industry Heat Exchange Equipment Shell-and-tube heat exchanger shells, tube sheets, floating head baffles for crude oil fractionation, natural gas desulfurization and hydrogenation workshops; high-temperature cooling exchangers for ammonia synthesis devices.
- Power Generation Industry Waste Heat Recovery Exchangers Heat exchange pressure shells for thermal power plant waste heat boilers, steam-water heat exchangers, flue gas waste heat recovery heat exchangers, bearing alternating hot flue gas and cooling water circulation.
- Fine Chemical & Fertilizer Plant Exchangers High-temperature reaction medium heat exchangers, acid-base medium cooling heat exchangers for pesticide, chemical fiber and nitrogen fertilizer production lines, resisting mild corrosive working conditions.
- Metallurgical Hot Blast & Cooling Equipment High-temperature heat exchange chambers of blast furnace hot blast stoves, circulating cooling exchangers for non-ferrous metal smelting autoclaves.
- Offshore Oil & Gas Skid-Mounted Exchangers Compact heat exchanger pressure casings on offshore platform process modules, adapting offshore alternating temperature and weak hydrogen corrosion environments.
One-Stop Service Support From GNEE Steel
As professional A204 Grade B heat exchanger steel plate manufacturer & exporter with 18 years industry experience, GNEE provides full-cycle customized solutions for global heat exchanger manufacturers:
Complete Quality Certification & Test Reports
All A204 Gr.B plates comply with ASTM A204 & ASME SA204 standards, supplied with EN 10204 3.1/3.2 original mill test certificates. Optional tests: -30℃ low-temperature impact test, 100% UT ultrasonic flaw detection (ASTM A578), SGS/BV/TÜV third-party inspection support. We hold ISO9001 quality system certification and PED CE certification for European pressure vessel projects.
Export Logistics & After-Sales Technical Support
Seaworthy wooden pallet packaging with waterproof film, delivery from Tianjin/Shanghai/Qingdao port. Professional steel technical team provides free material selection, welding process and high-temperature performance consultation for heat exchanger design engineers; after-sales tracking for overseas project usage feedback.
FAQ
What is the difference between ASTM A204 and ASME SA204 Grade B for heat exchangers?
There is no technical difference between ASTM A204 Grade B and ASME SA204 Grade B; they are identical and interchangeable material specifications. The prefix ASTM designates the material standard set by the American Society for Testing and Materials, while the ASME SA prefix denotes the exact same specification adopted by the American Society of Mechanical Engineers for use in pressure vessels and heat exchangers under the Boiler and Pressure Vessel Code.
What maximum working temperature can A204 Grade B heat exchanger plate withstand?
ASTM A204 Grade B molybdenum-alloy steel plate can withstand a maximum code-defined temperature limit of 371°C (700°F) under certain ASME Section VIII-1 applications, though general elevated-temperature industrial and structural operations safely utilize its properties up to 500°C–540°C (932°F–1000°F) depending on specific creep and design criteria.
Can A204 Grade B be used to manufacture thin-plate plate heat exchangers?
No, ASTM A204 Grade B is an alloy steel plate intended for heavy-duty welded pressure vessels and boilers, with typical and standardized thicknesses ranging from 5 mm to 150 mm. It is poorly suited for thin-plate plate heat exchangers due to its lack of corrosion resistance and inability to be economically formed into thin, complex corrugated sheet profiles.
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