SA662 Grade B is a low-alloy, high-strength carbon steel plate specifically engineered for low-temperature service applications, boasting excellent toughness and weldability at subzero temperatures. It is a standard specification from the American Society for Testing and Materials (ASTM), widely utilized in the fabrication of pressure vessels, storage tanks, and structural components that operate in cold environments, where resistance to brittle fracture is a critical performance requirement. This grade exhibits consistent mechanical properties across its thickness, with reliable formability and machinability, making it a preferred material choice for industrial equipment in petrochemical, power generation, and cryogenic processing sectors.
Chemical Composition( %):
|
Grade/ Material |
Element |
Composition( Max-A, Min-I) |
|
SA662 Grade B/ SA662 GrB |
C |
A:0.19 |
|
Mn |
0.85-1.50 |
|
|
Si |
0.15-0.40 |
|
|
P |
0.035 |
|
|
S |
0.035 |
Mechanical Properties( Mpa)
|
Grade/ Material |
Tensile Test |
MPa |
|
SA662 Grade B/ SA662 GrB |
Tensile Strength |
450-585 |
|
Yield Strength |
275 |
|
|
Elongation |
20% |
|
|
Impact Test( if any) |
|
SA662 Grade B Applications
Low-temperature pressure vessels: It is a preferred material for manufacturing pressure vessels operating in subzero environments, such as those used in cryogenic gas separation, liquefied natural gas (LNG) processing and storage. The steel's outstanding toughness at low temperatures effectively prevents brittle fracture under high pressure and low-temperature conditions, ensuring the safe and stable operation of equipment in petrochemical and natural gas industries.
Cold-region storage tanks: Used to fabricate storage tanks for low-temperature media like liquid oxygen, liquid nitrogen, and refrigerants. These tanks often work in harsh cold environments (e.g., high-altitude or polar regions). SA662 Grade B's good formability and machinability allow easy shaping into large-volume tanks, while its cold resistance guarantees long-term storage safety without material degradation.
Low-temperature structural components: Applied in structural parts of industrial equipment that withstand low temperatures, such as supports, brackets, and connecting components in power generation (especially thermal power and nuclear power auxiliary equipment) and cryogenic processing plants. Its high strength and stable mechanical properties across thickness ensure structural integrity and load-bearing capacity in cold working conditions.
SA662 Grade B Application Conditions
Temperature Service Range
Operates reliably at subzero temperatures down to -46°C (-50°F), the core condition for its low-temperature toughness application. It resists brittle fracture under extreme cold, avoiding material embrittlement that ordinary carbon steel suffers in low-temperature working environments.
Pressure & Load Requirements
Suitable for moderate to high pressure working conditions (common in pressure vessel and tank fabrication), with stable mechanical properties under static and cyclic pressure loads. Its uniform strength across thickness adapts to medium and heavy load-bearing structural applications in cold industrial settings.
Welding & Forming Working Conditions
Applied in fabrication processes requiring extensive welding and cold/hot forming. It has excellent weldability without preheating or post-weld heat treatment under general workshop conditions, and maintains structural integrity during bending, rolling and other forming operations, matching the processing needs of industrial equipment manufacturing.
Atmospheric & Media Conditions
Adaptable to dry and low-humidity industrial atmospheres in petrochemical, cryogenic processing and power industries; compatible with non-corrosive media such as liquefied gas, cold water and industrial gas, suitable for ordinary industrial corrosive-free working environments.
SA662 Grade B Core Advantages
Superior low-temperature toughness
Excels in subzero environments down to -46°C, with high impact resistance that effectively prevents brittle fracture-eliminating the embrittlement issue of conventional carbon steel in cold working conditions, and ensuring equipment operational safety.
Excellent weldability & formability
Features good weld performance without complex preheating or post-weld heat treatment under general workshop conditions, enabling smooth welding fabrication. It also maintains structural stability during cold/hot forming like rolling and bending, meeting diverse processing needs of industrial components.
Stable mechanical properties
Boasts uniform high strength and toughness across the entire plate thickness, with consistent performance under static and cyclic loads. It resists deformation and fatigue in moderate to high pressure working conditions, ensuring long-term structural integrity of equipment.
Practical industrial adaptability
As a cost-effective low-alloy steel, it balances high performance and economic efficiency, and adapts to dry/low-humidity industrial atmospheres and non-corrosive media, making it a reliable and economical choice for cold-region industrial fabrication.
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What is SA662 Grade?
SA662 Grade is a low-alloy carbon steel plate specified by ASTM standards, mainly used for pressure vessels and structural components. It has good toughness, weldability and high-temperature resistance, suitable for moderate pressure and temperature working environments.
What are the main chemical components of SA662 Grade?
The main chemical components include C (carbon) ≤0.20%, Mn (manganese) 0.70-1.00%, Si (silicon) 0.15-0.35%, P (phosphorus) ≤0.035%, S (sulfur) ≤0.035%, and trace alloying elements.
What is the minimum yield strength of SA662 Grade?
The minimum yield strength of SA662 Grade is 240 MPa (35,000 psi) at room temperature. This strength level ensures it can withstand certain pressure and load without permanent deformation in service.
What is the tensile strength range of SA662 Grade?
Its tensile strength ranges from 415 MPa to 550 MPa (60,000 psi to 80,000 psi). This range makes it suitable for structural parts and pressure vessels that require balanced strength and toughness.
What standards does SA662 Grade comply with?
SA662 Grade complies with ASTM A662/A662M, a standard issued by the American Society for Testing and Materials (ASTM) that specifies the requirements for low-alloy carbon steel plates for pressure vessels.
What is the maximum thickness of SA662 Grade plates usually supplied?
SA662 Grade plates are usually supplied with a maximum thickness of 150 mm (6 inches), but can be customized to thicker specifications according to customer needs and manufacturing capabilities with proper testing.
Is SA662 Grade weldable?
Yes, SA662 Grade has excellent weldability. It can be welded using common methods such as arc welding, gas welding and resistance welding without preheating under normal conditions.
What heat treatment is required for SA662 Grade?
SA662 Grade is generally supplied in the as-rolled or normalized state. Normalization heat treatment (heating to 890-950°C, holding, then air cooling) improves its structure uniformity and toughness.
What is the application scope of SA662 Grade?
It is widely used in manufacturing pressure vessels, boilers, storage tanks, pipelines and structural components in petroleum, chemical, power generation and other industries, suitable for moderate pressure and temperature conditions.
What is the Brinell hardness of SA662 Grade?
The Brinell hardness of SA662 Grade is usually between 110-160 HB. This moderate hardness balances its machinability and toughness, facilitating subsequent processing and forming.