ASME SA662 Gr.B Carbon-Manganese-Silicon Steel Plates

 

ASME SA-662 Grade B is a carbon-manganese-silicon steel plate engineered specifically for pressure vessel applications in moderate- and lower-temperature service. This steel grade complies with ASME SA-662/SA-662M (identical to ASTM A662/A662M Grade B).

ASME SA-662 Grade B is the most widely specified grade within the A662 specification family, delivering an optimal balance of strength, notch toughness, weldability, and cost efficiency. Specifying a minimum yield strength of 275 MPa (40 ksi) and a tensile strength range of 450–585 MPa (65–85 ksi), it provides higher load-bearing capacity than Grade A while maintaining equivalent ductility and comparable weldability.

 

 

Element	Specification (%)
Carbon (C)	≤ 0.22
Silicon (Si)	0.13 – 0.45
Manganese (Mn)	0.79 – 1.62
Phosphorus (P)	≤ 0.035
Sulfur (S)	≤ 0.035

Grade	Thickness (mm)	Yield, min (MPa)	Tensile (MPa)	Elongation, min (%)
SA662GrB	6 – 50	275	450 – 585	23
	50 – 200	275	450 – 585	20

 

 

Parameter	Range
Thickness	6 mm – 300 mm
Width	1,500 mm – 4,050 mm
Length	3,000 mm – 15,000 mm

 

 

As-Rolled (Default for ≤40mm)

Fastest delivery · Lowest cost. The plate is supplied in the condition produced by hot rolling - no additional heat treatment. This is the standard condition for Grade B plates 40mm and under. Adequate for most pressure vessel applications where service conditions are moderate.
Normalized (Mandatory for >40mm)

Required by standard for thickness >40mm. The plate is heated to ~870–900°C and air-cooled, refining grain structure and ensuring uniform properties. This adds processing time but is non-negotiable for thick plates per ASTM A662.
Optional: Stress Relieved

Additional cost · Extended lead time. Heat treatment at 550–650°C to reduce residual stresses. Specify when the application involves severe service conditions or when the construction code requires it.
Optional: Normalized + Stress Relieved

Additional cost · Longest lead time. Combined treatment for maximum property optimization. Specify for critical applications where both grain refinement and stress relief are required.

 

ASME SA662 Gr.B steel plates are used in pressure vessel and boiler applications requiring moderate strength and verified low-temperature toughness:

Petrochemical industry: Reactors, separators, and heat exchangers in moderate/low-temperature process service

Oil & gas: Pressure vessels and process equipment in refineries and gas plants

Power generation: Boiler drums and pressure components in moderate-temperature service

Industrial gas: Air separation unit equipment and moderate low-temperature gas processing

Storage tanks: Process storage vessels for moderate low-temperature service

 

 

• Mill Test Certificate (EN 10204 3.1 or 3.2)
• Material Test Report (chemistry + mechanical + impact)
• Charpy V-notch impact test report (at specified temperature)
• Heat treatment records (if normalized or stress-relieved)
• Ultrasonic test report (if UT specified)
• Third-party inspection certificate (if required)
• Material certificate of compliance (ASME Form)

 

 

GNEE Steel provides comprehensive processing services so your plates arrive ready for fabrication:

Service	Description
Cutting to size	Plasma, flame, or waterjet cutting to your exact dimensions
Beveling	Edge preparation for welding (V, U, X groove configurations)
Drilling	Hole drilling for bolting, nozzle attachments, and instrumentation
Welding preparation	Tack welding, fitting, and weld preparation per your WPS
Shot blasting	Surface cleaning to SA 2.5 for coating or inspection
Painting	Primer and topcoat application for corrosion protection during transport and storage
Curving/rolling	Plate rolling to cylindrical or conical shapes for vessel shells

 

 

What is the preheat temperature for welding ASME SA662 Gr.B steel plates?

Thin Plates (under 16 mm / 5/8 inch): Often require only ambient temperature preheat, provided the steel is dry and the temperature is above 50°F (10°C).

Thicker Plates (16 mm to 38 mm): Typically require a minimum preheat of 50°F to 175°F (10°C to 80°C), depending on restraint and hydrogen control.

Heavy Sections (over 38 mm): Higher preheat temperatures (often 200°F / 93°C or higher) are commonly recommended to slow cooling rates and prevent hydrogen-induced cracking.

 

Which welding methods can be used for ASME SA662 Gr.B steel plates?

SMAW (Shielded Metal Arc Welding / Stick): Common for manual and field repairs. Use low-hydrogen electrodes like E7016 or E7018.

SAW (Submerged Arc Welding): Efficient for heavy plate fabrication and long structural seams. Use compatible combinations like F7A2-EM12K.

GTAW (Gas Tungsten Arc Welding / TIG): Preferred for high-purity root passes and precision work. Use filler wire like ER70S-6.

GMAW (Gas Metal Arc Welding / MIG): Used for production speed and semi-automated setups.

FCAW (Flux-Cored Arc Welding): Frequently chosen for high deposition rates in heavy structural and pressure vessel joints.

 

Are ASME SA662 Gr.B steel plates suitable for cryogenic environments?

ASME SA662 Grade B steel plates are not suitable for true cryogenic environments.

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