ASME SA387 Grade 91 Class 2 (SA387 Gr 91 Cl 2) Steel Plate

ASME SA387 Grade 91 Class 2 (SA387 Gr 91 Cl 2) alloy steel plates are an advanced 9Cr-1Mo-V grade in the ASME SA387 specification, designed for extreme thermal and pressure conditions. This SA387 Gr 91 Cl 2 grade is quenched and tempered, offering tensile strength (585–760 MPa) and yield strength (minimum 415 MPa) with outstanding creep rupture strength and resistance to oxidation.

The SA387 Grade 91 Class 2 plates are manufactured using precise quenching and tempering heat treatment, stabilizing the martensitic microstructure for superior toughness and longevity at ultra-high temperatures, making them essential for supercritical boilers, power plant piping, and refinery systems facing intense operational demands.

SHH STEEL supplies ASME SA387 Gr 91 Cl 2 alloy steel plates in a wide size range from 6mm to 100mm thickness, up to 4600mm width, and up to 12000mm length, meeting both ASME Section VIII pressure vessel code and customer-specific requirements.

As a production and export expert at SHH STEEL, we can confirm that ASME SA387 Grade 91 Class 2 alloy steel plates are governed by ASME SA-387/SA-387M, the standard for pressure vessel plates, alloy steel, chromium-molybdenum.

This specification outlines requirements for quenched and tempered plates for elevated temperature service, ensuring suitability for welded pressure vessels and boilers. SHH STEEL complies fully with this standard, providing plates in quenched and tempered conditions to optimize mechanical properties.

The specification supports thicknesses from 6mm to 100mm, widths up to 4600mm, and lengths to 12000mm, with custom dimensions available for vessel designs. Ultrasonic examination per ASME SA-578 Class 1 detects laminations, guaranteeing defect-free material, while dual certification with ASTM A387 Gr 91 Cl 2 or EN 10028-2 is offered for international compatibility.

This makes our ASME SA387 Gr 91 Cl 2 plates a reliable choice for global buyers, supported by mill test certificates for complete traceability.

At SHH STEEL, we ensure the chemical composition of ASME SA387 Grade 91 Class 2 is tightly controlled per ASME SA-387/SA-387M to guarantee ultra-high temperature stability and weldability.

The carbon content is 0.08-0.12% for optimal hardenability, while manganese (0.30-0.60%) and silicon (≤0.50%) aid deoxidation. Phosphorus and sulfur are limited to 0.020% max each to prevent cracking, with chromium (8.00-9.50%), molybdenum (0.85-1.05%), vanadium (0.18-0.25%), niobium (0.06-0.10%), and nitrogen (0.03-0.07%) ensuring precipitation strengthening and creep resistance.

Our testing per ASME SA-350 maintains low impurities. Melt analysis (heat analysis) and product analysis differ slightly with tolerances. Melt analysis is stricter for ladle chemistry, while product analysis allows variation for finished plates.

This ensures consistency, making ASME SA387 Gr 91 Cl 2 plates a reliable choice for buyers searching for “ASME SA387 Gr 91 Cl 2 chemical composition.”

As a production and export expert at SHH STEEL, we can assure you that ASME SA387 Grade 91 Class 2 pressure vessel steel plates deliver strong mechanical properties, tested per ASME SA-370 for tensile/yield, ASME SA-23 for impact, and ASME SA-466 for fatigue.

With a minimum yield strength of 415 MPa and tensile range of 585-760 MPa, these plates support high load-bearing capacity, while 18% elongation ensures ductility for forming. The impact energy of 27J typical prevents brittle failure, and the modulus of elasticity (200 GPa) provides structural stability.

The fatigue limit (250 MPa est.) varies with surface finish, optimized by our grinding process. This makes ASME SA387 Gr 91 Cl 2 plates a reliable choice for buyers searching for “ASME SA387 Gr 91 Cl 2 mechanical properties.”

• SHH STEEL provides ASME SA387 Gr 91 Cl 2 plates in normalized, quenched, and tempered condition as standard, normalized at 1040-1090°C, quenched at 870-900°C, and tempered at 760-790°C to achieve optimal creep strength for ultra-high temperature applications.
  

  Factor	Value/Condition	Standard	Recommended	Keywords
  Heat Treatment	Normalize 1040-1090°C, Quench 870-900°C, Temper 760-790°C	ASME SA387	Q&T standard	SA387 Gr 91 Cl 2 heat treat

Plates are delivered with normalized options for flexibility, including heat numbers for traceability. Our global shipping ensures timely delivery, with 3-7 days to Asia for standard orders.

We maintain strict tolerances per ASME SA-20: thickness ±1.5mm for <40mm and ±2.0mm for thicker up to 100mm; width/length ±10mm (or ±5mm custom); flatness 3mm per meter. EN 10029 Class B available for European compatibility.

ASME SA387 Gr 91 Cl 2 is highly weldable with low CE ≤0.45 per AWS D1.1. SHH STEEL recommends preheating at 200-250°C for thicknesses over 25mm to prevent hydrogen-induced cracking, with post-weld heat treatment (PWHT) at 730-770°C for stress relief. Supported processes include GTAW, SMAW, and GMAW with E9018-B3 filler (AWS A5.1), achieving 90-95% joint efficiency per ASME Section IX. Low sulfur (≤0.020%) reduces hot shortness, and 18% elongation ensures ductility. Testing includes bend tests (ASTM E190) for 3t radius and ultrasonic for weld integrity per ASTM A435.

Global equivalents for ASME SA387 Gr 91 Cl 2 facilitate international projects, offering similar tensile and yield properties for pressure vessel use. For example, X10CrMoVNb9-1 (EN 10028-2) is a European equivalent with 585-760 MPa tensile and 415 MPa yield, suitable for EU power plants. STBA28 (JIS G4109) serves Japanese applications with 585-760 MPa tensile and 415 MPa yield, ideal for high-strength vessels. 10Cr9Mo1VNb (GB/T 713) is the Chinese standard equivalent, providing 585-760 MPa tensile and 415 MPa yield for cost-effective high-temperature equipment in Asian markets. These equivalents ensure cross-compatibility, allowing buyers to substitute ASME SA387 Gr 91 Cl 2 plates seamlessly in global supply chains.

Supplementary requirements for ASME SA387 Gr 91 Cl 2 pressure vessel steel plates enhance performance for specialized applications. They offer buyers tailored options.

These include ultrasonic testing (Class 1 per ASTM A435 for no laminations >0.25% thickness). Charpy impact at -50°C (27J min per ASTM A20 for cold service) is another. Heat analysis per heat number (ASTM E350 for traceability) ensures quality. Product analysis allows ±0.02% tolerance on elements. Shot blasting to Sa 2.5 (50-100μm profile per ISO 8501-1) is available for surface preparation.

• 15+ years experience in supplying Grade 91 alloy steel plates
• Large global stock, quick delivery
• Mill test certificates EN 10204 3.1 / 3.2 available
• Customized cutting, beveling, and machining
• Strong track record in power generation and petrochemical projects

ASME SA387 Grade 91 Class 2 (SA387 Gr 91 Cl 2) steel plates are premium chrome moly alloy steel plates with superior creep resistance, oxidation resistance, and weldability. Designed for high-pressure boilers, nuclear reactors, and petrochemical vessels, they are the benchmark alloy for high-temperature performance.

With extensive stock and global delivery, SHH STEEL is a trusted supplier of SA387 Gr 91 Cl 2 steel plates, offering certified quality and reliable service for your projects.