ASME SA387 Grade 21 Class 2 (SA387 Gr 21 Cl 2) Steel Plate

ASME SA387 Grade 21 Class 2 (SA387 Gr 21 Cl 2) alloy steel plates are a premium chrome-moly grade in the ASME SA387 specification. Unlike Class 1, which is normalized for moderate strength, Class 2 is quenched and tempered, providing higher tensile strength (515–690 MPa) and yield strength (minimum 310 MPa) with superior creep and oxidation resistance.

The plates are manufactured using quenching and tempering heat treatment, which refines the microstructure for enhanced toughness and durability at elevated temperatures, making them ideal for boilers, pressure vessels, and petrochemical equipment under extreme high-heat conditions.

SHH STEEL supplies ASME SA387 Grade 21 Class 2 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 21 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 21 Cl 2 or EN 10028-2 is offered for international compatibility.

This makes our ASME SA387 Gr 21 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 21 Class 2 is tightly controlled per ASME SA-387/SA-387M to guarantee elevated temperature stability and weldability.

The maximum carbon content is 0.15%, preventing brittleness, while manganese (0.30-0.60%) and silicon (0.50 max) enhance strength and deoxidation. Phosphorus and sulfur are capped at 0.025% each to minimize cracking, chromium (3.00-3.50%) and molybdenum (1.00-1.50%) provide creep resistance.

Our testing per ASME SA-350 maintains a Carbon Equivalent (CE) ≤0.45 per AWS D1.1. 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 21 Cl 2 plates a reliable choice for buyers searching for “ASME SA387 Gr 21 Cl 2 chemical composition.”

As a production and export expert at SHH STEEL, we can assure you that ASME SA387 Grade 21 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 310 MPa and tensile range of 515-690 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 (220 MPa est.) varies with surface finish, optimized by our grinding process. This makes ASME SA387 Gr 21 Cl 2 plates a reliable choice for buyers searching for “ASME SA387 Gr 21 Cl 2 mechanical properties.”

SHH STEEL provides ASME SA387 Gr 21 Cl 2 plates in quenched and tempered condition as standard, quenched at 870-900°C and tempered at 620-650°C to achieve higher strength and toughness for elevated temperature applications.

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 21 Cl 2 is highly weldable with low CE ≤0.45 per AWS D1.1. SHH STEEL recommends preheating at 150-200°C for thicknesses over 25mm to prevent hydrogen-induced cracking, with post-weld heat treatment (PWHT) at 620-650°C for stress relief. Supported processes include GTAW, SMAW, and GMAW with E7018 filler (AWS A5.1), achieving 90-95% joint efficiency per ASME Section IX. Low sulfur (≤0.025%) 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 21 Cl 2 facilitate international projects, offering similar tensile and yield properties for pressure vessel use. For example, 13CrMoV9-10 (EN 10028-2) is a European equivalent with 440-590 MPa tensile and 290 MPa yield, suitable for EU boilers. STBA29 (JIS G4109) serves Japanese applications with 440-590 MPa tensile and 290 MPa yield, ideal for high-strength vessels. 12Cr3MoVSiTiB (GB/T 713) is the Chinese standard equivalent, providing 440-590 MPa tensile and 295 MPa yield for cost-effective high-temperature equipment in Asian markets. These equivalents ensure cross-compatibility, allowing buyers to substitute ASME SA387 Gr 21 Cl 2 plates seamlessly in global supply chains.

Supplementary requirements for ASME SA387 Gr 21 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.

SHH STEEL provides these to meet stringent needs. Buyers search for “SA387 Gr 21 Cl 2 supplementary requirements.”

ASME SA387 Gr 21 Cl 2 pressure vessel steel plates are versatile for elevated-temperature and pressure environments. They have good toughness and formability.

Details: Pressure vessels benefit from 515-690 MPa tensile at 600°C. Boilers handle 600°C with 18% elongation for forming. Heat exchangers use 6-30mm plates for 200 bar at 550°C. Storage tanks leverage 30-80mm for 150 bar at 550°C per API 650. Steam drums utilize 20-60mm plates for 350 bar at 600°C, per ASME Section VIII for efficient steam generation.

SHH STEEL offers ASME and ASTM-certified SA387 Gr 21 Cl 2 plates. We provide custom thicknesses up to 300mm. Heat treatments are tailored to your project. Our 15-year track record includes zero defect deliveries to 50+ countries. This is backed by SGS verification and mill test certificates.

SHH STEEL’s ASME SA387 Gr 21 Cl 2 Pressure Vessel Steel Plates provide unmatched strength and reliability for high-temperature pressure vessels and boilers. With precise tolerances, superior weldability, and global equivalents, we offer customized solutions. Trust SHH STEEL for your steel needs.