SA387GR21L Steel Plate | ASME SA387 Grade 21L Class 1 Supplie

SA387GR21L Steel Plate | ASME SA387 Grade 21L Class 1 Supplier – Gangsteel

Gangsteel is a trusted manufacturer and exporter of SA387GR21L Steel Plate (ASME SA387 Grade 21L). With more than 15 years of experience in chromium-molybdenum alloy steels, we specialize in supplying SA387 Gr21L plates for moderate to high-temperature pressure vessels and boilers. This low-carbon version of Grade 21 offers improved weldability and toughness while maintaining good creep resistance, making it a popular choice for fabricators who require easier welding on large equipment.

What Is SA387GR21L Steel Plate?SA387GR21L is the low-carbon (L) variant of SA387 Grade 21 (1.25Cr-0.5Mo alloy). The “L” designation significantly reduces carbon content, which greatly enhances toughness, ductility, and weldability compared to standard SA387 Gr21. It is specifically designed for applications where on-site welding is required and where moderate high-temperature service up to 540°C is needed.

Chemical Composition (Heat Analysis, %)

Gangsteel produces SA387GR21L strictly in accordance with ASME SA387 specifications. Full chemical analysis reports are provided with every shipment.

Mechanical Properties (Class 1 – Normalized and Tempered)

• Tensile Strength: 415 – 585 MPa
• Yield Strength: ≥ 205 MPa
• Elongation in 50 mm: ≥ 22%
• Reduction of Area: ≥ 40%

Equivalent Material Table

Main ApplicationsSA387GR21L Steel Plate is commonly used in:

• Power plant boilers and steam drums
• Petrochemical heat exchangers and reactors
• Refinery pressure vessels
• Medium-temperature hydrogen service equipment

Why Choose Gangsteel SA387GR21L?

• Direct mill supply with full EN 10204 3.1 / 3.2 material certificates
• 100% ultrasonic testing (UT) and hardness testing on every plate
• Excellent weldability due to low carbon design
• Wide thickness range from 6 mm to 150 mm
• Large regular stock availability for fast delivery
• Professional technical team offering welding procedure qualification support

Real Supply ExperienceIn 2025, Gangsteel supplied more than 720 tons of SA387GR21L plates to a petrochemical expansion project in Southeast Asia. The plates were used for critical heat exchangers operating at 480°C. The customer particularly appreciated the material’s superior weldability during field fabrication and the consistent mechanical properties across all batches.

Comparison with Other GradesSA387GR21L offers better weldability than standard SA387GR21, while providing higher creep resistance than carbon steels. It serves as a cost-effective middle ground between carbon steel and higher-alloy grades like SA387GR22.

Request a QuoteIf you need SA387GR21L steel plates in specific thickness, width, length, or require Class 1 / Class 2 heat treatment, please contact Gangsteel today. We provide formal quotations with complete mill test certificates and technical data packages within 24 hours.

Keywords:SA387GR21L Steel Plate, ASME SA387 Grade 21L, SA387 Gr21L Low Carbon Steel Plate