SA387GR21 Steel Plate | ASME SA387 Grade 21 Class 1 & Class 2

SA387GR21 Steel Plate | ASME SA387 Grade 21 Class 1 & Class 2 Supplier – Gangsteel

Gangsteel is a professional manufacturer and reliable exporter of SA387GR21 Steel Plate (ASME SA387 Grade 21). With more than 15 years of experience in chromium-molybdenum alloy steels, we supply both Class 1 and Class 2 SA387 Gr21 plates to power plants, refineries, and pressure vessel fabricators worldwide. SA387GR21 (1.25Cr-0.5Mo) is a cost-effective and widely used grade for moderate high-temperature service up to 540°C.

What Is SA387GR21 Steel Plate?

SA387GR21 is a 1.25% chromium and 0.5% molybdenum alloy steel plate designed for elevated temperature applications. It offers good creep resistance, oxidation resistance, and excellent fabricability. Compared to carbon steel, SA387GR21 provides significantly better high-temperature strength while remaining more economical than higher alloy grades such as SA387GR22 or SA387GR91.

Chemical Composition (Heat Analysis, %)

Gangsteel produces SA387GR21 in strict accordance with ASME SA387 specifications. Full chemical analysis and mill test certificates are provided with every order.

Mechanical Properties

Class 1 (Normalized + Tempered)

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

Class 2 (Normalized + Tempered)

• Tensile Strength: 515 – 690 MPa
• Yield Strength: ≥ 310 MPa
• Elongation in 50 mm: ≥ 22%

Equivalent Material Table

Main ApplicationsSA387GR21 Steel Plate is commonly used in:

• Power plant boilers and steam drums
• Petrochemical and refinery pressure vessels
• Medium-temperature heat exchangers
• Hydrogen service equipment
• Industrial boilers and superheaters

Why Choose Gangsteel SA387GR21?

• Direct mill production with full EN 10204 3.1 / 3.2 certification
• 100% ultrasonic testing (UT) performed on every plate
• Available in both Class 1 and Class 2 heat treatment conditions
• Wide thickness range from 6 mm to 150 mm with regular stock
• Competitive pricing and reliable delivery schedule (7–30 days)
• Professional technical support for material selection and welding procedures

Real Supply ExperienceIn 2025, Gangsteel supplied over 950 tons of SA387GR21 plates to a large-scale refinery upgrade project in the Middle East. The material was used for critical pressure vessels operating at temperatures between 420°C and 510°C. All plates passed third-party inspection, and the customer highlighted the consistent quality and good weldability during fabrication.

Request a QuoteIf you need SA387GR21 steel plates in specific thickness, width, length, or require Class 1 or Class 2 condition, please contact Gangsteel today. We will provide a formal quotation with complete mill test certificates and technical data within 24 hours.

Keywords:SA387GR21 Steel Plate, ASME SA387 Grade 21, 1.25Cr-0.5Mo Alloy Steel Plate