ASTM A 387 Grade 9 Class 2 Plates
Product Overview
ASTM A387 Grade 9 Class 2 plates are chromium-molybdenum alloy steel plates used for pressure
vessel and boiler applications operating at elevated temperatures. The alloy composition provides
high strength, oxidation resistance, and resistance to hydrogen attack in severe service conditions.
Material Designation
Standard: ASTM A387 / ASME SA387
Grade: 9
Class: 2
Chemical Composition
Carbon (C): 0.15% max
Manganese (Mn): 0.30 – 0.60%
Silicon (Si): 0.50% max
Chromium (Cr): 8.00 – 10.00%
Molybdenum (Mo): 0.90 – 1.10%
Phosphorus (P): 0.025% max
Sulfur (S): 0.025% max
Mechanical Properties
Tensile Strength: 620 – 795 MPa
Yield Strength: 415 MPa minimum
Elongation: 18% minimum
Heat Treatment
Class 2 plates are supplied in quenched and tempered condition to achieve higher strength and
improved toughness compared to Class 1 material.
Physical Properties
Density: Approximately 7.85 g/cm³
Melting Range: 1370 – 1400°C
Dimensions & Supply Range
Thickness: 6 mm to 150 mm
Width: Up to 3000 mm
Length: Up to 12000 mm
Key Characteristics
• High strength at elevated temperatures
• Improved oxidation resistance
• Resistance to hydrogen-induced cracking
• Suitable for high-pressure service
Welding Considerations
Preheating and post-weld heat treatment are recommended. Low-hydrogen welding consumables
are generally used.
Typical Applications
• Pressure vessels and reactors
• Boilers and heat exchangers
• Refinery and petrochemical equipment
Inspection & Testing
• Chemical analysis
• Tensile and impact testing
• Ultrasonic testing
• Dimensional and visual inspection
Certification & Documentation
Supplied with Mill Test Certificates in accordance with EN 10204 3.1 or 3.2.
Summary
ASTM A387 Grade 9 Class 2 plates are suitable for pressure equipment requiring reliable
mechanical performance and oxidation resistance at elevated temperatures.
1
/
3
100%
