What Is A387 Grade 11 Class 2
ASTM A387 Grade 11 Class 2 is a chromium-molybdenum alloy steel plate for pressure vessels and industrial boilers in high-temperature service. With a nominal composition of about 1.25 percent chromium and 0.5 percent molybdenum, the Class 2 condition provides a minimum yield strength of 310 MPa through normalized and tempered or quenched and tempered delivery.
Chemical Composition
Product analysis limits are carbon 0.04 to 0.17 percent, manganese 0.35 to 0.73 percent, silicon 0.44 to 0.86 percent, phosphorus and sulfur 0.035 percent, chromium 0.94 to 1.56 percent, and molybdenum 0.40 to 0.70 percent.
Mechanical Properties
Class 1 has a tensile strength of 415 to 585 MPa with a yield of 240 MPa minimum; Class 2 has a tensile strength of 515 to 690 MPa with a yield of 310 MPa minimum, with elongation of 22 percent in 50 mm and 18 to 19 percent in 200 mm.
Specifications and Sizes
Plates are supplied in thicknesses of 4 to 400 mm with widths of 500 to 4500 mm and lengths of 700 to 12000 mm, in hot-rolled, polished, or pickled finishes with normalized and tempered or quenched and tempered delivery conditions.
Equivalents and Compliance
Engineering equivalents include EN 10028 13CrMo4-5, the British BS 621B, and the Chinese GB 14Cr1MoR. Testing includes chemical, mechanical, and non-destructive verification, with EN 10204 3.1 or 3.2 certificates and sour-service compliance available.
Applications
The plate serves pressure vessels, boiler drums, heat exchangers, and high-temperature process equipment in petrochemical, power, and refining service, with resistance to pitting, crevice corrosion, and stress corrosion cracking.
Frequently Asked Questions
Q: What is A387 Grade 11 equivalent to?
A: ASME SA387 Grade 11 and EN 13CrMo4-5 for reference.
Q: What is the difference between Cl1 and Cl2?
A: Cl2 has 310 MPa yield versus 240 MPa for Cl1.
Q: What is the difference between A182 and A387?
A: A182 is forging material; A387 is plate material.
Q: What tempering applies?
A: Minimum 620 degrees C for Class 2.
Q: What thickness range is available?
A: 4 to 400 mm.
Q: What certification is provided?
A: EN 10204 3.1 or 3.2 with NACE compliance on request.
For A387 Gr.11 Cl2 plate quotations, contact our sales team.