ASME SA266 GR.2(K03506) Carbon Steel Forged Ring for Pressure Vessel Parts Application

ASTM A266/ A266M is the standard specification for carbon steel forgings for pressure vessel components. It covers four grades of carbon steel forgings for boilers, pressure vessels, and associated equipment: Grade 1, Grade 2, Grade 3, and Grade 4. The UNS number designation for each grade is K03506 [Grade 1], K03506 [Grade 2], K05001 [Grade 3], and K03017 [Grade 4], respectively. The most commonly used forgings manufactured in accordance with ASTM A266 include tube sheets, hubbed flat heads, or nozzles, that are ordered for ASME Boiler and Pressure Vessel Code applications.

The steel shall be made by a melting process and shall be subsequently forged as closed as practical to the specified shape and size of finished products. Surfaces of ASTM A266 forgings shall be machined as designated by the purchaser. Unmachined surfaces shall be sufficiently free of scale to permit inspection. Machining are generally performed after heat treatment. Welding repair is not permitted to ensure good quality.

Chemical Composition Requirements

How to calculate the carbon equivalent of ASTM A266 forgings?

Carbon equivalent CE = C + Mn /6 + ( Cr + Mo + V ) / 5 + ( Ni + Cu ) / 15. The carbon equivalent shall not exceed 0.45 for Grade 1 or 0.50 for Grade 2 or 4. After forging and before reheating for heat treatment, the forgings in accordance with ASTM A266 shall be cooled in such a manner as to prevent injury and to accomplish transformation.