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ASTM A508 Class 2 steel has been used in the United States for the past 34 years for pressure vessels, largely for nuclear reactor components. Although users prefer this normally silicon-deoxidized NiCrMo steel because of its low cost and weldability, forging producers and fabricators often experience difficulties meeting specification requirements. Problems such as inadequate hardenability, upper nose temper ambrittlement, highly variable toughness, inadequate elevated temperature tensile properties and reheat cracking have been experienced during the manufacturing of heavy section components. This paper reviews these metallurgical problems, with the aim of highlighting the limitations of this grade for heavy section applications. The mechanical properties of A508 Class 2 forgings are compared to those of A508 Class 4 forgings where possible. The superior mechanical properties of A508 Class 4 make it more suitable for heavy section applications than A508 Class 2.