API RP 934-C

Abstract

This recommended practice presents materials and fabrication requirements for new 1 &#188;Cr-&#189;Mo steel heavy wall pressure vessels and heat exchangers for high-temperature, high-pressure hydrogen service. It applies to vessels that are designed, fabricated, certified, and documented in accordance with ASME <em>BPVC</em>, Section VIII, Division 1 or Division 2. This document may also be used as a resource for equipment fabricated of 1Cr-&#189;2Mo Steel. <br>This document may also be used as a resource when planning to modify an existing heavy wall pressure vessel. <br>The interior surfaces of these heavy wall pressure vessels may have an austenitic stainless steel or ferritic stainless steel weld overlay or cladding to provide additional corrosion resistance. <br>For this recommended practice, the heavy wall is defined as shell thickness 2 in. (50 mm) or greater but less or equal to 4 in. (100 mm). Integrally reinforced nozzles, flanges, tubesheets, bolted channel covers, etc. can be greater than 4 in. (100 mm). At shell or head thicknesses greater than 4 in. (100 mm), 1 &#188;Cr-&#189;Mo has been shown to have difficulty meeting the toughness requirements given in this document. Although outside of the scope of this document, it can be used as a resource for vessels down to 1 in. (25 mm) shell thickness with changes defined by the purchaser. <br>This recommended practice is not intended for use for equipment operating above 825 &#176;F (441 &#176;C) or in the creep range.