ASME Issues Welding Supplement for Post Construction Standard

ASME Issues Welding Supplement for deutsche post dhl Construction voreingestellt ASME Issues Welding Supplement for Post Construction Standard ASME Issues Welding Supplement for Post Construction StandardEarlier this month, ASME released a supplement which covers repair welding considerations for chrome moly (Cr-Mo) steel pressure vessels for its Post Construction Standard on Repair and Testing (PCC-2). The supplement provides a high-level overview of deterioration mechanisms and subsequent factors that need to be considered in developing a detailed repair, examination and testing plan for the successful repair of Cr-Mo pressure vessels.This Cr-Mo Welding Considerations supplement is applicable to pressure vessels for refinery, petrochemical, power generation, and other similar services. Cr-Mo steel pressure vessels have been in service, typically in reactor vessels and coke drums for refinery operations, since the 1940s. Usually, for coke drums as an example, these service condition s mean that the coke drums are subjected to extreme thermal cycling with internal temperatures reaching above 900 degrees F and then the drums are subjected to water quenching. This severe service results in several different types of damage such as shell bulging, skirt attachment weld cracking, weld seam cracking, and internal weld overlay cracking.One important feature of the supplement is its table on types of damage, operating conditions under which to expect damage, the specific degradation phenomena, and which materials are typically susceptible to the damage. It also includes typical considerations for weld repair of in-service degradation based on the type of damage and provides a detailed repair approach sequence, from the initial identification of flaws to the examination and pressure test.The ASME Post Construction Standards Committee opened a technical revision in 2010 to address repair welding considerations for Cr-Mo pressure vessels. Over a period of 4 years, the arti cle was refined by the ASME PCC Subcommittee on Repair and Testing and the ASME PCC Standards Committee through the ASME/ANSI consensus process.The supplement on Cr-Mo Repair Welding Considerations will be included in subsequent editions of the ASME PCC-2 Standard. Future editions of the supplement may be expanded to include considerations for repairs to vanadium modified Cr-Mo alloys commonly used today in hydrocracker and hydrotreater reactors. Other future considerations may include expounding on the relationship between post weld heat treatment, improvement in toughness, reduction of hardness, and the degradation of tensile and toughness properties of Cr-Mo steels through excessive post weld heat treatment.The driving force for the Cr-Mo Repair Welding Considerations supplement was Dr. Takayasu Tahara, PCC-2 Committee Contributing Member and Chair of the Japan Welding Engineering Societys Working Group on the English Version of Guidelines for Repair Welding of Pressure Equipment , JWES-CP-0902E. The vision was for PCC-2 to develop and include much-needed guidelines for carrying out successful welded repairs on Cr-Mo pressure vessels. Dr. Tahara developed the basic outline of the paper and provided a significant portion of its contents, figures and tables. The supplement was completed thanks to the combined efforts of the committee members, who fine-tuned the document through a balloting process.The ASME PCC-2 Repair of Pressure Equipment and Piping with Supplement is available in both print and digital versions on ASME.org, at www.asme.org/products/codes-standards/pcc2-2015-repair-pressure-equipment-piping-(2). - Leslie Antalffy, Fluor, Process Technology and Engineering- Richard Lucas, ASME Codes and Standards