91钢与奥氏体钢焊接指南-EPRI
PRIMARY AUDIENCE: Research engineersSECONDARY AUDIENCE: Plant, corporate, and design engineersKEY RESEARCH QUESTIONThere is limited information in the open literature regarding the fabrication and performance of dissimilar metalwelds (DMWs) between 9%Cr creep-strength-enhanced ferritic (CSEF) steel and austenitic stainless steelcomponents. Furthermore, the results from the available studies have not established the factors thatcontribute to the fusion line cracking reported for some in-service failures. This report provides examples ofindustry failures in several end-use components and links them to the key contributions from design,operation, fabrication, and metallurgy of DMWs.RESEARCH OVERVIEWThis report provides important guidelines regarding the design, fabrication, and construction of DMWsbetween 9%Cr CSEF steel and austenitic stainless steel components that are designed to transport or collectsteam. This report does not address details specific to the following: overlay welding, such as for corrosionresistance; repair welding, such as might be addressed by the American Society of Mechanical Engineers(ASME) Post Construction Code or the National Board Inspection Code; prescriptive guidance, including howto use particular welding processes; or qualification guidelines addressed by the ASME Boiler and PressureVessel Code, Section IX. Numerous practical considerations exist regarding the specification and fabricationof DMWs, and it is not possible to address all potential concerns regarding this type of connection in thisreport. Instead, this report provides basic guidelines that are important to the goal of promoting “better”practice and providing equipment owners and operators with information to consider regarding additionalrequirements that are relevant to purchasing specifications. Specific factors that affect performance in thecontext of design, fabrication, operation, and metallurgical risk are addressed.KEY FINDINGSThe summary of recommendations in this report provides a concise set of guidelines regarding key aspectsof DMW construction, including restrictions on the end-use application, weld joint geometry, welding process,post-weld heat treatment, transition pieces, operation, and special considerations.WHY THIS MATTERSEvery steam-raising power boiler in a power generating plant is made with a range of different steels. Thepressure boundary joints necessitate welding of the steels. Despite the number of joints that exist, there hasnot been an extensive evaluation of fabrication factors that affect performance in cross-weld creep for DMWsconstructed between 9%Cr CSEF steel and austenitic stainless steel components. This report provides insightinto the factors that contribute to performance with respect to when a weldment fails and how it fails (that is,damage tolerance).9842144EX