API TR 942-B

Abstract

Technical Approach/Report Organization and Scope As a basis of this report, technical literature, industry experience, and published case studies were reviewed. The review included materials of construction, damage mechanisms, and component-specific fabrication and repair issues. The scope of this report includes the following wrought austenitic alloys: Alloys 800, 800H, 800HT®, and 300 series austenitic stainless steels, and corresponding welding consumables. Limits in chemical composition, microstructural requirements, and heat treating practices that mitigate susceptibility to embrittlement and cracking are identified. Potentially viable upgrades to commonly used alloys are identified where applicable. The remainder of this report is organized as follows. Section 3, Process Units, gives a brief process overview followed by an explanation of the various damage mechanisms found in that unit. Component specific considerations and examples of in-service damage are also included. Inspection recommendations and general repair method considerations are also included. Section 4, Damage Mechanisms, contains detailed discussions of high-temperature damage mechanisms; including fundamental details of the solid state reactions, their rate of reaction, and recommended mitigation measures. Section 4 also incorporates fabrication and repair practices that can be used for cracked or embrittled equipment. NOTE Excluded from the scope of this document are Hydrogen Reformer catalyst tubes, outlet pigtails and outlet headers. With the exception of catalyst tubes, these are covered in TR 942-A, Materials, Fabrication, and Repair Considerations for Hydrogen Reformer Furnace Outlet Pigtails and Manifolds. Also excluded are expansion bellows in elevated temperature service.