|Spoluautoři SIEFERT John|
Creep strength enhanced ferritic steels such as Grade 91 are the preferred material for much of the high temperature boiler tubing and piping components used in modern power generating plants. Validation of temperbead welding techniques is particularly important for Grade 91 steel as accurate post weld heat treatment (PWHT) has proven to be difficult in field applications. Even a well controlled PWHT can degrade the base material strength and poorly performed heat treatment can lead to subsequent creep properties being below the minimum expected by codes. Successful demonstration of temperbead techniques for Grade 91 steel would alleviate these concerns and create options for a ‘well-engineered’ repair. The present paper outlines a major project which will establish information critical to repair of Grade 91 components, and describes details of metallographic characterization of the welds produced.