Remaining life estimation method for estimating remaining life of high-chromium steel pipe

A remaining life estimation method for estimating remaining life of high-chromium steel pipe through which high-temperature and high-pressure fluid is allowed to flow, the high-chromium steel pipe formed by integrating base members made of high-chromium steel by welding, the method comprising:

• obtaining a constant indicating a product of a strain rate and a rapture time in Monkman-Grant analysis by multiplying
• a first coefficient to transform uniaxial rupture ductility into multiaxial rupture ductility, the uniaxial rupture ductility being obtained from a specimen of the high-chromium steel pipe,
• a second coefficient to amend consumed life of the specimen, and
• a third coefficient to amend a measurement pressure into an assessment pressure;
• measuring a strain of an outer surface of the high-chromium steel pipe by measuring a distance between two points on the outer surface of the high-chromium steel pipe, using a sensor mounted to the outer surface of the high-chromium steel pipe on both sides of a welding material sandwiched therebetween;
• recording strain information by recording, at a plurality of times, the strain information indicating the strain of the outer surface of the high-chromium steel pipe, in association with time information indicating a measurement time;
• and
• estimating remaining life of the high-chromium steel pipe, from the constant and a plurality of sets of the strain information and the time information.