CREEP LIFE EVALUATING METHOD FOR HEAT RESISTANT MATERIAL WELDED PART

• Main Author: KOYAMA TERUO
• Format: Patent
• Language: English
• Published: 18.03.1997
• Edition: 6
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To enhance the accuracy of evaluating the duration of the creep life by plotting the relation of a distance from the boundary (bond) between the quantitative value of cavities and welding metal, drawing a regression line, obtaining the maximum value of the quantitative value in a welded head affected part, and estimating the damage ratio from the relationship between the previously obtained quantitative value and the creep damage ratio. SOLUTION: The distance from a bond and a cavity area ratio are plotted to obtain a regression curve, and the maximum value in a welded heat affected part is estimated. A testpiece that the affected part is previously reproduced is formed, a creep test is conducted, the relationship between the cavity area ratio and the creep damage ratio is obtained, the maximum value of the cavity area ratio is applied, and the creep damage ratio of a welding joint is estimated. When the damage ratio is a specific value or less, the area ratio is 0%. In this case, this is caused by the setting of the damage ratio as the value of the safety side. Thus, the welding joint life for string the most creep damage can be accurately estimated by the cavity, and hence the damage can be prevented.