Life Prediction of IN738LC Considering Creep Damage under Low Cycle Fatigue

• Published in: International Journal of Precision Engineering and Manufacturing-Green Technology, 5(2) Vol. 5; no. 2; pp. 311 - 316
• Main Authors: Lee, Jeong-Min, Wee, Sunguk, Yun, Junghan, Song, Hyunwoo, Kim, Yongseok, Koo, Jae-Mean, Seok, Chang-Sung
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society for Precision Engineering 01.04.2018; Springer Nature B.V; 한국정밀공학회
• Subjects: Centrifugal force; Creep (materials); Damage; Electric power generation; Energy Efficiency; Engineering; Fatigue failure; Fatigue life; Fatigue tests; Greenhouse gases; High temperature; Industrial and Production Engineering; Life prediction; Low cycle fatigue; Materials fatigue; Nickel base alloys; Operating temperature; Power plants; Predictions; Regular Paper; Superalloys; Sustainable Development; Turbine blades; Turbines; 기계공학; Life prediction; Gas turbine blade; Inconel 738LC; Creep; Low cycle fatigue
• ISSN: 2288-6206; 2198-0810
• DOI: 10.1007/s40684-018-0033-6

As growing attention on greenhouse gas reduction, developing an eco-friendly power generation system of power plants and enhancing its efficiency has been actively researched. In order to increase the efficiency, the operating temperature has been raised, and hence the application of Ni-base super-alloy has increased to a core component of the power generation system like a turbine blade, a rotor and a boiler. Especially, turbine blades are exposed to high-temperature and high-pressure, and they bear mechanical loads due to the centrifugal force of the high-speed rotation. Thus, the durability of the blade material should be tested under high temperature conditions. In high temperature LCF tests, damage occurs in specimens because of creep. Hence, the aim of this study is to estimate the life of LCF precisely by considering the creep damage in specimens generated during the LCF test. We conducted the LCF tests to propose a new life prediction method considering the fatigue and creep damage. Finally, this study demonstrates the reliability of the prediction method by comparing the predicted life with the actual fatigue life. Through this, we expect to predict the fatigue life more accurately by predicting the fatigue life under different fatigue strain frequencies considering the creep damage.