Study on LCF Lifetime Prediction of Thermal Shock

Gray cast iron specimen was heated to a fixed temperature with high frequency induction heating equipment, then was cooled to room temperature by spraying water to the heated surface. This process was repeated until a crack whose length exceeds 3mm appeared. Transient cyclic heat transfer and stress-strain FEA analysis was conducted to obtain specimen's stress-strain state, then different LCF life prediction methods based on strain and energy were presented and contrasted, and results showed modified dissipated energy method with maximal hydrostatic pressure was more accurate than other methods. With the help of modified dissipated energy method, the relationship between thermal shock life, highest cooling temperature and cooling speed was studied, and the effect law of highest cooling temperature and cooling heat transfer coefficient on life was obtained.