Abstract: Aiming at the strength of stress corrosion cracking on the inner wall of heat exchange tube, the KI model for stress intensity factor of inner surface meridian plane containing semielliptical crack was studied. The crack model was prepared by mechanical process which got the KI determined by photo elastic method. The reliability verification of the numerical solution model was carried out. Additionally, the law of distribution and expansion of KI values was summarized under complex loads, different crack depths, a, (i.e. 1 mm, 1.25 mm, 1.5 mm and 1.75 mm) and different crack shape ratios, a/b, (i.e. 0.1, 0.2, 0.3 ... 0.8 and 0.9). Some suggestions on reliability analysis of fatigue life design, working condition monitoring of heat exchange tube were put forward. The results indicate that the pressure, Pi, on the inner wall determines the KI distribution, in addition, the temperature difference between inner wall and outer wall, ΔT, is also relatively large influence on the KI distribution. Meanwhile, some numerical calculation values are compared with the experimental values and manual calculation values which shows that the values fit preferably.
Key words: stress intensity factor; inner surface meridian plane semi-elliptical crack; stress corrosion crack（SCC）; heat exchange tube; numerical calculation