An investigation was carried out to examine the influence of temperature and overload plastic zone size on stress corrosion crack (SCC) growth behavior in a low-alloy steel. Compact tension specimens with TL orientation prepared from SAE 4140 steel in hardened and tempered condition were used. Two pertinent variable conditions were chosen: (1) cold deionized water at 23°C and (2) hot deionized water at 80°C. The specimens were precracked in fatigue and then overloaded to various extent (5, 10, 25, and 50%). The SCC behavior of these specimens was studied, keeping them submerged in hot and cold deionized water.
The results of the present investigation demonstrate that the incubation period for crack growth decreases with increasing initial stress intensity factor and increasing temperature. The incubation period for crack growth was found to increase as an exponential function of the overload plastic zone size. In overloaded specimens, once the crack growth initiated, the crack growth rate was observed to be much higher than in the non-overloaded specimens. The crack growth rate in Region I was found to increase with increasing initial stress intensity factor andtemperature. The crack growth rate in Region II was also found to increase with temperature, but was independent of the stress intensity factor.