RESTRAINT CRACKING TECHNIQUE FOR USE IN SIMULATED WELD THERMAL CYCLING STUDIES.
Research and development rept.,
NAVY MARINE ENGINEERING LAB ANNAPOLIS MD
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Weld hot-cracking tendencies of five experimental HY-80 steels were studied with the time-temperature cycling apparatus developed at Rensselaer Polytechnic Institute. Restraint was introduced by restricting the longitudinal expansion and contraction of 0.25-in. diameter test specimens sub jected to thermal cycles corresponding to various welding conditions. The restrained specimens were monitored during cycling by an ultrasonic flaw detector to record the temperature of crack initiation. Cracking was detected during only the cooling portion of the thermal cycles and generally within the temperature range of 2400 to 2000F. Crack initiation appeared to be controlled by both the degree of restraint and the peak temperature. Cracking tendencies of the steels were related to sulphur content by this technique.