It is very important to evaluate fatigue crack growth in welded joints where the unwelded part can be regarded as a crack-like defect.
Fatigue crack growth tests were performed for transverse welding bead of arc welded SA516-70 steel plates and also for unwelded base metal. Through the tests, fatigue crack closure behavior was monitored by the unloading elastic compliance technique using a personal computer system. Fatigue crack growth rates were well expressed by the effective stress intensity factor range based on crack closure measurements.
From the experiment's results, fatigue crack growth rates as a function of the effective stress intensity factor range $\Delta K_{eff}$ are nearly identical or slightly lower in transverse weld metal than in unwelded base metal.
