Hydrogen Induced Damage in Heavily Cold-Drawn Wires of Lean Duplex Stainless Steel

The paper addresses the sensitivity to hydrogen embrittlement of heavily cold-drawn wires made of the new generation of lower alloyed duplex stainless steels, often referred to as lean duplex grades. It includes comparisons with similar data corresponding to cold-drawn eutectoid and duplex stainless steels. For this purpose, fracture tests under constant load were carried out with wires in the as-received condition and fatigue-precracked, in air and exposed to ammonium thiocyanate solution. Microstructure and fractographic observations were essential means for the cracking analysis. The effect of hydrogen-assisted embrittlement on the damage tolerance of lean duplex steels was assessed regarding two macro-mechanical damage models that provide the upper bounds of damage tolerance and accurately approximate the failure behavior of the eutectoid and duplex stainless steels wires.