ABSTRACT

The Rising Step Load (RSL) method allows us to precisely measure the threshold stress for the onset of hydrogen stress cracking in a real-time, cost-effective manner. It combines the best of a slow strain rate test and a sustained load cantilever bend test to permit measurement of the threshold. The loads are applied at a modified slow displacement rate but in incrementally increasing steps in accordance with ASTM F1624. As shown in Figure 7, the threshold is compared to the fracture strength measured at ASTM E8 loading rates, to quantify the degradation of the part due to hydrogen embrittlement from processing or environmental exposure.