Monotonic and Cyclic Slow Strain Rate Testing of Super 13% Chromium Steel Welds Under Cathodic Protection

Monotonic and cyclic slow strain rate tests have been conducted on a super 13% Cr steel welded with a super duplex stainless steel (SDSS) filler or with a matching 13% Cr filler. The tests were carried out under cathodic protection conditions with an applied potential of –1,100 mV vs saturated calomel electrode (SCE) and a test temperature of 23°C. Under monotonic straining at 10⁻⁶ s⁻¹, the resistance to cracking of the parent material and the matching weld was relatively high and significantly greater than for the SDSS filler. There was a modest effect of hydrogen precharging on strain to failure. Cyclic straining of the SDSS weld specimen at the same nominal strain rate between preset loading limits gave rise to such work hardening during the first cycle that subsequent cycles showed predominantly elastic deformation; no cracking was observed. For work-hardening corrosion-resistant alloys, there would seem to be little merit in the adoption of cyclic slow strain rate testing.