Alloy 36Mo is a new high strength super austenitic stainless steel for wirelines in sour service. Testing has shown tensiles around 300 ksi with good fatigue properties and excellent corrosion resistance.
Fatigue testing, simulating a wheel used for winding a wireline up and down a well, and corrosion testing, including pitting corrosion testing and sour service cracking testing using SSRT in high concentrated chloride solutions containing 350 psi (0,98 MPa) H2S, have been performed. The
metallurgy of Alloy 36Mo, 27Cr - 34Ni- 5.4Mo- 0.4N, gives an over all improvement of properties compared to the currently used materials UNS N08028 and UNS S08926. Alloy 36Mo shows a high PRE of 51 giving an improved pitting resistance and the high chromium and nickel contents increase the resistance to sour environment cracking.
Keywords: wirelines, sour service, austenitic stainless steels, hydrogen sulfide, SSC, pitting, fatigue