Mechanical Properties and Hydrogen-Induced Stress Corrosion Cracking of Super 13Cr Steel Welded Joints

摘要

Significant interest exists in the use of supermartensitic materials for oilfield applications. However, reliable attainment of NACE MR0175 limits (23 HRC) can be extremely difficult, particularly in welded joints. Therefore, further studies to quantify the mechanical properties of welded joints and variables controlling the SSC resistance in the as-welded condition remain necessary both for economical fabrication and to ensure reliable service operation. In this program, the as-welded mechanical properties of three different supermartensitic pipe steels were compared using different welding consumables and welding procedures. The susceptibility to hydrogen-induced stress corrosion cracking of selected weldments under slightly sour conditions and under cathodic protection was evaluated. The results show that the filler metal and welding procedure combination affect the matching characteristics of the welded joint and their toughness and ductility properties. Additionally, supermartensitic steel welded joints with a maximum hardness ranging from 282 to 313 HV1 and under an applied stress level equal to the measured yield strength of the base material did not crack under slightly sour conditions. Supermartensitic steel welded joints with a maximum hardness ranging from 301 to 378 HV1 and under an applied stress level equal to the measured yield strength of the base material did not crack under cathodic protection (-800mV SCE).