In the past few years the development of supermartensitic stainless steels for flow-line materials has been fast. Recently the demand for weldable 13%Cr with larger outside diameter such as 18", 20" and
24" has increased greatly. Considering such a requirement, a new production route for big size pipes with OD over 16" was developed.
A girth weld on 20" pipe was produced with GTAW procedure utilizing duplex and superduplex filler wire. No post welding heat treatment was applied. The mechanical properties of both the base material and welded joints met the target requirements. Corrosion qualification was aimed to determine the Sulfide Stress Cracking (SSC) resistance of weldable supermartensitic steel to be used as flow-line in slightly sour oil and gas wells. SSC resistance of the welded joints was excellent in 5% NaCl solution with 0.004 MPa of H2S partial pressure at pH 4.5. The influence of chloride concentration ...
Keywords: Supermartensitic steels, flow-line, slightly sour, Gas Tungsten Arc Welding (GTAW), toughness, Sulfide Stress Corrosion (SSC), Uniform corrosion.