| New martensitic stainless steel pipes (HP13Cr,
UHP15Cr) which improve the CO2 corrosion resistance and sulfide stress
corrosion (SSC) resistance of API-13Cr were developed and their application limits
were clarified. The composition of the products features low C and addition of
Ni and Mo. CO2 corrosion resistance was greatly improved by adopting
a high Cr, low C composition
design, while SSC resistance was substantially improved by Mo addition. The critical
temperature for HP13Cr in high CO2 environments is 160°C. UHP15Cr
has high strength, with Yield strength (YS) exceeding 861 MPa, and can be used
in high CO2 environments at temperatures up to 200°C. These new
martensitic steel pipes show excellent properties in sweet, high temperature,
high CO2 environments and slightly sour environments
containing small amounts of H2S where conventional
13Cr pipes could not be used. |
