Effect of Environmental Factors on Corrosion Fatigue Performance of Duplex 2507

2012 ◽  
Author(s):  
Ramgopal Thodla ◽  
Carlos Joia ◽  
Palmieri Baptista
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulfide ◽  
Corrosion Fatigue ◽  
Environmental Effect ◽  
Fatigue Performance ◽  
Duplex Microstructure ◽  
Partial Pressures ◽  
Frequency Scan ◽  
Austenite Grains ◽  
Weakly Dependent

Corrosion fatigue performance of welded duplex 2507 riser material environments containing high partial pressures of carbon dioxide (100–200 bar) and limited quantity of hydrogen sulfide (0–0.12 bar) is presented in this paper. da/dN vs ΔK at different frequencies as a function of various environmental were studied. In the range of environments studies there was no significant environmental effect on the FCGR. da/dN measurements were performed starting at an initial ΔK of 150Nmm-3/2 and crack growth was readily established suggesting that ΔKth were lower than this value. Frequency scan tests were performed in various environments and the FCGR was found to be weakly dependent on frequency. The highest increase in FCGR was about 3–4x over the air values. The effect of duplex microstructure will also be discussed by comparing results from plate samples of 2507 with differing microstructure. The FCGR was higher with the plate samples which had precipitation of ferrite within the austenite grains which may have led to the higher FCGR. Frequency scan results for the plate samples will be compared with the results from the riser material.

Corrosion Fatigue Performance of Duplex 2507 for Riser Applications

2010 ◽  
Author(s):  
Feng Gui ◽  
Ramgopal Thodla ◽  
Ken Evans ◽  
Carlos Joia ◽  
Ilson Palmieri Baptista
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Growth Rates ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Performance ◽  
Partial Pressures ◽  
Crack Growth Rates

Corrosion fatigue performance is of interest for high strength steels in riser applications. This work investigated the corrosion fatigue performance of 2507 duplex stainless steel for use as riser materials in environments containing high partial pressures of carbon dioxide (50–100 bar) and limited quantity of hydrogen sulfide (0–0.12 bar). The procedures developed for controlling oxygen and Fe2+ contamination as well as methods to evaluate the concentration of H2S in the autoclave are presented. The crack growth rates and ΔKth for these materials in the pressure environments were discussed along with procedures to obtain ΔKth, when they were below 5ksi√in. Low crack growth rates in the range of 1×10−8 in/cycle were measured and the effect of sour environments was quantified. The fatigue crack growth rate in sour environments on 2507 duplex stainless steel is a 10x higher than in air.

Corrosion Fatigue of Steel Armours in Flexible Risers

2002 ◽  
Author(s):  
Tore Roberg Andersen
Keyword(s):  
Carbon Dioxide ◽  
Fatigue Life ◽  
Corrosion Fatigue ◽  
Hydrogen Sulphide ◽  
Fatigue Performance ◽  
Corrosive Environment ◽  
Test Program ◽  
Flexible Risers

Fatigue life calculation of flexible risers is normally based on the assumption that the annulus is dry. Experience has, however, shown that the annulus may become water flooded. Carbon dioxide and hydrogen sulphide permeate from the bore and into the annulus, making the annulus environment corrosive. In such conditions the influence of corrosion fatigue on fatigue life has to be taken into account. A test program was performed to investigate the corrosion fatigue performance of steel armour in water containing carbon dioxide. The results showed that the corrosive environment reduced the fatigue life to about 1/10 to 1/50 of that derived in air. The lifetime was significantly shorter in the environment with 0.1 bar compared to 0.01 bar, indicating that corrosion fatigue becomes more pronounced as the corrosivity increases. The work shown that corrosion fatigue has to be considered for flexible risers with annulus that is or may be water flooded.

Corrosion Fatigue Performance of a Carbon Steel in Brine Containing Air, H2S and CO2

CORROSION ◽  
1966 ◽  
Vol 22 (12) ◽  
pp. 325-335 ◽  
Author(s):  
PARVIS MEHDIZADEH ◽  
R.L. McGLASSON ◽  
J. E.LANDERS
Keyword(s):  
Carbon Steel ◽  
Corrosion Fatigue ◽  
Fatigue Performance
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