Sour Service Research Articles

SUMITOMO SM2535-110

Abstract Sumitomo SM2535 is a high strength austenitic stainless steel for use in oil country tubular goods as a material suitable for severe sour service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: SS-1256. Producer or source: Nippon Steel and Sumitomo Metal Corporation.

Effect of bainite in microstructure on hydrogen diffusion and trapping behavior of ferritic steel used for sour service application

Abstract

The Slow Strain Rate Stress Corrosion Cracking Test—A 50 Year Retrospective

The history of dynamic straining in stress corrosion cracking studies and the evolution of the slow strain rate test (SSRT) are reviewed. Smooth and notched specimens; the importance of strain rate, electrode potential, and other environmental factors; the evaluation of test results; and comparisons to other techniques are addressed. The SSRT’s application in research for oil and gas sour service, buried natural gas pipelines, ethanol transportation, nuclear power, low pressure turbines, and mechanism studies is summarized and its usage by material, industry, and geographic region quantified. Standard test procedures are compared and improvements suggested. The more recent use of cyclic loading is discussed and areas for future study proposed.

VALLOUREC VM 125 13Cr SS

Abstract Vallourec VM 125 13Cr SS is a 13Cr super martensitic steel for use in oil country tubular goods as a material suitable for sour service. The CY version offers corrosion and SCC resistance on a greater usage domain than API L80-13Cr in terms of temperature and chloride content. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: SS-1254. Producer or source: Vallourec USA Corporation.

VALLOUREC VM 110 13Cr SSCY

Abstract Vallourec VM 110 13Cr SSCY is a 13Cr super martensitic steel for use in oil country tubular goods as a material suitable for sour service. The CY version offers corrosion and SCC resistance on a greater usage domain than API L80-13Cr in terms of temperature, H2S, and chloride content. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: SS-1251. Producer or source: Vallourec USA Corporation.

VALLOUREC VM 110 13Cr SS

Abstract Vallourec VM 110 13Cr SS is a super martensitic steel for use in oil country tubular goods as a material suitable for sour service. It has a minimum yield strength of 758 MPa (110 ksi). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-201. Producer or source: Vallourec USA Corporation.

VALLOUREC VM 95 13Cr SS

Abstract Vallourec VM 95 13Cr SS (minimum yield strength 95 ksi, or 655 MPa) is a super martensitic steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-200. Producer or source: Vallourec USA Corporation.

VALLOUREC VM 95 13Cr

Abstract Vallourec VM 95 13Cr (minimum yield strength 95 ksi, or 655 MPa) is a low alloy carbon steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-199. Producer or source: Vallourec USA Corporation.

Corrosion Resistant Plates for Pipes Operated in Sour Environments

Based on physical metallurgy principles, specialists of Severstal and I. P. Bardin Institute developed chemical composition and manufacture technology for microalloyed steel plates for sour service line pipes with minimum guaranteed tensile strength 510 MPa, produced by TMCP (thermo-mechanical controlled process). The key elements of newly developed technology were: low-carbon, low-manganese chemical composition with balanced microalloying; production of clean steel in melting shop; microstructure control during all stages of manufacture process.

Effect of nitrogen in backing gas on duplex root weld properties of heavy-walled pipe

Duplex stainless steels are increasingly used for offshore subsea components as the technology allows for deeper recovery of oil and gas reserves. Alloy UNS S31803 (EN 1.4462/UNS S32205) combines high strength with good resistance to pitting and crevice corrosion. This grade is alloyed with nitrogen and has good weldability. For heavy-walled process piping intended for subsea sour service, the properties of the root pass are of high importance. For this reason, the effect of using nitrogen in the backing gas was investigated. Test pieces were manually welded with the gas tungsten arc welding (GTAW) process using an ER2209 filler wire. Tensile, bending and hardness testing was carried out and showed acceptable results across all specimens. Higher contents of nitrogen in the backing gas showed more austenite formation and a significant increase in pitting corrosion resistance when compared with pure argon. With Ar + 2 % N2, there was no pitting, but a small weight loss of 1.7 g/m2 was measured. 10 % N2 was required to pass both the corrosion tests ASTM G48 Method A (4 g/m2) and ASTM A923 (1 g/m2). The highest average impact toughness was achieved with pure nitrogen as the backing gas.

VALLOUREC VM 85 13Cr

Abstract Vallourec VM 85 13Cr (minimum yield strength 85 ksi, or 586 MPa) is a low alloy carbon steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-198. Producer or source: Vallourec USA Corporation.

Hydrogen-Induced Cracking Assessment in Pipeline Steels Through Permeation and Crystallographic Texture Measurements

Electrochemical hydrogen charging and permeation techniques were used to characterize hydrogen distribution, trapping, and diffusion in X60 and X60 sour service (X60SS) pipeline steels. The results obtained contribute to better understanding of hydrogen-induced cracking (HIC). SEM observations illustrated that all HIC cracks were formed at the center of cross section in the X60 steel after 3-h hydrogen charging and length of cracks increased with charging time. No HIC cracks were recorded at the cross section of X60SS steel after the same charging for different durations. Hydrogen permeation tests showed that the density of reversible hydrogen traps was lower at the center of cross section in the X60SS steel compared to the X60 one, and this is considered as one of the main reasons for high resistance of X60SS steel to HIC. EBSD orientation imaging results proved that the accumulation of ||ND-oriented grains at the center of the cross section in the X60SS steel was high. This is also considered as another reason for higher resistance of this steel to HIC. Finally, the center segregation zone with higher hardness value in the X60 steel was more pronounced than in the X60SS steel which made the X60 steel susceptible to HIC cracking.

VALLOUREC VM 90 13CR

Abstract Vallourec VM 90 13CR (minimum yield strength 90 ksi, or 620 MPa) is a low alloy carbon steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-197. Producer or source: Vallourec USA Corporation.

VALLOUREC VM 80 13CR

Abstract Vallourec VM 80 13CR (minimum yield strength 80 ksi, or 550 MPa) is a low alloy carbon steel for use in oil country tubular goods as a material suitable for sour service. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming. Filing Code: CS-195. Producer or source: Vallourec USA Corporation.

An extensive study of hydrogen-induced cracking susceptibility in an API X60 sour service pipeline steel

API X60 sour service (X60SS) pipeline steel was subjected to electrochemical hydrogen-charging for different durations in order to evaluate its hydrogen-induced cracking (HIC) susceptibility. SEM observations of the hydrogen-charged specimens documented that no HIC cracks appeared at the cross section of steel, which is strong evidence of a high resistance to HIC. However, hydrogen-discharging results show that a considerable amount of hydrogen can enter the X60SS steel through its hydrogen traps. Moreover, a hydrogen-permeation test proved that the trapping behavior was almost identical at the center and surface layers of the cross section in this steel. However, the density of hydrogen traps at the center of the cross section was slightly higher than at the surface. Tensile and fatigue experiments were carried out in the air and in a hydrogen-charging environment using a newly constructed experimental setup. Tensile results show that the ductility dropped by 83% in the hydrogen-charging environment. Electron backscatter diffraction (EBSD) technique was used to analyze the HIC cracks in the X60SS steel. HIC cracks appeared after charging under tensile/fatigue tests. Therefore, high HIC-resistant steel showed susceptibility to HIC when charging and tensile stresses were applied simultaneously. The effects of different factors on HIC crack propagation such as micro-texture, type of grain boundaries, Kernel Average Misorientation (KAM), special coincidence site lattice (CSL) boundaries and recrystallization fraction, were discussed.

Analysis of the various processes downstream cathodic hydrogen charging III: Mechanistic issues on charging, degassing and sulfide stress cracking

The elementary steps of hydrogen charging and degassing are identified from a combination between reaction orders and acoustic emission, and the higher degassing rate on the H 2 S side makes the natural permeation in the field still more different from its laboratory model. In sour service, airstream measurement devices are certainly able to measure a permeation flux, but the true difficulty is to subsequently derive reliable information on the actual level of hydrogen charging throughout the steel wall. Regarding sulfide stress cracking (SSC), all what is known since 70 years is both consistent and contradictory, i.e. with very deep trends, like the involvement of a surface directly exposed to cathodic charging, or the combination of shear strain, dislocation glide and hydrogen drag, but also approximate, oversimplified or obsolete assumptions. Hence, the systematic failure of standard mechanics to explain all aspects of SSC. Similarly in metallurgy, a mere steric effect associated with the outdated atomic hydrogen cannot be at the same time sufficiently large or small for simultaneously explaining Cottrell clouds and dislocation drag. Nevertheless, the reality of the SSC mechanism should not be basically different from the previous thoughts, but substantially more complicated, and this will be addressed in Part IV.

Detection, characterization and sizing of hydrogen induced cracking in pressure vessels using phased array ultrasonic data processing

Pressure vessels operating in sour service conditions in refinery environments can be subject to the risk of H₂S cracking resulting from the hydrogen entering into the material. This risk, which is related to the specific working conditions and to the quality of the steel used, shall be properly managed in order to maintain the highest safety at a cost-effective level.Nowadays the typical management strategy is based on a risk based inspection (RBI) evaluation to define the inspection plan used in conjunction with a fitness for service (FFS) approach in defining if the vessel, although presenting dangerous defects such as cracks, can still be considered “fit for purpose” for a given time window based on specific fracture mechanics analysis.These vessels are periodically subject to non-destructive evaluation, typically ultrasonic testing. Phased Array (PA) ultrasonic is the latest technology more and more used for this type of application.This paper presents the design and development of an optimized Phased Array ultrasonic inspection technique for the detection and sizing of hydrogen induced cracking (HIC) type flaws used as reference for comparison. Materials used, containing natural operational defects, were inspected in “as-service” conditions.Samples have then been inspected by means of a “full matrix capture” (FMC) acquisition process followed by “total focusing method” (TFM) data post processing. FCM-TFM data have been further post-processed and then used to create a 3D geometrical reconstruction of the volume inspected. Results obtained show the significant improvement that FMC/TFM has over traditional PA inspection techniques both in terms of sensitivity and resolution for this specific type of defect. Moreover, since the FMC allows for the complete time domain signal to be captured from every element of a linear array probe, the full set of data is available for post-processing.Finally, the possibility to reconstruct the geometry of the component from the scans, including the defects present in its volume, represents the ideal solution for a reliable data transferring process to the engineering function for the subsequent FFS analysis.

Effect of Reeling on Sour Service Fatigue Crack Growth Behavior of Welded API5LX65 Line Pipe

The effect of reeling on the fatigue crack growth rate (FCGR) behavior of welded pipe was investigated both in-air as well as in sour environment. The FCGR behavior of the reeled pipe in various notch locations, such as parent pipe (PP), weld center line (WCL), and heat affected zone (HAZ), did not exhibit any effect of reeling (i.e., the properties in the strained and aged conditions were similar to the as-fabricated welds). Frequency scan FCGR tests in sour environment (pH = 5/0.0031 MPa H2S) exhibited maximum FCGR in the range of 10× to 35× higher than the in-air values at frequencies in the range of 3–1 mHz and 3× to 5× at frequencies in the range of 0.3 Hz (risers). In sour service, WCL exhibited better fatigue performance than the PP and HAZ in all conditions. Fatigue performance of PP and WCL was independent of reeling. The poorest fatigue performance was observed in unstrained HAZ. Fatigue performance of HAZ extrados (side last strained in compression) and intrados (side last strained in tension) was similar and better than unstrained HAZ. It was also found that the FCGR in sour environments was controlled by the internal hydrogen due to bulk charging from the sour environment. The overall conclusion is that reeling has no detrimental effect on sour service fatigue crack growth behavior, i.e., sour service fatigue performance of reeled pipe is the same as unreeled pipe.

SUMITOMO SM125S

Abstract Sumitomo SM125S is a low alloy high strength carbon steel for use in oil country tubular goods as a material suitable for medium severity sour service. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: CS-191. Producer or source: Nippon Steel and Sumitomo Metal Corporation.

SUMITOMO SM125ES

Abstract Sumitomo SM125ES is a low alloy, high strength carbon steel for use in oil country tubular goods as a material suitable for high severity sour service. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: CS-190. Producer or source: Nippon Steel and Sumitomo Metal Corporation.