Review of the Effect of Hydrogen Gas on Fatigue Performance of Steels

Author(s):  
Yan Hui Zhang

To develop hydrogen energy, it is important to understand the effects of hydrogen on mechanical properties in all applications — production, transportation, storage and fuel cells. Although a considerable amount of work has been carried out on hydrogen related embrittlement, there is comparatively less work on the effect of a hydrogen environment on fatigue performance of steels. It is essential to carry out comprehensive and coordinated research to understand how a component is affected when exposed to a hydrogen environment, how to prevent or minimise the failure probability, and finally to gather critical data to develop design guidance and government regulations to ensure safe operation of infrastructures involving hydrogen environment. The paper reviews the effect of a gaseous hydrogen environment on fatigue endurances and fatigue crack growth rates of steels, identifies the major factors promoting hydrogen effects and reviews the requirements for carrying out fatigue tests in hydrogen environment. The review covers degradation on fatigue performance of many variables including steel grades, ΔK magnitude, hydrogen partial pressure, loading frequency, gas composition, stress ratio, microstructures, base and weld metals and temperature. The mechanisms responsible for the accelerated crack growth rates in hydrogen environment and the implication of the degradation on fatigue design are also discussed. It was found that, unlike hydrogen embrittlement, fatigue performance of steels in hydrogen is degraded in both ferritic and austenitic steels, and in both low and high strength steels. The degradation by hydrogen gas is more pronounced with respect to fatigue crack growth rate than fatigue endurance of steels. Based on the results of the review, recommendations are made with respect to further research work required.

Author(s):  
Joe A. Ronevich ◽  
Brian P. Somerday

Fatigue crack growth rate (da/dN) versus stress intensity factor range (ΔK) relationships were measured for various grades of pipeline steel along with their respective welds in high pressure hydrogen. Tests were conducted in both 21 MPa hydrogen gas and a reference environment (e.g. air) at room temperature. Girth welds fabricated by arc welding and friction stir welding processes were examined in X65 and X52 pipeline grades, respectively. Results showed accelerated fatigue crack growth rates for all tests in hydrogen as compared to tests in air. Modestly higher hydrogen-assisted crack growth rates were observed in the welds as compared to their respective base metals. The arc weld and friction stir weld exhibited similar fatigue crack growth behavior suggesting similar sensitivity to hydrogen. A detailed study of microstructure and fractography was performed to identify relationships between microstructure constituents and hydrogen accelerated fatigue crack growth.


Author(s):  
Kevin A. Nibur ◽  
Chris San Marchi ◽  
Brian P. Somerday

Fatigue crack growth rates and rising displacement fracture thresholds have been measured for a 4130X steel in 45 MPa hydrogen gas. The ratio of minimum to maximum load (R-ratio) and cyclic frequency was varied to assess the effects of these variables on fatigue crack growth rates. Decreasing frequency and increasing R were both found to increase crack growth rate, however, these variables are not independent of each other. Changing frequency from 0.1 Hz to 1 Hz reduced crack growth rates at R = 0.5, but had no effect at R = 0.1. When applied to a design life calculation for a steel pressure vessel consistent with a typical hydrogen trailer tube, the measured fatigue and fracture data predicted a re-inspection interval of nearly 29 years, consistent with the excellent service history of such vessels which have been in use for many years.


Author(s):  
Takeshi Ogawa ◽  
Yuki Sugiyama ◽  
Toshihiko Kanezaki ◽  
Noboru Hayashi

A hydrogen gas container is one of the critical components for fuel cell vehicles (FCV), which is expected for CO2-free personal transportation. In the early stage of commercial FCV, the major container structure will be a compressed hydrogen gas cylinder, which consists of metal or plastic linear with metal boss and carbon fiber reinforced plastics (CFRP). In order to choose an appropriate material for the metal boss and metal liner, corrosion resistance should be evaluated for various aspects such as corrosion fatigue crack growth (CFCG) and stress corrosion cracking (SCC) in the high pressure hydrogen as well as in salt water environment for the purpose of vehicle use. In the present study, CFCG characteristics were evaluated for several aluminum alloys in air and in salt waters with various concentrations. The results showed that the crack growth rates were accelerated in salt water for all the materials and their environmental sensitivities were compared. The concentrations of the salt water exhibited minor effect on the fatigue crack growth rates. These CFCG characteristics were compared with the corrosion test results based on the ISO 7866 Annex A [1]. A basic idea was proposed for the evaluation of compressed hydrogen gas containers and the important material properties were suggested.


2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Brian P. Somerday ◽  
Monica Barney

Hydrogen-assisted fatigue crack growth rates (da/dN) were measured for SA516 Grade 70 steel as a function of stress-intensity factor range (ΔK) and load-cycle frequency to provide life-prediction data relevant to pressure swing adsorber (PSA) vessels. For ΔK values up to 18.5 MPa m1/2, the baseline da/dN versus ΔK relationship measured at 1 Hz in 2.8 MPa hydrogen gas represents an upper bound with respect to crack growth rates measured at lower frequency. However, at higher ΔK values, baseline da/dN data must be corrected to account for modestly higher crack growth rates at the lower frequencies relevant to PSA vessel operation.


Author(s):  
Brian Somerday ◽  
Paolo Bortot ◽  
John Felbaum

The objective of this study was to explore an approach for measuring fatigue crack growth rates (da/dN) for Cr-Mo pressure vessel steels in high-pressure hydrogen gas over a broad cyclic stress intensity factor (ΔK) range while limiting test duration, which could serve as an alternative to the method prescribed in ASME BPVC VIII-3, Article KD-10. Fatigue crack growth rates were measured for SA-372 Grade J and 34CrMo4 steels in hydrogen gas as a function of ΔK, load-cycle frequency (f), and gas pressure. The da/dN vs. ΔK relationships measured for the Cr-Mo steels in hydrogen gas at 10 Hz indicate that capturing data at lower ΔK is valuable when these relationships serve as inputs into design-life analyses of hydrogen pressure vessels, since in this ΔK range crack growth rates in hydrogen gas approach rates in air. The da/dN vs. f data measured for the Cr-Mo steels in hydrogen gas at selected constant-ΔK levels demonstrate that crack growth rates at 10 Hz do not represent upper-bound behavior, since da/dN generally increases as f decreases. Consequently, although fatigue crack growth testing at 10 Hz can efficiently measure da/dN over a wide ΔK range, these da/dN vs. ΔK relationships at 10 Hz cannot be considered reliable inputs into design-life analyses. A possible hybrid approach to efficiently establishing the fatigue crack growth rate relationship in hydrogen gas without compromising data quality is to measure the da/dN vs. ΔK relationship at 10 Hz and then apply a correction based on the da/dN vs. f data. The reliability of such a hybrid approach depends on adequacy of the da/dN vs. f data, i.e., the data are measured at appropriate constant-ΔK levels and the data include upper-bound crack growth rates.


Author(s):  
Andrew J. Slifka ◽  
Elizabeth S. Drexler ◽  
Robert L. Amaro ◽  
Damian S. Lauria ◽  
Louis E. Hayden ◽  
...  

Pipelines are widely accepted to be the most economical method for transporting large volumes of hydrogen, needed to fuel hydrogen-powered vehicles. Some work has been previously conducted on the fatigue crack growth rates of base metals of pipeline materials currently in use for hydrogen transport and on pipeline materials that may be used in the future. However, welds and their heat-affected zones are oftentimes the source and pathway for crack initiation and growth. The heat-affected zones of welds can exhibit low resistance to crack propagation relative to the base metal or the weld itself. Microstructural irregularities such as chemical segregation or grain-size coarsening can lead to this low resistance. Therefore, in order to have adequate information for pipeline design, the microstructures of the heat-affected zones must be characterized, and their mechanical properties must be measured in a hydrogen environment. With that in mind, data on the fatigue crack growth rate is a critical need. We present data on the fatigue crack growth rate of the heat-affected zones for two girth welds and one seam weld from two API 5L X52 pipes. The materials were tested in hydrogen gas pressurized to 5.5 MPa and 34 MPa at a cyclic loading rate of 1 Hz, and an R ratio of 0.5.


Author(s):  
Stephen J. Hudak ◽  
James H. Feiger ◽  
Jason A. Patton

Corrosion-fatigue is a significant design consideration in deepwater floating production systems. Mechanical loading is accentuated due to the compliant nature of these structures, and sour service conditions can also occur either due to the nature of the crude production or due to seawater flooding of the reservoir to enhance production yield. New high-strength riser steels have recently been developed to meet the demands of deepwater development. The objective of this study was to characterize the corrosion-fatigue resistance of these materials in terms of crack growth rates as a function of applied stress intensity factor range (ΔK), as well as cyclic loading frequency. Experiments were performed on five different steels with yield strengths ranging from 848 to 1080 MPa. Two environments were considered: seawater with cathodic protection to simulate the environment outside of the riser, and a sour brine environment with low oxygen (< 10 ppb) to simulate the environment inside the riser. Not all steels were tested in the sour brine environment since not all were designed to operate in sour service. For both environments, higher strength steels were found to exhibit higher growth rates and lower saturation frequencies. Fatigue crack growth rates as a function of ΔK were also measured, and exhibited two different frequency responses. At high ΔK, the classical frequency response occurred: decreased frequency gave increased crack growth rates. At low ΔK, an inverse frequency effect was observed: deceased frequency gave decreased crack growth rates, as well as increased corrosion-fatigue crack growth thresholds. These differences are believed to be caused by different underlying processes controlling crack growth — specifically, material-environment reaction kinetics at high ΔK, and crack closure due to corrosion-product wedging at low ΔK. The practical significance of these results is discussed, including selection of frequencies for corrosion-fatigue crack growth testing, and applicability of results to structural integrity assessments.


Author(s):  
Joseph Ronevich ◽  
Chris San Marchi ◽  
Kevin A. Nibur ◽  
Paolo Bortot ◽  
Gianluca Bassanini ◽  
...  

Abstract Following the ASME codes, the design of pipelines and pressure vessels for transportation or storage of high-pressure hydrogen gas requires measurements of fatigue crack growth rates at design pressure. However, performing tests in high pressure hydrogen gas can be very costly as only a few laboratories have the unique capabilities. Recently, Code Case 2938 was accepted in ASME Boiler and Pressure Vessel Code (BPVC) VIII-3 allowing for design curves to be used in lieu of performing fatigue crack growth rate (da/dN vs. ΔK) and fracture threshold (KIH) testing in hydrogen gas. The design curves were based on data generated at 100 MPa H2 on SA-372 and SA-723 grade steels; however, the data used to generate the design curves are limited to measurements of ΔK values greater than 6 MPa m1/2. The design curves can be extrapolated to lower ΔK (< 6 MPa m1/2), but the threshold stress intensity factor (ΔKth) has not been measured in hydrogen gas. In this work, decreasing ΔK tests were performed at select hydrogen pressures to explore threshold (ΔKth) for ferritic-based structural steels (e.g. pipelines and pressure vessels). The results were compared to decreasing ΔK tests in air, showing that the fatigue crack growth rates in hydrogen gas appear to yield similar or even slightly lower da/dN values compared to the curves in air at low ΔK values when tests were performed at stress ratios of 0.5 and 0.7. Correction for crack closure was implemented, which resulted in better agreement with the design curves and provide an upper bound throughout the entire ΔK range, even as the crack growth rates approach ΔKth. This work gives further evidence of the utility of the design curves described in Code Case 2938 of the ASME BPVC VIII-3 for construction of high pressure hydrogen vessels.


2013 ◽  
Vol 37 (5) ◽  
pp. 517-525 ◽  
Author(s):  
E. S. Drexler ◽  
A. J. Slifka ◽  
R. L. Amaro ◽  
N. Barbosa ◽  
D. S. Lauria ◽  
...  

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