Characterization of INCONEL alloy 740 H for Tube , Pipe and Fittings for Advanced-Supercritical CO 2 Systems

Nickel-base alloys are required for many of the components in advanced supercritical CO2 power systems operating at temperatures and pressures exceeding 700°C and 25 MPa. Age-hardened alloys offer a distinct advantage over traditional solid solution strengthened alloys by virtue of their significantly higher creep strength. This makes it possible to reduce wall thickness and, thereby reduce total materials cost. INCONEL® alloy 740H® is an age-hardened alloy that was developed and extensively characterized for Advanced-Ultrasupercritical steam boilers. Material testing by the A-USC Consortium and US Department of Energy led to ASME Code Case 2702 covering UNS N07740. Alloy 740H is the first age-hardened, nickel-base alloy permitted for welded construction for use in the creep limited temperature regime. More recent development work on the alloy has focused on product forms and environments relevant to supercritical CO2 systems. Various laboratories have reported on oxidation properties of the alloy under simulated operating conditions. This paper focuses on the manufacturing and properties of tubing and fittings that are being applied for the various sCO2 projects, planned or now underway. As many of the structures are constructed by welding, a review of welding practices and experiences is presented with reference to dissimilar metal welds.

[1]  R. W. Swindeman,et al.  BOILER MATERIALS FOR ULTRASUPERCRITICAL COAL POWER PLANTS , 2003 .

[2]  B. Baker,et al.  Corrosion Resistance of Alloy 740 as Superheater Tubing in Coal Fired Ultra Supercritical Boilers , 2004 .

[3]  J. Lippold,et al.  Welding Metallurgy and Weldability of Nickel-Base Alloys , 2009 .

[4]  G. Pharr,et al.  Testing and Analysis of Full-Scale Creep-Rupture Experiments on Inconel Alloy 740 Cold-Formed Tubing , 2013, Journal of materials engineering and performance (Print).

[5]  J. Ramirez.  Evaluation of Susceptibility of Alloy IN 740 to HAZ Stress-Relaxation Cracking The susceptibility of Ni-Cr-Co Alloy IN 740 to heat-affected zone stress-relaxation cracking was evaluated and compared to precipitation strengthening Alloys IN 718 and Waspaloy ® BY , 2013 .

[6]  J. Shingledecker.  CURRENT STATUS OF THE U.S. DOE/OCDO A-USC MATERIALS TECHNOLOGY RESEARCH AND DEVELOPMENT PROGRAM , 2013 .

[7]  S. Mayadevi.  Supercritical Carbon Dioxide , 2014 .

[8]  K. Unocic,et al.  Creep-Rupture Behavior of Precipitation-strengthened Ni-Based Alloys under Advanced Ultrasupercritical Steam Conditions , 2014 .

[9]  D. Bechetti,et al.  Homogenization and Dissolution Kinetics of Fusion Welds in INCONEL® Alloy 740H® , 2014, Metallurgical and Materials Transactions A.

[10]  S. David,et al.  Weldability and weld performance of candidate nickel based superalloys for advanced ultrasupercritical fossil power plants Part II: weldability and cross-weld creep performance , 2016 .

[11]  Clifford K. Ho,et al.  Concentrating Solar Power Gen3 Demonstration Roadmap , 2017 .

[12]  J. J. deBarbadillo.  INCONEL alloy 740H , 2017 .

[13]  Takashi Sasaki,et al.  Demonstration of the Allam Cycle: An Update on the Development Status of a High Efficiency Supercritical Carbon Dioxide Power Process Employing Full Carbon Capture , 2017 .