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An investigation of the elevated temperature cracking susceptibility of alloy C-22 weld-metal

Gallagher, Morgan Leo
http://rave.ohiolink.edu/etdc/view?acc_num=osu1198824264

Abstract Details

2008, Doctor of Philosophy, Ohio State University, Welding Engineering.
The use of nickel-base alloys has increased in recent years as the demand for high-temperature corrosion resistant alloys increases. However, the introduction of new alloys can present challenges in materials joining. During fabrication involving welding, both solidification cracking and ductility-dip cracking (DDC) cracking may occur in these alloys if proper precautions are not followed. One such nickel-base alloy is Alloy C-22, which has limited weldability data to date. Alloy C-22 is one of the most corrosion resistant Ni-Cr-Mo alloys available today, and is particularly versatile. As a result, Alloy C-22 is being considered for use in the construction of storage canisters for permanent disposal of radioactive waste in the Yucca Mountain Project. However, in such a critical application, weld related defects (such as these two forms of cracking) are simply unacceptable. This investigation examined the solidification cracking and ductility-dip cracking susceptibility of Alloy C-22 in two phases. The first phase or the investigation determined the baseline susceptibility of two commercial heats of Alloy C-22 to these two forms of weld cracking. Solidification cracking was evaluated using the transvarestraint test, and ductility-dip cracking was evaluated using the strain-to-fracture and hot-ductility tests. The alloy was found to be highly resistant to solidification cracking, yet susceptible to ductility-dip cracking in the strain-to-fracture test. However, it is noted that Alloy C-22 has not been found to be susceptible to ductility-dip cracking within industry. The second phase of the investigation examined the effects of compositional variation (specifically the variation of Mo, W, and Fe) on solidification cracking and ductility-dip cracking. This was accomplished using a combination of thermodynamic simulations and button melting experiments. The button melting experiments were coupled with a new version of differential thermal analysis known as single-sensor differential thermal analysis. Experimental results indicate that compositional variation within the limits that define the alloy as C-22 will not significantly increase the susceptibility of the alloy to solidification cracking or ductility-dip cracking.
John Lippold (Advisor)
196 p.
Alloy C-22; Corrosion Resistant Alloys; Yucca Mountain Project; Weldability; Solidification Cracking; Ductility Dip Cracking; Varestraint Test; Strain to Fracture Test; Hot Ductility Test

Recommended Citations

Citations

  • Gallagher, M. L. (2008). An investigation of the elevated temperature cracking susceptibility of alloy C-22 weld-metal [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1198824264

    APA Style (7th edition)

  • Gallagher, Morgan. An investigation of the elevated temperature cracking susceptibility of alloy C-22 weld-metal. 2008. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1198824264.

    MLA Style (8th edition)

  • Gallagher, Morgan. "An investigation of the elevated temperature cracking susceptibility of alloy C-22 weld-metal." Doctoral dissertation, Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1198824264

    Chicago Manual of Style (17th edition)

osu1198824264
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This open access ETD is published by The Ohio State University and OhioLINK.