Stress-corrosion cracking in copper refrigerant tubing
- 250 Downloads
A metallurgical failure analysis was conducted to determine the cause of cracking in several sections of copper refrigeration tubing. The tubing in question was part of a new mechanical design, implemented to mitigate fatigue failures of solder joints that had occurred in tubing systems fabricated under the previous design. A comprehensive metallurgical evaluation revealed intergranular fracture of the copper in a region of the tubing that had been significantly cold worked during manufacture. On discovery of a source of moist ammonia in the system, associated with the location of failure, intergranular stress-corrosion cracking (SCC) was identified as the failure mechanism. A modified design, incorporating annealing of the formed copper tube section, was recommended to avoid future failures.
Keywordsammonia copper stress-corrosion cracking
Unable to display preview. Download preview PDF.
- 1.Copper and Copper Alloys, ASM Specialty Handbook, J.R. Davis, ed., ASM International, Materials Park, OH, 2001.Google Scholar
- 2.S.P. Lynch: “Failures of Structures and Components by Environmentally Assisted Cracking,” Eng. Fail. Anal., 1994, 1(2).Google Scholar
- 3.N.W. Olin: “Corrosion of Copper an Copper Alloys,” Corrosion, vol. 13, ASM Handbook, ASM International, Metals Park, OH, 1987, pp. 610–40.Google Scholar