Metallurgist, Naval Ship Research and Development Center, Annapolis, Md.
Pages: 20 Published: Jan 1969
This investigation summarizes the general and stress-corrosion cracking behavior of several classes of high-strength steels in the marine environment. Eleven experimental heats of maraging steel were evaluated for resistance to stress-corrosion cracking in seawater. Those alloys containing 10 and 12 percent nickel were found to be susceptible to pitting attack and stress-corrosion cracking, while 18 percent nickel maraging steels were found to be highly resistant to pitting attack.
The corrosion characteristics of 5Ni-Cr-Mo-V HY-130 steel were also investigated in natural seawater. The stress corrosion threshold stress for HY-130 was determined utilizing the criteria of no failure after six months of exposure in natural seawater under sustained stress in the precracked cantilever test. A major portion of the investigative work was concentrated on answering the question of whether long-term continuous cathodic protection of HY-130 in natural seawater will lead to eventual problems associated with hydrogen embrittlement. Preliminary work utilized precracked cantilever specimens, which were precharged with hydrogen at several high-current density levels and then step loaded to failure while still being cathodically protected. Cathodic protection tests were also carried out utilizing two-point loaded bent-beam specimens stressed to 90 percent of the 0.2 percent yield strength which were cathodically protected at 13 and 130 mA/ft2 current densities for one year in low-velocity flowing seawater. The effect of cathodic protection on the low-cycle corrosion fatigue behavior of HY-130 was also determined.
high-strength steels, corrosion, stress corrosion, hydrogen embrittlement, evaluation, tests
Paper ID: STP32016S