Properties of M54 Steel
E. U. Lee, M. Stanley, B. Pregger and C. Lei
Naval Air Warfare Center Aircraft Division
Patuxent River, MD
Specimens of a M54 steel were subjected to electrochemical measurement, mechanical test in air, fatigue test in air and 3.5% NaCl solution, stress corrosion cracking (SCC) test in 3.5% NaCl solution, and SEM fractograph examination. Compared to the currently available high strength steels, 4340, 300M and AerMet 100, this steel has extra alloying elements V and W. The result of this study indicates the following. The open circuit potential of the M54 steel is -0.55 volt, which is less than that of AerMet 100 steel but greater than those of 4340 and 300M steels in 3.5% NaCl Solutiion of pH 7.3. The threshold stress intensity for SCC KISCC of the M54 steel is far greater (about 4 times) than those of the other three high strength steels in 3.5% NaCl solution. However, the M54 steel is still susceptible to corrosion fatigue as those three high strength steels in 3.5% NaCl solution. The greater threshold stress intensity range for fatigue crack growth DKth and KISCC of the M54 steel in 3.5% NaCl solution may be associated with its extra alloying elements V and W.