EDM and the resulting hydrogen embrittlement of maraging steel
- 95 Downloads
The use of electrical discharge machining (EDM), or spark erosion as it is sometimes called, introduces hydrogen into maraging steel 250 such that brittle fracture surfaces result from embrittlement accelerated by slow-strain-rate tensile tests. Brittle fracture features indicate potential premature failure due to hydrogen embrittlement. Experimental control was provided by test specimens machined by abrasive waterjet, a machining technique that does not evolve hydrogen as a part of the machining process. Hydrogen concentration measurements indicate the hydrogen concentration of specimens fabricated by EDM is approximately 0.5 ppm, while that of specimens machined by abrasive waterjet is approximately 0.1 ppm. On the basis of constant-load tests, the time to failure of test specimens machined by EDM and loaded to 50% of the yield strength is estimated to be a minimum of 30 years.
KeywordsTest Specimen Electrical Discharge Machine Hydrogen Concentration Hydrogen Embrittlement Maraging Steel
Unable to display preview. Download preview PDF.
- 1.C.A. Zapffe and C.E. Sims, “Hydrogen Embrittlement Internal Stress and Defects in Steel,” Trans. AIME, 145 (1941), pp. 225–259.Google Scholar
- 2.D.P. Smith, Hydrogen in Metals (Chicago: University of Chicago Press, 1948).Google Scholar
- 3.R.P. Frohmberg, W.J. Barnett, and A.R. Troiano, “Delayed Failure and Hydrogen Embrittlement in Steel,” Trans. ASM, 47 (1955), pp. 892–925.Google Scholar
- 4.E.P. Klier, B.B. Muvdi, and G. Sachs, “Hydrogen Embrittlement in an Ultra-High-Strength 4340 Steel,” Trans. AIME, 209 (1957), pp. 106–112.Google Scholar
- 5.A.R. Troiano, “The Role of Hydrogen and Other Interstitials in the Mechanical Behavior of Metals,” Trans. ASM, 52 (1960), pp. 54–80.Google Scholar
- 6.H.R. Gray and A.R. Troiano, “How Hydrogen Affects Maraging Steel,” Metal Progress, 75 (1964), pp. 75–78.Google Scholar
- 7.H.H. Johnson, “Overview on Hydrogen Degradation Phenomena,” Hydrogen Embrittlement and Stress Corrosion Cracking (Metals Park, OH: ASM, 1984), pp. 3–27.Google Scholar
- 8.V. Husman, “Traveling Wire EDM—Applications and Considerations of Job and Guidelines,” Electrical Discharge Machining: Tooling, Methods and Applications Dearborn, MI: SME, 1983), pp. 191–202.Google Scholar
- 9.J.B. Condon, R.A. Strehlow, and G.L. Powell, “An Instrument for Measuring the Hydrogen Content of Metals,” Analytical Chem., 43(11) (1971), pp. 1448–1452.Google Scholar
- 10.H.H. Johnson, J.G. Morlet, and A.R. Troiano, “Hydrogen, Crack Initiation, and Delayed Failure in Steel,” Trans. Met. Soc. AIME, 212 (1958), pp. 528–536.Google Scholar