Hydrogen-Induced Cracking (HIC) of Hardened and Tempered Steel Fastener Used in Space Application
- 163 Downloads
Cadmium-plated 0.35C–3.5Ni–1.5Cr–0.5Mo steel threaded fasteners of 1230 MPa properties class are used for aerospace applications. These fasteners were torqued to 13 N·m. Few fasteners parted into two pieces while in use under sustained assembly load for a period of 50 days. The fracture surface of the failed fasteners had two distinct regions when viewed under microscope at higher magnification. Fractography revealed that the larger region consisted of predominantly intergranular features, whereas the smaller region had features of microvoid coalescence. From the metallography evidences it was concluded that the fastener failure was due to hydrogen embrittlement. Electro-deposit of cadmium was identified to be the main source for hydrogen entrapment, which could not be compelled completely by post-plating baking treatment.
Keywords0.35C–3.5Ni-1.5Cr–0.5Mo steel Hydrogen embrittlement
The authors thank Dr. P.P. Sinha, Deputy Director, VSSC (MME), for his technical support during the investigation. They are indebted to Dr. K. Radakrishnanan, Director, VSSC, for permission to publish this work.
- 2.ASTM International, B 850-90 (reapproved 2004) standard guide for post-coating treatment of steel for reducing risk of hydrogen embrittlementGoogle Scholar
- 4.Troiano, A.R.: The role of hydrogen and other interstitials in the mechanical behaviors of metals, 1959 Edward De Mille Campbell Memorial Lecture, Trans ASM, vol. 52, pp. 54–80 (1960)Google Scholar
- 6.Gerberich, W.W., Marsh, P.G., Hoehn, J.W.: Hydrogen induced cracking mechanism—Are there critical experiments? Hydrogen Effects Mater. Miner. Met. Mater. Soc. 539–551 (1996)Google Scholar
- 7.Olden, V., Thaulow, C., Johnson, R.: Modelling of hydrogen diffusion and hydrogen induced cracking in supermartensitic and duplex stainless steels. Mater. Des. 29, 1934–1948 (2008)Google Scholar
- 14.Lynch, S.P.: Scr. Mater. doi: 10.1016/j.scriptamat.2009.02.031