Enhanced fatigue resistance in 316L austenitic stainless steel due to low-temperature paraequilibrium carburization

• Published in: Acta materialia Vol. 55; no. 16; pp. 5572 - 5580
• Main Authors: Agarwal, N., Kahn, H., Avishai, A., Michal, G., Ernst, F., Heuer, A.H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2007; Elsevier Science
• Subjects: Applied sciences; Austenitic stainless steels; Austenitic steels; Carburization; Carburizing; Compressive properties; Exact sciences and technology; Fatigue; Fatigue (materials); Fatigue failure; Fatigue limit; Heat resistant steels; Heat treatment; Internal stresses; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nucleation; Production techniques; Stresses; Tension test; Thermochemical treatment and diffusion treatment; Fatigue; Internal stresses; Austenitic steels; Tension test; Carburization; Thermochemical treatment; Austenitic stainless steel; Temperature; Mechanical properties; Internal stress; Fatigue strength; Austenitic steel; Stainless steel; Carburizing; Stainless steel-316L; Low temperature
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2007.06.025

Fully reversed fatigue tests have been performed on wrought 316L stainless steel samples after low-temperature carburization. The resulting 25 μm case depth, with a surface hardness three times that of the core and a surface compressive stress greater than 2 GPa, leads to significantly enhanced fatigue performance. The so-called endurance limit (defined as the stress at which the fatigue life is 10 7 cycles) increased from about one-third to about one-half the yield stress (from ∼200 to ∼325 MPa). Fractographic investigations reveal that the surface stresses change the preferred site of fatigue crack nucleation from the surface for noncarburized samples to the interior for carburized samples.