Influence of heat treatment and surface hardening on the fatigue resistance of constructional steel parts

Autor: M. Ya. Belkin, Leonid Belkin
Rok vydání: 1985
Předmět:
Zdroj: Metal Science and Heat Treatment. 27:601-604
ISSN: 1573-8973
0026-0673
DOI: 10.1007/bf00699360
Popis: To investigate the influence of structural factors on the sensitivity to the appearance of the scale effect 12-, 20-, and 160-mm-diameter specimens, unnotched and with press fitted sleeves, which imitated the stress concentration related to the influence of press fitted parts, were fatigue tested. The specimens of 35 and 45 steels were fatigue tested in the normalized condition and those of 40KhNMA and 34KhN1M after hardening and tempering using the standard cycles. The structure of 35 and 45 steels was ferrite and lamellar pearlite and the grain size No. 7, and the structure of 40KhNMA and 34KhN1M steels was tempering sorbite across the whole cross-section in the 12- and 20-mm-diameter specimens and to a distance of 3/4 of the radius from the surface in the 160-mm-diameter specimens. As a result of hardening and tempering of medium carbon steels, a tempering sorbite structure is formed, which provides high static strength, plasticity, and impact strength but together with them a high sensitivity of the steel to stress concentration in cyclic loading. As the result after the hardening and tempering parts do not always possess high fatigue resistance. To provide high fatigue resistance in parts weakened by stress raisers, it is shown tomore » be desirable to use hardening and tempering in combination with strengthening treatments creating residual compressive stresses in the surface layers such as surface plastic deformation, accelerated water or oil cooling from temperatures below the critical, or a combination of these strengthening treatments.« less
Databáze: OpenAIRE
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