Abstract
This study deals with the experimental investigation of the notch effect of steel welded joints. For the selected type of weld, experiments were carried on welded low carbon steel specimens prepared by MIG technology to separate the influence of geometrical and technological factors on fatigue life and to define dependence of total, technological and geometrical notch coefficients of the welded joints on number of cycles to failure. The effect of notch and removing the geometrical concentrator by weld grinding is analyzed from the probability viewpoint, both in low and high cycle domains. The results show that the weld grinding is not always positive on fatigue life, and probabilistic approach is necessary to define its optimal use. Fractography analysis shows that the fatigue crack is initiated exclusively in the weld toe and within the inner weld defects at the high cycle domain and high-stress amplitude loading, respectively.

Key words
welded joint, weld notch coefficient, weld grinding effect, fatigue life, probabilistic analysis, random loading

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