| 摘要 |
PURPOSE: To make the coat thickness of a stress concentration part controllable, and to calculate quantitatively the degree of stress concentration of a coated surface test part by a method wherein one groove-shaped through-notch is provided perpendicularly to the length direction in the center in the length direction of one surface of a rectangle and a coating material is applied on the whole of the opposite surface. CONSTITUTION: While a coated test surface 1 is made planar so that a coating material be applied uniformly on a test part 1, one groove-shaped through notch 2 is provided in one surface of a flat plate on the opposite side of the coated surface 1, for the purpose of evaluating corrosion fatigue characteristics of a stress concentration part. Any of an oily material, resin, organic zinc and others may be used as the coating material. Coating may be conducted by any of a brush method, a roller method and the like. A coat thickness (tp) is made to be in the range of 10μm to 10mm generally. The notch 2 is made to be of a U type, a V type, a circular-arc type or the like and the dimension is made to be in the range of 1.5 to 5.0 generally so that a stress concentration factor corresponding to the purpose of an experiment be obtained. A notch depth (d) is made to be in the range of 5 to 90% of the thickness (ts) of a test piece and the radiusρof curvature of the the fore end in the range of 1mm to a plate thickness. The maximum value of a repeated load is made a yield stress of a material or below so as to prevent plastic deformation. Pins 3 and 3' for four-point bending loading are provided for giving a bending load.
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