Question

1. what is the strength of a material with an extremely small defect?

Answer 1

The effect of a small artificial defect ( a drilled hole, the diameter (40 to 200 μm) on the fatigue strength of low carbon steel and medium carbon steel investigated found that, the fatigue strength of the specimen containing the very small hole was found to be of almost the same order of magnitude as the fatigue limit of the plain specimen - that is, the existence of the very small hole did not weaken the fatigue strength of the holed specimen. .all of this can be applied to the evaluation of fatigue notch sensitivity of materials with high tensile strength or high hardness, and, from the metallurgical aspect, to the quantitative control of defects or inclusions in metals.