(1) The dimensional changes of carbon steel bars due to heating above the transformation points and cooling are not attributed to errors of measurement owing to the small pressure of dilatometer-spring. (2) When the steel bars become long and slender, their lengths tend to decrease by heating and cooling, regardless of their carbon contents. However the effect is constant when the ratio of the length to the diameter exceeds a certain value. If the shape of specimen approaches a sphere, such dimensional changes become smaller. (3) It is considered that the carbon content, the microstructure, the dimension (and the shape) of a carbon steel bar are factors which influence the dimensional changes due to heating and cooling.
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