INFLUENCE OF DAMAGEABILITY OF LOW-ALLOYED STEEL ON ITS PHYSICAL AND MECHANICAL PROPERTIES

The authors have investigated the influence of structure damageability of low-alloy and carbon steels, formed during the cyclic  deformation by curve at the coercive force and electrical resistivity.  Samples of low-alloy and carbon steel (09G2S, 10G2S1 and 3sp steel)  were deformed cyclically according to the scheme of pure bending at  a symmetrical cycle. The steel damageability was assessed by the ratio  of the number of bending cycles to the number of bends at destruction. Increase of damage up to 0.2 – 0.3 was accompanied by intense  hardening, and then the stabilization occurs. The coercive force with  increasing degree of deformation under tension is growing on a decaying curve. The electrical resistance changes similarly. During cyclic  deformation, the coercive force varies in a complicated way. This is  due to the nature of the changes of dislocation structure and the occurrence of compressive stresses near the sample surface and the stretching tension in the center. During cyclic deformation, the resistivity  initially increases slightly, then stabilizes and then abruptly increases.  Such an abrupt change of the electrical resistance of steels at cyclic  deformation is apparently caused by the occurrence of vacancies when  the direction of deformation is changed. On the basis of the conducted  research the authors have made the conclusion about the possibility of  control of structure damageability according to the changes of physical  and mechanical properties of steels.

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