Влияние режимов обкатывания роликом на формирование шероховатости поверхности

Abstract

Изложены результаты экспериментальных исследований по изучению влияния подачи, скорости и количества проходов на шероховатость поверхности вала. Установлено, что в диапазоне изменения варьируемых параметров с увеличением скорости, количества проходов и уменьшением подачи значение шероховатости приближается к оптимальной – регламентируемой техническими условиями. При одинаковых условиях обработки шероховатость валов из стали 40Х на 15–35% больше шероховатости валов из стали 45.

The results of experimental studies on the effect of feed, speed and number of passes on the roughness of the shaft surface are presented. One of the promising methods that have become more widely used at the final stages of processing is surface plastic deformation, the essence of which is that the required dimensions and quality characteristics are achieved by plastic shaping of the surface layer of the material. Due to plastic deformation, the surface layer is hardened, residual compressive stresses occur. Difficulties in applying this processing of parts are due to the fact that in each specific case additional studies are required, since the parameters of processing regimes are assigned based on the results obtained empirically, which does not always lead to the desired result. The most widespread use in practice was the treatment of PPD with a roller. Analysis of the obtained dependences of the roughness of the shafts on the speed testifies to their practically linear dependence. Under the same machining conditions, the roughness of the 40X steel shafts is 20­25% greater than the roughness of the shafts of steel 45. Should be noted that increasing the speed to 180 m / min does not lead to a noticeable decrease in the roughness, a further increase in it leads to an increase in Ra. Analysis of the dependence of the roughness of the shaft surfaces Ra on the feed shows that for steel 40X it approaches linear, for steel 45 it has a nonlinear character. Under the same processing conditions, the roughness of 40X steel shafts is 20­35% higher than the roughness of shafts made of steel 45. The analysis of the obtained experimental roughness dependences on the number of passes showed that they are non­linear in nature, the minimum roughness values are realized on the 2 passes. With the increase in the number of passes, the subsurface layer of the workpiece undergoes a perforation, and the resulting compressive stresses may exceed the tensile strength of the workpiece material. Under the same machining conditions, the roughness of the 40X steel shafts is 15­20% greater than the roughness of the shafts made of steel 45.