Modeling the distribution of internal stresses in surface strengthened layer of steel parts after cementation and hardening

Based on the analysis of existing trends in mechanical engineering, it is established that the complexity of modern gear parts imposes on the material increasing technological requirements for stamping, machinability, welding, hardenability, cementing and gouging in the hardening process, which explains the need for alloying, chemical elements. The influence of different compositions of steels for gears on the level of internal stresses that occur in the parts during heat treatment has been studied. The optimal composition of complex-alloyed cementing steel is established. Analysis of the results of modern research allows us to state that the residual stresses in the surface layers of steel parts after cementation and hardening may be appropriate. These are the cases when their direction of residual stresses is opposite to the direction of stresses that arise during the operation of steel parts. Complex alloying with titanium and niobium allows to increase manufacturability of steel and, as a result, to increase operational indicators of products of mechanical engineering of details. In the course of research, it was found that the level of grooving of parts in the process of chemical-thermal treatment will provide tolerances of 0.029 mm, steel 12Cr3Ni (minimum P and S) – 0.055 mm and is directly dependent on the level of internal stresses.