residual stress

The article analyzes modern technologies for machining workpieces of hard-to-machine materials with a hardness parameter higher than 45 HRC (Rockwell hardness). It is shown that the mechanics and thermodynamics of the forming process in such materials are subject to specific laws of cutting theory, which have systemic differences from the processing of traditional engineering materials. The advantages and disadvantages of machining chromium-nickel alloys using CNB inserts instead of grinding are analyzed.

Machining difficult-to-cut materials, which include most high-alloy chromium-nickel steels and alloys, requires optimization of cutting parameters, correct application of tool materials, cutting blade geometry, etc. The particular relevance of a scientifically based analysis in addressing these issues is due to the large costs incurred in machining products made from such materials. The possibilities of experimental research to provide correct technological recommendations are quite limited.

The design of banding shells of rotary units is analyzed. It is shown that combined welding and cast manufacturing of bandings is used in the case of large structural sizes. The basic materials (30, 35, 25 HSL and 30 HML), being used in this process, are characterized by the tendency of forming of hardening structures due to the thermal cycle of welding. As a result of this, the cracks in the heat-effected zone, which lead to the destruction of the connection under the influence of welding residual stresses.