Evaluation of the Accuracy of Dimensional-Strengthening Heat-Oxidation Treatment of Carbide Products

The article investigates the accuracy of dimensional strengthening thermo-oxidative treatment of hard-alloy products. The study analyzes how temperature field nonuniformity in the furnace and temperature fluctuations during processing influence the dispersion of dimensions of tungsten–cobalt alloy parts. A theoretical model describing the relationship between dimensional deviations before and after thermo-oxidation is developed using statistical methods and the theory of random processes. The influence of constant temperature gradients and random temperature fluctuations on the oxidation depth and dimensional accuracy is analytically evaluated. Correlation functions of temperature variations in furnaces with different control systems are determined, and their effect on the variance of the removed material layer during thermo-oxidation is established. Experimental studies on hard-alloy samples confirm the theoretical dependences and demonstrate that even small temperature differences in the furnace can lead to noticeable dimensional deviations. The research also examines the effect of oxidation conditions (air and oxygen atmosphere) on the dimensional accuracy of hard-alloy elements used in high-pressure chambers. Results show that thermo-oxidative treatment improves surface microrelief and can slightly reduce the dispersion of dimensions. It is established that increasing the oxidation time while decreasing the oxidation rate and furnace temperature can significantly reduce dimensional variance and improve processing accuracy. The obtained results provide recommendations for optimizing thermo-oxidative processing parameters and improving dimensional accuracy in the manufacturing of hard-alloy components.