Effect of abrasive flow machining on the roughness and microhardness the small channels (holes) surface in samples of 12X18N10T steel workpieces

The article contains the results of research on the effect of abrasive flow machining on the roughness and microhardness of the surface of small channels (holes) in samples of workpieces made of 12X18N10T steel. Empirical dependences of the change in roughness and microhardness of the surface of a small channel on the degree of filling of the working medium with a plasticizer and the shear pressure of the hydraulic system with the extrema of these functions in the studied area are obtained. Based on these dependencies, the composition of the working environment was selected: the degree of filling of the working media base (with a constant content of white electro corundum – 30 %) with a plasticizer in the form of diamond paste (ASN 60/40 VOM G) Ka 40 % and SKT rubber 30 %, respectively. As a result of abrasive flow machining, it was possible to reduce the roughness of the surface layer from Ra = 0.49…0.62 µm to Ra = 0.047…0.06 µm, and also to increase the microhardness of the surface from h = 188…192 HB to h = 213…220 HB. The thickness of the hardened layer is ≈ 7.24 µm. Analysis of surface profilograms shows that as a result of abrasive flow machining, both the height roughness parameters (average – Ra, Rz, Rp; maximum – Rmax) and the depth roughness parameters (Rk) were significantly reduced. Using electron microscopy (SEM MAG), a qualitative assessment of the structure of the surface layer of the small channel was carried out. The obtained results show good machinability by abrasive flow of austenitic steel blanks, in particular 12X18N10T steel.