Improving the efficiency of surface-thermal hardening of machine parts in conditions of combination of processing technologies, integrated on a single machine tool base

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 technology Fig. 11 . Dependence of the temperature-time characteristic on the carbon concentration in steel: 1 – obtaining homogeneous austenite; 2 – carbon content in austenite, at which 50% of martensite can be fixed in the cooling stage To establish the functional dependencies of the integral temperature-time characteristic S on the technological processing modes for the steel grades under consideration, experimental data were processed using the software products STATISTICA 6.0 and Table Curve 3D v 4.0 : S ( q s , V p ) = a + bV p + cq s + dV p 2 + eq s 2 + fV p q s + gV p 3 + hq s 3 + iV p q s 2 + jV p 2 q s (5) for steel 45: a = –3.601893, b = 243.31624, c = 3,048266 · 10 –7 , d = –2277.1586, e = 7.0241349 · 10 –16 , f = –8.7904966 · 10 –6 , g = –2797.853, h = 5.5163545 · 10 –25 , i = –1.0355329 · 10 –14 , j = 6.4796934 · 10 –5 . for steel U8A: a = –85.253883, b = 3173.1572, c = 4.8366164 · 10 –7 , d = –19522.903, e = 1.8005625 · 10 –15 , f = –2.2665061 · 10 –5 , g = –122995.64, h = 4.0624994 · 10 –24 , i = –5.344947 · 10 –14 , j = 2.7815479 · 10 –4 ; The maximum error of the measurement does not exceed 5 %. Since the change in the geometric parameters of the source during the HEH HFC is associated with the labor-intensive manufacture of a new inductor, the specific power of the heating source and the speed of its movement are taken as variable values. Therefore, in the practice of induction heating, it is customary to initially set the size of the source, and then determine the other two technological parameters.