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 r = –543.57972, s = 1.233 · 10 –26 , t = 1.139227 · 10 –16 , u = 2.287546 · 10 –7 . Thus, the determination of the specific power and the speed of movement of the source during surface quenching is carried out by solving a system of equations 45/U8 45/U8 45/U8 ( ); ( , ); ( , ) s p S h S q V qs Vp Ψ      for given values of the quench- ing depth and the relative size of the transition zone. Figure 12 shows a graphical solution to this problem. It can be noted that the obtained range of processing modes is significantly narrower in relation to the pur - pose of the modes based on providing only a given depth of the hardened layer (curves 1 and 2). Fig. 12. The dependence of specific power of the source on its speed while hardening steel 45 and U8 by applying HEH HFC to a depth of h = 0.62 mm: 1 – steel 45; 2 – steel U8A. * The level of microhardness of the surface layer of the part, achieved after the transition “Hardening by HFC” To ensure the depth of the hardened layer h = 0.62 mm, we accept the following operating parameters: 1) for steel 45, the range of recommended modes is limited to points A and B on curve 1 – q s = = (3.0...3.4)·10 8 W/m 2 , V p = (74...81) mm/s; 2) for steel U8A, the range of recommended modes is limited to points C and D on curve 2: in this case, q s = (2.4...2.8)·108 W/m 2 , V p = (68...75) mm/s. The obtained processing modes guarantee obtaining the necessary quenching depth and a rational value of the transition zone. Since hardening is carried out in one setting of the part, then T aux = 0 s. In this case, the piece productivity will be equal to the technological productivity. The calculation of productivity and energy consumption at the transition “HFC hardening” is carried out according to the formulas: ( ) p p V D b P L π = , ( ) s s s s p p q bR q bR L E P V D b = = π