Calculation of temperatures during finishing milling of a nickel based alloys

Abstract

Introduction. One of the most important tasks in cutting metals and alloys is the control of the temperature factor, since temperature is one of the limitations in determining cutting conditions. This approach makes it possible to determine rational (in some cases, optimal) milling modes. Experimental methods for determining the temperature are labor-consuming, costly and not always available. The labor-consuming nature lies in the need for constant adjustment of experimental equipment due to changing cutting conditions, electrical insulation of the tool and workpiece, the appearance of parasitic electrical micro-voltage (if we are talking about temperature measurement methods with thermocouples), constant calibration of instruments and selection of thermal radiation coefficients (if we are talking about non-contact measurement methods). In this regard, there is a need for a theoretical determination of temperatures during milling with minimal use of experimental data. The purpose of the work: to develop a method for theoretical calculation of temperature during milling (cutting) of nickel-based heat-resistant materials on the example of 56% Ni -Cr-W Mo-Co-Al alloy (56% Ni, 0.1% C, 10% Cr, 6.5% W, 6% Al, 6.5% Mo, 0.6% Si, 13 % Co, 1% Fe). Research methodology. To determine theoretically the cutting temperatures, a mathematical model is formed that takes into account the mechanical and thermophysical properties of the material being processed and its change depending on the temperature variations during milling, the geometry of the cutting tool and the features of the schematization of the milling process. The experimental part of the study is carried out on a console milling machine KFPE-250 with a CNC system Mayak-610. The 56% Ni -Cr-W Mo-Co-Al material is processed with a Seco JS513050D2C.0Z3-NXT cutter with different speeds and feeds. The temperature is measured using a Fluke Ti400 thermal imager. Results and discussion. A theoretical model for calculating the temperature (for the group of 77% Ni - Cr - Ti - Al - B, 66% Ni - Cr - Mo - W - Ti - Al, 73% Ni-Cr-Mo-Nb-Ti-Al and 56% Ni -Cr-W Mo-Co-Al alloys) during milling of heat-resistant nickel-based alloys is developed, which makes it possible to predict the temperature value at the face and flank of the tool when changing cutting conditions (speed, feed, depth, cutting tool geometry), as well as the cutting temperature. An analysis of the experimental and theoretically predicted values of the cutting temperature showed a satisfactory agreement between the corresponding values.