Investigation of the Effects of Austenitizing Heat Treatment on Energy Consumption of Pipe Threading

Abstract

Energy consumption is an important part of the production cost of mass production industrialenterprises. The casting, heat treatment and threading processes involved in the industrialproduction of fittings result in high energy consumption. In serial production, the threading ofpipe fittings is carried out using high torque and low speed. The thin-walled designs of thefittings lead to rapid cooling, causing the formation of a high rate of pearlite microstructuresand subsequent low or extremely hard machinability. Heat treatment with long austenitizingtime in the furnace reduces the pearlite ratio, thus enabling a ferritic microstructure to beobtained. In this study, the ½-inch BSP threading process was applied to materials having bothmicrostructures after casting and heat treatment. As in the mass production pipe threadingprocess, fittings were threaded in a multi-threading process using a universal lathe and in asingle threading process using a CNC mill. The Power Index (PI) was measured during themetal removal process and the energy consumption of the products was calculated viaenergy/power conversion equations. In addition, a new model was proposed that takes intoconsideration the energy consumption per product (ECPP) in the mass production machiningprocess. As a result of combining the energy consumption and energy - power transformationtheory with an experimental investigation, 39% optimization was achieved. That's a result ofthis experimental study resulted in energy savings of 8755 kWh annually.