TURNING MACHINABILITY OF SINTERED HEAT TREATED POWDERED ARTIFACTS, BEING AFFECTED BY RESIDUAL POROSITY FILLING WITH ADVANCED INORGANIC SEALING COMPOSITIONS

摘要

Turning machining of shape details, being otherwise difficult to obtain by conventional powder metal (PM) processing routine, frequently presents a significant challenge for both quality and productivity of PM parts fabrication due to "interrupted cut" phenomena and detrimental cutting tools chattering during turning operations. Therefore, multiple efforts to fix such problems have been undertaken through the certain period of time within and outside of PM Industry. Among those endeavors by diverse development and manufacturing centers, it is worth to mention various additives like Manganese Sulfide and comparable supplements as well as resin impregnation technique, being applied towards residual porosity within PM parts. However, usage of additives like sulfides may diminish corrosion resistance of PM parts, whereas utilization of resin impregnation requires its subsequent costly removal before hardening procedures because of the danger for resin's thermal decomposition that may vary PM parts' final Carbon content. Recently developed after-sintering processing of PM parts with advanced Inorganic Sealing (IS) compositions may offer treatment of powdered artifacts that can withstand heat treatment temperatures without detrimental effect on corrosion resistance while leading to significantly enhanced turning machinability of PM processed parts including sizable increase in tool life with simultaneous improvement of quality of turning operations. Obtained results of this study are presented and discussed.