masterThesis
Medição da temperatura de corte no torneamento do aço-ferramenta AISI D6 temperado e revenido auxiliado por LN2
Fecha
2020-02-17Registro en:
LIMA JÚNIOR, Edmilson Dantas de. Medição da temperatura de corte no torneamento do aço-ferramenta AISI D6 temperado e revenido auxiliado por LN2. 2020. 135f. Dissertação (Mestrado em Engenharia Mecânica) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2020.
Autor
Lima Júnior, Edmilson Dantas de
Resumen
The present work has the main purpose to investigate the cutting temperature
when machining quenched and tempered AISI D6 tool-steel assisted by liquid
nitrogen (LN2). Uncoated PCBN inserts were used as cutting tools during turning
trials. Tool-work thermocouple was the method used in this investigation. In this
technique, the contact between the workpiece and the cutting tool makes the hot
junction of the thermocouple and the other extremities connected to the workpiece
and the cutting tool makes the cold junction. By the Seebeck effect, as long as
these junctions are submitted to different temperatures, an electromotive force will
arise in the circuit which can be associated with the hot junction temperature. In
order to obtain the relation between the hot junction temperature and the generated
electromotive force, it was performed a calibration of the system using a
conventional lathe. An oxyacetylene flame and an LN2 delivery system were used
to obtain high temperatures (from the environment to 800oC, approximately) and
low temperatures (including sub-zero temperatures), respectively. In order to
minimize undesirable voltage, it was used the concept of physical compensation,
where an element made of the same workpiece material was connected to the
circuit. The results obtained through the calibration tests show a practically linear
behavior between temperature and electromotive force along with the range of
temperature used for calibration. Cylindrical turning trials were performed in which
the cutting speed and the cooling condition (dry or LN2) were varied. A platform
based on Arduino UNO was developed for data acquisition. It was observed a
marginal reduction in the cutting temperature in the cryogenic condition compared
to the dry condition.