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Recubrimiento de <i>Stellite 6</i> sobre acero inoxidable realizado con láser de CO₂ para válvulas de escape de motores diesel

2002; Spanish National Research Council; Volume: 38; Issue: 6 Linguagem: Espanhol

10.3989/revmetalm.2002.v38.i6.432

1988-4222

M. Cadenas, J.M. Cuetos, J.E. Fernández, R. Fernández, Luis M. Vega, J. de Damborenea,

Gas Sensing Nanomaterials and Sensors

To reduce the recovery or the replacement costs of diesel engine exhaust valves, they are manufactured with an economic base material, and a coating which is deposited on the seat valve in order to reach high hardness and good impact, corrosion and high temperature wear resistance (>550 °C) and without lubrication. In this work, appropriate laser cladding parameters have been determined to obtain Stellite 6 coatings over AISI 304 steel (as plane test specimens) and SAE EV8 steel (as valves) substrates. One and two superimposed tracks were deposited on the seat valves, and modifying the laser power as a function of the rotated angle at the beginning and the end of the circular tracks, pores and cracks have been minimized and the thickness of the track were made uniform. Hardness, dilution and final microstructure of the different coatings have been analysed. A 10 % dilution and 550 HV in the tracks over plane test specimens was observed, while valves with one track showed 25 % and 430 HV respectively. With two superimposed tracks the hardness was up to 470 HV in the upper track.