Laser fusion of the surface of cast iron with scanning of the beam
In fusion of the surface of gray iron by a laser beam with scanning the thickness of the fused layer with a constant scanning frequency is proportional to the parameter P/(dv)0.4, where P, d, and v are the power, diameter, and rate of linear movement of the laser beam, respectively. This relationship was obtained in solution of the threedimensional problem of laser heating.
The zone of laser fusion of the iron has a dispersed dendritic structure and the phase composition is an α+γ+Fe3C mixture. With a change in rate of movement of the specimen (v) from 1.7 to 10 mm/sec the quantity of the phases in the remelted layer remains practically constant. With scanning the quantity of the phases does not change in comparison with treatment without scanning. With an increase in rate the carbon content in the austenite increases from 1.2 to 1.5%. The microhardness of the zone of fusion does not depend upon v and is 900–1000 H.
KeywordsIron Austenite Laser Beam Carbon Content Phase Composition
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