Oxidizing Influence over Surface Structures and Properties for A3k Steel Nitrocarburized in Fluidized Bed

Surface duplex thermochemical treatment (oxinitrocarburizing) has principal scope to obtaining superficial mechanical higher properties with increasing corrosion capacity. The paper is based by oxinitrocarburizing experiments made in laboratory conditions over steel samples (low carbon steels, A3k). Active media for treatments was obtaining by ammonia, methane and air. Effective treatment was made in endothermic atmosphere, methane and ammonia that produced smooth fluidization. In a second stage o postoxidation at different time was made. The results of duplex surface treatments were investigated by superficial hardness (HV5) and by metallographic structure