EFFECT OF LASER HARDENING ON THE PROPERTIES OF PM STEELS

Abstract

The article deals with the influence of laser beams, which when acting on materials affect their surface. Depending on the intensity of exposure and the speed of displacement of the beam, due to the heating of the material and the subsequent cooling, there occurs the change in the pattern of the surface and of course to a change in the properties in the volume that was exposed to the temperature changes. For the tests the sintered material based on iron powder type Astaloy CrL and CrM containing 0.7% C was used. Results showed that by the appropriate combination of laser parameters it was be possible to obtain the same structures as by using the technology of "sinterhardening". Compared to sintered state, the hardness of the surface of a material CrL +0.7% C values increased from 248 to 911 - 1000 and at material CrM +0.7% C values from 450 to 1043 - 1100 HV 0.05, depending on the velocity of displacement of the beam. The same is true for the values of microhardness. Hardness values reflect the structural changes that occur in the material due to rapid heating and subsequent rapid cooling. The first tests of this technology demonstrated its high variability and the potentials of replacing classical procedures.

Keywords

• laser hardening
• sintered material
• structure
• hardness