Product Code: ICAL06_P549

The Influence of the Cooling Rate on Structure of Laser Boronizing Layer on Nodular Iron
Authors:
Marta Paczkowska, Poznan University of Technology, Institute of Working Machines and Motor Vehicle; Poznan Poland
Wlodzimierz Waligora, Poznan University of Technology; Poznan Poland
Presented at ICALEO 2006

This article refers to laser alloying surface modifications. In presented research nodular iron laser boronizing effects were studied. The cooling rate effect on melted zone was particularly investigated. Different cooling rates were achieved by using appropriate combination of laser treatment parameters: laser beam interaction time and laser beam power. 5 laser beam velocities with constant laser beam radius r = 2 [mm] were applied. As a result, particular samples area was heating with different interaction times from 0,25 [s] to 1,25 [s]. In the order to obtain three different amount of energy delivered to surface unit (20, 30, 40 J/mm2) different laser beam power were used. Laser treatment was performed with molecular CO2 continuous Triumph TLF 2600t laser with 2,6-kW output power and TEM0,1 mode. The results of the laser treatment were analyzed by means of: optical microscope, Vickers microhardness tester, Auger Electron Spectroscope, and X-ray diffraction. It was found that melted zones are almost utterly homogenous. I was stated it is possible to achieve high microhardness of those zones (even 5 times higher than core hardness). It was showed that microhardness of melted zone created after laser boronizing increases with increasing cooling rate to critical value of 3x103 oC/s.