Laser Treatment of Cast Iron Engine Cylinder Bore with Nanosecond Laser Pulses

Abstract

The environmental and polluting materials emission standards in Europe are going to be always stricter, so in order to keep up with them, one of the largest European automotive manufacturer performs a laser treatment on the cylinder bores of their internal combustion engines. Due to the laser treatment, the near surface area of the cylinder bore becomes harder and more wear resistant, furthermore, due to the inhomogenity of the pearlitic matrix and graphite lamellae, oil reserving holes are formed. In our present work we investigated the laser treated layer of cast iron cylinder bores with lamellar graphite. Samples prepared with two different lasertypes and different energies were investigated on behalf of metallographic and functional aspects.

Laser Surface Hardening of Ni-hard White Cast Iron

“…Regarding the work of M. Adel et al, [21] the use of Nd-YAG pulsed wave laser modified and refined the surface microstructure of acicular bainitic ductile iron, also the wear rate increased with the increasing in the normal loads at constant sliding speed and sliding time. Majlinger et al, [22] studied the laser-treated layer of cast iron cylinder bores with lamellar graphite, the near surface area of the cylinder bore becomes harder and more wear resistant, furthermore, due to the inhomogeneity of the pearlitic matrix and graphite lamellae, oil reserving holes are formed. Both G. Marest et al, [23] and D. Pantelis et al [24] used excimer laser to heat treat different types of cast iron alloys, the microstructure and hardness were improved after laser hardening.…”

Formation of an ultrafine grained layer due to high temperature treatment of the surface of a cast iron cylinder bore

“…Images were taken from regions at least 10 µm away from the graphite lamellaes to avoid their influence. In earlier work [20][21][22], cavities were cut out with the ion beam and then images were taken, with lowered ion current, of the wall of the obtained cavity. This process was simplified, by making the FIB cut on the edge of polished bulk specimens.…”

“…This process was simplified, by making the FIB cut on the edge of polished bulk specimens. The deposition of the generally applied protective Pt layer [20][21][22] was also skipped. The main parameters for FIB machining and imaging are displayed in Table 2.…”