2,681 research outputs found
An experimental investigation on metal surface treatment by means of diode laser beams
No full textSurface treatment of steel, for a higher wear resistance, is necessary in all industrial branches that deal with steel. One of the most effective methods of metal surface heat treatment is represented by laser hardening. In general, compared to other techniques, laser hardening needs a much lower heat input into the material. Compared with other conventional processes, diode laser treatment allows to obtain some advantages, such as minimum distortion in the parts and selective hardening of specific areas of components. In this paper, an experimental investigation on the surface thermal treatment of different steels by means of a diode laser was carried out. Experimental tests were performed on three types of steels, selecting different values of beam power and workpiece speed. Hardness and micro-hardness measurements were executed on the treated samples in order to assess the influence of laser machining parameters and workpiece materials on the treatment process. Experimental results were compared with those obtained by using a mono-dimensional thermal model. The morphology of heat affected zone of the specimens was investigated by scanning electron microscopy
An Experimental Study on Bending Process of AISI 304 Steel Sheets by using Diode Laser Forming
No full textLaser bending is a promising technique utilised in order to deform metal sheets that offers the advantage of requiring no hard tooling and no external forces, thus reducing cost and increasing flexibility. Laser forming involves a complex interaction of many process parameters, ranging from those connected with the irradiation of the laser beam to those regarding the thermal and mechanical properties of the workpiece material. The present work is focused on the laser bending of AISI 304 steel sheets by using of a diode laser. The influence of process parameters, such as the power of laser beam and the scanning speed as well as the metal sheet thickness on the bending angle has been taken into account. The investigation has also analysed the effect of rolling direction of the metal sheets and the conditions of cooling on the bending process
Fatigue characterization of drilled components in polymer matrix composites
No full textComposite materials have been initially used in the aerospace, defence and aircraft industries, but nowadays they are finding applications in consumer oriented applications. For some requirements of connection in components, it is necessary to drill workpiece materials. Drilling of fibre reinforced composites can produce typical problems such as delamination of material and fibre pullout, which decrease the fatigue strength of components. The prediction of fatigue life in composites components is not easy because of the several number of possible failure mechanisms which can occur when these materials are cyclically stressed.
In this paper an experimental investigation on the behaviour concerning fatigue strength and life of drilled components in composite materials subjected to fatigue loading is presented. The cutting force components measured during drilling operation have been related to the cutting parameters. The influence of cutting speed and feed rate on the fatigue strength of machined holes has been taken into consideration. Results obtained from repeated flexural fatigue tests on glass and carbon fibres reinforced epoxy matrix have been used to compare the behaviour of different composite materials. Both thrust force and torque measured during drilling operation show a decreasing trend as the ratio between cutting speed and feed rate increases.
Fatigue tests have been carried out both on non drilled and drilled specimens. Tests conducted on non drilled materials have allowed to define a threshold typical level of maximum force of fatigue loading. Failure cycles number has been taken into consideration comparing the threshold value with the traces of fatigue behaviour acquired during drilled components characterisation. Failure cycles number determined for glass fibres reinforced composites, is not dependent on speed ratio. The extension of damaged area at the exit side of the hole does not significantly affect the fatigue strength of drilled components
Experimental Investigation on the Surface Quality of Natural Stones Machined by Grinding Technology
No full textThe Influence of Drilling Parameters and Hole Damage on GFRP Composites Fatigue Strength
No full textApplication of Holographic Interferometry for Detection of Flaws in Ceramic Coatings on Metal Surfaces
No full text
- …
