Effect of feed rate on laser surface cladding of cold rolled carbon steel

Abstract

Oil and gas industries require much equipment and tools having extra ordinary hardness, strength, wear and chemical properties. They have been established well that the important manufacturing processes to achieve these properties are laser cladding of special alloys on cheap substrates such as carbon steels. In order to achieve the optimum properties for these industries, controllable dilution between substrate and clad coating should obtained. In this study, the performance of laser cladding is found to be controlled by two important outputs geometry dimensions and microstructure. The geometry dimensions include many features of clad width, clad height, cont act angle, depth of penetration and dilution area. In order to determine the quality of clad coatings, these features were correlated with laser processing parameters such as specific energy. An experimental study has been concentrated on determine the all dimensions and dilution area on cladding Ni- 5 wt% Al mixed powder on a cold rolled low carbon steel. Wide ranges of traverse speeds in the range of 1.5 to 12.5 mm/s were used to produce clad coatings with different dilutions from the substrate. The laser power, laser beam diameter and powder feed rate employed were 1.8 kW, 2.5 mm and 10 g/min respectively; the specific energies used were 58 to 480 J/mm2. Many single or combined features were developed and their values were determined for cladding tracks having different dilutions. It was postulated that the successful cladding process could be described by new developing terms such as effective clad thickness, effective clad dimensions, dilution aspect ratio and effective specific energy. The data obtained could be used effectively to distinguish between cladding and highly alloyed tracks as a function of specific energy and geometry dimensions of the deposit coatings.