Optimisation of grinding parameters for wheel loading and dressing
Grinding is a finishing process often used to produce desired surface roughness with required precision and quality. The performance of grinding wheel significantly depends on the nature of the wheel, morphology of the abrasive grits and the grinding parameters namely speed, feed and depth of cut. As the wheel is performing its grinding operation, its cutting surface is being loaded with metal particles of the workpiece. This wheel loading also affects the surface finish of the workpiece. Hence monitoring the grinding wheel loading and dressing at proper time intervals becomes mandatory to get the desired surface finish. In the quest of developing a low cost monitoring system, it is good enough to analyse the wheel loading on widely used metal specimens such as mild steel, HCHCr steel and aluminium under optimised cutting conditions using the conventional silicon carbide and aluminium oxide wheels for better evaluation of the results. In this work the grinding parameters are optimised by using ANOVA technique. A full factorial experiment was carried out at 5% level of significance, i.e. at 95% confidence level.
Optimization Of Process Parameters For Friction Stir W elding Of Aluminium Alloy 6061 Using Anova.
AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance. Fusion welding of aluminum alloys poses certain problems like porosity, distortion due to high thermal conductivity and solidification shrinkage. Compared to the fusion welding processes that are routinely used for joining aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. In the present work an attempt is made to study the feasibility of joining AA 6061 aluminium alloy by friction stir welding (FSW) technique. In addition ANOV A analysis with three factors is performed and results indicate that among the parameters considered (i.e., the tool rotation speed, welding speed, and the axial force), the most significant parameter on the tensile strength is rotational speed, followed by the axial force and welding speed.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.