Metal matrix composites being used in automobile, aviation, naval, space and other structural applications because of their unique balance of physical and mechanical properties. The metal matrix composites are produced using diverse technologies in order to meet the market demand such as lower density, higher wear resistance, thermal stability at lower cost per component. Composite materials replace almost all the monolithic material while posing challenges for machining hence are graded as difficult to machine materials. The hetrogeneous structure of the composite materials leads to the failure of cutting tool during machining composites are mainly attributed for the presence of hard particles which leads to higher surface roughness value. Thus, present paper presents the results on surface roughness values of K10 grade carbide and Poly Crystaline Diamond (PCD) inserts while turning Al6061-flyash composites containing 0% to 15% fly ash in step of 5%. Parametric studies have been carried out as per ISO3685 standards following dry machining condition. The machining parameters are cutting speeds of 300m/min to 600m/min in step of 100m/min, feed of 0.06mm/revolution to 0.24mm/revolution in step of 0.06mm/revolution using a constant depth of cut of 1.2 mm which is equal to three times to the nose radius of the cutting tool. The results revealed that PCD inserts exhibits lower surface roughness while turning composites containing 10% filler material when compared with that of K10 grade tungsten carbide insert.

No abstract

This paper reveals the influences of pulsed current parameters namely peak current, back current, pulse and pulse width on the ultimate tensile strength of Micro Plasma Arc Welded Inconel 625 sheets. Mathematical model is developed to predict ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 sheets. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical model has been developed by using Response Surface Method. The adequacy of the developed model is checked by using Analysis of Variance technique. By using the developed mathematical model, ultimate tensile strength of the weld joints are predicted with 99% confidence level. Validation experiments are conducted to validate the predicted values of the developed mathematical model. From the contour plots, it is understood that ultimate tensile strength is more sensitive to peak current and pulse. Also it is found that peak current is most dominant parameter out of all the selected parameters. The developed mathematical model has been optimized using Response Surface Method to maximize the ultimate tensile strength. The weld joints fabricated using peak current of 7 Amps, back current of 4 Amps , pulse of 40 pulses/sec and pulse with of 50% yielded superior ultimate tensile strength of 833 MPa compared to the other joints.

No abstract

No abstract