Abstract: Determining tool steels properties, especially deformation and flow behavior in the semi-solid zone, is an essential parameter for thixoforming process. The main objective of this work is an analysis microstructure and flow behavior determining of AISI D2 tool steel in the combined uniaxial constant load compression and electrical resistance heating in the semi-solid state. The as-received material used for experiments, were in the hot rolled-annealed condition. The globular solid particles suspended in liquid phase, were obtained by the joule heating of samples. The experiments were carried out for 0.2 to 0.3 liquid phase fraction under 160N uniaxial constant load in the specimens with 10 mm height and the same Diameter value. Microstructural evaluation before and after heating has also been presented. Structural and elemental analysis was performed with the help of optical microscopy and scanning electron microscopy. The microhardness test has been carried out on the solid particles of quenched samples. The hardness values were changed from 317HV0.1 to 463HV0.1 by increasing the liquid phase. Finally, a new approach based on plastic instability and power law equation was used for flow behavior detection. The results showed that combination joule heating and plastic instability approach is compatible for flow behavior detection of AISI D2 steels in the semi-solid state.

Abstract: Stability of process of welding of copper with copper and copper with steel is provided with a special thermal cycle which includes preliminary heating before welding. Difficulties welding copper and steel are connected with its physical and chemical properties, high affinity of copper to oxygen, the low temperature of melting of copper, considerable absorption by liquid copper of gases, various sizes of coefficients of heat conductivity, linear expansion etc. In view of high heat conductivity of copper the most part of heat entered at welding is removed from heat input zone that leads to necessity of supply to a place of welding considerably a more heat, than at welding other metals. More rational is the local heating. Using impulse heating of welded details at welding copper and steel instead of gas flame lowers carbonization of details’ surfaces. Uniformity of welded details microstructure is provided. Welding defects caused by non-uniform heating are eliminated.

Abstract: An experimental study was conducted for measuring the quality of surface finishing roughness using magnetic abrasive finishing technique (MAF) on brass plate which is very difficult to be polish by a conventional machining process where the cost is high and much more susceptible to surface damage as compared to other materials. Four operation parameters were studied, the gap between the work piece and the electromagnetic inductor, the current that generate the flux, the rotational Spindale speed and amount of abrasive powder size considering constant linear feed movement between machine head and workpiece. Adaptive Neuro fuzzy inference system (ANFIS) was implemented for evaluation of a series of experiments and a verification with respect to specimen roughness change has been optimized and usefully achieved by obtained results were an average of the error between the surface roughness predicted by model simulation and that of direct measure is 2.0222 %.

Abstract:

Abstract: Galvanizing plant waste (zinc dross) containing 27.66% zinc was leached in HCl solutions. Zinc in solution was precipitated as Zn(OH)₂ by adding ammonium hydroxide. The product was characterized by atomic absorption spectroscopy, thermogravimetric analysis, x-ray diffraction analysis, and scanning electron microscopy. X-ray diffraction analysis confirmed that when heated at 500^oC, the product possesses hexagonal zincite structure. Scanning electron microscopy confirmed that the shape of zinc oxide particles was spherical and compares well with the standard product. A maximum of 93.7% zinc contained in the dross could be extracted and converted to zinc oxide having a purity of 98.8%.