MATHEMATICAL MODELING OF FRICTION FORCE AND FRICTION COEFFICIENT AT DEEP DRAWING PROCESS
This paper includes: experimental determination of process and blank holder forces at plate deep drawing, calculation of friction force and friction coefficient on the basis of achieved experimental results, determination of mathematical models Ft = f (SHP, φ, pd) and μ = f (SHP, φ, pd), as well as graphical simulations and analyses of achieved mathematical models. As substance for cooling and lubrication molybdenum disulfide and oil EP50 were used, while tribological conditions of contact surfaces were varied using phosphated and non-phosphated plate (EN 10027-1: DC04; DIN: RRSt14). Research results have shown that the best tribological conditions were achieved with molybdenum disulfide on phosphated plate, and the most influencing parameter is material deformation degree.
Experimental Friction Test by Sheet Metal Deep Drawing Process
Friction in forming processes is a very complex phenomenon depending on the workpiece material, tool work zone geometry, deformation degree and drawing speed, contact conditions quality, motion and lubricant type. The knowledge of intensity and distribution of the contact stresses and the friction coefficient in metal forming processes is the importance both from the theoretical standpoint of process analysis and the practical application. The direct contact stresses determining method has been applied. On the basis of this has been conceptually elaborated and designed a sensor for normal (pn) and tangential contact stresses (tauf) measurement by deep drawing process of sheet metal. On the basis of the measuring results it has been analyzed the dependence of the friction contact coefficient (mi) on the technological lubricant type (lambda) and degree of deformation (fi).
Growth from Solutions
Growth from solutions is the crystallization of a compound whose chemical composition differs markedly from that of the initial liquid phase. Commonly used solvents are water, multicomponent aqueous or nonaqueous solutions, and melts of some chemical compounds. Differentiations are made based on growth temperatures and on the chemical nature of the solvent. In growth from low-temperature aqueous solutions, the temperatures generally do not exceed 80–90°C; in growth from superheated aqueous solutions (hydrothermal method), they reach 800°C, and in growth from salt melts (molten-salt, flux, or fluxed melt growth), they usually do not exceed 1200–1300°C, but sometimes reach 1500°C.