Plastic Deformation Of Sheet Research Articles

Variation of surface roughness, micro-hardness and friction behaviour during sheet-metal forming

The aim of the research described in this paper is to analyse the evolution of the main surface parameters values and friction coefficient value due to the sheet deformation. Frictional properties of the deep-drawing quality steel sheets were investigated using the strip drawing test under both dry and lubricated conditions. An increase in the plastic deformation of sheets in the range of true strain between 0 to 0.28 caused an increase in the value of amplitude roughness parameters Ra, Rp, Rt, measured along the rolling direction of the sheet metal and perpendicular to this direction. The character of frictional phenomena of the deformed sheets is a complex function of sheet directional topography, formed by pre-straining and strain-hardening phenomena. It was also found that owing to the strain-hardening phenomenon the micro-hardness of the sheet increased with the sheet deformation. However, this relation was near linear.

On the influence of deformation of deep drawing quality steel sheet on surface topography and friction

In this paper, the effect of sheet deformation on the change of the surface roughness parameters and friction coefficient value is considered. For this purpose, deep drawing quality (DDQ) steel samples were straightened using a uniaxial tensile test to different true strain values. The correlation between the surface roughness parameters and frictional conditions of the tested sheets was investigated in the strip drawing test. It was found that the friction coefficient determined for all pre-strained samples decreases with increasing nominal pressure of rolls under both dry and lubricated conditions. An increase in the plastic deformation of sheets under the uniaxial tensile stress state causes a nearly linear increase in the value of basic amplitude parameters of surface roughness.

Cu-Ti-B Composite Powder Prepared by Mechanical Alloying

Taking Cu, Ti and B powder as raw material, Cu-Ti-B composite powder was prepared by mechanical alloying (MA). The phase, microstructure of the powder during MA process was studied by XRD and SEM, and combining the flour yield to study the best ball mill time. The result shows that: Early ball milling, powder particle size drops rapidly. Extruding and shearing force between grinding balls, plastic deformation of sheets. After 15h, XRD diffraction peak intensity decrease stabilize, particle size reduce to around 20 um. Ball milling after 20 h, powder refining trend slowing, produce powder together. Considering the efficiency of ball milling and powder particle size requirements, determine the best ball milling time for 15 h.

Cu-Ti-B Composite Powder Prepared by Mechanical Alloying

Taking Cu, Ti and B powder as raw material, Cu-Ti-B composite powder was prepared by mechanical alloying (MA). The phase, microstructure of the powder during MA process was studied by XRD and SEM, and combining the flour yield to study the best ball mill time. The result shows that: Early ball milling, powder particle size drops rapidly. Extruding and shearing force between grinding balls, plastic deformation of sheets. After 15h, XRD diffraction peak intensity decrease stabilize, particle size reduce to around 20 um. Ball milling after 20 h, powder refining trend slowing, produce powder together. Considering the efficiency of ball milling and powder particle size requirements, determine the best ball milling time for 15 h.

Effect of temperature on plastic deformation of sheet by electromagnetic force

Based on the new method of controlling welding distortion with trailing electromagnetic force, the electromagnetic force and the plastic deformation of sheet by electromagnetic force at different temperature was simulated by ANSYS. The circuit–electromagnetic–structural coupling was carried out with physical environment method. The results show that the magnitude of peak axial force decreases and the magnitude of peak radial force increases with increasing temperature. The variation of electromagnetic force with temperature is nonlinear. The variation rate of axial force decreases and the variation rate of radial force increases with increasing temperature. The driving force of sheet deformation decreases with increasing temperature because the axial force is larger than radial force so much. But the plastic strain of sheet by electromagnetic force increases with increasing temperature due to the decreasing yield strength. Compared with the post-welding processing, the energy supplied to processing is reduced when the electromagnetic force is applied to the controlling of welding distortion as an impactive source during welding.