Adel Mahmood Hassan

The effects of ball- and roller-burnishing on the surface roughness and hardness of some non-ferrous metals

Simple ball- and roller-burnishing tools were used for the experimental work of the present study, these tools being quite similar in their design principles. The performance of the tools, together with the effects of the burnishing force and the number of burnishing tool passes on the surface roughness and surface hardness of commercially available aluminum and brass, were studied. The results show that improvements in the surface roughness and increases in the surface hardness were achieved by the application of both ball burnishing and roller burnishing with the non-ferrous metals under consideration.

Influence of burnishing process on surface roughness, hardness, and microstructure of some non-ferrous metals

Burnishing is a cold working process, which easily produces a smooth and work-hardened surface by plastic deformation of surface irregularities. In the present work, the influence of the main burnishing parameters (speed, feed, force, number of tool passes, and ball diameter) on the surface roughness and the hardness of two different non-ferrous metals were studied. Furthermore, subsurface hardness and microstructure under specific conditions were also studied. It was found that the burnishing forces and the number of tool passes are the most pronounced parameters, which have great effects on the workpieces surface during the burnishing process. A simple, inexpensive and newly designed ball-burnishing tool, with interchangeable adapter for using different ball diameters, was used throughout the experimental work presented in this paper.

Improvements in some properties of non-ferrous metals by the application of the ball-burnishing process

Abstract In the present study, commercial purity aluminum and brass were selected as materials for making the specimens, and 10 mm carbon chromium balls were used for the burnishing process. The specimens were machined to the proper dimensions using a conventional turning machine or a copying lathe machine. These machined specimens were then burnished by a simple, newly-designed ball-burnishing tool. The surface roughness, hardness, proof stress, ultimate tensile strength and fatigue strength before and after burnishing were studied, the results showing some improvement in the above-mentioned properties due to the burnishing process.

The effects of initial burnishing parameters on non-ferrous components

Abstract Most of the previous works published on burnishing process concentrated on the effects of load, feed, speed, and number of tool passes. In the present study the effects of additional parameters such as the initial surface roughness and hardness of the workpiece, the ball diameter of the burnishing tool and the use of different lubricants on this process were studied. Two non-ferrous workpiece materials, namely free machining brass and cast Al–Cu alloy, were used. The results show that most of the above-mentioned initial burnishing parameters have significant effects on the burnishing process.

Improvement in the wear resistance of brass components by the ball burnishing process

Abstract In the present work a ball-burnishing tool was used to improve the surface roughness and surface hardness of brass components. The burnishing process was carried out under different forces and number of tool passes. A simple wear-testing device was designed and constructed to meet the present work requirements. The results obtained from the wear tests show that the burnishing process can be used to improve the wear resistance of the brass components considered.

An investigation into the surface characteristics of burnished cast AlCu alloys

Abstract Burnishing is considered as a surface finishing process. In this process the metallic surface of the workpiece undergoes plastic deformation by the pressing action of a hard and highly polished rotating burnishing ball or roller. In the present work an attempt was made to study the effects of different burnishing parameters (force, speed and feed) on surface roughness and hardness of cast AlCu alloys. The experiments were conducted with a simply designed ball burnishing tool. The results obtained show that an improvement in surface characteristics can be achieved by the application of this process on cast AlCu workpieces.

Further improvements in some properties of shot peened components using the burnishing process

Abstract Shot peening and burnishing are considered to be cold working processes, where both processes are used to improve some metallic surface properties, due to the plastic deformation induced into these surfaces. The first process causes an increase in the roughness, while the other, in opposition to the first process, improves the smoothness of metallic surfaces. The present work is an attempt to apply the burnishing process onto shot peened components, in order to decrease the roughness of the metallic surface caused by the shot peening process. From the results obtained it was found that the burnishing process not only improves the surface finish, but it also introduces further improvements in surface hardness, fatigue strength and corrosion resistance for the two non-ferrous metals considered in this work, namely aluminium and brass. Accordingly, it can be suggested that burnishing of shot peened components may be used with benefits in industry for further improvements in the properties of metallic surfaces.

Effect of Graphite and/or Silicon Carbide Particles Addition on the Hardness and Surface Roughness of Al-4 wt% Mg Alloy

In this study, the fabrication of Al-4 wt% Mg-graphite and/or silicon carbide (SiC) particulate composites is described. Composites of Al-4 wt% Mg alloy with different volume percentage values of graphite and/or SiC particles are prepared using the compocasting technique. In this technique, graphite particles and/or SiC particles are added into a semi-solid slurry during the stirring of the melt. A pitched blade stirrer is used to stir the reinforcement particles in the slurry. The slurry is then poured in a metallic mold to obtain the cast composites. The effect of the addition of graphite and/or SiC particles and porosity content on the Rockwell hardness and machinability is studied in the present work. The results show that the porosities increase with increase in particles content while Rockwell hardness decreases with increase of graphite particles. But SiC particles are found to increase the hardness of composites. Surface roughness improves with graphite content in the cast composite, and poor surface finish is obtained when SiC particles are added.

Surface Characteristics of Some Roller Burnished Non-ferrous Components

Abstract Burnishing as a cold working process can be used to decrease the roughness of surfaces, and to increase the surface hardness as a result of work hardening. In the present work, a roller type burnishing tool was used to study the influence of the main burnishing parameters on the surface roughness and hardness of commercial aluminum and brass. It was found that roller-burnishing can be used successfully to improve surface roughness and to increase surface hardness. Also, it was found that burnishing force and number of burnishing tool passes are the predominant parameters, for control of surface roughness and hardness of rolled-burnished components.

Effect of Processing Parameters on Friction Stir Welded Aluminum Matrix Composites Wear Behavior

In the present work, the aluminum matrix composites reinforced with both SiC and graphite particles are joined using a friction stir welding (FSW) process. The wear characteristics of the welded joints were investigated at constant load of 50 N and a rotational speed of 1,000 rpm using a pin-on-disk wear testing apparatus. This study focuses on the influences of the FSW processing parameters (tool geometry, rotational speed, and welding speed) on the wear characteristics of the welded joint of the considered hybrid aluminum matrix composite under dry sliding conditions. The experimental results indicate that the wear resistance of the joint increases at high welding speeds (>45 mm/min) and/or low value of rotational speeds. Different tool pin profiles (square, octagonal, and hexagonal) are developed to perform the welding process, and the effects of the tool pin profile on the weldments were studied. It is found that joints welded with square pin profile have better wear resistance compared to the other pin profiles. The results demonstrate that the FSW processing parameters greatly affect on the wear resistance of the welded joints due to various microstructural modifications during welding that cause an improvement in the welded zone hardness and wear properties.