Surface Evaluation of a Multi-Pass Flexible Magnetic Burnishing Brush for Rough and Soft Ground 60/40 Brass

Abstract

Burnishing is an advanced finishing process that produces higher-quality surfaces with better hardness and roughness than conventional finishing processes. Herein, a flexible magnetic burnishing brush comprising stainless steel pins under permanent magnet poles was used to investigate the influence of multiple passes and directions on the produced surface of soft and rough ground prepared brass. In total, five different samples were burnished on each of the two brass samples prepared. Four samples were processed in the same direction for up to four passes and the fifth sample was processed with two passes in the opposite direction. Results indicate that there was approximately a 30% increase in hardness and an 83% increase in microroughness for rougher-surface brass samples. For smoothly prepared surfaces, there was approximately a 14% increase in hardness and a 35% increase in microroughness. In the same direction of multi-pass burnishing, increasing the number of passes negatively affected surface roughness; for rougher surfaces, the surface hardness reduced and process uniformity increased owing to surface over-hardening and flaking mechanisms, and for smoother surfaces, the hardness, roughness, and process non-uniformity increased with the number of passes owing to repeated surface deformation at some locations and high flaking at other locations. Compared to single-pass burnishing, wherein the surface roughness and microhardness showed almost no change with high process uniformity, in burnishing with two opposite-direction passes, the produced surface exhibited better surface roughness, process uniformity, and microhardness improvements owing to a reverse strain mechanism. Hence, opposite burnishing passes are recommended.

Novel Permanent Magnetic Surface Work Hardening Process for 60/40 Brass

“…Only one exception occurred at a speed of 1250 rpm, where the highest microhardness average was observed at a low feed rate of 6 mm min −1 ; it also exerted the optimum condition among all the tested conditions. The results of this study conform to those of previous studies that have reported an increase in hardness values on the deformed layer of materials treated by shot peening [27], the waterjet peening process [28], ultrasonic cavitation modification [29], flexible magnetic burnishing brush [20,21], and the ultrasonic surface rolling process [30].…”

“…They showed that the burnishing speed and feed rate determine the surface quality and homogeneity, improving the microhardness by 40%, microroughness by 76%, and corrosion rate at a certain range of speed and feed rate. Alaskari et al [ 21 ] examined the influences of multi passes and directions of FMBB on different initial brass surface conditions at a fixed optimum speed and feed rate. They proved that the initial surface roughness, number of passes, and reverse strain mechanism primarily affect the surface properties and integrity.…”

Surface Characterization of Carbon Steel after Rolling Burnishing Treatment

“…Burnishing is one of the methods of finishing metals and their alloys, sinters and plastics, which involves the use of local plastic deformation [1][2][3], generated in the surface layer of the object [4][5][6][7][8][9], as a result of specific (force and kinematic) interaction of hard and a smooth tool (in the shape of a ball, disc, roller or other) with a machined surface [10][11][12][13][14][15][16][17][18]. The surface state and quality after previous treatment significantly depend on its quality after previous treatment [15][16][17][18][19].…”

“…Jordi Llumà et al proved that an increase in burnishing preload diminishes the ductile behavior of the material and increases its strength representative values, although the proportion of affected material in the cross-section of the specimen is reduced with regard to the whole surface. The influence of multiple passes and directions on the produced surface of soft and rough ground-prepared brass was recommended by Alaskari [10]. The surface after-slide burnishing parameters on the surface roughness of shafts were tested using the artificial neural networks with the best regression statistics, which predicted an average surface roughness of the shafts with R 2 = 0.987 [11].…”