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

Ayman M Alaskari,Tatiana Liptakova,Abdulaziz I Albannai,Meshal Y Alawadhi,Abdullah A Alazemi,Abdulkareem S Aloraier

doi:10.3390/ma13194465

Ayman M Alaskari, Tatiana Liptakova + Show 4 more

Open Access

https://doi.org/10.3390/ma13194465

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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.

Highlights

All machined surfaces have inherent peaks and valleys, known as surface roughness, which are produced by tools and other factors such as vibrations in machine structures, wear, and process parameters
Decreased with the number of passes with a minor exception for the third pass, where a slight increase microhardness values decreased with the number of passes with a minor exception for the third pass, in microhardness was observed
The burnishing parameters used in present study were selected based on the optimum surface quality, hardness, roughness, and corrosion the present study were selected based on the optimum surface quality, hardness, roughness, and resistance of a previous study conducted only on 180 grit of C274 brass samples [20], wherein the corrosion resistance of a previous study conducted only on 180 grit of C274 brass samples [20], optimum parameters, which in turn correspond to the optimum force, were found to be 1000 rpm and wherein the optimum parameters, which in turn correspond to the optimum force, were found to be 12 mm min−1

Summary

Introduction

All machined surfaces have inherent peaks and valleys, known as surface roughness, which are produced by tools and other factors such as vibrations in machine structures, wear, and process parameters. Some conventional machining processes that depend on chip removal, such as turning and grinding can produce surfaces with high surface roughness; such surfaces are of low quality owing to surface abrasion and geometric tolerance problems caused by machined chips [3]. Post-machining surface finishing methods, such as burnishing, which is based on the cold working principle, are employed to achieve good surface roughness along with other added advantages such as high microhardness, wear resistance, fatigue strength, and corrosion resistance [5]. Burnishing is a mechanical surface modification technique and chipless operation that can be utilized in various industries as a final finishing process to generate smooth high-quality surfaces or surfaces with specific structures [3,6]. Burnishing is intentionally employed to induce compressive residual stresses on the surface of load-bearing engineering components such as the landing gear, leaf springs, pipeline seams, and turbine blades [8]

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