Ball Burnishing Research Articles

Effect of sequential turning and burnishing on the surface integrity of Cr–Ni-based stainless steel formed by laser cladding process

Laser cladding has been developed to be an important surface modification technique in re-manufacturing and maintenance fields. However, few components can be fabricated directly to their final shape and simultaneously met the dimension and accuracy requirements by laser cladding method. A ball burnishing process has been adopted as an alternative finishing approach to grinding process. The effects of sequential turning and burnishing process on surface topography, residual stress, microhardness, porosity content and bonding strength of the Cr–Ni-based stainless steel cladding were systematically investigated in this research. Surface topography, residual stress and microhardness were improved by the sequential burnishing process due to the plastic deformation caused by rolling ball. Biaxial compressive residual stress states were generated in the cladding layer. Both the porosity and bonding strength of cladding layer were improved because of the generation of compressive residual stress. The bonding strength of the cladding layer showed several times higher than other coatings formed by high velocity oxy-fuel (HVOF) as well as plasma spraying. The surface integrities of the cladding layers were further evaluated with five-axial polar diagrams. Burnishing process showed a dependency on the pre-procedure, while smooth surfaces would weaken the burnishing effect induced by the rolling ball. The processing chain, sequential turning with wiper insert adopting a high feed rate and burnishing process, is optimized based on the required surface integrity.

Grey-based fuzzy algorithm for the optimization of the ball burnishing process

Abstract In the present study, Grey based fuzzy algorithm was used for the optimization of complex multiple performance characteristics of the ball burnishing process. Experiments have been planned according to Taguchi's L16 orthogonal design matrix. Burnishing force, number of passes, feed rate and burnishing speed were selected as input parameters, whereas surface roughness and microhardness were selected as output responses. Using Grey relation analysis (GRA), Grey relational coefficient (GRC) and Grey relation grade (GRG) were obtained. Then, Grey-based fuzzy algorithm was applied to obtain Grey fuzzy reasoning grade (GFRG). Analysis of variance (ANOVA) was carried out to find the significance and contribution of parameters on multiple performance characteristics. Finally, a confirmation test was applied at the optimum level of GFRG to validate the results. The results also show the feasibility of the Grey-based fuzzy algorithm for continuous improvement in product quality in complex manufacturing processes.

Analysis of Effect of Ball and Roller Burnishing Processes on Surface Roughness on EN8 Steel

Analysis of Effect of Ball and Roller Burnishing Processes on Surface Roughness on EN8 Steel

Modelling of the ball burnishing process with a high-stiffness tool

This paper deals with the problem of forming a surface roughness profile of a machined surface and a definition of the optimal depth of penetration in ball burnishing which would allow minimization of surface roughness. The assumptions, which have been numerically and experimentally verified, claim that maximum surface quality, i.e., minimum surface roughness, Ra, is achieved when the depth of ball penetration into the workpiece material is approximately equal to the maximum peak height, Rp. For the purpose of numerical simulations, a surface roughness model based on milling kinematics was used. Numerical simulations and the used roughness model support the claim that penetrating with a stiff tool up to the mean line of the roughness profile yields best surface quality. The authors maintain that ball penetrations, which exceed Rp, cannot significantly improve surface quality. Furthermore, the phenomenon of profile peak deformation is substantially clarified. The analysis of internal stresses within the workpiece after ball burnishing allowed a relationship to be established between internal stress distribution along the depth of the hardened layer and ball penetration depth.

Application of the response surface methodology in the ball burnishing process for the prediction and analysis of surface hardness of the aluminum alloy AA 7075

Abstract In this study, AA 7075 aluminum alloy has been burnished using different burnishing parameters such as burnishing force, number of passes, feed rate and burnishing speed with a ball burnishing apparatus. Burnishing parameters, which affect the surface hardness, were examined using response surface methodology with rotatable central composite design and analysis of variance. Using the experimental results, a regression model has been developed to predict surface hardness. The statistical analysis showed that, burnishing force and number of passes have the most significant effect on surface hardness. These results, which were obtained from the regression model, are highly consistent with the experiments. The absolute average error between the experimental and predicted values for surface hardness was calculated as 2.79 %. The results of our study show that response surface methodology is a suitable technique that can be efficiently used to predict surface hardness in ball burnishing process.

The inducement of residual stress through deep rolling of AISI 1060 steel and its subsequent relaxation under cyclic loading

The inducement of compressive residual stress by means of deep rolling (also known as ball or roller burnishing) has been widely investigated over the last decades; however, the influence of cyclic loading on stress relaxation of rolled components has not received the same attention. Therefore, the principal aim of this work is to study the behaviour of macro- and microresidual stresses (the latter assessed in terms of the full width at half maximum, FWHM) on the surface of AISI 1060 steel specimens under rotating bending tests. For this purpose, samples with three distinct heat treatments (subcritical annealing, full annealing and hardening by quenching and tempering) were deep rolled at various combinations of rolling pressure and number of passes. The results indicate that the tensile residual stress obtained after turning shifted to compressive stress after deep rolling. The FWHM decreased after deep rolling at the lowest pressure, thus suggesting that deep rolling promoted a better distribution of the dislocations induced by previous turning; however, the further elevation of rolling pressure and number of passes caused the elevation of the FWHM. The macro- and microresidual stress values were not drastically altered after rotating bending testing with an applied stress corresponding to 50 % of the yield strength. Nevertheless, residual stress relaxation was observed with an applied stress of 80 % of the yield strength, though the FWHM did not provide evidence of microresidual stress relaxation. Finally, the analysis of the fractured cross-sections of hardened specimens indicated that the location of the crack initiation site deepens with the elevation of rolling pressure.

Study the influence of a new ball burnishing technique on the surface roughness of AISI 1018 low carbon steel

Hard roller burnishing with a ball tool is a surface-finishing where a free-rotating tool rolls over the machined surface under high pressures and flattens the surface roughness peaks by cold work. In the present work, a new burnishing technique has been applied which enables both single and double ball burnishing process in site after turning without releasing the specimen. Sets of experiments are conducted to investigate the influence of burnishing force, feed, speed and number of tool passes on surface roughness of AISI 1018 Low Carbon Steel specimens. Burnishing results showed significant effectiveness of the new burnishing technique in the process. The results revealed that minimum surface roughness are obtained by applying the double ball burnishing process on AISI 1018 Low Carbon Steel specimens. Improvement in surface finish can be achieved in both single and double ball burnishing by increasing the number of burnishing tool passes. The results are presented in this paper.

Experimental Characterization of the Influence of Lateral Pass Width on Results of a Ball Burnishing Operation

Ball burnishing has proved to be a highly effective mechanical finishing process of industrial workpieces, because of the excellent surface roughness and fatigue performance that induces in treated workpieces. In order to obtain specific target results from this complex plastic deformation process, its parameters must be accurately controlled. This paper focuses on the influence of the lateral pass width on the average surface roughness of aluminum 2007. Two values of lateral pass width are tested, with two control variables: number of burnishing passes and applied burnishing force. Furthermore, the ball burnishing operation is performed with two different tools: a conventional non-assisted ball-burnishing tool, and a vibrations-assisted one. The most suitable lateral pass width proves to be the distance between the highest peak and lowest vale of the P-profile of the burnishing path, and significantly better results are obtained by assisting the process with vibrations. At the end of the paper, values for lateral pass width for each group of operation conditions are recommended.

MODELADO TRIDIMENSIONAL DE RUGOSIDAD SUPERFICIAL PARA EL PROCESO DE BRUÑIDO

Ball burnishing is a plastic deformation process that improves the surface quality of mechanical parts decreasing roughness. The surface roughness is an important parameter of study; it is known that affects friction, lubrication and wear. In this work, a general methodology for finite element and a programming routine based on Parametric Design Language was developed and validated. This methodology is useful to generate parametric models of three-dimensional rough surfaces in a commercial software of finite element. The routine produces a random surface roughness using the mean (x ?) and standard deviation (s) of a normal distribution of real surface roughness. The routine was used to generate roughness models of rectangular and cylindrical specimens. The nodal density for generating roughness and repeatability for a given surface finish were evaluated to optimize the modeled surface roughness. The numerical results show a good correlation to the experimental results. In a future, the routine can be used to generate models through the finite element method to simulate any machining process with random roughness and this enable to study the processes, allowing reducing the high costs of experimental tests.

High-precision Finishing Hard Steel Surfaces Using Cutting, Abrasive and Burnishing Operations

This paper presents the technological and functional capabilities of surface textures produced by high-precision cutting, abrasive and ball burnishing operations on hardened steel parts of about 60 HRC hardness. Special focus was placed on surface textures generated by hard turning, belt grinding and ball burnishing operations which are characterized by the Sz roughness parameter of about 1.3μm and distinctly different values of the Sa parameter. Apart from the standard 2D and 3D roughness parameters, the fractal and motif parameters were analyzed.

Experimental Investigation of the Effect of Burnishing Force on Service Properties of AISI 1010 Steel Plates

This paper presents the results obtained with a new ball burnishing tool developed for the mechanical treatment of large flat surfaces. Several parameters can affect the mechanical behavior and fatigue of workpiece. Our study focused on the effect of the burnishing force on the surface quality and on the service properties (mechanical behavior, fatigue) of AISI 1010 steel hot-rolled plates. Experimental results assert that burnishing force not exceeding 300 N causes an increase in the ductility. In addition, results indicated that the effect of the burnishing force on the residual surface stress was greater in the direction of advance than in the cross-feed direction. Furthermore, the flat burnishing surfaces did not improve the fatigue strength of AISI 1010 steel flat specimens.

Burnishing of aerospace alloy: A theoretical–experimental approach

Burnishing is well known as a very effective surface enhancement method for manufacturing. The current work focuses on obtaining predictable models of surface roughness and residual stresses based on experimental data. Smoother surfaces of aerospace material modified by ball burnishing have been achieved and significant influences of process parameters on both surface roughness and maximum residual stresses are established. A second-order empirical model involving pressure, speed, and feed is developed for surface roughness prediction. The predictive values are compatible with experimental results. Pressure plays an important factor on compressive residual stresses; however, the empirical models only have qualitative compatibility with the experimental results.

Prediction of roughness after ball burnishing of thermally coated surfaces

An analytical model for a ball burnishing process is developed, which allows a prediction of the roughness of a thermally sprayed coating after a post treatment. Based on the observation of a roughness peak, a correlation between the leveling during rolling and the surface pressure under the rolling ball as well as a material parameter is derived and made mathematically describable. The model is verified by experimental studies with various rolling parameters and materials. The agreement between the experimental data and the calculated values is satisfactory.

ANALYSIS OF SURFACE INTEGRITY AFTER HARD TURNING WITH WIPER INSERTS

This paper deals with analysis of surface integrity after hard turning with wiper insert. Surface integrity expressed in terms of surface roughness, microstructure and residual stress state is compared with conventional insert geometry. Structure and stress state after hard turning is also compared with the following super finished and ball burnished surfaces. The results show that wiper cutting insert enables obtaining surface of low surface roughness at high feeds as well as more favourable stress and structure state as opposed to those produced by conventional insert. Surfaces produced by wiper insert exhibit higher resistance against mechanical load as those induced by ball burnishing.

Analysis of surface roughness and hardness in ball burnishing of titanium alloy

Ball burnishing is a popular post-machining metal finishing operation. An attempt has been made in this paper to optimize the process parameters during burnishing of titanium alloy (Ti–6Al–4V). Ball burnishing process parameters such as burnishing speed, burnishing feed, burnishing force and number of passes were considered to minimize the surface roughness and maximize the hardness. The lubricated ball burnishing experiments were planned as per L25 orthogonal array and signal to noise (S/N) ratio was applied to measure the proposed performance characteristics. The validation tests with the optimal levels of parameters were performed to illustrate the effectiveness of Taguchi optimization. The optimization results revealed that burnishing feed and burnishing speed are the significant parameters for minimizing the surface roughness, whereas burnishing force and number of passes play important roles in maximizing the hardness. The optimization results showed greater improvements in surface finish (77%) and hardness (17%) when compared to pre-machined surfaces.

Austenite–martensite phase transformation of biomedical Nitinol by ball burnishing

Nitinol has received considerable attention for biomedical and aerospace applications due to its shape memory and superelastic properties. Shape memory and superelasticity are induced in Nitinol by transforming austenite into martensite. Austenite can transform to martensite by applying stress or heat. One promising method to initiate a stress induced phase transformation is ball burnishing. In this study, phase transformation of Nitinol (Ni50.8Ti49.2) (at.%) by ball burnishing at various forces was investigated. Burnishing tracks were characterized and microstructures in the subsurface were investigated. Also, a corresponding burnishing simulation was performed to gain insight into the phase transformation mechanism of Nitinol by burnishing.

Selection Of Optimal Process Parameters In Ball Burnishing Of Titanium Alloy

The current study deals with the analysis and optimization of the ball burnishing process of titanium alloy (Ti-6Al-4V). The Taguchi method was employed to determine the best combination of ball burnishing process parameters—such as burnishing speed, burnishing feed, burnishing force and number of passes—to minimize surface roughness and maximize hardness. The dry burnishing experiments were planned as per L9 orthogonal array (OA,) and signal-to-noise (S/N) ratio was applied to measure the proposed performance characteristics. Analysis of means (ANOM) and analysis of variance (ANOVA) were carried out to evaluate the optimal levels and to obtain the level of importance of the burnishing parameters, respectively. Validation tests with optimal levels of parameters were performed to illustrate the effectiveness of Taguchi optimization. The optimization results revealed that burnishing feed and burnishing force are the significant parameters for minimizing the surface roughness, whereas number of passes and burnishing force play important roles in maximizing the hardness.

Thermally sprayed finestructured WC-12Co coatings finished by ball burnishing and grinding as an innovative approach to protect forming tools against wear

The forming of high-strength steel sheets offers novel possibilities to produce lightweight structural parts with a high stiffness for the aircraft and automotive industries. However, the employment of such sheet materials leads to intense wear and thus reduces the lifetime of forming tools. At the same time, the requirements concerning their performance, their geometrical complexity, and their shape accuracy have been significantly increased. To counteract this problem, the tools are either treated by different thermo-chemical processes (e.g. hardening, nitriding) or are coated using thin film techniques such as PVD or CVD.In this study, thermal spraying is presented as a cost efficient and more flexible approach to protect the surface of forming tools against wear. For this purpose, planar samples as well as cylindrical deep drawing dies were coated by means of the high velocity oxy-fuel (HVOF) flame spraying technique, utilizing a fine WC-12Co powder (agglomerate size 2–10μm) with a carbide size of 400nm. Prior to the coating operation, a comprehensive parameter optimization was performed based on the statistical design of experiments (DOE) to achieve coatings with improved mechanical and tribological properties. The planar samples were used to ascertain the sliding and rolling wear behavior within two standardized test methods (Ball-on-Disc and Taber Abraser tests). The coated dies were smoothened by ball burnishing as well as grinding and afterwards evaluated within the deep drawing of high strength (HC380LA) steel sheets. In addition, the results were compared to those achieved with an uncoated conventional cold work steel die, which is commonly employed for this operation. In contrast to the cold work steel, both coated dies, the ball burnished as well as the ground die, showed a significantly better wear performance after the forming of 10,000 parts.

Surface Integrity of Inconel 718 by Ball Burnishing

Inconel 718 has wide applications in manufacturing mechanical components such as turbine blades, turbocharger rotors, and nuclear reactors. Since these components are subject to harsh environments such as high temperature, pressure, and corrosion, it is critical to improve the functionality to prevent catastrophic failure due to fatigue or corrosion. Ball burnishing as a low plastic deformation process is a promising technique to enhance surface integrity for increasing component fatigue and corrosion resistance in service. This study focuses on the experimental study on surface integrity of burnished Inconel 718. The effects of burnishing ball size and pressure on surface integrity factors such as surface topography, roughness, and hardness are investigated. The burnished surfaces are smoother than the as-machined ones. Surface hardness after burnishing is higher than the as-machined surfaces, but become stable over a certain burnishing pressure. There exists an optimal process space of ball sized and burnishing pressure for surface finish. In addition, surface hardness after burnishing is higher than the as-machined surfaces, which is confirmed by statistical analysis.

Characterization of Surface Integrity Produced by Sequential Dry Hard Turning and Ball Burnishing Operations

This paper presents the state of surface integrity produced on hardened-high strength 41Cr4 steel after hard machining and finish ball burnishing. Surfaces machined by sequential machining processes were characterized using 2D and 3D surface roughness parameters. Moreover, detailed functionality of the generated surfaces was performed using a set of 3D functional roughness parameters. Among the characteristics of the surface layer, its microstructure, the distribution of microhardness and the residual stresses were determined. This investigation confirms that ball burnishing allows producing surfaces with lower surface roughness and better service properties than those generated by cubic boron nitride (CBN) finish hard turning operations.