Query: burnishing

title: Surface Texture Analysis of Hardened Shafts after Ceramic Ball Burnishing
abstract: This article represents the results of testing the surface condition of shafts manufactured by the burnishing process. The shafts with a hardness of approximately 62 HRC (Rockwell C) were burnished with a ceramic ball (Si3N4) where the force range was controlled by the means of a hydraulic system. The machining process consisted of hard turning shafts with cubic boron nitride (CBN) inserts, followed by burnishing with the use of various machining parameters, such as feed and force. The research focused on the examination of burnished surfaces, which was conducted for various structures after hard turning, and with variable burnishing parameters. The results obtained for the decrease of roughness are presented as the relation between the parameters Rat/Rab, which is approximately 2, while for Rpkt/Rpkb, it is around 3.7, respectively. Sat/Sab is around 2, while Spkt/Spkb is around 3.5 (where an index denotes the t surface after turning, and the index b surface after burnishing) The structure of the surface after burnishing and turning is described with roughness parameters, as well as with the photographs of the specimen surface, and the bearing area curve.

title: Analytical modeling of ultrasonic surface burnishing process: Evaluation of residual stress field distribution and strip deflection
abstract: Ultrasonic surface burnishing (USB) process is a promising surface enhancement technique that improves fatigue life of components by exerting work hardening and compressive residual stress of the surface layers. However, USB is a complex process in practice, and there is not an analytical model published to facilitate the design and comprehension of the process. In the present paper an analytical elastic plastic model was developed to correlate USB process factors to residual stress field (RSF) Also, deformation of strip samples was determined in the analytical approach. Parameters such static force, ultrasonic vibration amplitude, ball material and its diameter as well as ultrasonic vibration frequency were included in the model to find how they influence the residual stress variation and strip deflection. Two types of material constitutive equation i.e. Johnson Cook (JC) that is sensitive to strain rate as well as Chaboche hardening that is influenced by cyclic loading were considered to find which material behavior is more consistent with experimental results. The experiments have been carried out on two different materials with various initial state of residual stress field (IRSF) It was obtained from the results that residual stress field variation and strip deflection obtained by experiments are consistent well with the values derived from analytical model. Therefore, the model was comprehensively used to find how the USB process factors influence the RSF and strip deflection.

title: Joining metrics enhancement when combining FSW and ball burnishing in a 2050 aluminium alloy
abstract: This report describes the effect of the ball burnishing process on the mechanical properties of 2050 aluminium alloy that was previously friction stir welded. This process is a fast, environmentally friendly and cost effective surface treatment based on the plastic deformation of the surface irregularities. Consequently, residual stress, material hardening and micro structural alterations are investigated to improve fatigue strength and wear resistance. The results show that the ball burnishing treatment enhances the surface properties by increasing the material hardness about 37.5% and by decreasing the average surface roughness from 2.23 mm to 0.06 mm when a high pressure and a perpendicular burnishing is deployed. Additionally, in depth compressive residual stresses are generated from 315 MPa to 700 MPa depending on the burnishing configuration. Finally, a numerical simulation of the material elastoplastic response is performed to analyze the residual stress continuity in the cross sectional area when using two radial feeds and burnishing pressures. In short, the present study helps to reduce time consumption by selecting the larger radial feed combined with a proper burnishing pressure to ensure the desired quality and compressive residual stress at the surface, which are indices of enhancing the fatigue strength at the nugget zone of the welded area.

title: Influence of hydrostatic burnishing strategy on the surface topography of martensitic steel
abstract: This paper describes a study on the stereometric structure of an X38CrMoV5 1 surface after ball burnishing. The features of burnishing include a good roughness and an improvement in the mechanical characteristics of the surface owing to an implementation of compressive stresses into the surface layer. A burnishing as a finishing operation was conducted using two different strategies: raster and spiral techniques. The raster strategy is most appropriate for rectangular shapes and consists of creating a raster texture in a model edges and projecting it onto the mold surface. The spiral burnishing strategy provides a constant step over relative to the burnishing surface. Surface topographies were measured using non contact 3D surface profiler Talysurf Lite with correlation coherence interferometry technology and the external source of white light. CCI is an advanced optical technique and can be used for precise measurement of surface topography especially those, which are characterized by a complex structure. This paper presents the influences of hydrostatic burnishing strategies and burnishing parameters on the roughness for X38CrMoV5 1 steel. The investigation shows that the using the raster strategy Sq was lowered to the mean value of 0.3 0.1 mm. A different impact was observed for the spiral strategy. Due to the path of a tool handling, significant deterioration of the surface was observed after burnishing. For both of the analysed machining strategies, the kurtosis of height distribution Sku is higher than 3, which means that the surface will be characterized by peak presence. The density of peaks Spd parameter show that raster strategy is a far more stable process, almost comparable with milling. The raster strategy is a good solution in the burnishing of curved shapes surfaces due to the process stability.

title: Effect of shot peening and low plasticity burnishing on the high cycle fatigue strength of DIN 34CrNiMo6 alloy steel
abstract: This work presents a study and comparison of the effect of shot peening (SP) and low plasticity burnishing (LPB) on the high cycle fatigue of a DIN 34CrNiMo6, quenched and tempered, steel. Additionally, this work also provides data, coefficients, and procedures for the fatigue design and analysis of components treated by SP and LPB. Four sets of specimens have been tested to obtain alternating bending S N curves, namely, machined, mirror polished, and SP and LPB treated specimens. Compared with the machined specimens, the fatigue limit of the SP specimens increased by 39% whereas that of the LPB specimens increased by 52% Attention has been given to the measurement of the surface and in depth residual stress field of the SP and LPB specimens, including a study on the relaxation of the surface residual stresses under cyclic load and the development of a model to predict the evolution of residual stresses with time.

title: Analytical modeling of ultrasonic burnishing process: Evaluation of active forces
abstract: In our recently published work i.e. Teimouri et al.  mechanic of forces acting during burnishing process has been identified and fully discussed. The process was modeled based on slab method theorem and effect of burnishing parameters on horizontal and vertical forces were identified. However, the present work is an analytical approach to find effect of ultrasonic vibration parameters and pass number considering elastic rebound of work surface. In the proposed methodology effect of different parameters such as feed rate, ball diameter, depth of burnishing, vibration amplitude and pass number on the burnishing force. The comparison with experimental results allows to affirm that the model is a useful tool to predict the value of resultant burnishing force.

title: Analytical modeling of ultrasonic surface burnishing process: Evaluation of through depth localized strain
abstract: During surface treatment process, microstructure change beneath the surface layers and relevant mechanical properties depend to amount of work hardening occurs through depth of the treated samples. In the present work, an analytical model of surface plastic strain based on contact mechanic theorem is proposed to analyze the ultrasonic burnishing parameters. The model comprises effect of factors such static force, feed rate, ball diameter and ball material as well as ultrasonic vibration parameters such as amplitude and frequency. To incorporate effect of feed rate, two important parameters such as linear coverage coefficient and overlapping ratio have been defined and contributed in the model. The through depth localized plastic strain has been verified by 3D finite element simulation model for different parameter combination. Since, in surface treatment process such as ultrasonic burnishing the surface hardness and microstructure is directly influenced by the plastic strain, a series of experiments have been carried out and through depth hardness profiles has been obtained. It was found from the results that the through depth plastic strain distribution is consistent well with that derived from FE simulation. According to the analytical model, surface plastic strain and relevant affected depth increases by increase of static force and vibration amplitude. Also, it decreases by increase of ball radius and feed rate. On the other hand, it was found that using tungsten carbide ball significantly enhances the surface plastic strain compared to the ball made of steel and silicon nitride. The analytical model of strain and relevant affected depth was completely in line with the variation of through depth hardness and relevant hardened depth.

title: Comprehensive analysis of surface integrity modification of ball end milled Ti 6Al 4V surfaces through vibration assisted ball burnishing
abstract: This paper is an experimental research about the mechanical effects on Ti 6Al 4V surfaces treated with an ultrasonic vibration assisted ball burnishing process. Its aim is to define the process parameters to achieve the best surface integrity on the target workpiece, as well as identifying the effects caused by the introduction of vibrations as a means of assistance. A Taguchi orthogonal array including five factors (preload, number of passes, feed velocity, strategy and original surface texture) was applied to perform the process on ball end milled surfaces. A comprehensive analysis of the effects was performed, by considering in depth three different facets of surface integrity, namely, topology, residual stress and hardness. Hence the extensive result datasets presented in this paper, which deliver an exhaustive description of the process effects by combining a triple approach in the results analysis section. The effect of vibrations is proved positive to enhance the texture as long as the original surface is not characterized by Sq >2 mm. Furthermore, only the preload and number of passes influence the results. In terms of residual stress, all parameters are influential in the results, especially the burnishing strategy, through which a specific direction can be reinforced. Finally, the burnishing operation proves to modify the hardness of deep layers down to 0.5 mm, applying the vibration assisted process. The main conclusion derived from these works is a technical recommendation to treat the Ti 6Al 4 V surface through the process, aiming to find a balanced comprehensive surface integrity enhancement.

title: Burnishing of FSW Aluminum Al Cu Li Components
abstract: Ball burnishing is presented herein as a mechanical surface treatment for improving mechanical properties after the friction stir welding process. Ball burnishing provides good surface finish, high compressive residual stresses, and a hardness increase of the surface layer. These characteristics are key for the fatigue life improvement of the component, and for wear resistance due to the higher hardness. This work presents a complete analysis of surface and sub surface hardness values focusing on the determination of each process parameter influence. Burnishing pressure, radial width, and burnishing direction influence were analyzed. The tested material was 2050 aluminum alloy with two different heat treatments (T3 and T8) The optimum parameters were established, and a complete analysis of the surface hardness was performed. Results show that burnishing is an economical and feasible mechanical treatment for the quality improvement of component surfaces.

title: Correlation of surface integrity with processing parameters and advanced interface cooling/lubrication in burnishing of Ti 6Al 4V alloy
abstract: Burnishing (also known as deep rolling) is a chipless finishing process used to improve the surface integrity of metals by severe plastic deformation (SPD) of surface asperities. As surface integrity has a large impact upon the functional performance of aerospace components and assemblies, burnishing is a means of significantly increasing the cyclical fatigue life of critical components, such as turbine and compressor airfoils. The objective of this study was to evaluate the process induced surface integrity of Ti 6Al 4V alloy as a function of number of overlapping passes, loading force, as well as feed and speed, for four cooling/lubrication conditions: conventional flood cooling (emulsion) minimum quantity lubrication (MQL) cryogenic cooling (LN2) and hybrid cooling/lubrication (MQL+LN2) Analysis revealed that all examined burnishing parameters, with the exception of speed, play a fundamental role in controlling the processed surface integrity and thus also in the likely functional performance of Ti 6Al 4V aerospace components.