Effects of roller burnishing process parameters on surface roughness of A356/5%SiC composite using response surface methodology

In this study,a simple roller burnishing tool was made to operate burnishing processes on A356/5%SiC metal matrix composite fabricated by electromagnetic stir casting under different parameters.The effects of burnishing speed,burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured.Scanning electron microscopy(SEM) graphs of the machined surface with PCD(insert-10) tool and roller burnished surface with tungsten carbide(WC) roller were taken into consideration to observe the surface finish of metal matrix composites.The mechanical properties(tensile strength,hardness,ductility) of A356/5%SiC metal matrix composites were studied for both unburnished samples and burnished samples.The results revealed that the roller burnished samples of A356/5%SiC led to the improvement in tensile strength,hardness and ductility.In order to find out the effects of roller burnishing process parameters on the surface roughness of A35675%SiC metal matrix composite,response surface methodology(RSM)(Box-Behnken design) was used and a prediction model was developed relevant to average surface roughness using experimental data.In the range of process parameters,the result shows that roller burnishing speed increases,and surface roughness decreases,but on the other hand roller burnishing force and number of passes increase,and surface roughness increases.Optimum values of burnishing speed(1.5 m/s),burnishing force(50 N) and number of passes(2)during roller burnishing of A356/5%SiC metal matrix composite to minimize the surface roughness(predicted1.232 urn) have been found out.There was only 5.03%error in the experimental and modeled results of surface roughness.     

Investigations on the Effect of Ball Burnishing Parameters on Surface Hardness and Wear Resistance of HSLA Dual-Phase Steels

Surface finish has a vital influence on most functional properties of a component like fatigue life, wear resistance, corrosion resistance, etc. This has given birth to processes such as lapping, honing, burnishing, etc. Burnishing is a fine finishing operation involving the cold working plastic deformation of surface layers to enhance the surface integrity and the functional utility of a component. The present study has been carried out to establish the effect of burnishing parameters viz. feed rate, speed, force, ball diameter and lubricant on surface hardness, and wear resistance of HSLA dual-phase steel specimens. The result indicates that burnishing parameters have significant effect on the surface hardness and wear resistance.     

Surface Characteristics of Some Roller Burnished Non-ferrous Components

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.     

Investigation of TiAlN coated roller burnishing on Al-(B4C)p MMC workpiece material

Burnishing avoids the need for super finishing operations after the conventional turning process, to enhance the surface quality. This paper deals with the surface modifications of Al(B₄C)_p Metal Matrix Composites (MMC) workpiece material after burnishing with a TiAlN coated WC roller. The burnishing speed, lubrication type, burnishing passes, and coating were the input parameters. Surface hardness and roughness after the burnishing were studied. It was found that the coating on the WC roller had enhanced the hardness in the workpiece after burnishing in the case of Al-5?wt.% (B₄C)_p, under all conditions. The effect of the coating on the work piece surface hardness was not significant with Al-10?wt.% (B₄C)_p. While burnishing Al-5?wt.% (B₄C)_p, the minimum surface roughness combined with maximum surface hardness was obtained, during the third pass under dry condition using uncoated rollers. The number of passes to achieve the desired surface conditions reduced, on using coated rollers with kerosene as the lubricant.     

Optimization of interior roller burnishing process for improving surface quality

Improving the surface characteristics of roller burnishing processes is one of effective approaches to decrease the machining costs and time. This paper systematically investigates the nonlinear relationships between machining parameters and surface characteristics, including surface roughness (R_a), surface hardness (H), and hardness depth (HD) of the interior roller burnishing using response surface method (RSM) model. Three process parameters considered include spindle speed S, feed rate F, and burnishing depth D. A set of physical experiments was carried out with AISI 1045 steel on a computer numerical control (CNC) milling machine using the roller burnishing tool. The target of the current complex optimization is to enhance the surface hardness and hardness depth, while the surface roughness is considered as the constraint. Finally, an evolutionary algorithm entitled archive-based micro genetic algorithm (AMGA) was used to generate a set of feasible optimal solutions and determine the best machining conditions. The results show that an appropriate trade-off solution can be drawn with regard to the low surface roughness and high the surface hardness as well as hardness depth. Furthermore, the integration of RSM model and AMGA can be considered as a powerful approach for modeling and optimizing interior roller burnishing processes.     

Experimental investigation on the ball burnishing of carbon fiber reinforced polymer

The polymer-based materials are generally used in all industrial applications. Even if polymer bars can be machined easily, they need surface finishing treatment after the machining process. The ductile properties make coarse roughness on the surface that causes the elastic structure of polymer materials. The carbon fiber reinforced composite materials differ from polymer-based materials by high strength and stiffness. Its structure exhibits similar performances such as metallic materials. The effect of ball burnishing on the surface quality of rod workpiece was investigated in this study. To enhance the surface quality of high strength carbon fiber reinforced polymer rod workpiece, burnishing process was performed in three different parameters (force, feed rate, number of passes) and under four different mediums (dry, wet, boron oil, and mineral oil) conditions. The results of the experiments were analyzed, and optimum burnishing parameters were determined and discussed in detail. The best surface roughness value of the CFRP material used in the experiments was obtained as burnishing force: 250 N, feed rate: 0.05 mm/rev, four passes and wet medium. According to the results of variance analysis, it was found that the CFRP workpiece is the important leading factor for surface roughness with a contribution ratio of 62.47%.     

Verschleißanalyse gewalzter und geschliffener Eisenbasislegierungsschichten mit und ohne Hartstoffverstärkung

In this research work the wear behavior of thermal sprayed wear resistant coatings, which are finished by incremental roller burnishing and by grinding in order to smooth the surface, are analyzed by means of the Pin‐on‐Disc test. Two different arc sprayed coatings WSC‐FeCSiMn and FeCrBSiMn are compared to each other. At first the microstructure of the smoothed coatings were characterized by investigation of the topography and morphology. After that the wear behavior was analyzed with two different counterparts made of stainless steel and ceramic. In order to determine the different wear mechanisms the wear traces have been investigated by scanning electron microscope.     

液晶聚芳酰胺自组装膜的摩擦学性能

研究了液晶聚芳酰胺在表面羟基化载玻片上的自组装行为及液晶聚合物薄膜的摩擦磨损性能。结果表明．自组装液晶聚芳酰胺薄膜修饰的基底在低载荷下与Si3N4陶瓷球对磨时的摩擦系数非常低和稳定，耐磨寿命较其它聚酰胺类固体润滑膜更长。因此，自组装液晶聚芳酰胺超薄膜可以作为低载荷下硅基材料的减摩抗磨防护层。     

聚有机硅氧烷改性尼龙的摩擦性能研究EI

用环块磨损仪研究了不同结构的聚有机硅氧烷改性尼龙-6的摩擦性能。试验表明加入少量(<5％)的聚有机硅氧烷可降低尼龙塑料的摩擦系数和磨耗。在低速度下,聚二乙基硅氧烷改性的效果较好;但在高速下,表面迅速破坏。聚二甲基硅氧烷和聚二甲基二苯基硅氧烷改性的尼龙都有较低的摩擦系数,但后者的磨耗更小一些。     

Optimization of burnishing parameters and determination of select surface characteristics in engineering materials

The present study is aimed at filling the gaps in scientific understanding of the burnishing process, and also to aid and arrive at technological solutions for the surface modifications based on Burnishing of some of the commonly employed engineering materials. The effects of various burnishing parameters on the surface characteristics, surface microstructure, micro hardness are evaluated, reported and discussed in the case of EN Series steels (EN 8, EN 24 and EN 31), Aluminum alloy (AA6061) and Alpha-beta brass. The burnishing parameters considered for studies principally are burnishing speed, burnishing force, burnishing feed and number of passes. Taguchi technique is employed in the present investigation to identify the most influencing parameters on surface roughness. Effort is also made to identify the optimal burnishing parameters and the factors for scientific basis of such optimization. Finally, a brief attempt is made to construct the Burnishing maps with respect to strength level (in this case, average micro hardness of unburnished material).     

Surface Hardening of High-Strength Low Alloy Steels (HSLA) Dual-Phase Steels by Ball Burnishing Using Factorial Design

Burnishing is used increasingly as a finishing operation which gives additional advantages such as increased hardness, fatigue strength, and wear resistance. Experimental work based on 3⁴ factorial design was carried out to establish the effects of ball burnishing parameters on the surface hardness of high-strength low alloy steels (HSLA) dual-phase (DP) steel specimens. Statistical analysis of the results shows that the speed, feed, lubricant and ball diameter have significant effect on surface hardness.     

氟化石墨改性适配器PTFE层摩擦磨损性能研究

目的研究适配器PTFE层氟化石墨填充改性后的摩擦磨损性能,提高适配器的耐磨性。方法以质量分数为2%,5%,8%,11%的氟化石墨为填料制备PTFE基复合材料,分别在20,40,60,80 r/min的转速下测试试样摩擦因数。通过三维视频显微镜采集试样表面磨损数据,并计算其体积磨损率。扫描电子显微镜(SEM)观察磨痕微观形貌。结果同一转速下,试样的摩擦因数随着氟化石墨质量分数的增加而增大。填充氟化石墨能显著降低试样的体积磨损率,填充物质量分数超过8%后,试样体积磨损率趋于稳定,试样摩擦因数得到明显增大。结论氟化石墨填充PTFE层可显著提高适配器的耐磨性,但质量分数不能超过8%,否则,会造成适配器与运输筒间的摩擦因数增大,增加航天器装填及出筒阻力。     

Einfluß des Festwalzens auf die Oberflächen‐ und Randzoneneigenschaften der Magnesiumlegierungen AZ31 und AZ91

Influence of burnishing operations on surface‐ and subsurface properties of AZ31 and AZ91 A mechanical surface treatment on magnesium‐alloys can be used to improve surface and subsurface characteristics after the cutting process. Investigations show, that the grooves, resulting from the turning process, are planed. The hardness of the surface rises. Compared to turned and polished samples, the increased strength and the induced residual stress of burnished samples cause an increased fatigue strength under rotating bending stresses. The corrosion resistance of AZ31 is enhanced by roller burnishing.     

Improvement of Flat Surfaces Quality of Aluminum Alloy 6061-O By a Proposed Trajectory of Ball Burnishing Tool

Burnishing is a profitable process of surface finishing due to its ability to be automated, which makes burnishing method more desirable than other finishing methods. To obtain high surface finish, non-stop operation is required for CNC machine and we can attain that by choosing a suitable trajectory of the finishing tool. In other words, burnishing paths should be multidirectional rather than monotonic, in order to cover uniformly the surface. Indeed, the burnishing force is also a key parameter of the burnishing process because it determines the degree of plastic deformation, and that makes determining the optimum burnishing force an essential step of the burnishing process a success. Therefore, we consider the strategy of ball burnishing path and the burnishing force as variable parameters in this study. In this paper, we propose a new strategy of burnishing tool path with trochoid cycles that achieves a multidirectional burnishing of the surface according to various patterns. Taking into consideration the optimum burnishing force, to improve flat surface finish of AL6061-O samples by reducing the surface roughness parameter (Rz). Experiments carried out on 3-axis milling machine show that the proposed trochoidal path is more effective than the conventional one.     

铜基复合材料干湿条件下的摩擦学行为

采用粉末冶金技术制备铜基复合材料,在制动压力0. 5～1. 2 MPa 范围内,通过定速摩擦试验机研究了干、湿条件下,速度、压力与材料摩擦磨损性能的关系,结果表明:影响摩擦磨损性能的重要因素在于载荷性质和第三体状态。在干摩擦条件下,处于低摩擦速度范围时,摩擦力的静载荷性质使第三体呈疏松状态,这增加了微凸体间的啮合程度而使摩擦系数处于较高值。随第三体致密性增加,其润滑作用增强,微凸体间的机械啮合程度减弱,使材料的摩擦系数和磨损量降低。在高速摩擦时,微凸体间的冲击作用使处于摩擦表层的硬质颗粒容易发生粉碎性破损而弥散分布,这强化了表面强度而使摩擦系数有所增加。摩擦压力对高速摩擦性能影响明显,原因在于高负荷加剧了摩擦面的变形和损伤程度。湿摩擦条件下,水膜的润滑和流动具有降低摩擦系数和增加磨损率的作用主要体现在低速低压条件下。在高摩擦速度和高压力条件下,水分的高温蒸发与离心作用明显,破坏了水膜的存在条件,从而使材料的摩擦磨损性能与干摩擦状态相近。      

Tribological behaviour and acoustic emissions of alumina, silicon nitride and SAE52100 under dry sliding

The friction, wear and acoustic emission behaviour of various combinations of alumina, silicon nitride, and SAE52100 steel, operating under dry sliding conditions, was investigated. A designed ball-on-flat-disc type of tribometer was used to conduct these experiments. This apparatus, equipped with a force sensor, using silicon strain gauges, measured simultaneously the normal load and friction force. Both forces were used to determine the real-time value of the dynamic coefficient of friction. The AE signal arising from the interaction of the surfaces in dynamic contact was also detected and a data acquisition system was used to gather this signal as well as the outputs from the force sensor, at high frequency. The effects of test duration, sliding speed and normal load on the above mentioned tribological parameters were evaluated. The interest of this study further extended to assess the correlations that may exist between the integrated rms acoustic signal (AE) and the friction mechanisms, wear volume, friction work as well as the material removal power. Under the specific conditions of the present experiments, no consistent relation was found between the variations of AE and corresponding dynamic coefficient of friction (COF) as function of time. The variation of COF and wear rate, obtained considering a fixed total sliding distance of 500 m, as function of a range of sliding speed (0.05–2.5 m/s) and normal load (5–40 N) are presented. It was found that the test duration has an important impact on wear results of the experiments conducted at different sliding speeds and fixed travelling distance. More expected behaviour was observed when the relationships between the AE and wear volume, friction work, and material removal power were investigated considering the data obtained at different loadings and fixed sliding speed. Some models representing interesting relationships which could be used for predicting tribological properties in the case of practical applications, similar to the tribo-systems investigated in this study, are proposed.     

Experimental research on the surface strengthening technology of roller cone bit bearing based on the failure analysis

The roller cone bit is one of the most important rock breaking tools used in the oil–gas drilling industry. Its performance directly influences the drilling quality, efficiency and cost. As the world’s oil–gas resource exploration continuously developed, the drilling speed accelerated, accelerating the failure speed of the bearing. The roller cone bit’s service life was almost directly dependent on that of the bearing. In this paper, a bearing failure analysis, and an experimental research on the surface strengthening technology of the bearing with field applications etc. were carried out. The results showed that the bearing’s main failure modes included fracture, plastic deformation and wear. The main reasons were overload and uneven distribution of the load; elevated temperature due to friction caused property and structure change in material; wear increased the fit clearance between the bearing and the cone, increasing dynamic impact load etc. The bearing surface strengthening technology, employing plasma-arc surfacing DH-60 wear resistance alloy, could prolong the service life of the bearing. Experimental research and field tests showed that the wear and impact resistance of the enhanced bearing increased by 30% with an increased service life of 12% on average.     

表面双重改性304钢干摩擦特性研究

为了改善304钢的干滑动摩擦学性能,采用激光打标机在304钢基体表面刻蚀出直径及间距为300μm的点坑状织构,之后对织构前后试样表面进行盐浴渗氮处理。分别采用D/MAX-Ultima+型X射线衍射仪、3D形貌仪、开尔文探针及Fisherscope型显微硬度测试仪对复合改性表面的化学成分、表面形貌、表面电子功函数及表面显微硬度进行了检测。采用CSEM旋转摩擦磨损试验机测试3种试样的摩擦学性能,试验条件为干摩擦。试验结果表明:盐浴渗氮处理后表面的显微硬度大大高于304钢基体表面,渗氮表面功函数明显高于304钢基体表面。渗氮光滑表面的抗磨性能显著优于304钢基体表面,而复合改性表面又明显优于渗氮光滑表面,说明复合改性表面具有极为优异的抗磨特性。     

基于摩擦磨损实验的双盘直槽研磨方法的研具选材研究

双盘直槽（double-disc and linear-groove, DDLG）研磨方法是以1个平端面研磨盘和1个具有多条直沟槽的研磨盘为对磨研具,对圆柱滚子的滚动面进行精密加工的新方法。在加工过程中,圆柱滚子沿直沟槽连续供料,在2个研磨盘的摩擦力矩驱动下连续自转。研磨盘材料的选择是搭建双盘直槽研磨设备的基础。为了确定适用于双盘直槽研磨方法的研磨盘材料组合,基于摩擦磨损实验展开相关研究。首先,基于摩擦原理,分析了圆柱滚子的运动状态和研磨盘材料的摩擦特性对研磨效果的影响,并确定了研磨盘材料摩擦系数的筛选条件。然后,通过销-盘摩擦磨损实验测试了铸铁、45钢、黄铜、聚四氟乙烯（polytetrafluoroethylene, PTFE）、有机玻璃（polymethyl methacrylate, PMMA）、125%铸铁基固结磨料和125%树脂基固结磨料等多种备选材料在研磨条件下的摩擦系数、耐磨性和排屑性能。最后,搭建了双盘直槽研磨试验台,通过观察圆柱滚子的自转情况来验证基于摩擦磨损实验的研具选材方法的合理性。通过摩擦磨损实验测得,铸铁和45钢的滑动摩擦系数大,磨削效率高,但耐磨性差,适合用作大去除量场合的上研磨盘材料;有机玻璃的滑动摩擦系数大,耐磨性好,磨削效率高,适合用作小去除量场合的上研磨盘材料;聚四氟乙烯的滑动摩擦系数小,耐磨性好,可用作下研磨盘直沟槽材料;固结磨料的滑动摩擦系数变化大且易堵塞,不适合用作研磨盘材料。研究结果可为双盘直槽研磨设备的设计提供可行的研具选材依据。     

Analysis of the apparent friction of polymeric surfaces

The apparent friction coefficient is the ratio between the tangential force and the normal load applied to moving body in contact with the surface of a material. This coefficient includes a so-called “true local friction” at the interface and a “geometrical friction” which is the ploughing effect. The material underneath a moving tip may display various types of behaviour: elastic, elastic–plastic where elastic and plastic strain are present in the contact area, or fully plastic. As is usual in polymers, the material behaviour is time and temperature dependent and may exhibit strain hardening. A surface flow line model of a scratching tip which links the apparent friction to the local friction and contact geometry was recently proposed. An inverse analysis is used in the present work to estimate the local friction from the measured apparent friction and a knowledge of the contact area and tip shape. The polymer true friction coefficient displays temperature and sliding speed dependency, which may be attributed to the surface thermodynamics. It is shown that the local friction depends on the level of strain in the polymer at the contact interface.