Showing papers on "Roller burnishing published in 2009"

Influence of process and geometry parameters on the surface layer state after roller burnishing of IN718

Abstract: Highly stressed components of modern aircraft engines, like fan and compressor blades, have to satisfy stringent requirements regarding durability and reliability. The induction of compressive residual stresses and strain hardening in the surface layer of these components has proven as a very promising method to significantly increase their fatigue resistance. The required surface layer properties can be achieved by the roller burnishing process, which is characterised by high and deeply reaching compressive residual stresses, high strain hardening and excellent surface quality. In order to achieve a defined state of the surface layer, the determination of optimal process parameters for a given task still requires an elaborate experimental set-up and subsequent time-consuming and cost-extensive measurements. The development of well funded process knowledge about the correlation of the process parameters, the processed geometry and the surface layer state is the subject of this article.

Effect of hybrid electrochemical smoothing–roller burnishing process parameters on roundness error and micro-hardness

Abstract: In this paper, a novel finishing process, which integrates the merits of electrochemical smoothing (ECS) and roller burnishing (RB) for minimizing the roundness error and increasing surface micro-hardness of cylindrical parts, is proposed. Through simple equipment attachments, electrochemical smoothing–roller burnishing (ECS–RB) can follow the turning process on the same machine. To explore the optimum combinations of the ECS–RB process parameters in an efficient and quantitative manner, the experiments were designed on the basis of the response surface methodology technique. The effect of ECS–RB parameters, namely, burnishing force, applied voltage, inter-electrode gap, and workpiece rotational speed on the roundness error and surface micro-hardness was studied. From the multi-objective optimization, the optimal combination of parameter settings are burnishing force of 350 N, applied voltage of 8.2 V, inter-electrode gap of 2.75 mm, and rotational speed of 970 rpm for achieving the required lower roundness error and higher surface micro-hardness. Surface micro-hardness considerably increases about 31.5% compared to the initial surface micro-hardness, and about 2.32 μm roundness error can be achieved using the optimum combination of process parameters. Therefore, the combination of ECS and RB is a feasible process by which it potentially reduces roundness error and surface micro-hardness of axis-symmetric parts improving their reliability and wear resistance.

Ball-Burnishing and Roller-Burnishing to Improve Fatigue Performance of Structural Alloys

Abstract: The HCF response to burnishing of a number of structural materials is compared and contrasted. It is shown that alloys which exhibit marked work-hardening during burnishing respond very beneficially with regard to HCF performance while others which show little work-hardening may even react with losses in HCF strength. Possible explanations for such behavior are outlined in terms of mean stress and environmental sensitivities of the fatigue strengths of the various materials and microstructures.

Study of roller burnishing process on En-8 specimens using design of experiments

Abstract: Roller burnishing process is a superior cold forming finishing process. It is done on machine or ground surfaces for both external and internal surfaces. In this process, a smooth, hard object (under considerable pressure) rubs over the minute surface irregularities that are produced during machining or shearing. The hardened rolls of the tool press against the surface and deform the protrusions to a more nearly flat geometry. Since the surfaces are cold worked and in residual compression, they possess improved wear and fatigue resistance. The burnishing process is an attractive finishing technique which can increase the work-piece surface finish as well as micro-hardness in a single process, with reduction in tool set-up time which is difficult in conventional processes. The increase in the surface strength mainly serves to increase fatigue behaviour of work-piece under dynamic load. In this study surface roughness and micro-hardness are the main response variables and the process parameters under consideration are spindle speed, tool-feed, number of passes and lubricants. The material under consideration is En-8, which is commonly used industrial standard. Applying Taguchi’s design of experiments on the specimens, the aim is to find optimized values for enhancing the surface quality and hardness economically. The standard orthogonal array L-9 has been used. On experimental analysis, it is found that all the process parameters significantly affect the quality and in EN-8 the micro-hardness values are larger due to work-hardening effect. After the burnishing process no change in surface micro-structure was seen. Key words: Roller burnishing, surface finish, micro-hardness, Taguchi techniques, micro-structure, optimization.

Estimation of the influence of passes number burnishing tool on ships pumps shafts surface layers strengthening and roughness changes

Abstract: Angular momentum pumps are very often applied on ships. Because the pumps are working in hard conditions they are made from cavitation wear proof and electrochemical corrosion resistant materials. The most popular damage of pump shaft is neck wear in place where seals are mounted. Burnishing as modern finish plastic tooling method makes it possible to achieve high technological quality of elements. Because of many burnishing advantages, the method was proposed to angular momentum pumps shafts treatment instead of finish machining (finish turning, grinding, lapping). The tool used was a roller burnishing tool SRMD type produced by Yamato. During the technological process, optimum burnishing parameters were applied in order to ensure high degree of surface layer relative hardness and to decrease surface roughness of angular momentum pumps shafts made of stainless steel X5CrNi1810. The object of the paper was to define the influence of burnishing tool passes number on the ships pumps shafts surface layers strengthening and roughness changes.

Effect of internal roller burnishing on surface roughness and surface hardness of mild steel

Abstract: Roller burnishing is a cold working surface treatment process to generate a uniform and work-hardened surface. This study presents two internal roller burnishing tools to perform roller burnishing process on mild steel under different speeds. Burnishing speed impact on surface roughness and surface hardness has been examined.

Influence of roller burnishing on surface properties and corrosion resistance in steel

Abstract: Purpose – Roller burnishing (RB) is a finishing treatment method that is used to impart certain physical and mechanical properties, such as surface roughness, improved visual appearance, or increased corrosion, friction, wear, and fatigue resistance. The purpose of this paper is to study, the influence of RB on corrosion resistance in A53 steel in HCl solution.Design/methodology/approach – Microhardness (MH), microstructure, weight loss, and potentiostatic polarization are investigated at pressing forces of 40, 60, 80, 100 and 120 N.Findings – MH increases with increasing the applied force and the percentage improvements are found to be 12, 24, 28, 35 and 65 percent for 40, 60, 80, 100 and 120 N RB pressing forces, respectively. Weight losses, in general, showed an optimum value at about 80 N. Corrosion potential and corrosion current decrease with increasing pressing force and reached a minimum at about 80 N, then begin to increase with increasing RB force.Originality/value – The results present in this ...

An Experimental Work on Multi-Roller Burnishing Process on Difficult to Cut Material – Titanium Alloy

Abstract: Burnishing is a cold working and chipless machining carried out to improve surface roughness, surface hardness, fatigue, compressive stress and corrosion resistance by using sliding speed, feed rate and depth of penetration. The process smooth out peaks valleys on the surface. This paper described the process carried out by multi-roller burnishing fitted in housing and rotated freely in a horizontal axis. The work material used was Titanium alloy Ti-6Al -4V. The process produced good surface roughness and hardness at high rotation of spindle coupled with high feed rate and high depth of penetration.

Roller burnishing tool and burnishing method using the same

Abstract: PROBLEM TO BE SOLVED: To provide a roller burnishing tool capable of smoothening the access of a vane into a groove and of performing a surface burnishing for reducing damage efficiently and stably at low cost. SOLUTION: This roller burnishing tool includes a shank detachably mounted on the drive section of a machining device, a drive shaft inserted and held in a cylindrical hollow section in the shank, and a generally cylindrical burnishing roller rotatably supported at the end of the drive shaft with a holder interposed therebetween. The burnishing roller is so formed that the ride section having a thickness corresponding to the width of a groove is integrally formed at the cylindrical outer peripheral surface center over the entire circumference. Both side wall surfaces of the ridge section and the outer peripheral surface of the roller are continued with each other through a curved surface with an arcuate cross section in the diameter direction of the cylindrical shape. COPYRIGHT: (C)2010,JPO&INPIT