Full Factorial Experimental Method Research Articles

ВЛИЯНИЕ РЕЖИМА НАНЕСЕНИЯ АНТИФРИКЦИОННОГО ПОКРЫТИЯ УЛЬТРАЗВУКОВОЙ ОБРАБОТКОЙ НА ШЕРОХОВАТОСТЬ ОБРАБАТЫВАЕМОЙ ПОВЕРХНОСТИ

The article presents an experimental study of the effect of the ultrasonic diamond smoothing mode on the surface roughness of the roller bearing roller end face in the presence of graphite nanopowder on the treated surface. In the presence of graphite nanopowder on the surface, the diamond smoothing process is accompanied by the formation of a solid antifriction coating on the treated surface, which can affect the formation of the microrelief of the treated surface. The design of an ultrasonic installation is described for diamond smoothing of the rollers end surface with the possibility of simultaneous application of a solid antifriction coating to this surface. The installation is assembled on the basis of a 16K20 screw-cutting machine. It consists of a device for installing rollers in the chuck of the lathe and an ultrasonic transducer mounted on the caliper of the machine. A diamond tip was used as a working tool in this device which was attached to the end of the oscillation concentrator of the ultrasonic transducer. Axle box bearing rollers of 36-42726E2M series (GOST 18855-94) were used as experimental samples. The subject of research was regression dependences of the influence of ultrasonic processing mode on the treated surface roughness. Full factorial experiment method was used to conduct the research. The tool tip rounding radius, tool transverse feed, specimen rotation speed, and tool pressure force on the machined surface of the specimen were used as varying factors. The power-law dependence of treatment indices on the adopted varying factors was taken as a mathematical model. It is shown that the greatest influence on the surface roughness is exerted by the tool transverse feed and the diamond tip rounding radius.

Development of a system for controlling a diamond drilling mode in terms of rock fault resistance

Relevance. Resistance to rock-cutting elements in rock destruction largely determines the effectiveness of drilling results. Information about the drag coefficient allows you to correctly and timely adjust the intensity of a drilling tool impact on the bottom of the well. To control the force contact of the drilling tool cutters with the bottom of the well, it is necessary to have a methodological apparatus that allows determining the rock destruction mechanism, taking into account the resistance forces. The existing methods for selecting combinations of diamond drilling mode parameters according to the known RPI index or according to the criterion of energy intensity of rock destruction N/vm , where N is the bottomhole power to overcome the resistance during rock destruction at the bottom hole; vm – mechanical drilling speed, have a number of disadvantages. They consist, for example, in occurrence of tool wear or the need to obtain a bottomhole power value in the current time mode, which is difficult under modern drilling conditions. Therefore, the study of rock resistance to destruction by a diamond cutter, based on application of the full factorial experiment method with obtaining mathematical models of factors and their graphical interpretation in combination with process control systems using computer technology in the current time mode, is a relevant topic. The disclosure of this topic will determine the direction of increasing technical and economic indicators of drilling. Aim. To develop a methodological apparatus that allows determining the mechanism of rock destruction taking into account the resistance forces to ensure optimal control of diamond drilling. Objects. Mechanism of rock resistance to destruction by a diamond cutter. Methods. Analysis, analytical research, full factorial experiment. Results. The paper presents an analytical analysis of the possibility of controlling drilling modes in order to achieve the greatest effect from drilling by estimating the drag coefficient as a function of the intensity of destruction or deepening per one revolution. Based on the analytical studies and the mode of drilling control by a computer in the real time mode, the authors have proposed a method for selecting the parameters of the drilling mode according to a given optimal value of the resistance index during drilling, and a way for its automatic implementation.

The Influence of Two-Jet Gas Shielding Parameters on the Structure and Microhardness of Steel 45 Joints during Consumable Electrode Welding

The paper presents the study results of the parameters influence of arc welding with a consumable electrode with two-jet gas shielding in CO2 on the structure and microhardness of high-strength steel 45 welded joints with slotted edges. Controlling the dynamic impact of the internal shielding gas jet on the processes in the welding zone changes the heat and mass transfer processes in the welding zone and results in the intensive mixing of the molten electrode metal with the base metal in the weld pool. The results of the studies determined the dynamic effect of the active shielding gas jet on the structure and microhardness of multilayered steel 45 welded joints with slotted edges using the method of full factorial experiment, developed dependences of chemical elements (carbon, silicon, manganese) content in the weld metal of multilayered steel 45 welded joints on the controlled parameters of the welding mode (Q, Iw, U). Due to uneven heat introduction into each of the welded plates during edge slotting, the asymmetric distribution of microhardness in the cross sections of welded joints relative to the weld axis indicates some differences in the structure and properties of the heat-affected zone (HAZ) and the weld. According to the results of the studies, consumable electrode arc welding with two-jet gas shielding provides faster distribution and equalization of heat on the product surface and reduces its instantaneous overheating, which improves the structural phase state of the welded joint made of steel 45 and reduces the microhardness gradient in the HAZ. An increase in the heat input of welding (a simultaneous increase in the welding current and voltage of the welding arc) leads to a decrease and smoothing of the microhardness peak in the HAZ.

USING OF THE MATHEMATICAL PLANNING OF THE EXPERIMENT FOR THE QUANTITATIVE ASSESSMENT OF THE METHOD OF PHYTOREMEDIATION RESTORATION OF SOILS CONTAMINATED WITH PETROCHEMICALS

Nowadays, the problem of soil contamination with oil products has global character. The issue of soil quality is particularly acute in technogenically loaded territories, which, in particular, include the territories of airports. To reduce the negative impact of petrochemicals on the condition of the soils and to restore their quality characteristics, various methods of destruction of petroleum hydrocarbons in contaminated soils are used. In recent years, biological methods of cleaning soils from oil products are gaining more and more popularity. These methods have a number of advantages over physic-chemical and mechanical methods of restoring the quality of the soils contaminated with petrochemicals. However, the most popular is the phytoremediation method. In our research, we have chosen this method of cleaning soils contaminated with aviation fuel, as it is one of the most ecologically safe, cost-effective, accessible and promising of the existing methods of restoring the quality of soils contaminated with petroleum products. The purpose of the work was to evaluate the use of phytoremediation to restore the quality characteristics of soil contaminated with aviation fuel, using the method of mathematical planning of the experiment, namely the method of full factorial experiment, which allows obtaining a statistical model of the influence of the factors involved, namely the presence of plants and petroleum products. To achieve the goal, the phytoremediation technology of soil samples artificially contaminated with TS-1 aviation kerosene was applied. The plants chosen for the study were oats (Avena Sativa L.) and timothy (Phleum L.). The change in the level of phytotoxicity of the soil samples after the application of phytoremediation technology was determined using a growth test with watercress (Lepidium sativum).
 The obtained data showed that on the 10th day of observation, the negative impact of aviation fuel (X2) and the positive impact of plants (X1) is observed. At the same time, strengthening the positive impact of plant action and reducing the negative impact of aviation fuel in the interaction of these two factors X1 and X2. Analyzing the obtained results, we can draw a conclusion about the possibility of using the technology of phytoremediation of oil-contaminated soils, which is quantitatively evaluated using the method of a full factorial experiment.

Investigation of the stress-strain state of a gravity dam made of cement-sandand gravel (CSG)

The article presents studies of the stress-strain state of a gravity dam of a homogeneous symmetrical profile made of cement-sandand gravel (CSG) on a rocky base. When performing computational studies, the method of full factorial experiment (PFE) was used. Based on this method, we take three variations factors the dam height, slope ratio, and the modulus of deformation of the dam. Calculations were carried out using the CRACK software package. The results allow us to optimize the dam profile (CSG) in a real project and evaluate the reliability of dam structures of this type.

Optimization of values of technological parameters for obtaining thermoplastic polymer composition for bottom shoes

This work reveals the dependence of the composition and production parameters on the properties of a thermoplastic polymer composition based on a copolymer of ethylene with vinyl acetate and suspension polyvinyl chloride (EVA / PVC-S), as well as the choice of the optimal composition of the mixture and finding the optimal technological parameters for its production. Thermoplastic polymer-sole compositions were obtained by the method of thermomechanical mixing. To describe the properties of polymer - plantar compositions, depending on the ratio of components and technological parameters of obtaining, the method of mathematical planning – “Full factorial experiment” of type № = 2k was chosen, which allows to obtain separate estimates of linear effects and two-, three-factor interactions. In this work, to build a mathematical model, the following factors were selected: the content of EVA in the composition, the temperature and mixing rate, and regression equations were used when obtaining a new type of shoe bottom material using a full factorial experimental method. Optimal results were obtained when the EVA content of the polymer composition was 15%, the mixing temperature was 185°C, and the mixing speed was 25 rpm. The strength and operational-technological indicators of the quality of a thermoplastic polymer composition for the bottom of footwear based on a copolymer of ethylene with vinyl acetate and suspension polyvinyl chloride have been determined. Regression equations for the dependence of the deformation-strength properties on the technological factors of the creation of polymer sole compositions are constructed. It has been proved that by selecting the optimal values of technological parameters it is possible to obtain a sole material with high deformation-strength and operational-technological characteristics.

Optimization of onion drying process parameters using the full factorial experiment method

Evaluation of the effectiveness of the influence of the main factors on drying using heat pipes, such as temperature, drying time and layer thickness of onions, was carried out for the first time using the method of full factorial experiment. For this, the variables were encoded, the experiment planning matrix was compiled, the regression equations were calculated, the equation was checked for adequacy, and a posteriori analysis was performed. The main factors influencing the drying of sliced onions in drying installations using heat pipes have been determined. The optimal mode of onion drying in a drying plant using heat pipes has been determined.

Study on vibration and surface roughness in MQCL turning of stainless steel

Abstract Minimum quantity cooling lubrication (MQCL) is an alternative to the conventional flood cooling method, which satisfies ecofriendly and low-cost requirements. In this study, the full-factorial experimental method of machining AISI 304 steel under MQCL and flood cutting conditions were investigated to evaluate the surface quality and tool vibration. The surface roughness characteristics were analyzed using the power spectral density, and vibration and surface roughness models were predicted using the response surface methodology. Finally, simulated annealing and particle swarm optimization were combined to optimize the process parameters. The results revealed that a decrease in the surface roughness and vibration occurred under MQCL conditions. The feed rate significantly influenced the surface roughness, axial vibration, and radial vibration, and their corresponding contributions were 69.8 %, 63 %, and 51.05 %, respectively. With an increase in the cutting speed, the vibrations and surface roughness decreased. However, the cutting depth did not significantly influence surface roughness. The low-frequency vibration of the surface profile resulted in the formation of grooves and ripples. Therefore, the optimized cutting parameters, minimum surface roughness, and vibration could be obtained.

ВИБІР НАПРЯМКУ РЕФОРМУВАННЯ ОРГАНІЗАЦІЇ В ПРОЕКТНОМУ СИСТЕМНОМУ УПРАВЛІННІ РОЗВИТКОМ

The subject of research in the publication is the process of managing the development of a high-tech organization. The object of research is project system development management. The work aims to choose the current direction of reforming a high-tech organization in conditions of limited opportunities. The article solves the following tasks: analyzes the problems of managing the development of the organization, identifies the main areas of reform associated with ensuring the competitiveness of the organization in the market of high-tech products. To substantiate the choice of the current direction of reform external experts are involved to assess several possible areas of development, considering the state and level of maturity of the organization, readiness for reforms, existing business process model, financial opportunities for development processes. Then based on expert assessments and the method of full factorial experiment, the analysis, and comparison of reform options is carried out to select the most relevant direction in the task of project development management. The limited resources of the enterprise and the requirements for the timeliness of reforms lead to the task of optimizing resources for the implementation of the reform project. The multiplicity of options for allocating resources at different stages of the reform project leads to the use of targeted search in the task of resource optimization. The optimization problem is set based on integer (Boolean) programming in two views: local and multi-criteria optimization. Costs, project deadlines, and the risk of successful project implementation were used as criteria for assessing the allocated resources and the success of the reform project. For multicriteria optimization, the significance of individual criteria is assessed. As a comprehensive criterion, a simple additive convolution of local criteria was used. To assess the correctness of the chosen reform option, the method of agent modeling is added. A set of agents has been formed, with the help of which all stages of the development project are simulated. This takes into account the time factor, allocated funds (costs of the organization), the risks of individual stages. The results of agent modeling will allow concluding the expediency and relevance of the choice of development direction for the subsequent project management of the reform. The scientific novelty of the publications to create a method by which derivative data are formed for the enterprise reform project. The publication uses the following methods: system analysis to justify and choose the direction of development; expert assessments for the formation of a factor experiment plan; the method of full factorial experiment, which allows to evaluate several options for reform and choose the current direction of development of the organization; method of integer (Boolean) programming for the purposeful choice of means during project implementation for development; the method of agent simulation modeling to simulate the implementation of individual stages of the development project. Conclusions: the proposed approach allows at the stage of a preliminary study of the development of the organization to choose the current direction of reform, considering the state of the high-tech organization, readiness to reform, as well as limited opportunities in the face of challenges and threats in the economy.

COMPLEX DEFLOCCULENT BASED ON SODA, LIQUID GLASS AND OXYETHYLIDENEDIPHOSPHONIC ACID IN CERAMIC CASTING TECHNOLOGY

Here are discussed some results to use oxyethylidenediphosphonic acid (OEDPA) and various additives as a deflocculant composition for controlling the rheological properties of a ceramic suspension. According to the results of determining thixotropy, it was found that a complex thinner based on soda and OEDPA is the most effective. It is desirable to replace a portion of the soda with liquid glass. By the full factorial experiment method, it was established the optimal composition of the components of the complex thinner. The proposed thinner is highly effective in a wide range of OEDPA, soda, and liquid glass concentrations. The resulting suspensions have stable, high structural–mechanical properties. A mathematical model describing the effect of the composition of the thinner on the viscosity and thixotropy of the suspension is presented. The effect of the diluent on the mechanical properties of the molded dried and fired samples was determined. The addition of OEDPA to the thinner significantly lowers the rheological parameters and the rheological properties of the suspensions approach the rheological properties of Newtonian systems. It was found that OEDPA lowers the mass buildup rate, which can be increased by lowering the moisture content in the suspension, which makes it possible to increase the post-casting and -drying density of the samples. The introduction of this additive leads to an increase in the hydrate shell around the clayey particle and an increase in the stability of the suspension, but the increase in the ζ - potential in comparison with the production additive is very small. The mechanism of action of a complex additive is proposed, including ion-exchange, complexation and chemisorption. An increase in the strength and density of dry and calcinated clay samples as well as a decrease in the shrinkage and porosity are observed. The complex additive makes it possible to optimize the technology at the stages of casting slip and to decrease the number of parts rejected during molding, drying and firing.

Pattern Recognition: Description of Modes of Teaching Boys Aged 7 Throwing a Small Ball at a Vertical Target

The study purpose was to determine the possibility of using pattern recognition methods to study the impact of physical exercises modes on teaching primary school children throwing a small ball at a vertical target.
 Materials and methods. The study participants were boys aged 7 years (n=48). The paper relied on analysis and generalization of data of scientific and methodological literature, general scientific methods of theoretical level, such as analogy, analysis, synthesis, abstraction, induction, as well as general scientific methods of empirical level: observation, testing, experiment.
 Results. The effectiveness of teaching boys aged 7 “throwing a ball at a vertical target” is positively influenced by 6-12 sets, 3 repetitions per set, rest interval of 60-180 seconds. The focus in choosing a teaching mode is on the number of repetitions per set.
 Conclusions. A full factorial experiment method makes it possible to mathematically describe the process in some local area of the factorial space and to verify the regression model. Regression equations provide an opportunity to select the modes of performing for each exercise being studied. Discriminant analysis has made it possible to determine the modes of physical exercises in the process of motor skills development; to answer the question as to how significantly the modes of training differ by the effectiveness of motor skills development; what motor tasks most substantially influence the differentiation of classes; what class the object belongs to based on the values of discriminant variables. To select the most rational mode of performing exercises in the process of motor skills development in boys aged 7, the first and second discriminant functions can be used, with a focus on the most informative variables.

Расчет, моделирование и исследование процесса электрохимического осаждения микросферных пленок

The paper presents the results of the calculation of the main parameters of electrochemical deposition of microsphere films from a colloidal solution. Within the research, we determined the factors affecting the rate of their growth. The study shows the results of mathematical simulation of the process, characterizing the change in the potential in the interelectrode space, as well as the results of experimental studies of the formation of microsphere structures. Findings of the research were used to estimate the uniformity of the formed structures according to the reflection coefficient. For this purpose we applied the method of full factorial experiment. The study shows that the uniformity of the structures deteriorates with increasing potential difference and pH of the solution. It was also found that with an increase in the process time, the thickness of the structure increases, while the uniformity and ordering decrease. Findings of the research can be used in the further formation of 3D nanocomposites for various applications, for example, to increase the magnetic recording density

Complex-modified basalt plastics

In view of the fact that the creation and development of the production of new polymers practically does not occur, the modification of known materials, the creation of polymer composites filled with various substances is today one of the priority directions in the creation of new polymeric materials. In this paper, the possibility of increasing the reactivity by processing corona discharge of large-capacity polymer-polyethylene when filled with modified basalt. The method of full factorial experiment, regression equations, analysis of which showed a prevailing influence of DC corona discharge on the physico-mechanical characteristics of polymeric composite materials. The optimal ratio of the components of the composite material and the current during the processing of polyethylene corona discharge were chosen by gradient method. The prospects and expediency of obtaining complex-modified basalt plastics on the basis of low-pressure polyethylene treated with corona discharge are proved, since all physical, chemical and mechanical properties of polyethylene composites are increased. The method of infrared spectroscopy shows that in a complex-modified basalt plastic there are practically no groups of hydroxyl groups, the intensity of peaks of methylol groups and peaks –Si-O-Si-is significantly reduced, which indicates the chemical interaction of polyethylene treated with corona discharge and modified basalt.

Synthesis of the equipment health management system of the turbine units' of thermal power stations

The aim of the research is the development of technical diagnostics subsystem with the possibility of its further integration into the automated system of equipment health management, which will improve the efficiency of data ware, hardware and software. Synthesis of intellectual diagnostic models was produced a by using the Matlab graphical agents. At the same time, there were synthesized models of three types: fuzzy, neural-network and model built by planning the full factorial experimental method. Was proposed the concept of the three-stage procedure of the diagnosis of the thermal power station's turbine unit, instead of the creation of diagnosis mathematical models and failure models of objects, immediately begin to develop an algorithm of diagnosis using advanced intelligent technologies. The technique of creating a sub-line diagnostics status of the turbine unit, which includes three main stages: identification of diagnostic features based on expert method; the synthesis of diagnostic model of the facility technical condition; research models on the stability, sensitivity and uniqueness, was proposed. The main diagnostic features of assessing the state of turbine equipment, which, in accordance with the concept developed, allow forming a matrix of planning a full factorial experiment. The proposed techniques and concepts were subjected to experimental verification. The intellectual diagnostic model of turbine unit equipment health was proposed, synthesized and investigated. It was found that the best model is the model, built using neuro-fuzzy algorithms. The simulation was provided for neuro-fuzzy algorithms and confirmed their effectiveness and compliance with the laws of the physical functioning of the HPC. The results of this research have been used in the development of Almaty CHP-2 turbine equipment health management subsystems, allow the further development of the theoretical foundations of intellectual systems, and demonstrate the possibility of using modern concepts to solve important technical problems. Subsystem of operative diagnosis and the following software implementation in a complex of automated technological process of thermal power control system allows one to make an early diagnosis of the equipment health. This significantly reduces the maintenance costs, improves reliability and security, as well as the effectiveness of the control system. In this regard, the results of this study provide further development of the theoretical foundations of the intellectual systems and demonstrate the possibility of modern concepts usage to determinate the important technical problems.

Calculation and experimental determination of the geometric parameters of the coatings by laser cladding

In the present work the experiments on laser cladding of powder Fe-B-Cr-6-2 on samples of steel 20. Metallographic studies of geometric parameters of deposited layers and the depth of the heat affected zone (HAZ). Using is the method of full factorial experiment (FFE) mathematical dependences of the geometrical sizes of the deposited layers of processing modes. Deviation of calculated values from experimental data is not more than 3%.

Experimental study of the elastic S-shaped cultivator rack

Cultivating paws on elastic struts at work have a deviation from the established depth of processing by 10-15 % more than with a rigid suspension and do not preserve the optimal cutting geometry. With increasing speed and depth of treatment, tractive resistance and deflection of the paw from a given depth of processing increase. Therefore, to ensure the quality and efficiency of the combined cultivator equipped with elastic S-shaped struts, it is necessary to change the rigidity of the racks. The purpose of the study is to improve the quality and reduce the energy consumption of surface tillage by regulating and optimizing the rigidity of the elastic strut of the cultivator. To study the work of the elastic S-pillar, the method of full factorial experiment was used, which allowed obtaining mathematical models, taking into account the selected controlled factors. For the controlled variables, the factors characterizing the work properties of the elastic S-pillar and having certain numerical values were taken. In the course of the study, the influence of the depth of treatment, the speed of the aggregate and the stiffness of the strut on the traction resistance and the deviation of the paw was studied. The results of the research showed that with an increase in processing depth from 0,04 m to 0,12 m at a speed of 3 m/s, the traction resistance of the S-pillar will increase from 105 N to 670 N. It should be noted that increasing the stiffness of the rack from 6226 N/m to 21815 N/m leads to a reduction in traction resistance by 100 N. With increasing depth of processing and speed of the unit - the deviation of the toe of the paw increases. With increasing stiffness of the stand, the deviation of the toe of the paw decreases. The maximum deviation is observed at a speed of 3 m/s, a depth of 0,12 m, rigidity of the rack 6826 N/m. As a result of the study, in order to fulfill the agrotechnical requirements for surface tillage, it is proposed to install a stiffness regulator in the design of the elastic S-bar.

A study on the wall thickness in the angular deep drawing process

Abstract The aim of this paper is the modeling and the corresponding experimental validation of angular deep drawing parameters on the tensile strength, wall thickness and height of the square profile cups. The full factorial experimental method was used to collect the data. FE analysis results were compared with experimental measurements. As a consequence, it was observed that angular deep drawing dies gave better results with different angle values than conventional dies with higher drawing ratios. In general, the product quality increased by an increase of the die/blank holder angle. FEM model results were in good agreement with experimental measurements.

Optimization of Conditions for Non-rigid Workpieces Flat Grinding by Elastic Deformations Controlling

The authors propose the technique for optimizing the conditions for non-rigid workpieces end surfaces flat grinding that guarantees obtaining the pre-defined quality requirements of the machined surface (surface roughness parameter Ra, absence of grinding burns, required flatness tolerance of end surface) while ensuring the maximum process efficiency.Mathematical models of the cutting force components, grinding ratio, and roughness of the machined surface (Ra parameter) are obtained by the full factorial experiment method. The input factors (grinding wheel hardness, depth of grinding, table feed speed and run) are considered as the grinding process optimization parameters. Mathematical models of the output factors are used to limit the range of optimization parameters allowable values. The resulted efficiency is an objective function. The optimization of parameters in the range of allowable values is carried out with the view of ensuring the maximum process efficiency.The required flatness admission is provided at the second optimization stage of the workpieces by controlling the elastic deformation extent.The varied parameters at controlling the maximum elastic deformation extent are cutting forces and attraction of the machine table magnetic field.The terms for providing of the required end surface flatness tolerance are determined for workpieces taking into account elastic deformation of the non-rigid workpieces under the magnetic field effect on the machine table and the radial component of the grinding force.

Obtaining of Oxycellulose from Cotton Fibers by Action of Various Oxidants

Background. Development of production technologies of materials for various purposes of alternatives to crude oil and natural gas sources of raw material, in particular cellulose.Objective. To determine the optimal values of technological parameters of cotton fiber oxidation by action of various oxidants – hydrogen peroxide, Oxone, PINO – on quality of oxycellulose.Methods. Oxidation of mechanically chopped cotton fibers by solution of hydrogen peroxide, Oxone and PINO was performed with air bubbling by the compressor through solution of cellulose in round-bottomed flask immersed in a water bath of the required temperature. The methods of experiment planning and optimization were used to determine the optimum process parameters.Results. Studied oxidants for oxycellulose of cotton fibers to increase efficiency are in the following order: hydrogen peroxide – Oxone – PINO. The method of full factorial experiment was used to determine the adequate regression equations that describe the process of oxycellulose obtaining by action of Oxone and PINO, and the Gauss-Seidel method was used to determine the optimal values of technological parameters of oxycellulose obtaining. It is shown that oxidation of cotton fibers for optimal values of technological parameters allows getting oxycellulose with the content of carboxyl groups to 3 %.Conclusions. The obtained oxycellulose can be used in medicine as a component of non-toxic, hemostatic, antimicrobial materials.

Effect of Diamond Ball Burnishing on Surface Characteristics and Fatigue Strength of XC55 Steel

Investigation on the effect of surface quality of lathe machined down XC55 steel work piece on the fatigue strength has been carried out. The mechanical surface treatment was achieved by elastic-plastic cold working in the near-surface region through a ball burnishing finishing operation. The results showed improvement in surface roughness (Ra) from 1.49 µm to 0.45 µm and increase in hardness (Hv) from 300.8 to 537.35. These were in good agreement with results predicted from a mathematical model based on full factorial experiment method. The fatigue strength of pieces subjected to ball burnishing revealed 40% and 30% high resistance then those pieces that have respectively undergone lathe turning and grinding. This was due to compressive residual stresses that the burnishing process generated on the outer surfaces.