Monika Madej

Tribological problems in shaft hoist ropes wear process

Purpose – The purpose of this paper was to create conditions for the correct decision concerning an exchange of the used rope for a new one. A cognitive goal was to indicate the causes of its wear and determining its mechanism reliability and durability. Design/methodology/approach – The magnetic, organoleptic and strength standard tests of lifting triangle-strand ropes of a mining hoist were carried out. This way the current state of the tested rope was defined. Findings – On the basis of an analysis of the results of the performed tests: magnetic, organoleptic and fatigue tests, it can be said that the magnetic one is accurate enough only to indicate the place of the rope’s biggest weakening, though the degree of weakening is not defined precisely – with significant excess. The accurate rope’s destruction degree is indicated by the strength tests. Practical implications – The results of described investigations can improve safety of the mining rope mechanisms operation, even for an increased resource. O...

Antiwear additives as retarding agents of elements with ceramic coatings wear

Purpose – The purpose of this paper is to determine the appropriate conditions for the chemical deposition of Ni‐P‐Al2O3 composite coatings, deposited on metalic matrix.Design/methodology/approach – Auto catalytic reduction of Ni in nickel sulfate and sodium hypophosphate bath, including 10 percent volume fractions of nanodispersive Al2O3 particles is treated in the alloy steel 100Cr6. The wear resistance and friction coefficient of the coatings are determined using tester T‐01M, a ball‐disc tester for mitigated solid friction conditions, in model lubricants: oil bases, oil bases with antiwear additives AW.Findings – The analysis of the properties of the Ni‐P‐Al2O3 deposits confirms that the presence of the dispersion phase of aluminium oxide determines the coating wearability.Practical implications – The paper presents some indications of proper selection of antiwear coating generation methods (their parameters and conditions).Originality/value – Investigations show that tribocatalytic effect of nickel c...

THE IMPACT OF THE TYPE OF CUTTING FLUID ON THE TURNING PROCESS

This article compares the test results concerning the wear of cutting tools after face turning under dry friction conditions and lubricated friction conditions with biodegradable cutting fluid or mineral-oil based emulsion. The turning was performed using a CTX 310 ECO machine tool. The wear of the cutting tools was measured by means of stereo zoom microscopy (SX80), while the elements were identified through scanning electron microscopy (JSM 7100F). The tribological tests were conducted for a ball-on-disc configuration in sliding contact using a T-01M tribometer. The surface textures of the face turned specimens were measured with a Talysurf CCI Lite optical profiler. The study also involved determining the foaming tendency and corrosive effects of both cutting fluids. The use of the biodegradable cutting fluid with low foaming tendency resulted in lower wear and higher corrosion resistance of the tool. Słowa kluczowe: biodegradowalna ciecz obróbkowa, toczenie, tarcie, zużycie. Streszczenie W artykule przedstawiono wyniki badań zużycia narzędzi skrawających po procesie toczenia czołowego w warunkach tarcia technicznie suchego, ze smarowaniem biodegradowalną cieczą obróbkową oraz emulsją opartą na oleju mineralnym. Badania wykonano na tokarce CTX 310 ECO. Po obróbce zmierzono zużycie narzędzi za pomocą stereoskopowego mikroskopu inspekcyjnego SX80, a identyfikację pierwiastków przeprowadzono z użyciem skaningowego mikroskopu elektronowego JSM 7100F. Testy tribologiczne wykonano na urządzeniu T-01M. Pomiary struktury geometrycznej powierzchni elementów toczonych czołowo wykonano profilometrem optycznym Talysurf CCI Lite. Dodatkowo przeprowadzono badania pienienia i korozji cieczy obróbkowych. Zastosowane w badaniach biodegradowalne chłodziwo wpłynęło na zmniejszenie wybranych wskaźników opisujących zużycie narzędzia, a także zapewniło lepsze właściwości przeciwkorozyjne oraz przeciwpienne. ∗ Kielce University of Technology, Faculty of Mechatronics and Mechanical Engineering, al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland. ∗∗ Air Force Institute of Technology, ul. Księcia Bolesława 6, 01-494 Warszawa, Poland, e-mail: andrzej.kulczycki@itwl.pl. INTRODUCTION Metalworking processes require the use of cutting fluids, which act both as coolants and lubricants. Their functions are numerous; they include cooling the cutting zone, lubricating the chip-tool-workpiece interface and removing chips from the cutting zone [L. 1, 2]. Conventional cutting fuels are based on mineral oil, which is hardly biodegradable and as such contributes to environmental pollution. Globally, more than 2,000,000 m3 of cutting fluids are used each year. Approximately 85% of them contain mineral oil. Improper disposal of spent cutting fluids leads to the pollution of surface water, groundwater, air, and soil, which, in consequence, affects food safety [L. 3–5, 6]. Metalworking fluids that are harmful to the environment and human health need to be replaced with ones that are safe and can be recycled or regenerated. The service properties of mineral oil-based cutting fluids are improved by introducing special-purpose additives, which generally are non-biodegradable and toxic to the ecosystem [L. 7, 8]. Cutting fluids also contain antiseptics to kill bacteria and fungi; prolonged or repeated exposure to these irritants may lead to occupational diseases such as skin inflammation, oil acne, respiratory tract infections, allergies, and even cancers [L. 9]. Chemists and tribologists have created new blends to be used instead of mineral oil-based cutting 120 ISSN 0208-7774 T R I B O L O G I A 3/2017 fluids. Alternatives include vegetable oils, which are renewable, nontoxic, environmentally friendly, and easily biodegradable [L. 10]. They are also characterized by good lubrication, low volatility, low emission of hydrocarbons, and good thermal properties [L. 11, 12]. Currently, much research is devoted to cutting fluids based on vegetable oils, for example, soya bean oil, castor oil, palm oil, coconut oil, and rapeseed oil [L. 13, 14]. The analysis presented in [L. 15] focuses on the effects of a cutting fluid based on neem oil. The results obtained for the alternative fluid were compared with those reported for a conventional cutting fluid and also those obtained under dry machining conditions. The turning process was performed using a TEX TRENCIN SN40B machine tool with tool bits made of HS6-5-2C high-speed steel (12x200 mm). The machining was carried out for three workpieces made of mild steel using different cutting depths and different spindle speeds. At the end of the process, the temperature was measured with a thermocouple. A PEL C960 digital camera was used to take photographs of the tools before and after turning in order to analyse their wear. The workpieces were cut into small pieces and then photographs were taken to examine their surfaces. The results show that the temperatures reported in machining with the neem oil-based cutting fluid were lower than those obtained during dry turning or turning with a conventional cutting fluid. From the analysis of the properties of the neem oil, it was evident that it is well-suited to be used as a metalworking fluid. The workpiece surface quality after turning with this alternative fluid was comparable with that obtained for a traditional cutting fluid.

THE USE OF BIODEGRADABLE CUTTING FLUIDFOR THIN AND HARD a-C:H AND TiAlN COATINGS

This paper presents results of tribological tests performed under lubricated friction conditions using a T-01M analyser. The lubricant was biodegradable cutting fluid containing a special-purpose additive – zinc aspartate. The discs for the ball-on-disc configuration were made of HS6-5-2C steel. The study involved testing coated and uncoated steel specimens. The a-C:H and TiAlN coatings were produced using physical vapour deposition (PVD). The structure of the coatings was analysed before and after the tribological tests with a JSM-7100F scanning electron microscope. The coating hardness was measured using a CSM Instruments nano-hardness tester (NHT). The coating surface texture of the coated and uncoated discs was determined by means of a Talysurf CCI Lite profilometer. The thin boundary films that formed in the friction area prevented the surfaces from coming into direct contact. The films improved the motion resistance and provided anticorrosive protection during the tests. The biodegradable cutting fluid used in the study had no negative effect on the environment. Słowa kluczowe: biodegradowalne ciecze obróbkowe, powłoka a-C:H i TiAlN, tarcie, zużycie. Streszczenie W artykule zestawiono wyniki badań tribologicznych wykonane na testerze T-01M w warunkach tarcia ze smarowaniem biodegradowalną cieczą chłodząco-smarującą zawierającą dodatek uszlachetniający – asparginian cynku. Tarcze były wykonane ze stali HS6-5-2C bez i z naniesioną powłoką a-C:H oraz TiAlN techniką fizycznego osadzania z fazy gazowej PVD. Obserwacje struktury powłok przed testem tribologicznym wykonano mikroskopem skaningowym SEM JSM-7100F. Twardość powłok przed testem tribologicznym zmierzono za pomocą nanotwardościomierza NHT CSM Instrument. Natomiast analizę struktury geometrycznej powierzchni tarcz bez powłoki i z powłokami przed oraz po testach tribologicznych wykonano profilometrem optycznym Talysurf CCI Lite. W miejscu tarcia powstały warstwy graniczne, które zabezpieczyły przed bezpośrednim kontaktem powierzchni współpracujących tarciowo. Warstwy te przyczyniły się do zmniejszenia oporów ruchu oraz zapewniły ochronę antykorozyjną w czasie prowadzenia testów. Ponadto użyta do badań ciecz chodząco-smarująca jest biodegradowalna i nie wykazała negatywnego wpływu na środowisko. * Kielce University of Technology, Faculty of Mechatronics and Mechanical Engineering, al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland, e-mails: ozimina@tu.kielce.pl, mmadej@tu.kielce.pl, jkowalczyk@tu.kielce.pl. ** Air Force Institute of Technology, ul. Księcia Bolesława 6, 01-494 Warsaw, Poland e-mail: andrzej.kulczycki@itwl.pl. INTRODUCTION With the industry sector expanding very fast, we observe higher energy consumption requirements and greater environmental pollution posing serious risks to human health. The environmental issues need to be addressed, not only with new legislation, but also environmentally friendly technologies [L. 1]. Machining, which is the most common manufacturing process found in practically all industries, involves removing material from the workpiece to achieve a desired final shape [L. 2]. Machining operations generally require applying cutting fluids, which may have a direct impact on the environment [L. 3]. In many countries, ‘spent’ fluids are classified as toxic or ‘hazardous waste’ [L. 4]. With the above factors taken into consideration, dry cutting is performed whenever possible. In some cases, however, the use of a cutting fluid is necessary to prevent seizure at the tool/workpiece interface, reduce tool wear, or control the workpiece thermal deformation. Narrow tolerances on dimensions and form may not allow dry cutting. Under such circumstances, special solutions are required. 46 ISSN 0208-7774 T R I B O L O G I A 6/2017 Machining performed under dry conditions means consuming much more energy. As the world energy consumption increases every day, future research should focus on energy savings. On average, there is a 15% rise in energy consumption every five years (Fig. 1). 0 100 200 300 400 500 600 700 800 90

Tribological Properties of Diamond-Like Carbon Coatings

The aim of the study was to analyze the superhard anti-wear diamond-like carbon coatings produced by Plasma Assisted Chemical Vapor Deposition (PACVD) and Physical Vapour Deposition (PVD). The a-C:H and a-C:H:W coatings were deposited on steel elements operating under friction conditions. The analysis involved comparing the tribological properties of coated metal elements with those of uncoated elements. It was essential to analyze how the coating composition and structure influence the tribological behaviour of elements under dry and lubrication friction conditions. The coating structure was analyzed by observing the topography of the surface and the cross-sections using an atomic force microscope (AFM) and a scanning electron microscope (SEM). The results were employed to determine the elemental composition and thickness of the coatings. The tribological tests were performed applying a ball-on-disc tribometer and using a pin-on-plate tribometer. The tribological properties were analyzed also in a micro scale using a microtribometer. Compared with the substrate material - steel, the diamond-like carbon coatings showed lower linear wear, lower friction coefficient and higher hardness.