Enver Atik

The effects of conventional heat treatment and boronizing on abrasive wear and corrosion of SAE 1010, SAE 1040, D2 and 304 steels

Abstract The effects of conventional heat treatment and boronizing on SAE 1010 and SAE 1040 structural steels, D2 tool steel, and 304 stainless steel were investigated. During this investigation, layer thicknesses, corrosion and wear strength were examined by applying carburisation, nitriding, transformation hardening and boronizing to the specimens. Abrasive wear tests were carried out in a wear cup model device. Sand of 1 mm diameter was used and the test duration was 40 hours with a velocity 0.157 m/s. Corrosion tests were undertaken in a 10% H 2 SO 4 solution at a temperature of 56°C. Through metallographic analyses, hard layer thicknesses and Vickers hardness values were determined for each hardening treatment.

Mechanical properties and wear strengths in aluminium-alumina composites

In this study, after producing metal matrix composite materials reinforced with ceramic particles by adding hard Al2O3 particles into a selected ageable aluminum alloy, the wear strengths were investigated. Composites of aluminum alloys containing 2 to 10 wt of Al2O3 particles in the size range of 23.4 to 108 μm were prepared by adding alumina particles to a partially-solid vigorously-agitated matrix alloy. For a given tribologic system, the sizes and ratios of optimum particles were determined from the point of the wear strengths of these materials, of which the wear strengths greatly increased according to the matrix materials. Alumina particles were subjected to preheating at 500°C for 8 hours. Particles were added into the alumina alloy heated up to semi-solid/semi-liquid phase interval in an argon medium by using a mixer. Then furnace temperature was raised up to 800°C step by step. Later the composite materials were die cast and solidified and aged. The behavior of the composites was studied by using a pin-on-disk type machine. The largest wear strengths were obtained at an average particle size of 76.5 μm and percentage of 4% wt Al2O3. Increase in the wear strength of the composites was obtained as 3.85 times the wear strength of the matrix material.RésuméAprès avoir fabriqué des matériaux composites à matrice métallique, renforcés de particules céramiques, par l’ajout de particules dures d’Al2O3 dans un alliage d’aluminium soumis au vieillissement, on a conduit une étude sur leurs résistances à l’usure. Des composites d’alliages en aluminium, ayant une teneur de 2 à 10% (en poids) de particules d’Al2O3 de dimensions allant de 23,4 à 108 μm, ont été préparés par l’ajout de particules d’alumine à une matrice d’alliage partiellement solidifiée et vigoureusement agitée. Pour un système tribologique donné, les dimensions et les taux optimaux des particules ont été déterminés sur la base des résistances à l’usure des matériaux en question, dont les résistances se sont accrues de manière significative selon les matériaux des matrices. Les particules d’alumine ont été soumises à un préchauffage à 500 °C pendant 8 heures. Ensuite, elles ont été ajoutées à l’alliage alumine, préalablement chauffé jusqu’à la phase semi-solide/semi-liquide dans un milieu d’argon, au moyen d’un malaxeur. Ensuite, la température du four a été augmentée par paliers jusqu’à 800 °C. Plus tard, les matériaux composites ont été coulés sous pression, solidifiés et vieillis. Le comportement des composites a été étudié sur une machine d’essai à l’usure. Les meilleures résistances à l’usure ont été obtenues avec une particule ayant une dimension moyenne de 76,5 μm, à une teneur de 4% (en poids) de Al2O3. L’accroissement de la résistance des composites obtenue était de 3,85 supérieur à la résistance de la matrice.In this study, after producing metal matrix composite materials reinforced with ceramic particles by adding hard Al2O3 particles into a selected ageable aluminum alloy, the wear strengths were investigated. Composites of aluminum alloys containing 2 to 10 wt of Al2O3 particles in the size range of 23.4 to 108 μm were prepared by adding alumina particles to a partially-solid vigorously-agitated matrix alloy. For a given tribologic system, the sizes and ratios of optimum particles were determined from the point of the wear strengths of these materials, of which the wear strengths greatly increased according to the matrix materials. Alumina particles were subjected to preheating at 500°C for 8 hours. Particles were added into the alumina alloy heated up to semi-solid/semi-liquid phase interval in an argon medium by using a mixer. Then furnace temperature was raised up to 800°C step by step. Later the composite materials were die cast and solidified and aged. The behavior of the composites was studied by using a pin-on-disk type machine. The largest wear strengths were obtained at an average particle size of 76.5 μm and percentage of 4% wt Al2O3. Increase in the wear strength of the composites was obtained as 3.85 times the wear strength of the matrix material.

Experimental microhardness for AA 1030, Cu, CuSn7, CuZn30 and 6114 alloys and a correlation with the Hall-Petch relation

In this experimental study, the strip-formed specimens made from aluminum alloy 1030, pure Cu, CuSn7, CuZn30, and low-carbon steel 6114 were cold worked to different ratios. To determine the microhardness values of the materials, microhardness tests were applied. The grain sizes of the materials were determined by the Heyn method, using a metal microscope. The hardness of materials, H, is dependent on the grain diameter, d, in a way similar to the yield stress in the Hall–Petch relation H = H0 + KHd−1/2, where H0 and KH are constants. The microhardness of the materials was found, with reasonable accuracy, to vary with grain size according to the Hall–Petch equation.

Investigation of tribological properties of boronised pure Cu journal bearings

Abstract Cu based materials are widely used as journal bearings. These materials have a good tribological performance in journal bearings. Pure copper is not generally used due to its low mechanical and wear properties. It is generally used as alloys. In this study, tribological properties of copper bearings manufactured from pure copper were investigated by boronising at 950°C. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N load and 1500 rev min–1 speed every 30 min for 2·5 h using radial journal bearing wear test rig. As a result, boronising increased wear resistance.

Tribological behaviors of polymer-based particle-reinforced PTFE composite bearings

In this study, tribological behaviors of polymer-based particle-reinforced PTFE bearings have been investigated and evaluated. Tribological properties of these particle-reinforced PTFE composite bearings have improved two- or three-fold.

Comparison of effect of induction and classical sintering to mechanical properties of powder metal components

Because of solidifying to component, sintering is the most important step of the production of powder metal parts. Generally it is made classical furnace. Alternatively sintering furnace, it is done that induction sintering studies. Induction sintering provide a grand time and energy savings since components hot up rapidly and sintering time is lower than classical sintering in furnace. Because of that induction sintering is an important alternative at sintering process. In this study, mechanical properties of induction sintered Fe based components included Cu and Graphite were compared with classical sintered components. Parameters of same mechanical properties of induction sintered and classical sintered components were identified.

Mechanical properties of conventionally and induction sintered Fe-based powder metal bushings

Abstract Mechanical properties of powder metal parts are directly related to the shape, distribution and the amount of pores. In this study, mechanical properties of induction sintered Fe based components were investigated dependent on the changing of sintering time and pore structures. For this purpose, compression tests were applied to sintered bushings and microstructural photographs were taken. The compression tests were accompanied by respective finite element analyses. The numerical values were compared to experimental results. It turned out that the micro-stress values were dependent on the amount and distribution of porosity.

Study on lubricant quality and its effect on engine component performance

Purpose – This paper aims to determine the usage time of the test lubricant N0, prepared from base oils of Aliaga Plant, Izmir, in gasoline and diesel‐engines, and the investigations of high‐temperature oxidation, engine‐protective properties, and property changes of the lubricant in performance time.Design/methodology/approach – Physical and chemical properties of the lubricating oil were initially established, and the oil was then subjected to Petter W‐1 gasoline and Petter AV‐1 diesel test engines. Dismantling of the engine parts was followed by the examination of pistons, piston rings and bearings, and analysis of the lubricant was also undertaken. The engine performance test results and the quality control of the lubricating oil assessments were evaluated according to the International Engine Lubricant Specifications.Findings – The lubricating oil, under sluggish experimental conditions, appears to meet a 40‐hour test in gasoline engines and a 120‐hour test in diesel engines with the specifications. ...

Quenching and tempering of 51CrV4 (SAE-AISI 6150) steel via medium and low frequency induction

Abstract Mechanical and microstructural properties of quenched steel are directly related to tempering time and temperature. In many applications, conventionally quenched and tempered steel is widely used for acquiring high strength and toughness. The present study was carried out to investigate the variation in mechanical properties, observation of diminished energy consumption and evaluation of the microstructural properties in SAE-AISI 6150 steel components by induction heating, compared with those of steel tempered by conventional method. Induction quenched and tempered steel provides a shorter process time, less energy consumption and improved mechanical properties through the inhibition of grain growth. In this study, quenching and tempering processes were carried out on medium and low frequency induction units and by using a conventional electrical resistance furnace for the sake of comparison. It was observed that cementite particles began changing their shape from spherical to fine-grained in the induction tempered samples. The sample tempered by low frequency induction manifests superior mechanical properties and offers a potential advantage for significant cost savings.