Browsing by Subject "Boronizing"

Now showing 1 - 12 of 12
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    Production and characterisation of Fe2B powders; [Fe2B tozlarinin üreti̇m ve karakteri̇zasyonu]
    (1999) Şahin S.; Meriç C.
    In this study, Boronizing, which is used as a surface hardening method against wear and corrosion, is applied to iron powder commercial known as ASC 100.29. In boronizing process with solid boron yielding substances, powder with a commercial name Ekabor-HM is used boronizing material. The effects of temperature, time and particule size on boronizing iron powders are investigated and depending upon process conditions Fe2B phase is obtained in whole or a cerain part of iron powders. The microstructure and microhardness analysis of bornized iron powders are made.
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    Boronizing of iron based P/M materials; [Demir esasli T/M malzemelerin borlanmasi]
    (2002) Atik E.; Meriç C.; Yavuz N.
    Iron based machine parts produced by powder metallurgy become widespread in industry. Since these parts are produced from low carbon iron powders, they are used generally in sintered form without a heat treatment. The boronizing method which is already used for hardening of metalsurfaces can be applied to sintered iron based machine parts subjected to friction. With boronizing, which produced hard, low friction coefficient, high wear resistant surfaces under appropriate tribological conditions, resistance to corrosive environment can also be achieved.
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    Effects of boronizing process on the surface roughness and dimensions of AISI 1020, AISI 1040 and AISI 2714
    (2009) Şahin S.
    In this study, the effects of boronizing treatment on material's dimensional changes and surface roughness were investigated. The parameters chosen were substrate material composition, surface roughness before boronizing treatment, and boronizing time. The AISI 1020, AISI 1040 and AISI 2714 were chosen as substrate materials whereas Ekabor I was selected as boronizing powder. Materials were boronized at 900 °C by using a solid boronizing method for 2 or 4 h. The gradual growth of boride layer on the surface, dimensional changes and their effects on surface roughness were investigated. Variations in topographical surface roughness were determined by SEM. With the boronizing treatment, dimensional increases of the material's were observed. The dimensional increase was one fifth of boride layer thickness for AISI 1020 or AISI 1040, whereas it was one third of boride layer thickness for AISI 2714. Boronizing treatment had also a significant effect on surface roughness of materials. A "threshold roughness" term was defined in our study. This term is a surface roughness value for smooth surfaces, which received boronizing treatment. For the same material and with the same boronizing conditions, the threshold roughness value was achieved after boronizing, when surface roughness of material was below the threshold roughness value, before boronizing was applied. However, when surface roughness of a material was above that threshold roughness value, surface roughness value decreased with boronizing treatment. The thereshold roughness value depended on substrate material composition and boronizing parameters. © 2008 Elsevier B.V. All rights reserved.
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    Effect of boronizing and shot peening in ferrous based FeCu-Graphite powder metallurgy material on wear, microstructure and mechanical properties
    (2010) Yilmaz S.S.; Ünlü B.S.; Varol R.
    Ferrous based materials manufactured by powder metallurgy (P/M) method are widely used in industry. These materials are very important because they do not require machining, have self-lubricated properties as journal bearing material, find applications in medical industry. In this study, powder metal parts were manufactured from ferrous based FeCu-Graphite composites by P/M method. Wear and mechanical test samples were manufactured and boronizing and boronizing. +. shot peening was applied to samples. Wear properties of these parts were investigated by wearing at 17. N load and 50. rpm on pin-on-disc wear test rig under dry conditions. Moreover, mechanical properties of powder parts were investigated in detail. © 2010 Elsevier Ltd.
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    A study for boronizing process within nonextensive thermostatistics
    (Association for Scientific Research, 2010) Kayacan O.; Şahin S.; Taştan F.
    In this study, diffusion mechanism of the boronizing process of AISI 1040 has been investigated. A nonlinear diffusion equation, which was proposed earlier, has been employed and compared with the experimental data. An interesting property of the diffusion equation used here is that it establishes a connection between the diffusion process and nonextensivity. The theoretical model also exhibits a possible connection between the exponents appeared in the differential equation and the entropic index. In this manner, the possible effects of nonextensivity on the boronizing process have been shown theoretically. We believe that a diffusion equation based on the nonextensive formalism is first applied to the boronizing process in literature. © Association for Scientific Research.
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    Production of ferroboron powders by solid boronizing method
    (2010) Sahin S.; Meric C.; Saritas S.
    Ferroboron is an iron-boron alloy containing 10-20% of boron by weight. Commercial ferroboron production is made by two main processes: carbothermic reaction and aluminothermic reaction. Ferroboron also occurs in steel surfaces due to boronizing, which is applied to increase surface hardness in steel. Boronizing is a thermo-chemical surface hardening treatment. The ferroboron phases like Fe2B, FeB form by diffusing of boron element into iron. These phases are very hard, wear strengths are high, and friction coefficients are low. In this study, ferroboron powder was obtained by boronizing ASC 100.29 iron powder that was used widely in powder metallurgy area. Solid boronizing method was preferred due to its advantages in applications and Ekabor-HM powder was used as the boronizing agent. The 80% ASC 100.29 and 20% Ekabor HM were mixed homogeneously and subjected to boronizing at 850-950 °C for 1-6 h. Formation and development of ferroboron phase on the samples was determined by metallographic studies depending on various treatment conditions. The X-ray diffraction analysis revealed that the Fe2B phase did form but FeB phase did not. Micro hardness distributions were measured on the powder grains. Eighteen GPa hardness was measured at Fe2B phase obtained by boronizing while hardness of non-boronized iron powders was 1.06 GPa. The thickness of ferroboron layer formed by boronizing changed with boronizing conditions. The thickness of ferroboron layer increased with boronizing temperature or boronizing time. Depending upon processing parameters, ferroboron layers was formed partially or throughout ferrous powder structure. Since boronizing can be applied to iron powders having any size or shape, ferroboron production with required shape and size is possible. Finally, a new method, namely solid boronizing method, was developed in ferroboron powder production. © 2010 The Society of Powder Technology Japan.
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    Investigation of tribological properties of boronized Fe-based SAE 1020 and TS-DDK 40 journal bearings at high loads
    (2010) Ünlü B.S.; Atik E.
    In practice, ferrous based materials are not used because they show similar properties to shaft material and are known to cause adhesive wear in journal bearings. With boronizing process, adhesive wear can significantly be decreased. In this study, boronizing has been applied to some ferrous based (SAE 1020, TS-DDK 40) journal bearings. Wear experiments were done on SAE 1050 steel shaft as counter abrader with 100 N loads, and 1500 rpm for 5 h by using a radial journal bearing test rig. Boronizing treatment increased wear resistance of SAE 1020, TS-DDK 40 about 10-25, and 5-7 times respectively. © 2009 Elsevier Ltd. All rights reserved.
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    Mechanical properties of heat treated iron based compacts
    (Elsevier Ltd, 2015) Çavdar U.; Ünlü B.S.; Pinar A.M.; Atik E.
    In this study, powder metal (PM) compacts were prepared by mixing iron powder with 1-6. wt.% ratio of Cu and 0.2-0.8. wt.% ratio of graphite. The 20 different PM compacts compositions were prepared with a 0.8. wt.% ratio of zinc striate as the lubricant. The dimension of compacts were 10. ×. 10. ×. 55. mm. All the compacts were pressed at 600. MPa and, sintered at 1120. °C for 30. min using a conventional sintering furnace and then boronizing, steaming and carbo-nitriding heat treatments were applied. The results of all compacts for the bending test, microstructure images and HV microhardness results were compared. As a result of the experiments, it was concluded that, the highest bending strength was obtained at carbo-nitrided samples, the highest surface hardness was measured at boronized samples and all these heat treatments increase the densities of iron based samples. © 2014 Elsevier Ltd.
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    Tribological properties of boronized ferrous based PM journal bearings
    (Carl Hanser Verlag, 2015) Ünlü B.S.; Yilmaz S.S.; Kurgan N.; Varol R.
    Ferrous based PM (powder metallurgical) materials are widely used in journal bearings since they provide a good tribological performance. These bearings are self-lubricating and can be used in places where lubricating is not possible. This also applies to the shaft material which shows adhesive wear. Tribological properties can be improved and adhesive wear can be decreased by boronizing. In this study, tribological properties of ferrous based boronized and non-boronized Fe-graphite, FeCu-graph-ite and CuSnFe-graphite bearings manufactured by PM method have been determined and compared. Boronizing treatment was carried out at 950°C for 4 hours. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N loads and 1500 rpm every 30 minutes for 2.5 hours. © Carl Hanser Verlag, München. © Carl Hanser Verlag GmbH & Co. KG.
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    A study of soil tillage tools from boronized sintered iron
    (Springer New York LLC, 2017) Yazici A.; Çavdar U.
    Acomparative analysis of the properties of boronized sintered iron and quenched steels 30MnB5, 28MnCrB5 used for making soil tillage tools is performed. The microstructure, phase composition, hardness and strength characteristics of the materials are studied. The composition of the boride phase formed in the sintered iron after boronizing is determined by an x-ray method. The losses to abrasive wear are evaluated with the help of a device containing a special bin with a sample of abrasive soil. © 2017 Springer Science + Business Media New York.
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    Characteristics of boronized Ti6Al4V alloy using boric acid based boronizing mixture
    (Elsevier Inc., 2022) Türkmen İ.; Kanbur K.; Sargin F.
    Boronizing processes of Ti alloys are generally performed in atmosphere-controlled furnaces. In this study, it is aimed to carry out boronizing process under atmospheric conditions by using an alternative boronizing mixture containing boric acid and to better the surface characteristics of Ti6Al4V alloy by boronizing. The efficiency of the boronizing mixture was evaluated by performing boronizing at different process temperatures (900-1100 °C) and durations (12 and 20 h). Microstructural (OM, SEM) and chemical (XRD, EDS, XPS) analyzes were performed to characterize the boride layers formed on the surfaces of the boronized samples. As a consequence of these analyzes, it was found out that a two-phase boride layer (TiB2 + TiB) was obtained in the samples. In addition, in vitro tests were done for specifying the bioactivity of boronized samples. In order to determine the effect of boronizing on the corrosion resistance of Ti6Al4V alloy, corrosion tests were performed by the Tafel extrapolation method. The adhesion behavior of the boride layers was determined by the Daimler-Benz Rockwell C indentation test. As a result, boronizing studies have been performed successfully without atmospheric-controlled conditions and it has been defined that surface characteristics of the Ti6Al4V alloy have bettered through the boride layers formed on the alloy surface. © 2022 Elsevier Inc.
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    Boronizing of Monel K500 alloy: Microstructural characterization and modeling of boron diffusion
    (Elsevier Inc., 2024) Türkmen İ.; Keddam M.
    In this study, the thermochemical treatments were carried out using the powder-pack boronizing method at temperatures ranging from 1123 K to 1223 K for durations of 2 to 6 h, with the aim of improving the surface properties of Monel K500 alloy. Microstructural investigation of the boride layers, conducted using optical microscopy (OM) and scanning electron microscopy (SEM), revealed a needle-like layer structure with high porosity homogeneously distributed on the surface. The results of XRD analysis showed that the boride layer contained different nickel borides (Ni2B, Ni3B, Ni4B3 and NiB12), iron borides (Fe2B and Fe3B) and complex borides (Fe4.5Ni18.5B6 and Fe3Ni3B). The presence and amount of elements in the boride layer were determined by EDS analysis. This study focused mainly on diffusion kinetics studies of boronized Monel K500 alloy. Growth kinetics of the boride layer were investigated using three different approaches such as parabolic growth model, regression model and mean diffusion coefficient (MDC) model. Boron activation energy values were calculated and found to be quite similar, at 266.14 kJ mol−1 and 266.17 kJ mol−1 using the MDC model and parabolic growth model, respectively. These values were compared with similar results reported in the literature. © 2024 Elsevier Inc.