• Title/Summary/Keyword: Brinell Hardness

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Evaluation of Brinell Hardness of Coated Surface Using Finite Element Analysis: Part 1 - A Feasibility Study (유한요소해석에 의한 코팅면의 브리넬 경도 평가: 제1보 - 타당성 연구)

  • Park, TaeJo;Kang, JeongGuk
    • Tribology and Lubricants
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    • v.36 no.6
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    • pp.378-384
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    • 2020
  • The friction surfaces of mechanical parts are heat-treated or coated with hard materials to minimize wear. Increasing the hardness is a very useful way to reduce abrasive wear. The general Brinell hardness test, which is widely used for metallic materials, is not suitable because it hardly shows any change in hardness when coated with thin films. In this study, we propose a basis for the application of the new Brinell hardness test method to the coated friction surface. An indentation analysis of the rigid sphere and elastic-perfectly plastic materials is performed using a commercial finite element analysis software. The results indicate that their loadto-diameter ratio is the same; the Brinell hardness test method can be applied even when the indenter diameter is on the micrometer scale. In the case of hard coating, it is difficult to calculate Brinell hardness using the diameter of the indentation, but the study revealed, for the first time, that it can be calculated using the depth of the indentation regardless of coating. The change in hardness owing to thin film coating over a wide load range implies that the hardness evaluation method is appropriate. Additional studies on various properties related to the substrate and coating material are required to apply the proposed method.

A Study on the Evaluation of Brinell Standard Hardness Tester and Automatic Indentation Measurement System (브리넬 경도 표준 시험기 및 압입 자국 자동 측정장치의 특성 평가에 대한 연구)

  • Bahng, G.W.;Tak, Nae-Hyung
    • Journal of the Korean Society for Heat Treatment
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    • v.12 no.4
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    • pp.294-302
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    • 1999
  • Evaluation of Brinell standard hardness tester was carried out to secure its application as a national standard for Brinell hardness. Accuracies and reliabilities in load application, indenter diameter and indentation measurement were tested through evaluation of these components. The accuracies of load application for various loading conditions were within the limit of ISO and KS specifications. Errors in the indentation measurement due to the difference in personnel characters were successfully removed by utilising automatic indentation measurement system. In overall, the tester and the indentation measuring system were found to be eligible as a national standard of Brinell hardness.

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Hardness Estimation of Compressor Journal for a Use of Instrumented Indentation Techniques (계장화 압입시험법을 이용한 차량용 컴프레서 저널 경도 평가)

  • Kwak, Sung-Jong;Jin, Ji-Won;Kim, Tae-Seong;Noh, Ki-Han;Kang, Ki-Weon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.376-381
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    • 2012
  • This paper deals with application of instrumented indentation technique for quality inspection methodology for automobile component. For this, the instrumented indentation tests were performed the normal and cracked compressor journal, which is made from spheroidal graphite cast iron and utilized in air-conditioning system. And the Brinell hardness was estimated using the unloading slope and maximum indentation force. With the aid of Normal distribution, this Brinell hardness was statistically compared and analyzed with hardness measured by indentation hardness tests. Also, application possibility of reliability-based quality inspection criteria for compressor journal was evaluated through the probabilistic analysis for the Brinell hardness estimated by instrumented indentation technique.

Determination of Brinell Hardness through Instrumented Indentation Test without Observation of Residual Indent (계장화압입시험법을 이용한 비압흔관찰 브리넬 경도 평가)

  • Kim, Sung-Hoon;Choi, Yeol;Kwon, Dong-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.5
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    • pp.578-585
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    • 2004
  • Hardness test is performed for determination of the other properties, such as strength, wear resistance and deformation resistance, as well as hardness itself. And it is performed for prediction of residual lifetime by analysis of hardness reduction or hardness ratio. However, hardness test has limitation that observation of residual indent is needed for determination of hardness value, and that is the reason for not to be widely used in industrial field. Therefore, in this study, we performed researches to obtain Brinell hardness value from quantitative numerical formula by analysing relationship between indentation depths from indentation load-depth curve and mechanical properties such as work hardening exponent, yield strength and elastic modulus.

A Study on the Evaluation of Long Term Stability of Brinell Standard Hardness Tester and Automatic Indentation Measurement System and Optimum Test Condition (브리넬 경도 표준 시험기 및 압입자국 자동 측정 장치의 장기 안정도 평가와 최적 시험조건에 관한 연구)

  • Bahng, G.W.;Tak, Nae-Hyung;Hwang, N.M.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.1
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    • pp.10-15
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    • 2000
  • Evaluation of long term stability of the Brinell standard hardness tester was carried out to secure its application as a national standard in Brinell hardness. Accuracy and repeatability in load application were tested through evaluating errors in hardness measurement of certified reference blocks. All of those requirements in KS as well as ISO specifications were satisfied by this standard hardness tester. In addition to this, long term stability test of automatic indentation measurement system was carried out. The scattering range was almost the same with its error range. To figure out an optimum test condition for better repeatability and long term stability, the effect of load variation, load application speed and time have been studied using orthogonal array experimental plan. It was found that the best combination is $30{\mu}m/s$ of load application speed and 25 seconds of load application time.

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Evaluation of Brinell Hardness of Coated Surface Using Finite Element Analysis: Part 3 - Application to Multilayer Coatings (유한요소해석에 의한 코팅면의 브리넬 경도 평가: 제3보 - 다층 코팅에 적용)

  • Park, TaeJo;Kang, JeongGuk
    • Tribology and Lubricants
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    • v.37 no.6
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    • pp.240-245
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    • 2021
  • Ceramic coatings with high hardness and excellent chemical stability have been successfully applied to various machine elements, tools, and implants. However, in the case of monolayer coating on soft substrates, a high-stress concentration at the interface between the coating and the substrate causes delamination of the coating layer. Recently, to overcome this problem, multilayer coatings with a metal layer with a low modulus of elasticity added between the ceramic and the substrate have been widely applied. This study presents the third part of a recent study and focuses on the effect of the number of coating layers on the Brinell hardness of multilayered coating with TiN/Ti, following the two previous studies on a new Brinell hardness test method for a coated surface and on the influence of substrate and coating thickness. Indentation analyses are performed using finite element analysis software, von Mises stress and equivalent plastic strain distributions, load-displacement curves, and residual indentation shapes are presented. The number of TiN/Ti layers considerably affect the stress distributions and indentation shapes. Moreover, the greater the number of TiN/Ti layers, the higher is the Brinell hardness. The stress and plastic strain distributions confirm that the multilayer coatings improve the wear resistance. The results are expected to be used to design and evaluate various coating systems, and additional study is required.

Evaluation of Brinell Hardness of Coated Surface by Finite Element Analysis: Part 2 - Influence of Substrate and Coating Thickness (유한요소해석에 의한 코팅면의 브리넬 경도 평가: 제2보 - 모재와 코팅두께의 영향)

  • Park, TaeJo;Kang, JeongGuk
    • Tribology and Lubricants
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    • v.37 no.4
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    • pp.144-150
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    • 2021
  • The most cost-effective method of reducing abrasive wear in mechanical parts is increasing their hardness with thin hard coatings. In practice, the composite hardness of the coated substrate is more important than that of the substrate or coating. After full unloading of the load applied to an indenter, its indentation hardness evaluated based on the dent created on the test piece was almost dependent on plastic deformation of the substrate. Following the first part of this study, which proposes a new Brinell hardness test method for a coated surface, the remainder of the study is focused on practical application of the method. Indentation analyses of a rigid sphere and elastic-perfect plastic materials were performed using finite element analysis software. The maximum principal stress and plastic strain distributions as well as the dent shapes according to the substrate yield stress and coating thickness were compared. The substrate yield stress had a significant effect on the dent size, which in turn determines the Brinell hardness. In particular, plastic deformation of the substrate produced dents regardless of the state of the coating layer. The hardness increase by coating behaved differently depending on the substrate yield stress, coating thickness, and indentation load. These results are expected to be useful when evaluating the composite hardness values of various coated friction surfaces.

The Effect of Resin Impregnation Ratio on the Properties of Woodceramics Made from Broussonetia Kazinoki Sieb (수지함침율이 닥나무 우드세라믹의 성질에 미치는 영향)

  • Byeon, Hee-Seop;Kim, Jae-Min;Hwang, Kyo-Ki;Park, Seong-Cheol;Oh, Seung-Won
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.3
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    • pp.178-184
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    • 2010
  • This study was carried out to investigate the properties of woodceramics made from woody part of Broussonetia Kazinoki at different impregnation ratios of phenolic resin of 40, 50, 60, 70%. The physical and mechanical properties increased with increasing impregnation ratio. The highest mean values of density, bending strength, Brinell hardness and compressive strength were 0.66 g/$cm^3$, 53 kgf/$cm^2$, 187 kgf/$cm^2$, 126 kgf/$cm^2$, respectively. There were close correlations between density and bending strength, Brinell hardness and compressive strength, and between MOE and MOR.

Properties of Boards Prepared From Woody of Broussonetia Kazinoki Sieb. (닥나무 목질부로 제조된 보드의 성질(I))

  • Oh, Seung Won;Park, Seong Cheol
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.3
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    • pp.216-221
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    • 2009
  • This study was investigated the properties of boards prepared from woody of Broussonetia Kazinoki differed in density of board and mixed quantity of powdered phenolic resin. Water absorption decreased as the density of boards and resin content increased, but bending strength and brinell hardness increased as the density of board and the quantity of resin added increased. Thickness swelling increased as the density of boards went up, and that, in contrary, decreased as the quantity of resin added to the boards.