IMEKO Event Proceedings

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John Ndanusa Akanya, Obiora Ferdinand Manafa
STANDARDIZATION – THE SON EXPERIENCE
Standards Organisation of Nigeria (SON) was established by Decree No. 56 of 1971 and statutorily charged with the responsibility for National Policy on Metrology, Standards, Testing and Quality Control (MSTQ) in Nigeria. Standardization activities carried out by SON range from development and approval of standards, quality assurance, inspection and testing, certification and calibration. Hardness measurement plays a vital role in Standardization. Product and System certification programmes of SON have recorded a considerable number of hardness measurements in industries, oil & gas facilities, laboratories and research institutions. This paper gives a detailed report of the Standardization activities in SON with emphases on Metrology. It started by giving a full description of the corporate entity, legal status, organizational structure, human and technical resources of SON. The paper goes further to show the functions and detailed activities of SON, including limits of capability. The role of hardness tests and values in quality assurance activities is given a considerable portion in this paper. The development of Metrological Infrastructure, which enhanced the promotion of Standardization activities in SON, is also highlighted. Fields of Measurements available in SON Metrology laboratory are enumerated. Institutional support and international co-operation with various foreign bodies and international organizations are included in the paper. In conclusion, the paper outlines the way forward to ensure the growth of metrology, hardness measurement in particular, and effective Standardization activities in SON.
HARDMEKO 2004, Washington, DC, USA, 2004

Edward Aslanyan, Alexander Doynikov, Victor Pivovarov, Igor Temnitsky, Vasily Shlegel, Denis Golotvin, Rustem Fazliakhmetov
TESTING HARDNESS OF METAL ITEMS WITH MET-UD COMBINED PORTABLE HARDNESS TESTER
A new approach to portable hardness testers has been developed and introduced. It makes it possible to inspect hardness by one and the same hardness tester applying both, the ultrasonic contact impedance method and rebound method. Hardness tester wide possibilities which allow to inspect hardness of metal and alloy products with all standardized scales (Rockwell, Brinell, Vickers and Shore) have been demonstrated. The possibility to improve the precision of portable hardness testers of this type by calibrating them for each of the above listed scales with hardness reference blocks only without any conversion tables has been shown. Experiments and real measurements conducted on cold rolls showed that change in hardness of a hardened layer in depth and surface stresses influence can be disclosed in the process of hardness measurement by portable combined hardness tester by two different methods.
HARDMEKO 2004, Washington, DC, USA, 2004

V.Augutis, V,Vasauskas, D.Gailius, S.Jacenas
INDENTATION HARDNESS FOR LOW DENSITY MATERIALS
There is a demand of a system for the nondestructive control of one of the basic quality parameters for wood-based low-density boards (Softboard). A relatively non-destructive method was analyzed on a purpose to find a parameter to measure that has the biggest possible correlation with the bending strength. 13 different softboards were investigated using two different techniques. The boards were tested using another two non-destructive methods: velocity measurement of ultrasonic Lamb waves and impact parameters measurement. Out of all experiment results the highest correlation between bending strength and the conical indenter impact pulse peak force was found.
HARDMEKO 2004, Washington, DC, USA, 2004

Giulio Barbato, Alessandro Germak, Claudio Origlia, Francesco Turotti, Manfredo Vattasso
HARDNESS TESTERS CALIBRATION PRACTICE
In the framework of the standardization and laboratory activities concerning the calibration of hardness testers, in particular for indirect verification there are some questions to be answered to decide an efficient metrological confirmation strategy: a) how many points on each scale shall be checked? b) How many levels of the indentation scale shall be checked? c) How many levels of forces shall be checked? d) Is the correlation between indirect results and direct results strong enough to allow a partial check of the hardness scales of the tester? A number of tests have been made and the results have been statistically elaborated to give an answer to these questions.
HARDMEKO 2004, Washington, DC, USA, 2004

Giulio Barbato, Alessandro Germak
PRACTICAL IMPLICATIONS TO THE IMPROVEMENT OF HARDNESS SCALES DEFINITIONS
Recently, in the framework of the Working Group on Hardness (WGH) of the Consultative Committee for Mass and Related Quantities (CCM) of the Comité International des Poids et Mesures (CIPM), the opportunity to improve the definitions of the hardness scales has been discussed. In this paper is investigated, from the theoretical point of view, the benefits in terms of decreasing of uncertainty subsequently to the approval of new definitions. The analysis will be done on the most important Rockwell, Vickers and Brinell hardness scales, but it will be possible to extend the benefits easily to all other scales.
HARDMEKO 2004, Washington, DC, USA, 2004

Laurence Brice
ESTABLISHMENT OF A MARTENS HARDNESS CALIBRATION SERVICE
As part of the UK’s National Measurement System Mass Programme, and as a result of industrial demand, it was decided to establish a Martens hardness calibration service. This report describes the basis of Martens hardness measurement, work done to determine the ability of NPL’s 1,5 kN hardness machine to measure Martens hardness, the process of establishing the calibration service, and the setting up of instrumented indentation hardness tests.
HARDMEKO 2004, Washington, DC, USA, 2004

André L. M. Costa, David J. Shuman, Renato R. Machado, Margareth S. Andrade
DETERMINATION OF THE COMPLIANCE OF AN INSTRUMENTED INDENTATION TESTING MACHINE
A major factor in calibrating a depth-sensing indentation tester is to determine its load-frame compliance. In this work a simplified theoretical approach and a computerized iterative method were developed to calculate the load-frame compliance of our laboratory commercial instrumented indentation tester. In addition, this research discusses many of the problems associated with the calibration of this type of testing machine. Three materials were used for the load-unload tests: fused silica, 6066-O aluminum and electrolytic copper. A value of load-frame compliance of 0,23 nm/mN was obtained with fused silica. This value was considered acceptable because the calculated elastic modulus for fused silica was comparable to those found by other researchers using a similar strategy of unload curve analysis. This calculated load-frame compliance is in the range found in literature for other instrumented indentation testers. The load-frame compliance values obtained with the two metals were unacceptable because of errors probably associated with pile-up and strain hardening.
HARDMEKO 2004, Washington, DC, USA, 2004

Robert Ellis, Paul Mumford, Sam Low, Andy Knott
CHARACTERIZING ROCKWELL DIAMOND INDENTERS USING DEPTH OF PENETRATION
Diamond indenters used in a Rockwell hardness tester can dramatically affect the performance of the test. For this reason, it is important to find a method that can characterise the indenter. Current methods of verifying diamond indenter geometry have failed to thoroughly predict the performance when in use in the Rockwell tester. The paper addresses a possible method to use depth data during the test to characterise the indenter.
HARDMEKO 2004, Washington, DC, USA, 2004

Masayuki Fujitsuka, Chiaki Sato
NANO-INDENTATION TESTING ON IN SITU MECHANICAL PROPERTIES OF ADHESIVES
The mechanical properties of adhesives are determined either from bulk material samples from adhesively bonded joints. For many years there has been controversy as to whether the mechanical properties obtained through testing bulk material are representative of the adhesive in its thin-film form. The use of adhesive bonding as a method of joining structural members in advanced structures is increasing. A major advantage of adhesive bonding is that it enables dissimilar materials to be joined and reduces the localized stresses encountered when using mechanical fastening such as bolts and rivets. In design process it is important to know unambiguously the mechanical properties of the materials being used. Because the adhesive is used in thin-film from, to obtain the mechanical characteristics of the adhesive in situ is hoped. In several papers it has been found that the adhesive material has different mechanical properties when tested in the thin-film form and bulk form, and further that a thickness effect exists, causing the properties to depend on the thickness of the bondline. However, the good agreement between thin-film and bulk properties is obtained in other papers. Moreover, the existence of the boundary layer in the adhesive layer is reported. In this paper, nano-indentation testing is carried out for the calibration specimens and two kinds of the specimens of adhesive. And the method in the former paper applied to know the distribution of local mechanical properties in the adhesive layers and the bulk material.
HARDMEKO 2004, Washington, DC, USA, 2004

M. Griepentrog, U. Beck, D.C. Hurley, D.T. Smith, S. Sasaki, H. Ogiso
EVALUATION OF MECHANICAL PROPERTIES IN THE NANOMETER RANGE - PRECISION AND TRUENESS
HARDMEKO 2004, Washington, DC, USA, 2004

Koichiro HATTORI, Satoshi TAKAGI, Hajime ISHIDA and Takashi USUDA
TRACEABILITY SYSTEM OF ROCKWELL HARDNESS C SCALE IN JAPAN
In the early of 2003, the traceability system of the Rockwell hardness standard have been developed in Japan. The National Metrology Institute of Japan (NMIJ) started to provide the national primary hardness standards, one of which is the hardness reference blocks, and the other one is the accreditation of the Rockwell hardness tester. In this paper, we present the detail of uncertainty transfer between the NMIJ and the secondary standard laboratories.
HARDMEKO 2004, Washington, DC, USA, 2004

K. Herrmann, G. W. Bahng, J. Borovsky, L. Brice, A. Germak, L. He, K. Hattori, S. Low, R. Machado, A. Osinska-Karczmarek
CCM VICKERS KEY COMPARISON - STATE OF THE ART AND PERSPECTIVES
In the framework of the Working Group on Hardness (WGH) of the Consultative Committee for Mechanical Measurements (CCM) in the year 2003 the key comparison Vickers was finished. In the comparison the hardness laboratories of 10 national metrology institutes participated: IMGC (Italy), NIST (USA), INMETRO (Brazil), NIM (P.R. China), KRISS (Republic of Korea), NMIJ (Japan), CMI (Czech Republic), GUM (Poland), NPL (U.K.), and PTB (Germany) served as the pilot laboratory. The comparison of the Vickers primary hardness standard machines was carried out with three sets of hardness reference blocks of the Vickers scales HV0,2, HV1 and HV 30 each with the hardness levels 240 HV, 540 HV and 840 HV. The Vickers key comparison for all used test forces ranges (Micro Vickers, Small Force Vickers, Macro Vickers) delivered valuable metrological data, and its main results are presented. The ways to determine the reference values are discussed. The uncertainties of the reference values can be considered as the present accuracy limits of Vickers measurements in the investigated ranges of hardness scales.
HARDMEKO 2004, Washington, DC, USA, 2004

H. Ishida, T. Sanponpute, R. Wongpithayadisai, S. Miyata, V. Tulasombut, T. Usuda, J. Matsuda, Y. Akimoto, B. Suktat
BILATERAL COMPARISON IN HRC BETWEEN NMIJ AND NIMT
This bilateral comparison in HRC between National Metrology Institute of Japan, (NMIJ) and National Institute of Metrology (Thailand), (NIMT) was done in order to establish the hardness scales of NIMT and confirm their accuracy, which was designated by NIMT ( 0.45 HRC). The hardness blocks of 20 HRC, 30 HRC, 40 HRC and 60 HRC, which all have uniformity within 0.1 HRC according to EN ISO 6508-3, were used in this comparison. They were measured by NMIJ and NIMT with different conditions in order to indicate the performance of machines and hardness scales. Agreement of machine performance is within ± 0.13 HRC and agreement of hardness scales is within ± 0.24 HRC.
HARDMEKO 2004, Washington, DC, USA, 2004

M. Kompatscher
EQUOTIP - REBOUND HARDNESS TESTING AFTER D. LEEB
Hardness tests have always been important to conclude on specific mechanical properties of materials in a fast and economic manner, i.e. in a (quasi) non destructive test. This paper has its focus on the most recent test method, the dynamic rebound hardness test method after D. Leeb. The EQUOTIP, Leeb's original instrument, is fully discussed and newest improvements are presented. So far, PROCEQ SA, Swiss manufacturer of the instruments, maintained and protected the constancy of the L-Value over the last 30 years. Recent round robin results show the way, where standardization work can be improved to hold the high level of reliability of the measuring base, the L-Value.
HARDMEKO 2004, Washington, DC, USA, 2004

Yuhong Li, Wansheng Li
CALIBRATION OF PORTABLE BRINELL HARDNESS TESTERS
The paper describes calibration method of portable Brinell hardness testers, which have been manufactured for many years and used popularly in China, especially used in testing hardness of ferrous metals. A series of experiment have been done concerning hardness levels for calibration, thickness of hardness blocks, supports of the blocks, diameters of ball indenters and touch-method between the block and the support. Based on result obtained from tests mentioned above, it is given that specifications of portable Brinell hardness testers including indication error of 7%, repeatability of 4%, etc. Besides that, this paper, also, provide an equation of Brinell values vs indentation diameters based on a table, which could be useful for application of the testers.
HARDMEKO 2004, Washington, DC, USA, 2004

Li Ma, Samuel R. Low and James Fink
EFFECT OF STEEL AND TUNGSTEN CARBIDE BALL INDENTERS ON ROCKWELL HARDNESS TESTS
Rockwell hardness (HR) is a valuable and widely used indentation hardness test for evaluating mechanical properties of metallic materials. For the Rockwell scales that use a ball indenter, either a steel or tungsten carbide (WC) ball indenter is permitted to be used in the test method standards of ASTM International and International Organization for Standardization (ISO). However, significant differences occur in Rockwell hardness tests depending on whether a steel or WC ball is used. In this paper, finite element analysis (FEA) is used to simulate the HR indentation process. The effects of four different sizes of steel and WC ball indenters on different Rockwell hardness scales are studied and compared with experimental measurements. This study provides important approximations of the differences between the performance of steel and WC Rockwell hardness indenters.
HARDMEKO 2004, Washington, DC, USA, 2004

Fu-Lung Pan, Yu-Yi Su
UNCERTAINTY EVALUATION OF THE THIN-FILM INDENTATION SYSTEM
Center for Measurement Standards (CMS) had established a thin-film indentation testing system based on Akashi MZT-522. The electronic balance was made use of calibrating the testing force and the internal depth sensor was calibrated by laser hologauge. Five other uncertainty was also evaluated in the paper. Finally, the uncertainty of the thin-film indentation testing system reached a total of 5.02 %.
HARDMEKO 2004, Washington, DC, USA, 2004

George D. Quinn, Robert Gettings, and Lewis K. Ives
A STANDARD REFERENCE MATERIAL FOR VICKERS HARDNESS OF CERAMICS AND HARDMETALS
Standard Reference Material (SRM) 2831 was developed to improve Vickers hardness testing of Ceramics and Hardmetals. It may be used with conventional hardness testing machines that make indentations that are measured with an optical microscope. The SRM is a hot-isostatically pressed tungsten carbide with 12 % cobalt disk which has five indentations made at a load of 9.8 N (1 kgf). Each SRM is individually certified for the size of each of the 5 indentations, the average diagonal length ( 35.0 m), and the average hardness HV1. The HV1 is nominally 15 GPa which is in middle of the hardness range for most ceramics and cutting tool carbides.
HARDMEKO 2004, Washington, DC, USA, 2004

Nicholas X. Randall
DIRECT MEASUREMENT OF RESIDUAL CONTACT AREA AND VOLUME DURING THE NANOINDENTATION OF COATED MATERIALS AS AN ALTERNATIVE METHOD OF CALCULATING HARDNESS
The mechanical properties of thin films can be measured by a variety of different techniques, with nanoindentation being one of the most recent developments in this growing field. By using a depthsensing indentation method it is possible to obtain quantitative values for the hardness and modulus, and thus gain better insight into the response of a material to controlled deformation at such small scales. However, previous work has shown that the effects of pile-up, particularly in soft films deposited on hard substrates, can produce significant overestimation of the hardness and modulus due to an underestimation of the true contact area by common nanoindentation analysis procedures. By measuring the topography of the residual indent using Scanning Force Microscopy (SFM) and combining this information with the indentation data, it is possible to gain a fuller understanding of the indentation method and its effects on the material being tested. In addition, the true contact area can be directly measured from the SFM images and subsequently used to recalculate the hardness of the material more accurately. Moreover, the SFM allows the plastic volume of indentation to be measured, from which hardness can also be calculated in terms of plastic work. Experimental results are presented for two types of thin film deposited on hard substrates where SFM analysis of indentations at varying depths gives significant additional information concerning the true response of the system to instrumented indentation at a nanometric scale. Pile-up effects can be precisely monitored as a function of depth and correlated to hardness variations encountered across the coating/substrate interface.
HARDMEKO 2004, Washington, DC, USA, 2004

David Shuman; Margareth S. Andrade
USING NEWATOMIC FORCEMICROSCOPE SOFTWARE TO MEASURE THE HARDNESS OF GRAINS AND MICROCONSTITUENTS
It is desirable to measure the hardness of individual grains and microconstituents to have control over the mechanical properties of materials. An ultra-micro or nanoindenter is required to make indents small enough to fit inside a single grain or phases that is smaller than 10 mm diameter. Because the indents are too small for an optical microscope an atomic force microscope was used to view the location and measure the contact area. Measuring the contact area of indents from an atomic force microscope image is unreliable because it is difficult to manually locate the indent edge. To solve this problem computerized image analysis software called NanoMc was used to measure the residual indent contact area. This software digitally reconstructed the residual indent back into the fully loaded indentation shape and then measures the contact area and depth. This method avoids the complicated tip rounding and load-frame compliance problems. As an example this method was used to measure the hardness of pearlite and ferrite microconstituents in SAE 1020 steel.
HARDMEKO 2004, Washington, DC, USA, 2004

Anton Stibler, Samuel Low, Robert Ellis
COMPARATIVE MEASUREMENTS OF SLOVENIAN AND USA ROCKWELL C HARDNESS SCALES
A national scale is set up for each hardness scale representing the reference hardness values in each country. From metrological and international trade aspects agreement between the national scales is very important. Good agreement makes possible good industrial cooperation. Therefore comparison between national scales is necessary. Comparison between national hardness scales and hardness scales set up by the producers of the reference blocks is necessary as well. The Rockwell measurement method is the most widely used hardness measurement method throughout the world. The measurement is practical, relatively easy to carry out and the measurement result is quickly and simply indicated on the indicator. Among the different Rockwell scales, the C scale is very useful. It satisfies demands for accurate hardness measurement especially during hardening process of steel, which is often applied in industry. In this paper comparative measurements between the Rockwell C national scales of Slovenia as measured by Zavod za gradbeni?tvo Slovenije (ZAG) and USA as measured by the National Institute of Standards and Technology (NIST) and the scale set up by a producer of reference blocks, David L. Ellis Co., Inc., are presented.
HARDMEKO 2004, Washington, DC, USA, 2004

Anton Stibler, Konrad Herrmann, Zoran Susteric
LONG-TERM STABILITY OF RUBBER HARDNESS REFERENCE BLOCKS
Methods for hardness measurement on elastomers are characterized by a set-up where indenters with various defined geometries are pressed under defined test forces into the surface of testing material. The hardness value represents the resistance of the material to the rigid indenter and is calculated from the indentation depth of the indenter in the to be tested material. The test methods IRHD and Shore are the most common methods used in the field of rubber hardness measurements. Appropriate hardness measuring instruments are spread world wide. A periodic verification has to be carried out to assure the accuracy of these measuring instruments. Direct and indirect verification methods are recommended to be used. For the indirect method rubber hardness reference blocks are used. This indirect verification method is especially appropriate for the daily check of hand held rubber hardness testers. On the other side the direct verification of test force, depth measuring system and indenter geometry is suited for the periodic calibration of rubber hardness testers. For the rubber hardness reference blocks their accurate hardness reference value and the long-term stability are the most important characteristics. In this paper the long-term behaviour of hardness of rubber blocks which at present are available on the market and are made by different producers is presented. For the measurements the Shore and IRHD hardness standard devices in the PTB have been used. In order to determine the relationship between hardness and time under the specified conditions a regression analysis of the obtained measurement results was carried out. The results of this analysis can be used for the improvement of quality assurance systems in the field of rubber hardness measurements.
HARDMEKO 2004, Washington, DC, USA, 2004

Satoshi Takagi, Hjime Ishida, Takashi Usuda, Haruo Kawachi, Kazutomi Hanaki
DIRECT VERIFICATION AND CALIBRATION OF ROCKWELL DIAMOND CONE INDENTERS
The direct verification and the calibration of Rockwell diamond cone indenters in NMLT and JBI are described. Developed instrument can verify the roundness of the spherical part of the indenters, measure the radius of indenter tip and the cone angle by the optical methods. The regression analysis of the geometry of indenters and hardness value can determine the bias of each indenter in each hardness level. This bias can be used to correct the hardness value. To investigate the availability of the correction of hardness value, the experiments were carried out to analyze the relation between the indenters and other testing conditions. The results show that the effect of indenters are independent with other factors and the correction of hardness values are available. Hardness values were agreed within 0.04 HRC (standard deviation) after the correction is was applied.
HARDMEKO 2004, Washington, DC, USA, 2004

Christian Ullner
CRITICAL POINTS IN ISO 14577 PART 2 AND 3 CONSIDERING THE UNCERTAINTY IN MEASUREMENT
Based on the estimation of uncertainty the present requirements of the standard are discussed. Additional requirements needed for improving the reliability and the reproducibility are proposed. Especially the compliance of the machine affects strongly the parameters EIT and HMs in the macro range.
HARDMEKO 2004, Washington, DC, USA, 2004

Vytautas Vasauskas, Vytautas Capas
ENERGY CONCEPT IN COMPARISON OF STATIC AND DYNAMIC HARDNESS
This paper outlines the development of a simple predictive model for comparison of static and dynamic hardness. The model is essentially based on the energy - balance considerations and uses work of indentation divided by deforming volume to define hardness. The dynamic hardness was evaluated from measurements of residual contact dimensions and continued force - displacement over the velocity range 1 to 10 m s-1, based on the energy loss models and the energy conservation principle. The total and reversible work of indentation, defined as the respective area under the loading and unloading curves, has also been studied. The correlation between the static and dynamic loading results is satisfying, indicating that the effect of velocity on the energy absorbing is negligible. The obtained value for several engineering metals of dynamic hardness was 1,12?1,40 higher than the static hardness.
HARDMEKO 2004, Washington, DC, USA, 2004

Hiroshi Yamamoto, Takashi Yamamoto Hiroyuki Kawashima, Mikie Shibata
DEFINITION OF LOADING FOR HARDNESS BLOCKS
In a previous report, the authors investigated changes in hardness measurements when load rise time (LRT) was changed over a broad range in Vickers harness tests with loads of between 15 kgf and 150 kgf. As a result, we reported that hardness measurements varied according to the LRT value for every test load, while they remained almost constant between 15 kgf to 150 kgf if LRT was the same, although the indentation velocity of the indenter differed by more than three times between the two loads. It is very interesting that the considerable difference in indentation velocity due to varied test loads was not reflected much in hardness measurements. We, therefore, verified the effects of loading speed on hardness measurements theoretically from the strain rates of indentation deformation under the indenter and obtained some findings as follows. (1) It is necessary to define loading conditions to ensure the reliability of hardness blocks (2) The loading condition, namely the strain rate under indentation could be determined by the equation which was newly introduced by the authors. (3) According to this equation, loading conditions for general harness tests could be defined by loading time (LRT) regardless of load values. (4) Also considering that hardness measurements can vary according to load holding time, we may say that testing conditions can be "defined by time,". (5) Consequently, from the viewpoint of industrial practice, it would be reasonable to have rough criteria, that is, for how many seconds the test should be conducted, rather than to have scrutinized discussions on indentation velocity.
HARDMEKO 2004, Washington, DC, USA, 2004

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