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Jirí Nohava, Petr Haušild, David Gichangi Axelson, Gwenaél Bolloré
MECHANICAL PROPERTIES OF ALUMINUM ALLOYS BY INSTRUMENTED INDENTATION: CASE STUDY ON ALMIGO HARD


Shi Wei, Zeng Wu, Li Qingzhong
LEEB HARDNESS STANDARD WITH LASER MEASURING

The paper describes the principle, structure and performance of a Leeb Hardness Standard with Laser Measuring (HLSlaser). The range of the standard is (200 ~ 900) HL. At the same time, uncertainty of the standard has been evaluated, of which relative expanded uncertainties (k = 2) are at range of 1.0% ~ 1.2%. It has been done to make comparison of HL values tested by the standard and by six HL testers made by EQUOTIP Company of Switzerland with 6 HL blocks manufactured by the same company.

S. Low, K. Hattori, A. Germak, A. Knott
PROPOSED DEFINITION FOR THE BRINELL HARDNESS INDENTATION EDGE

The industrial Brinell hardness test has been in common use for over 100 years. The test is defined by standardized procedures stating that the Brinell hardness number is proportional to the test force divided by the surface area of the indentation. The test procedures require that the surface area be determined by measuring the indentation diameter after removing the test force. This measurement is usually made using an optical microscope, but without having a physical definition of the indentation edge. This paper proposes a physical definition of the indentation edge such that the Brinell indentation diameter can be unambiguously measured.

L. Ma, S. Low, J. Song
AN APPROACH TO DETERMINING THE BRINELL HARDNESS INDENTATION DIAMETER BASED ON CONTACT POSITION

Significant differences in Brinell hardness results have been observed worldwide largely due to the curved surface at the indentation edge making it difficult to measure its diameter. The indenter/material contact boundary under the test force should be the basis for the Brinell indentation diameter; however, the contact boundary cannot be observed using an optical microscope after the indenter is removed as is required by the test methods. Finite element analysis (FEA) models were used to develop a method to effectively determine the location of the indentation contact boundary after unloading allowing the indentation diameter to be physically defined and measured.

J. Song, S. Low
DEVELOPMENT OF NIST STANDARD REFERENCE METERIAL (SRM) ROCKWELL HARDNESS DIAMOND INDENTERS

The National Institute of Standards and Technology (NIST) is developing Standard Reference Material (SRM) Rockwell Hardness Diamond Indenters to support Rockwell hardness standardization in the U.S. One of the key steps is the geometrical calibration of the SRM indenters. Most tolerances for the geometrical parameters of the SRM indenters are adopted from those of the calibration grade Rockwell diamond indenters specified in the ASTM and ISO standards except for the form deviation from tip radius which was specified with a smaller tolerance of ± 0.8 µm. From the initial calibration results of the SRM indenters, it was found that the 0.5 µm tolerance for the cone flank straightness specified for the calibration grade diamond indenters by the ISO standard might be too tight to fit in the current production capability of the diamond manufacturers in different countries. As a result, although most SRM diamond indenters calibrated at NIST could meet all the technical requirements including the ± 0.8 µm reduced tolerance for the form deviation from the tip radius, none could meet the 0.5 µm tolerance of the cone flank straightness specified in the ISO standard when the calibrations were performed under the nominal window size. Furthermore, the window size and location for the geometrical calibration of the Rockwell diamond indenters are not clearly specified in the current standards, that also makes the geometrical calibration of Rockwell diamond indenter more difficult.

Satoshi Takagi
DETERMINATION OF THE GEOMETRICAL PARAMETERS OF ROCKWELL DIAMOND INDENTERS BY ITERATIVE REGRESSION METHOD

For the verification of Rockwell diamond indenter exactly following the international definition, an iterative method with the least square circle fitting was introduced. This method was applied to the analysis of verification data obtained with a laser probe 3D profile measurement instrument. It was demonstrated that the technique can be used to express the geometrical parameters properly with analytical results as an example. In addition, this technique can be applicable to determine equivalent geometrical parameters obtained with the optical measurement system currently used at NMIJ to establish the national standard indenters. It is shown that the proposed method can describe the geometry of indenter better than currently used method. These results suggest that the uncertainty of the national standard indenter could be improved through this high resolution geometry measurement and the multiple regression analysis NMIJ has been using.

Gun-WoongBahng, NaeHyungTak, Seong-Gu Hong, Junhee Hahn
TRACEABILITY IN MEASUREMENT FOR ROCKWELL, BRINELL AND VICKERS HARDNESS

The establishment of traceability in hardness measurement is still under discussion at the ISO TC 164 SC 3 subcommittee on hardness testing. Two paths for establishing traceability are proposed for Rockwell hardness measurement in ISO 6508-1. One way is to take a route to SI units through direct calibration of machine components; the other way is to take a route to the hardness measurement standard through indirect calibration of machine performance. This confusion is partly caused by the characteristics of hardness; i.e., a procedure dependent property. In this paper, methods for the establishment of traceability for Rockwell, Brinell, and Vickers hardness measurements are discussed based on the concepts defined in the international vocabulary of metrology (VIM).

C. Kuzu, C. Oysu, S. Fank, E. Pelit
ESTABLISHMENT OF ROCKWELL HARDNESS SCALES AT UME

A dead weight type Rockwell Hardness Standard Machine with a laser interferometer optic system was established to provide traceability in the field of hardness measurement for Rockwell Hardness scales at UME (National Metrology Institute of Turkey). Traceability of each component constituting Rockwell scales such as force, depth measuring system and testing cycle to national standards was provided by direct calibration. To realize performance tests of the machine as a whole, hardness reference blocks calibrated by PTB were used. In this paper, Rockwell Hardness Standard Machine of TÜBITAK UME Hardness Laboratory is introduced and its performance test results are interpreted.

Koichiro Hattori, Akihiro Ota
A ROUND ROBIN TEST OF ROKCWELL B SCALE HARDNESS

A round robin test of Rockwell B scale was carried out among the calibration class laboratories and testing class laboratories in Japan. Block calibration laboratories and general class machines are participated to the round robin test. The common indenter holder is prepared to investigate the indenter holder effect. Indenter ball (Tungsten carbide ball) is also provided and each participant uses the new ball for common and eachlaboratory’s holder, respectively. Blocks used are 30, 60, and 90 HRB and two blocks from different manufacturer is used for each level. The materials of the blocks are brass for 30 and 60 HRB and steel for 90 HRB, respectively. The variation of the test was about ±0.5 HRB for 60 and 90 HRB blocks, about ±1 HRB for 30 HRB hardness level, however, the some laboratory has large discrepancy. In addition, the hardness difference between steel (S) ball indenter and tungsten carbide ball indenter (W) is also investigated. The calculated hardness difference (S-W) is shown in Table 1. HS-W = 0.76 HRB for 90 HRB, HS-W = 0.67 HRB for 60 HRB block, HS-W = 0.90 for 30 HRB. The calculated standard deviations are 0.22, 0.26 and 0.41 HRB for 90, 60 and 30 HRB, respectively.

C.Landi, G. Del Prete, D.Gallo
REAL-TIME SMART METERS NETWORK FOR ENERGY MANAGEMENT

In this paper, an architecture of a low-cost ARMbased Smart Metering network is presented. The system is designed to be suitable for Smart Grids applications aimed to a more efficient energy use according to the article 13 of Directive 2006/32/EC. The network is composed by several slave smart meters that continuously monitor loads and energy generator to make available information in real-time such as power and energy consumption/generation and several power quality parameters to specific master device called data aggregator via CAN bus. This device integrating the information coming from slave smart meters and information regarding co-generator status, the forecast renewable source availability and, through a web service access, current energy prices can take decisions to suitable energy management cost strategy. So the user can remotely control their consumption using the web browser (Client), and locally thanks to the display of the data aggregator. To prevent external attacks a low computational burden software protection based on Message Authentication Code (MAC) has been implemented. Finally, characterization test of realized apparatus have shown good performances both in terms of communication errors and measurement uncertainty.

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