APMP.M.H-S3 Final Report Comparison on Hardness ... - BIPM

Revision: final <strong>Report</strong> 

Date: May 25, 2012 

<strong>APMP</strong>.M.H-<strong>S3</strong> 

<strong>Final</strong> <strong>Report</strong> 

<strong>Comparison</strong> on Hardness Measurement Rockwell scale A and B 

Tassanai Sanponpute 1 , Apichaya Meesaplak 1 , Febo Menelao 2 , T. K. Chan 3 , Gun-Woong 

Bahng 4 , S.S.K.Titus 5 , S.K. Jain 5 

1 NIMT: National Institute of Metrology (Thailand), 3/5 Moo 3, Klong 5, Klong Luang, 

Pathumthani Province, 12120, Thailand 

2 PTB : Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, 

Germany 

3 SCL: Standards and Calibration Laboratory, 36/F Immigration Tower, 7 Gloucester Road, 

Wanchai, Hong Kong 

4 KRISS: Korea Research Institute of Standards and Science 209 gajeong-ro, Yuseong-gu, 

Daejeon 305-340, Korea 

5 NPLI: Force & Hardness Standards, National Physical Laboratory, Dr. K.S. Krishnan 

Marg, New Delhi 110012, India 

Page 1 of 77

Revision: <strong>Final</strong> <strong>Report</strong> 

Date: May 25, 2012 

Abstract 

The <strong>APMP</strong>.M.H-<strong>S3</strong> Rockwell hardness intercomparison was initiated by NIMT, 

Thailand and the required protocol was prepared by NIMT and was checked by Dr.John 

Man, MNIA, Australia in 2009. In this comparison, PTB, Germany, Standards and 

Calibration Laboratory (SCL), Hong Kong, National Physical Laboratory (NPLI), India, 

and Korea Research Institute of Standards and Science (KRISS), Korea have 

participated. This comparison exercise was focused in the measurement range of 25-100 

HRBW scale and 35-85 HRA scale. The Round Robin test was done during the period 

of April 2010 to October 2010. The participated NMIs have demonstrated the capability 

of the machine and the operating conditions according to ISO 6508 Part3 to perform the 

measurements. However, SCL, Hong Kong could demonstrate their capability to 

perform the measurements only according to ISO 6508 part2. The CMC declared by the 

different laboratories lie in the range of 0.30 HRA to 0.40 HRA and 0.40 HRBW to 

0.75 HRBW. The CMC declared by SCL for the Rockwell B scale is 1.5HRBW due to 

the reason described above. It is observed from the results that the measurement 

uncertainty is estimated not less than the CMC declared by the laboratories. From the 

measurement results provided by all the participated laboratories, the En ratio was 

determined to establish the degree of equivalence. The En ratio was calculated by 

including as well as by excluding the results of the laboratory which has performed the 

test according to ISO 6508 Part2 in order to make sure that it does not affect the overall 

results. It is noticed that the En ratio still found to remain less than 1. 

Page 2 of 77


Date: May 25, 2012 

Content 

1. Introduction ............................................................................................................... 6 

2. Participating Institutes ............................................................................................... 6 

3. Schedule .................................................................................................................... 7 

4. Artifacts ..................................................................................................................... 8 

5. Measurement of Artifacts........................................................................................... 9 

6. HRA Measurement Data .......................................................................................... 10 

7. HRB Measurement Data .......................................................................................... 14 

8. Analyzing Method of <strong>Comparison</strong> Results ............................................................... 19 

9. <strong>Comparison</strong> Results ................................................................................................. 21 

10. Discussion and Conclusion ...................................................................................... 27 

11. Measurement <strong>Report</strong> ................................................................................................ 28 

Measurement report of PTB Laboratory .................................................................... 29 

Measurement report of NIMT Laboratory ................................................................. 36 

Measurement report of KRISS Laboratory ................................................................ 50 

Measurement report of NPLI Laboratory .................................................................. 61 

Measurement report of SCL Laboratory .................................................................... 69 

12. References ............................................................................................................... 77 

Page 3 of 77


Date: May 25, 2012 

Content of Table 

Table 1 List of participants ................................................................................................. 6 

Table 2 List of CMC declaration ........................................................................................ 7 

Table 3 Original schedule and actual time of measurement ................................................. 7 

Table 4 Artifact Identifications ........................................................................................... 8 

Table 5 NIMT’s HRA Measurement Result ..................................................................... 10 

Table 6 PTB’s HRA Measurement Result ........................................................................ 11 

Table 7 KRISS’s HRA Measurement Result .................................................................... 12 

Table 8 NPLI’s HRA Measurement Result ...................................................................... 13 

Table 9 NIMT’s HRB Measurement Result ...................................................................... 14 

Table 10 PTB’s HRB Measurement Result ....................................................................... 15 

Table 11 SCL’s HRB Measurement Result ....................................................................... 16 

Table 12 KRISS’s HRB Measurement Result ................................................................... 17 

Table 13 NPLI’s HRB Measurement Result .................................................................... 18 

Table 14 Conclusion of comparison evaluation on Rockwell hardness scale A ................. 21 

Table 15 Conclusion of comparison evaluation on Rockwell hardness scale B .................. 23 

Table 16 Conclusion of comparison evaluation on Rockwell hardness scale B without 

SCL’s results ............................................................................................................ 25 

Page 4 of 77


Date: May 25, 2012 

Content of Figure 

Figure 1 Indentation position .............................................................................................. 9 

Figure 2 Deviation from reference value of HRA measurement comparison ..................... 22 

Figure 3 En Ratio of HRA measurement comparison ........................................................ 22 

Figure 4 Deviation value of HRB measurement comparison ............................................. 24 

Figure 5 En Ratio of HRB measurement comparison ........................................................ 24 

Figure 6 Deviation value of HRB measurement comparison without SCL’s results.......... 26 

Figure 7 En Ratio of HRB measurement comparison without SCL’s results ..................... 26 

Figure 8 Variation of hardness measurement in Rockwell scale A .................................... 27 

Figure 9 Variation of hardness measurement in Rockwell scale B .................................... 27 

Page 5 of 77


Date: May 25, 2012 

1. Introduction 

There is a great demand to organize a measurement comparison in HRA and HRB from 

some National Institute of Metrology in ASEAN countries and may be in some <strong>APMP</strong> 

members in order to establish the CMC of the participating National Metrological 

Institutes (NMI). In view of this, the National Institute of Metrology, Thailand (NIMT) 

has taken the initiative to be the pilot laboratory to organize the comparison. 

Physikalish – Techniche Bundesansralt, Germany (PTB) has participated as an invited 

laboratory from EUROMET as they have a long experience and good reputation in 

hardness measurements. In this comparison, Standards and Calibration Laboratory 

(SCL), Hong Kong, National Physical Laboratory (NPLI), India, and Korea Research 

Institute of Standards and Science (KRISS), Korea have shown keen interest for 

participation. 

The first objective of this comparison is to determine the capability of the primary 

Rockwell hardness machine, including standard conditions, of each participant. The 

second objective is to confirm the calibration and measurement capability (CMC) of 

Rockwell hardness scale A and B measurement declared by the participants. 

2. Participating Institutes 

The list of participants and the CMC declared by them are given in table 1 and table 2 

as below: 

Table 1 List of participants 

Participant Address Contact information 

National Institute of 

Metrology (Thailand), 

NIMT 

Physikalisch-Technische 

Bundesanstalt, PTB 

Standards and Calibration 

Laboratory, SCL 

Korea Research Institute 

of Standards and Science, 

KRISS 

National Physical 

Laboratory, (NPLI) 

3 / 4-5 Moo 3, Klong 5, 

KlongLuang, Pathumthani 12120, 

Thailand 

5.12: Hardness and Layer 

Thickness Measurement 

Technique Bundesallee 100 38116 

Braunschweig 

Germany 

36/F Immigration Tower, 

7 Gloucester Road, 

Wanchai, Hong Kong 

209 gajeong-ro, Yuseong-gu, 

Daejeon 305-340, Korea 

Dr. K.S. Krishnan Marg, New 

Delhi 110012, India 

tassanai@nimt.or.th 

Tel: +66 (0)2584 3090 

febo.menelao@ptb.de 

Tel: +49 (0)531 592- 

5145 

tkchan@itc.gov.hk 

gwbahng@kriss.re.kr 

skjain@mail.nplindia.org 

Tel: +91 11 456 08680 

Page 6 of 77


Date: May 25, 2012 

Participant 

National Institute of 

Metrology (Thailand), 

NIMT 

Table 2 List of CMC declaration 

Calibration and Measurement Capability (CMC) 

Rockwell scale A Rockwell scale B 

0.38 HRA 0.40 HRB 


Bundesanstalt, PTB 

0.30 HRA 0.50 HRB 


Laboratory, SCL 

- 1.5 HRB 

Korea Research Institute 

of Standards and Science, 

KRISS 0.40 HRA 

0.60 HRB for nominal 

more than 50 HRB 


not more than 50 HRB 

National Physical 

Laboratory, NPLI 

0.30 HRA 


more than 60 HRB 


not more than 60 HRB 

3. Schedule 

The comparison started at the pilot lab, NIMT, in May 2010. The original schedule was 

to transfer the artifact from NIMT, PTB, NPLI, SCL, and KRISS respectively with 2 

weeks for measurement and 2 weeks for transportation process. The actual 

measurement schedule was slightly changed from the tentative one due to some 

problem in shipping the artifact to India. Thus, NPLI was scheduled to the last 

participant for measurement during October 2010 while measurements of the other 

participants went according to the original plan. 

The table 3 shows the original schedule and actual time of measurement 

Table 3 Original schedule and actual time of measurement 

Institute/Country Original schedule Actual schedule 

National Institute of Metrology 

(Thailand) 


Bundesanstalt (PTB) 


Laboratory (SCL) 

1-14 May 2010 1-14 May 2010 

1-15 June 2010 1-15 June 2010 

1-15 August 2010 1-15 August 2010 

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Date: May 25, 2012 

Korea Research Institute of 

Standards and Science (KRISS) 

National Physical Laboratory 

India 

1-15 September 2010 1-15 September 2010 

1-15 July 2010 1-15 October 2010 

SCL, Hong Kong was able to make the measurement only in HRB scale, while others 

participants made the measurement in all the range of hardness scales, i.e. both in HRA 

and HRB. 

4. Artifacts 

The artifact reference blocks for Rockwell hardness scale A and scale B are 

manufactured by Asahi Giken Co.,Ltd. Japan. Each scale consists of hardness block 

with serial number as in the table 4. The dimensions of the blocks are 65 mm in 

diameter and thickness of each block as in the table 4. All hardness block with 10.5 mm 

thickness are made from brass while the rest is made from steel. 

Table 4 Artifact Identifications 

HRA Set S/N Thickness HRB Set S/N Thickness 

35 HRA A32517 11.5 mm 25 HRB E1620 10.5 mm 

40 HRA A33781 11.5 mm 30 HRB B30120 10.5 mm 

55 HRA 25568 15 mm 40 HRB A31382 10.5 mm 

60 HRA B12037 15 mm 50 HRB A32411 10.5 mm 

70 HRA B15871 15 mm 60 HRB A33748 10.5 mm 

80 HRA A27761 15 mm 70 HRB A28422 10.5 mm 

85 HRA A21048 15 mm 80 HRB A35542 10.5 mm 

90 HRB 25566 15 mm 

100 HRB 30836 15 mm 

The surface of each artifact block was laser engraved with divided segments for 

indicating the indentation positions (Figure 1). Each segment is used for single 

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Date: May 25, 2012 

indentation in the comparison. There are 9 areas of measurement on each block. The 

rest of the segments on the block surface are reserved as alternative places for trial and 

error measurements 

Figure 1 Indentation position 

The plastic sheet indicating the indentation position of each participant will be 

enclosed with the artifact sets. It shall be placed on the artifact block in order to ensure 

the indentation position before making the indentation. 

5. Measurement of Artifacts 

The primary Rockwell hardness machines used for the comparison must be passed 

the verification according to ISO 6508-3 [1]. Before making the indentation on each 

block, the testing cycle must be adjusted to comply with ISO 6508-3. Then start to 

measure the hardness value of artifact blocks by making 9 indentations each block on 

the designated area on the indentation-positioning sheet. 

Each participant must give a characteristics description of your primary Rockwell 

hardness machine, your primary indenter, testing condition and environmental 

information. Also laboratory must report the measurement results for each indentation 

and the uncertainty of measurement of Rockwell hardness scale A and Rockwell 

hardness scale B, and uncertainty budget of measurement. 

Page 9 of 77


Date: May 25, 2012 

6. HRA Measurement Data 

Table 5 NIMT’s HRA Measurement Result 

Measure value (HRA) 

No. A32517 A33781 25568 B12037 B15871 A27761 A21048 

Nominal value 35 40 55 60 70 80 85 

Section1 35.41 38.99 54.98 60.47 70.53 81.29 85.43 









Average Value 35.25 39.10 55.05 60.44 70.58 81.30 85.32 

Uniformity 0.36 0.83 0.14 0.10 0.12 0.09 0.21 

Correction Value 0.08 0.08 0.08 0.08 0.08 0.08 0.08 

Corrected Value 35.33 39.18 55.13 60.52 70.65 81.37 85.40 

Expanded uncertainty (k=2) 0.40 0.43 0.39 0.39 0.39 0.38 0.39 

Page 10 of 77


Date: May 25, 2012 

Table 6 PTB’s HRA Measurement Result 


No. A32517 A33781 25568 B12037 B15871 A27761 A21048 

Nominal value 35 40 55 60 70 80 85 










Average Value 35.17 38.98 55.16 60.62 70.85 81.49 85.50 

Uniformity 0.67 0.73 0.29 0.10 0.15 0.08 0.20 




Page 11 of 77


Date: May 25, 2012 

Table 7 KRISS’s HRA Measurement Result 


No. A32517 A33781 25568 B12037 B15871 A27761 A21048 

Nominal value 35 40 55 60 70 80 85 










Average Value 35.58 39.42 54.90 60.30 70.71 81.36 85.43 

Uniformity 1.10 1.00 0.30 0.20 0.20 0.20 0.20 

Correction Value -0.03 -0.03 -0.03 -0.04 -0.04 -0.04 -0.04 



Page 12 of 77


Date: May 25, 2012 

Table 8 NPLI’s HRA Measurement Result 


No. A32517 A33781 25568 B12037 B15871 A27761 A21048 

Nominal value 35 40 55 60 70 80 85 










Average Value 35.31 39.16 55.21 60.59 70.85 81.56 85.80 

Uniformity 0.36 1.09 0.48 0.32 0.28 0.19 0.27 




Page 13 of 77


Date: May 25, 2012 

7. HRB Measurement Data 

Table 9 NIMT’s HRB Measurement Result 

Measure value (HRBW) 

No. E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

Nominal value 25 30 40 50 60 70 80 90 100 

Section1 23.88 28.60 37.82 51.05 59.70 69.74 79.79 90.13 100.14 









Average Value 24.07 28.52 37.71 50.99 59.57 69.59 79.56 90.44 100.04 

Uniformity 0.53 0.49 0.56 0.30 1.02 0.62 1.47 0.43 0.20 

Correction Value 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 

Corrected Value 24.13 28.57 37.77 51.05 59.63 69.65 79.61 90.49 100.10 

Expanded uncertainty (k=2) 0.40 0.40 0.40 0.40 0.40 0.40 0.41 0.40 0.40 

Page 14 of 77


Date: May 25, 2012 

Table 10 PTB’s HRB Measurement Result 


No. E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

Nominal value 25 30 40 50 60 70 80 90 100 










Average Value 23.35 28.59 37.65 50.95 59.95 69.88 79.62 89.98 99.68 

Uniformity 1.14 0.61 0.57 0.35 1.03 0.66 0.99 0.32 0.16 




Page 15 of 77


Date: May 25, 2012 

Table 11 SCL’s HRB Measurement Result 


No. E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

Nominal value 25 30 40 50 60 70 80 90 100 










Average Value 26.41 30.62 39.99 52.99 61.53 71.38 80.79 91.50 100.89 

Uniformity 1.40 2.40 0.95 0.70 0.80 0.40 1.25 0.20 0.20 

Correction Value -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 



Page 16 of 77


Date: May 25, 2012 

Table 12 KRISS’s HRB Measurement Result 


No. E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

Nominal value 25 30 40 50 60 70 80 90 100 










Average Value 23.59 29.46 38.59 51.00 59.79 70.17 79.86 90.37 100.10 

Uniformity 1.60 0.40 0.40 1.50 0.80 1.00 1.30 0.40 0.20 




Page 17 of 77


Date: May 25, 2012 

Table 13 NPLI’s HRB Measurement Result 


No. E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

Nominal value 25 30 40 50 60 70 80 90 100 










Average Value 24.28 29.52 37.65 51.26 59.06 69.83 79.36 90.13 99.87 

Uniformity 1.75 0.48 1.34 0.70 0.64 0.73 1.00 0.35 0.32 




Page 18 of 77


Date: May 25, 2012 

8. Analyzing Method of <strong>Comparison</strong> Results 

The measurement results are used to compute the degree of equivalence in <strong>Comparison</strong> 

Reference Value (CRV) and En ratio. The calculation is shown in following formulas: 

-Calculation of <strong>Comparison</strong> Reference Value (CRV) 

Pilot laboratory determined KCRV by calculating the weighted mean of 

measurements of all participants (xref). 

-The uncertainty of the CRV was calculated by following expression: 

Where: 

x = The measured value of participating institute i ( i =1,2,…,n) 

-Its deviation from CRV 

-The uncertainty of this deviation at a 95% level of confidence 

Where u( 

di 

) was given by 

And k = 2 

Page 19 of 77 

Eq. 1 

Eq. 2 

Eq. 3 

Eq. 4 

Eq. 5 

-Evaluation of Coefficient En 

The equivalence between the measurements of participating institutes was expressed 

by coefficient E as well. 

Where: 

x 

u 

ref 

2 

 

1 

( x 

ref 

x 

1 

u 

2 

( x ) x 

1 

2 

2 

2 

1 u ( x ) 1 

u ( x ) ... 1 

u ( x ) 

 

) u 

2 

1 

2 

1 

 

( x ) u 

1 

2 

u ( x ) ... x 

2 

1 

( x 

i 

u( xi 

) = The standard uncertainty of i x 

n 

E 

n 

 

d x x 

i 

i 

2 

2 

2 

... 

) u 

ref 

U ( di 

) k u( 

di 

) 

2 

n 

1 

( x 

2 

2 

2 

u ( d ) u ( x ) u ( x 

U 

2 

i 

x x 

i 

( x ) U 

i 

ref 

2 

i 

( x 

ref 

) 

ref 

2 

u ( x ) 

n 

) 

) 

n 

n 

Eq. 6


Date: May 25, 2012 

Where 

U ( xi 

) k u( 

xi 

) 

U ( xref 

) k u( 

xref 

) 

The was equivalent with CRV x at 95% confidence level, if E 

1. 

xi ref 

CRV is <strong>Comparison</strong> Reference Value 

U(CRV) is uncertainty of CRV 

D_NMI is deviation value of each NMIs from CRV 

U(D_NMI) is uncertainty of deviation value of each NMIs from CRV 

En ratio NMI is degree of equivalence of each NMIs result expressed in 

En ratio 

Ue is expanded uncertainty that evaluated by each NMIs 

n 

Page 20 of 77 

Eq. 7


Date: May 25, 2012 

9. <strong>Comparison</strong> Results 

The comparison results, comparison reference value (CRV), the deviation value of each NMIs from CRV as well as their uncertainty and En 

ratio, are calculated and shown in Table 15, Figure 2 and Figure 3 for Rockwell scale A. 

Table 14 Conclusion of comparison evaluation on Rockwell hardness scale A 

<strong>Comparison</strong> evaluation 

Nominal (HRA) 35 40 55 60 70 80 85 

CRV 35.31 39.15 55.12 60.53 70.78 81.46 85.55 

U(CRV) 0.18 0.21 0.17 0.17 0.17 0.17 0.17 

D_NIMT 0.02 0.03 0.01 -0.01 -0.12 -0.09 -0.15 

U(D_NIMT) 0.44 0.47 0.43 0.42 0.42 0.42 0.42 

En ratio NIMT 0.04 0.06 0.03 -0.02 -0.29 -0.21 -0.36 

D_PTB -0.14 -0.17 0.05 0.09 0.07 0.03 -0.05 

U(D_PTB) 0.40 0.41 0.35 0.35 0.35 0.34 0.35 

En ratio PTB -0.36 -0.41 0.13 0.27 0.20 0.08 -0.15 

D_KRISS 0.24 0.25 -0.25 -0.27 -0.10 -0.14 -0.16 

U(D_KRISS) 0.50 0.51 0.43 0.43 0.43 0.43 0.44 

En ratio KRISS 0.47 0.48 -0.56 -0.61 -0.24 -0.32 -0.36 

D_NPLI 0.00 0.01 0.10 0.07 0.07 0.10 0.25 

U(D_NPLI) 0.36 0.47 0.36 0.35 0.35 0.34 0.35 

En ratio NPLI -0.01 0.03 0.27 0.18 0.20 0.30 0.70 

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Date: May 25, 2012 

Deviation from CRV (HRA). 

En Ratio 

1.00 

0.50 

0.00 

-0.50 

-1.00 

<strong>Comparison</strong> result on Rockwell hardness scale A 

35 40 55 60 70 80 85 HRA 

D_NIMT D_PTB D_KRISS D_NPLI 

Figure 2 Deviation from reference value of HRA measurement comparison 

2.00 

1.00 

0.00 

-1.00 

-2.00 

Degree of equivalence expressed in En ratio 

35 40 55 60 70 80 85 HRA 

En ratio NIMT En ratio PTB En ratio KRISS En ratio NPLI 

Figure 3 En Ratio of HRA measurement comparison 

Page 22 of 77


Date: May 25, 2012 

The comparison results, comparison reference value (CRV), the deviation value of each NMIs from CRV as well as their uncertainty and En 

ratio, are calculated and shown in Table 16, Figure 4 and Figure 5 for Rockwell scale B show 

Table 15 Conclusion of comparison evaluation on Rockwell hardness scale B 

Nominal (HRBW) 25 30 40 50 60 70 80 90 100 

KCRV 23.93 28.95 37.84 51.08 59.65 69.85 79.62 90.28 99.95 

U(KCRV) 0.27 0.28 0.26 0.26 0.25 0.25 0.26 0.24 0.24 

D_NIMT 0.20 -0.38 -0.08 -0.03 -0.02 -0.20 0.00 0.21 0.14 

U(D_NIMT) 0.48 0.58 0.48 0.48 0.47 0.47 0.48 0.47 0.47 

En ratio NIMT 0.41 -0.66 -0.16 -0.07 -0.04 -0.42 -0.01 0.45 0.31 

D_PTB -0.58 -0.36 -0.19 -0.13 0.30 0.03 0.00 -0.30 -0.27 

U(D_PTB) 0.62 0.60 0.58 0.57 0.60 0.58 0.61 0.56 0.56 

En ratio PTB -0.94 -0.59 -0.33 -0.23 0.50 0.06 0.00 -0.54 -0.49 

D_SCL 1.98 1.17 1.64 1.41 1.38 1.04 0.67 0.72 0.44 

U(D_SCL) 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.01 2.01 

En ratio SCL 0.98 0.58 0.82 0.70 0.68 0.52 0.33 0.36 0.22 

D_KRISS -0.34 0.51 0.74 -0.08 0.14 0.32 0.24 0.09 0.15 

U(D_KRISS) 0.80 0.80 0.79 0.79 0.65 0.65 0.65 0.65 0.65 

En ratio KRISS -0.42 0.63 0.94 -0.10 0.22 0.50 0.37 0.14 0.23 

D_NPLI 0.36 0.57 -0.20 0.18 -0.59 -0.01 -0.26 -0.14 -0.09 

U(D_NPLI) 0.75 0.66 0.65 0.65 0.65 0.58 0.62 0.56 0.56 

En ratio NPLI 0.48 0.86 -0.30 0.27 -0.90 -0.02 -0.42 -0.26 -0.15 

Page 23 of 77


Date: May 25, 2012 

Deviation from CRV (HRB) 

En Ratio 

5.00 

4.00 

3.00 

2.00 

1.00 

0.00 

-1.00 

-2.00 

2.00 

1.00 

0.00 

-1.00 

-2.00 

<strong>Comparison</strong> result on Rockwell hardness scale B 

25 30 40 50 60 70 80 90 100 HRB 

D_NIMT D_PTB D_SCL D_KRISS D_NPLI 

Figure 4 Deviation value of HRB measurement comparison 


25 30 40 50 60 70 80 90 100 HRB 

En ratio NIMT En ratio PTB En ratio SCL 

En ratio KRISS En ratio NPLI 

Figure 5 En Ratio of HRB measurement comparison 

Page 24 of 77


Date: May 25, 2012 

To ensure that the SCL’ measurement results would not effect the other results, the evaluation on Rockwell scale B was done again without 

SCL’s measurement results. The comparison results, comparison reference value (CRV), the deviation value of each NMIs from CRV as well as 

their uncertainty and En ratio, are calculated and shown in Table 17, Figure 6 and Figure 7. 

Table 16 Conclusion of comparison evaluation on Rockwell hardness scale B without SCL’s results 

Nominal (HRBW) 25 30 40 50 60 70 80 90 100 

CRV 23.89 28.92 37.82 51.05 59.63 69.83 79.61 90.27 99.94 

U(CRV) 0.27 0.29 0.26 0.26 0.26 0.25 0.26 0.24 0.24 

D_NIMT 0.24 -0.35 -0.05 -0.01 0.00 -0.18 0.01 0.22 0.15 

U(D_NIMT) 0.48 0.58 0.48 0.48 0.48 0.47 0.48 0.47 0.47 

En ratio NIMT 0.49 -0.61 -0.10 -0.02 0.01 -0.38 0.02 0.48 0.32 

D_PTB -0.54 -0.33 -0.16 -0.11 0.33 0.05 0.01 -0.29 -0.27 

U(D_PTB) 0.62 0.60 0.58 0.57 0.60 0.58 0.61 0.56 0.56 

En ratio PTB -0.87 -0.55 -0.28 -0.19 0.54 0.09 0.02 -0.52 -0.48 

D_KRISS -0.30 0.53 0.77 -0.05 0.16 0.34 0.25 0.10 0.16 

U(D_KRISS) 0.80 0.80 0.79 0.79 0.65 0.65 0.65 0.65 0.65 

En ratio KRISS -0.38 0.66 0.97 -0.07 0.25 0.52 0.38 0.15 0.24 

D_NPLI 0.39 0.59 -0.17 0.20 -0.57 0.00 -0.25 -0.13 -0.08 

U(D_NPLI) 0.75 0.67 0.65 0.65 0.65 0.58 0.62 0.56 0.56 

En ratio NPLI 0.53 0.89 -0.26 0.31 -0.87 0.01 -0.40 -0.24 -0.14 

Page 25 of 77


Date: May 25, 2012 

Deviation from CRV (HRB) 

Figure 6 Deviation value of HRB measurement comparison without SCL’s results 

En Ratio 

-1.00 

-2.00 

2.00 

1.00 

0.00 

-1.00 

-2.00 

2.00 

1.00 

0.00 

<strong>Comparison</strong> result on Rockwell hardness scale B 

25 30 40 50 60 70 80 90 100 HRB 

D_NIMT D_PTB D_KRISS D_NPLI 


25 30 40 50 60 70 80 90 100 HRB 

En ratio NIMT En ratio PTB En ratio KRISS En ratio NPLI 

Figure 7 En Ratio of HRB measurement comparison without SCL’s results 

Page 26 of 77


Date: May 25, 2012 

10. Discussion and Conclusion 

From the above comparison results, the CMC claimed by the participated NMIs in 

the HRA scale is reaffirmed and hence they are acceptable. Also, it can be seen 

from the figure 8 that the variation of hardness measurement by different NMI at the 

prescribed nominal values is less than 0.25HRA. This indicated that a CMC value of 

0.30 HRA is possible to achieve by NMIs for hardness primary standard. 

Deviation (HRA) 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

0.00 

Figure 8 Variation of hardness measurement in Rockwell scale A 

Similarly, the variation of hardness values measured by different NMI at the given 

nominal values for the HRB scale is shown in figure 9. Here, unlike in the case of 

HRA scale, the deviation shown in the hardness measurement is very large 

(0.50HRB) for the lower range of HRB values i.e. for the soft materials having 

nominal values less than 60HRB. However the deviation reduces to 0.20 HRB in the 

higher range of HRB scale, ie for the relatively harder materials having the nominal 

hardness value more than one. This observation strongly suggests that NMI can 

achieve still a lower CMC in the higher range of hardness values (>60 HRB) for 

hardness primary standard 

Deviation (HRB) 

30 40 50 60 70 80 90 HRA 

0.70 

0.60 

0.50 

0.40 

0.30 

0.20 

0.10 

0.00 

Deviation Possible CMC achievement 

20 30 40 50 60 70 80 90 100HRB 

Deviation Possible CMC achievement 

Figure 9 Variation of hardness measurement in Rockwell scale B 

Page 27 of 77


Date: May 25, 2012 

11. Measurement <strong>Report</strong> 

Page 28 of 77


Date: May 25, 2012 

Measurement report of PTB Laboratory 

Page 29 of 77


Date: May 25, 2012 

Annex A Data report forms Page 1/6 

<strong>Report</strong> Form 1 (For Rockwell hardness scale A) 

Metrology information 

Model of hardness primary machine 

Serial number of hardness primary machine RNG10 

Manufacturer of hardness primary machine WAZAU 

Hardness indication system Laserinterferometer 

Test force system 

Relative error of preliminary test force 

Dead weight 

Relative uncertainty (2) of preliminary test force 

Relative error of total test force 

5*10^-4 

Relative uncertainty (2) of total test force 5*10^-4 

Uncertainty of depth measuring device 0.1 µm 

Serial number of the indenter 839 

The tip radius of curvature of the indenter 0.195 mm 

The apex angle of cone of the indenter 119°58' 

The calibration and measurement capability 

(CMC) 

0.3 HRA 

Testing condition 

Velocity of the indenter when reaching the surface 0.86 mm/s 

Holding time of preliminary test force 2.8 s 

Test force loading speed (final speed) 98.0 N/s 

Total test force duration time 5.6 s 

Time before reading permanent indentation depth 4.7 s 

Environment of comparison measurement 

Measurement place PTB 

Measurement date 2nd June 2010 

Environment (20 ± 1) °C 

Deformation of frame verification 

Deformation of frame (m) 

1 2 3 

0.227 0.215 0.199 

Page 30 of 77


Date: May 25, 2012 

Data report forms Page 2/6 

<strong>Report</strong> Form 1 (For Rockwell hardness scale B) 



Serial number of hardness primary machine RNG10 

Manufacturer of hardness primary machine WAZAU 

Hardness indication system Laserinterferometer 



Deth weight 



5*10^-4 

Relative uncertainty (2) of total test force 5*10^-4 

Uncertainty of depth measuring device 0.1 µm 

The calibration and measurement capability 

(CMC) 

0.5 HRB 


Velocity of the indenter when reaching the surface 0.86 mm/s 


Test force loading speed (final speed) 103 N/s 


Time before reading permanent indentation depth 4.8 s 


Measurement place PTB 

Measurement date 1st June 2010 

Environment (20 ± 1) °C 



1 2 3 

0.324 0.311 0.297 

Page 31 of 77


Date: May 25, 2012 

Laboratory: 

PTB 

<strong>Report</strong> Form2 - Result of the Rockwell hardness scale A measurements (35 - 85 HRA) Page 3/6 

Measured 

Checked 

Measured 

by: Febo Menelao 

by: S. Lutz 

date: 2nd June 2010 

Hardness Block Number A32517 A33781 A25568 

Measured value 

B12037 B15871 A27761 A21048 

Nominal Value (HRA) 35 40 55 60 70 80 85 

Section 1 34.84 38.84 54.96 60.66 70.79 81.47 85.55 









Average Value 35.17 38.98 55.16 60.62 70.85 81.49 85.50 

Uniformity 0.67 0.73 0.29 0.10 0.15 0.08 0.20 




Remark: In case of the participant made an incorrect indentation or is unsure about the measurement value, please report to the pilot institute. 

Page 32 of 77


Date: May 25, 2012 

<strong>Report</strong> Form3 - Result of the Rockwell hardness scale B measurements 

Laboratory: Measured Checked Measured 

PTB by: Febo Menelao 

by: S. Lutz 

measured value 

date: 1 st June 2010 

Hardness Block Number E1620 B30120 A31382 A32411 A33748 A34522 A35542 25566 30836 

Nominal Value (HRBW) 25 30 40 50 60 70 80 90 100 

Page 4/6 

Section 1 23.22 28 .84 37.86 51 .05 60.13 70 .32 79.25 89 .73 99 .76 





Section 6 23.38 28 .50 37.85 50 .99 59 .67 69.75 80 .24 90 .01 99.60 

Section 7 23.66 28.34 37 .52 50 .93 60 .04 69.80 80 .04 90 .05 99.60 



Average Value 23.35 28 .59 37 .65 50 .95 59.95 69.88 79 .62 89 .98 99.68 

Uniformity 0.34 0.25 0.19 0.12 0 .30 0 .23 0.34 0 .10 0.07 

Correction Value 

Corrected Value 23.35 28 .59 37 .65 50 .95 59.95 69.88 79 .62 89 .98 99.68 

Expanded uncertainty (k= 2) 0.56 0.53 0.52 0.51 0 .54 0 .53 0.55 0 .50 0.50 


Page 33 of 77


Date: May 25, 2012 

<strong>Report</strong> Form 4 Uncertainty budget of measurement Page 5/6 

Uncertainty budget for 35 HRA 

Quantity Estimated 

Standard Sensitivity Uncertainty 

value 

uncertainty coefficient contribution 

X i x i 

xi 

uxi 

 

3 

C i u i (H ) 

Preliminary test force, F 0 0.05 N 0.0289 0.2272 0.0066 

Total test force, F 0.3 N 0.1732 -0.0917 -0.0159 

Permanent depth of measuring device, h 0.1 µm 0.0577 0.5000 0.0289 

Preliminary test force dwell time, t 0 0.2 s 0.1155 0.0489 0.0056 

Indentation velocity, v 10 µm/s 5.7735 -0.0102 -0.0586 

Total test force dwell time, t 0.2 s 0.1155 -0.1060 -0.0122 

Indenter angle, 0.1 ° 0.0577 0.1800 0.0104 

Indenter radius, r 1 µm 0.5774 0.0580 0.0335 

Deformation of frame, DF 0.2 µm 0.1155 0.5000 0.0577 

Combined uncertainty, u c 

Expanded uncertainty, Ue 

0.0965 

k=2 0.19 

Page 34 of 77


Date: May 25, 2012 


Uncertainty budget for 25 HRB 

Quantity Estimated Standard Sensitivity Uncertainty 

value 


X i x i 

xi 

uxi 

 

3 

C i u i (H ) 

Preliminary test force, F 0 0.05 N 0.0289 0.1780 0.0051 


Permanent depth of measuring device, h 0.1 µm 0.0577 0.5000 0.0289 

Preliminary test force dwell time, t 0 0.2 s 0.1155 -0.0617 -0.0071 

Indentation velocity, v 10 µm/s 5.7735 0.0067 0.0387 


Indenter diameter, d 0.1 µm 0.0577 0.0098 0.0006 

Deformation of frame, DF 0.3 µm 0.1732 0.5000 0.0866 


Expanded uncertainty, Ue 

0.1050 

k=2 0.21 

Page 35 of 77


Date: May 25, 2012 

Measurement report of NIMT Laboratory 

Page 36 of 77


Date: May 25, 2012 

Annex A Data report forms 



Model of hardness primary machine SHT-31 

Serial number of hardness primary machine 310039 

Manufacturer of hardness primary machine Akashi – Japan 

Hardness indication system Laser hologauge 

Test force system Lever type 

Relative error of preliminary test force +0.01 % (+0.001 kgf) 

Relative uncertainty (2) of preliminary test force 0,030 % 

Relative error of total test force +0.001 % (+0.0033 kgf) 

Relative uncertainty (2) of total test force 0.01% 

Uncertainty of depth measuring device 0.2 m 


The tip radius of curvature of the indenter 200m ± 4m 

The apex angle of cone of the indenter 120 ± 0.1 

The calibration and measurement capability (CMC) 0.38 HRA 


Velocity of the indenter when reaching the surface 80-200 m/s 

Holding time of preliminary test force 3 s 

Test force loading speed 33 s 

Total test force duration time 4 s 

Time before reading permanent indentation depth 4 s 


Measurement place Hardness lab. NIMT 

Measurement date 28-29 April 2010 

Environment (23±1)C ,(50±10)%RH 



1 2 3 

0.14 0.14 0.15 

Page 37 of 77


Date: May 25, 2012 

Data report forms 





Manufacturer of hardness primary machine Akashi - Japan 

Hardness indication system Laser hologauge 

Test force system Lever type 

Relative error of preliminary test force +0.01 % (+0.001 kgf) 

Relative uncertainty (2) of preliminary test force 0,030 % 

Relative error of total test force +0.01 % (+0.0057 kgf) 


Uncertainty of depth measuring device 0.2 m 

The diameter of ball indenter 1.5875 m ±2m 

The calibration and measurement capability (CMC) 0.40 HRB 


Velocity of the indenter when reaching the surface 80-200 m/s 

Holding time of preliminary test force 3 s 

Test force loading speed 33 s 

Total test force duration time 4 s 

Time before reading permanent indentation depth 4 s 


Measurement place Hardness lab. NIMT 

Measurement date 28-23 April 2010 

Environment (23±1)C ,(50±10)%RH 



1 2 3 

0.11 0.13 0.11 

Page 38 of 77


Date: May 25, 2012 

<strong>Report</strong> Form2 - Result of the Rockwell hardness scale A measurements (35 - 85 HRA) 

Page 3/5 

Laboratory: NIMT Measured Checked Measured 

by: Mr.Nitiwat Sasom by:Mr.Tassanai Sanponpute date: 28/04/2010 

Hardness Block Number A32517 A33781 25568 B12037 B15871 A27761 A21048 











Average Value 35.25 39.10 55.05 60.44 70.58 81.30 85.32 

Uniformity 0.36 0.83 0.14 0.10 0.12 0.09 0.21 

S.D. 0.12 0.24 0.04 0.03 0.04 0.03 0.07 




Page 39 of 77


Date: May 25, 2012 

<strong>Report</strong> Form3 - Result of the Rockwell hardness scale B measurements (25-100 HRB) 

Laboratory: NIMT Measured Checked Measured 

Page 4/5 

by: Mr.Nitiwat Sasom by:Mr.Tassanai Sanponpute date: 28/04/2010 




Section 1 23.88 28.60 37.82 51.05 59.70 69.74 79.79 90.13 100.14 









Average Value 24.07 28.52 37.71 50.99 59.57 69.59 79.56 90.44 100.04 

Uniformity 0.53 0.49 0.56 0.30 1.02 0.62 1.47 0.43 0.20 

S.D. 0.20 0.16 0.18 0.11 0.31 0.22 0.49 0.12 0.08 




Page 40 of 77


Date: May 25, 2012 

Uncertainty budget of Hardness machine at 35 HRA A32517 

Hardness value, HRA 35.3 1242.9 35.3 1 

Quantity Unit Estimated Standard Sensitivity Uncertainty 

error value uncertainty coefficient contribution 

Xi xi u(xi) ci ui(H) Preliminary test force,F o N 0.020 0.011 0.226 0.003 

Total test force, F N 0.588 0.340 -0.091 -0.031 

Permanent depth of indentation, h m 0.2 0.115 -0.500 -0.058 

Preliminary test force dwell time,to s 0.5 0.289 0.049 0.014 

Indentation velocity, v mm/s -1 

0.3 0.173 -0.010 -0.002 

Total test force dwell time, t s 1 0.289 -0.106 -0.030 

Indenter angle, ° 0.1 0.058 0.180 0.010 

Indenter radius, r m 5 2.887 0.058 0.167 

Deformation of frame,DF m 0.25 0.144 0.500 0.072 

Combined uncertainty, u c HRA Combined uncertainty, uc 0.197 

Expanded uncertainty, U e HRA Expanded uncertainty, Ue 0.394 

Uncertainty budget of hardness measurement at 35 HRA A32517 


value uncertainty coefficient contribution 

X i x i u(x i) c i u i(H) 

Hardness machine, H phm HRA 35.3 0.197 1 0.197 

Readability,H res HRA 0 0.003 1 0.003 

Repeatability of measurement, H rep HRA 0 0.041 1 0.041 

Combined uncertainty, uc 0.201 

Measured hardness,H mh HRA 35.3 Expanded uncertainty, Ue 0.403 










0.3 0.173 -0.009 -0.002 
















Page 41 of 77


Date: May 25, 2012 

Uncertainty budget of Hardness machine at 55 HRA 25568 









0.3 0.173 -0.003 -0.001 







Uncertainty budget of hardness measurement at 55 HRA 25568 









Uncertainty budget of Hardness machine at 60 HRA B12037 









0.3 0.173 -0.001 0.000 







Uncertainty budget of hardness measurement at 60 HRA B12037 









Page 42 of 77


Date: May 25, 2012 

Uncertainty budget of Hardness machine at 70 HRA B15871 









0.3 0.173 0.002 0.000 







Uncertainty budget of hardness measurement at 70 HRA B15871 
















Preliminary test force dwell time,to s 0.5 0.289 -0.002 -0.001 


0.3 0.173 0.006 0.001 
















Page 43 of 77


Date: May 25, 2012 








Preliminary test force dwell time,to s 0.5 0.289 -0.006 -0.002 


0.3 0.173 0.007 0.001 
















Page 44 of 77


Date: May 25, 2012 

Uncertainty budget of Hardness machine at 25 HRB 25 

Hardness value, HRB 24.1 579.4 24.1 1 



Xi xi u(xi) ci ui(H) Preliminary test force, Fo N 0.020 0.011 0.180 0.002 



Preliminary test force dwell time, to s 0.5 0.289 -0.069 -0.020 


0.3 0.173 0.007 0.001 


Indenter ball diameter, d m 2 1.155 0.010 0.012 

Deformation of frame, DF m 0.25 0.144 0.500 0.072 

Combined uncertainty, u c HRB Combined uncertainty, uc 0.116 

Expanded uncertainty, U e HRB Expanded uncertainty, Ue 0.232 

Uncertainty budget of hardness measurement at 25 HRB 




Hardness machine, H phm HRB 24.1 0.116 1 0.116 

Readability,H res HRB 0 0.003 1 0.003 

Repeatability of measurement, H rep HRB 0 0.072 1 0.072 


Measured hardness,H mh HRB 24.1 Expanded uncertainty, Ue 0.273 








Preliminary test force dwell time, to s 0.5 0.289 -0.034 -0.010 


0.3 0.173 0.006 0.001 






Uncertainty budget of hardness measurement at 30 HRB 30 









Page 45 of 77


Date: May 25, 2012 








Preliminary test force dwell time, to s 0.5 0.289 0.029 0.008 


0.3 0.173 0.005 0.001 
























0.3 0.173 0.003 0.001 


Indenter ball diameter, d m 2 1.155 -0.003 -0.003 













Page 46 of 77


Date: May 25, 2012 










0.3 0.173 0.002 0.000 
























0.3 0.173 0.000 0.000 















Page 47 of 77


Date: May 25, 2012 










0.3 0.173 -0.001 0.000 
























0.3 0.173 -0.002 0.000 















Page 48 of 77


Date: May 25, 2012 










0.3 0.173 -0.004 -0.001 















Page 49 of 77


Date: May 25, 2012 

Measurement report of KRISS Laboratory 

Page 50 of 77


Date: May 25, 2012 

Annex A Data report forms Page1/5 





Manufacturer of hardness primary machine Akashi 

Hardness indication system Laser Hologauge 

Test force system Lever 

Relative error of preliminary test force -0.104% 

Relative uncertainty (2) of preliminary test force 0.099% 

Relative error of total test force -0.017% 


Uncertainty of depth measuring device 0.12 ㎛ 


The tip radius of curvature of the indenter 202.3 ㎛ 

The apex angle of cone of the indenter 119.99° 

The calibration and measurement capability (CMC) 0.4 HRA 


Velocity of the indenter when reaching the surface 25㎛/s ~ 37㎛/s 

Holding time of preliminary test force 3.0 sec 

Test force loading speed 5.0 sec 

Total test force duration time 4.0 sec 

Time before reading permanent indentation depth 1.0 sec 


Measurement place KRISS 

Measurement date Sep. 30, 2010 

Environment 23 °C, 43% R.H. 



1 2 3 

-0.2 -0.2 -0.2 

Page 51 of 77


Date: May 25, 2012 






Manufacturer of hardness primary machine Akashi 

Hardness indication system Laser Hologauge 

Test force system Lever 

Relative error of preliminary test force 0.166% 

Relative uncertainty (2) of preliminary test force 0.126% 

Relative error of total test force 0.025% 


Uncertainty of depth measuring device 0.12 ㎛ 

The calibration and measurement capability (CMC) 0.6 HRBW 


Velocity of the indenter when reaching the surface 25㎛/s ~ 37㎛/s 

Holding time of preliminary test force 3.0 sec 

Test force loading speed 5.0 sec 

Total test force duration time 4.0 sec 

Time before reading permanent indentation depth 1.0 sec 


Measurement place KRISS 

Measurement date Sep. 30, 2010 

Environment 23 °C, 43% R.H. 



1 2 3 

-0.2 -0.2 -0.2 

Page 52 of 77


Date: May 25, 2012 


Laboratory: KRISS Measured Checked 

by: N.H. Tak by: G.W. Bahng 

Measured 

date: SEP 30 , 2010 

Page 3/5 

Hardness Block Number A32517 A33781 25568 


B12037 B15871 A27761 A21048 











Average Value 35.58 39.42 54.90 60.30 70.71 81.36 85.43 

Uniformity 1.1 1.0 0.3 0.2 0.2 0.2 0.2 

Repeatability 0.12 0.13 0.04 0.03 0.03 0.02 0.03 

Correction Value -0.03 -0.03 -0.03 -0.04 -0.04 -0.04 -0.04 


Expanded uncertainty (k=2) 0 .46 0.47 0.40 0.40 0.40 0 .40 0.40 


Page 53 of 77


Date: May 25, 2012 

<strong>Report</strong> Form3 - Result of the Rockwell hardness scale B measurements (25-100 HRB ) 

Laboratory: KRISS Measured Checked Measured 

by: N.H. Tak by: G.W. Bahng 

Page 4/5 

date: SEP 30, 2010 













Average Value 23.59 29.46 38.59 51.00 59.79 70.17 79.86 90.37 100.10 

Uniformity 1.6 0.4 0.4 1.5 0.8 1.0 1.3 0.4 0.2 

R epeatability 0.21 0.06 0.06 0.16 0.08 0.12 0.17 0.05 0.03 

Correction Value 

Corrected Value 23.59 29 .46 38 .59 51.00 59 .79 70.17 79 .86 90.37 100.10 



Page 54 of 77


Date: May 25, 2012 


Uncertainty budget for 

35 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 

contribution 

i 

X i x i ux 

 

C i u i (H ) 

1 Preliminary test force 0.09 N 0.05 0.2272 0.0121 

2 Total test force 0.16 N 0.09 -0.09165 -0.0085 

3 Permanent depth of indentation 0.2 ㎛ 0.12 -0.5 -0.0577 

4 Preliminary test force dwell time 0.5 s 0.29 0.0489 0.0141 

5 Indentation velocity 6 ㎛/s 3.46 -0.01015 -0.0352 

6 Total test force dwell time 0.5 s 0.29 -0.106 -0.0306 

7 indenter angle 0.04 ° 0.02 0.18 0.0042 

8 Indenter radius 3.1 ㎛ 1.79 0.058 0.1038 

9 Deformation of frame 0.2 ㎛ 0.12 0.5 0.0577 

10 

Long-term stability of primary 

hardness testing machine 

0.24 HRA 0.14 1 

0.1386 

11 Combined uncertainty(HRA) 0.198 

12 Expanded uncertainty(HRA), k=2 0.40 


40 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 










10 



0.24 HRA 0.14 1 

0.1386 




55 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 










10 



0.24 HRA 0.14 1 

0.1386 



i 

i 

i 

x 

3 

3 

3 

Page 55 of 77


Date: May 25, 2012 


60 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 










10 



0.23 HRA 0.13 1 

0.1328 




70 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 





5 Indentation velocity 6 ㎛/s 3.46 0.0021 0.0073 





10 



0.23 HRA 0.13 1 

0.1328 




80 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 




4 Preliminary test force dwell time 0.5 s 0.29 -0.0006 -0.0002 






10 



0.20 HRA 0.12 1 

0.1155 



i 

i 

i 

3 

3 

3 

Page 56 of 77


Date: May 25, 2012 


85 HRA 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 










10 



0.20 HRA 0.12 1 

0.1155 



i 

3 

Page 57 of 77


Date: May 25, 2012 



No Quantity 

Estimated 

valus 

xi 

25 HRBW 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


xi 

X i x i ux 

 

C i u i (H ) 







7 indenter ball diameter 2.0 ㎛ 1.15 0.00975 0.0113 


9 



0.45 HRBW 0.26 1 

0.2598 

10 Comdined uncertainty(HRBW) 0.275 

11 Expanded uncertainty(HRBW), k=2 0.55 


30 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.45 HRBW 0.26 1 

0.2598 




40 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.43 HRBW 0.25 1 

0.2483 



i 

i 

i 

3 

3 

3 

Page 58 of 77


Date: May 25, 2012 


50 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 







7 indenter ball diameter 2.0 ㎛ 1.15 -0.0025 -0.0029 


9 



0.43 HRBW 0.25 1 

0.2483 




60 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.35 HRBW 0.20 1 

0.2021 




70 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.35 HRBW 0.20 1 

0.2021 



i 

i 

i 

3 

3 

3 

Page 59 of 77


Date: May 25, 2012 


80 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.35 HRBW 0.20 1 

0.2021 




90 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.34 HRBW 0.20 1 

0.1963 




100 HRBW 

No Quantity 

Estimated 

valus 

Unit 

Stadard 

uncertatinty 

Sensitivity 

coefficient 

Uncertainty 


X i x i 

xi 

ux 

 

C i u i (H ) 









9 



0.34 HRBW 0.20 1 

0.1963 



i 

i 

i 

3 

3 

3 

Page 60 of 77


Date: May 25, 2012 

Measurement report of NPLI Laboratory 

Page 61 of 77


Date: May 25, 2012 

Annex A Data report forms Page1/5 




Serial number of hardness primary machine 

Manufacturer of hardness primary machine 

Hardness indication system 





Relative uncertainty (2) of total test force 

Uncertainty of depth measuring device 

Serial number of the indenter 

The tip radius of curvature of the indenter 

The apex angle of cone of the indenter 

The calibration and measurement capability (CMC) 


Velocity of the indenter when reaching the surface 

Holding time of preliminary test force 

Test force loading speed 

Total test force duration time 

Time before reading permanent indentation depth 

Measurement place 

Measurement date 

Environment 




HSM HR/HV 2007-07 

2007/07 

LTF, Italy 

Laser Interferometer system 

Dead Weight System-Operated by 

controlled speed Servomoter 

0.0001 

0.0002 

0.0001 

0.0002 

20ppm 

4865 

197.3 µm 

119.96 o 

0.3 HRA 

0.1mm/s 

2s 

30µm/s 

4s 

3s 

NPL, New Delhi 

25-10-10 

Temp. (23±1) o C, Humidity (50±10)% 

1 2 3 

0.2 0.2 0.2 

Page 62 of 77


Date: May 25, 2012 





Serial number of hardness primary machine 

Manufacturer of hardness primary machine 

Hardness indication system 





Relative uncertainty (2) of total test force 

Uncertainty of depth measuring device 

The calibration and measurement capability (CMC) 


Velocity of the indenter when reaching the surface 

Holding time of preliminary test force 

Test force loading speed 

Total test force duration time 

Time before reading permanent indentation depth 


Measurement place 

Measurement date 




HSM HR/HV 2007-07 

2007/07 

LTF, Italy 

Laser Interferometer system 

Dead Weight System-Operated by controlled 

speed Servomoter 

0.0001 

0.0002 

0.0001 

0.0002 

20ppm 

0.6 HRBW for nominal not more than 60 HRB 

0.5 HRBW for nominal more than 60 HRB 

0.1mm/s 

2s 

30µm/s 

4s 

3s 

NPL, New Delhi 

29-10-10 

Temp. (23±1) o C, Humidity (50±10)% 

1 2 3 

0.3 0.3 0.3 

Page 63 of 77


Date: May 25, 2012 


Laboratory: Measured Checked 

National Physical Laboratory by: Dr.S.S.K.Titus by: Dr.S.K.Jain 

Measured 

date: 25-10-2010 

Page 3/5 

Hardness Block Number A32517 A33781 25568 


B12037 B15871 A27761 A21048 











Average Value 35.31 39.16 55.21 60.59 70.85 81.56 85.80 

Uniformity 0.36 1.09 0.48 0.32 0.28 0.19 0.27 

Correction Value Nil Nil Nil Nil Nil Nil Nil 




Page 64 of 77


Date: May 25, 2012 

<strong>Report</strong> Form 3 - Result of the Rockwell hardness scale B measurements ( 25- 100 HRB) 

Laboratory: Measured Checked 

National Physical Laboratory by: Dr.S.S.K.Titus by: Dr.S.K.Jain 


Measured 

date: 29-10-2010 

Hardness Block Number E1620 B30120 A31382 A 32411 A33748 A28422 A35542 25566 30836 

Nominal Value (HRB) 25 30 40 50 60 70 80 90 100 

Section 1 23 . 14 29.67 37.14 51. 41 59.32 69.76 79. 09 90. 12 99.96 


Section 3 23 . 59 29.43 36.90 51. 50 59.19 69.97 79. 80 90. 09 100 .08 







Average Value 24 . 28 29. 52 37.65 51. 26 59. 06 69.83 79. 36 90. 13 99.87 

Uniformity 1.75 0.48 1.34 0.70 0.64 0.73 1.00 0.35 0.32 

Correction Value Nil Nil Nil Nil Nil Nil Nil Nil Nil 

Corrected Value 24 . 28 29. 52 37.65 51. 26 59. 06 69.83 79. 36 90. 13 99.87 

Expanded uncertainty (k=2) 0 . 70 0.60 0.60 0 . 60 0. 60 0.52 0.56 0. 51 0. 51 

Page 4/5 

Page 65 of 77


Date: May 25, 2012 


Uncertainty budget for ___ HRA 35 55 



value 


X i 

Primary Hardness machine 

Dx i 

xi 

uxi 

 

3 

C i u i (H ) 

Hphs Res. Of Primary Hardness 

0.3 0.15 0.15 1 0.150 

machine Hres 0.01 0.005 0.003 1 0.003 

Repeatability of 

measurement H rep 0.09 0.045 0.045 1 0.045 


Expanded uncertainty, Ue k=2 0.31 

0.157 

Uncertainty budget for ___ HRA 85 55 



value 


X i Dx i 

 

 

x i 

u u 

x i 

 

 

 

 

3 C i u i (H ) 


Hphs 

Res. Of Primary Hardness 

0.3 0.15 0.15 1 0.150 

machine Hres Repeatability of 

0.01 0.005 0.003 1 0.003 

measurement Hrep 0.07 0.035 0.035 1 0.035 


0.154 


Page 66 of 77


Date: May 25, 2012 

Uncertainty budget for ___ HRB 25 55 



value 


X i 


Dx i 

xi 

uxi 

 

3 

C i u i (H ) 

Hphs 0.5 0.25 0.25 1 0.250 


machine Hres 0.01 0.005 0.003 1 0.003 




0.263 


Uncertainty budget for ___ HRB 100 55 



value 


X i 


Dx i 

xi 

uxi 

 

3 

C i u i (H ) 

Hphs 0.5 0.25 0.25 1 0.250 


machine Hres 0.01 0.005 0.003 1 0.003 




0.252 


Page 67 of 77


Date: May 25, 2012 

Uncertainty Budget, HRA A32517 A33781 25568 B12037 B15871 A27761 A21048 

35 40 55 60 70 80 85 

Primary Hardness machine H phs 0.15 0.15 0.15 0.15 0.15 0.15 0.15 

Res. of Primary Hardness machine H res 0.01 0.01 0.01 0.01 0.01 0.01 0.01 

Repeatability of measurement H rep 0.05 0.15 0.05 0.04 0.03 0.02 0.03 

Calculated_Ue 0.31 0.42 0.32 0.31 0.31 0.30 0.31 

CMC 0.30 0.30 0.30 0.30 0.30 0.30 0.30 

Expanded uncertainty, Ue 0.31 0.42 0.32 0.31 0.31 0.30 0.31 

Uncertainty Budget, HRB E1620 B30120 A31382 A32411 A33748 A28422 A35542 25566 30836 

25 30 40 50 60 70 80 90 100 

Primary Hardness machine H phs 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 

Res. of Primary Hardness machine H res 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 

Repeatability of measurement H rep 0.24 0.05 0.16 0.08 0.09 0.07 0.13 0.04 0.04 

Calculated_Ue 0.70 0.51 0.59 0.52 0.53 0.52 0.56 0.51 0.51 

CMC 0.60 0.60 0.60 0.60 0.60 0.50 0.50 0.50 0.50 

Expanded uncertainty, Ue 0.70 0.60 0.60 0.60 0.60 0.52 0.56 0.51 0.51 

Page 68 of 77


Date: May 25, 2012 

Measurement report of SCL Laboratory 

Page 69 of 77


Date: May 25, 2012 

Data report forms 



Model of hardness primary machine 8150TK (Note 1) 

Serial number of hardness primary machine 093925 (Note 1) 

Manufacturer of hardness primary machine Indentec (Note 1) 

Hardness indication system Length transducer 

Test force system Deadweight 

Relative error of preliminary test force 0.0 % 

Relative uncertainty (2s) of preliminary test force 1.0 % 

Relative error of total test force 0.0 % 

Relative uncertainty (2s) of total test force 0.1 % 

Uncertainty of depth measuring device 3 um 

The calibration and measurement capability (CMC) 1.5 HRBS (Note 2) 

Note 1: The machine is not a primary hardness machine, but a commercial hardness machine. 

Note 2: This CMC has not been submitted to <strong>APMP</strong> TCM for approval yet. 

Velocity of the indenter when reaching the surface NA* 


Test force loading speed 88 um/s 


Time before reading permanent indentation depth NA* 

Measurement place SCL Hong Kong 

Measurement date 3 August 2010 

Deformation of frame (um) 


* SCL hardness machine equips with a non-motorised leadscrew loading system with upward motion driven manually. 



(20 ± 1) o C 

(50 ± 8) %RH 

(991 ± 3) hPa 


1 2 3 

0.7 0.9 0.8 

Page 70 of 77


Date: May 25, 2012 

<strong>Report</strong> Form 3 - Result of the Rockwell hardness scale B measurements (25-100 HRB) 

Laboratory: Standards and Calibration Laboratory Measured Checked Measured 

by: 

by: 

date: 

K.H.Chan 

T.K.Chan 

3 Aug 2010 

Measured Value 


Nominal Value (HRB) 25 30 40 50 60 70 80 90 100 










Average Value 26.41 30.62 39.99 52.99 61.53 71.38 80.79 91.50 100.89 

Uniformity 1.40 2.40 0.95 0.70 0.80 0.40 1.25 0.20 0.20 

Correction Value -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 -0.50 

# Corrected Value (HRBW) 25.91 30.12 39.49 52.49 61.03 70.88 80.29 91.00 100.39 



# Using 1/16" carbide indenter ball and depth measurement probe. 

Page 71 of 77


Date: May 25, 2012 

<strong>Report</strong> Form 4 Uncertainty budget of measurement 

Uncertainty budget for 25 HRB 55 



i 

X i Dx u x i 

i 

C i u i (H ) 

Preliminary test force, Fo 1.0 N 0.58 0.178 0.103 


Permanent depth of 

indentation, h 

3.0 um 1.73 -0.5 -0.866 

Preliminary test force 

0.5 s 0.29 -0.0617 -0.018 

dwell time, t o 

Indentation velocity, v 3.0 um/s 1.73 0.0067 0.012 


Indenter ball diameter, d 1.7 um 0.98 0.0098 0.010 

Deformation of frame, DF 0.9 um 0.52 -0.5 -0.260 

Combined uncertainty, u c k=2 0.913 

Expanded uncertainty, Ue 1.9 




i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 -0.0224 -0.006 








x 

3 

x 

3 

Page 72 of 77


Date: May 25, 2012 




i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.0426 0.012 











i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.0896 0.026 




Indenter ball diameter, d 1.7 um 0.98 -0.0025 -0.002 




x 

3 

x 

3 

Page 73 of 77


Date: May 25, 2012 




i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.1186 0.034 











i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.1296 0.037 








x 

3 

x 

3 

Page 74 of 77


Date: May 25, 2012 




i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.1226 0.035 


Indentation velocity, v 3.0 um/s 1.73 -0.0010 -0.002 









i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.0976 0.028 








x 

3 

x 

3 

Page 75 of 77


Date: May 25, 2012 




i 

X i Dx u x i 

i 

C i u i (H ) 





3.0 um 1.73 -0.5 -0.866 


0.5 s 0.29 0.0546 0.016 








x 

3 

Page 76 of 77


Date: May 25, 2012 

12. References 

[1] ISO 6508-3: Metallic materials-Rockwell hardness test-Part 3: Calibration of 

reference blocks (scales A, B, C, D, E, F, G, H, K, N, T) 

[2] Technical Proposal of <strong>APMP</strong> <strong>Comparison</strong> in HRA and HRB, piloted by National 

Institute of Metrology (Thailand). 

Page 77 of 77

APMP.M.H-S3 Final Report Comparison on Hardness ... - BIPM

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