Hardness Testing of Metals Proficiency Testing Program Round 1, December 2008

REPORT NO. 603

Hardness Testing of Metals

Proficiency Testing Program

Round 1

March 2009

ACKNOWLEDGMENTS

PTA wishes to gratefully acknowledge the technical assistance provided for this program by Mr Cesare Zamuner, BlueScope Steel Limited. This assistance

included providing input into the design of the program, technical advice and

discussion of the final report, as well as supplying the samples.

PO Box 7507 Silverwater NSW 2128 AUSTRALIA

CONTENTS

1. FOREWORD 1

2. FEATURES OF THE PROGRAM 1

3. FORMAT OF THE APPENDICES 2

4. STATISTICAL DESIGN OF THE PROGRAM 2

5. EXTREME RESULTS 3 Table A: Summary Statistics for All Tests 3 Table B: Summary of Statistical Outliers 4

6. PTA AND TECHNICAL ADVISER'S COMMENTS 4

7. REFERENCES 7

APPENDICES APPENDIX A Summary of Results Brinell Hardness (HBW) A1 Vickers Hardness (HV) A2 Standard Rockwell Hardness (HRB) A3 Superficial Rockwell Hardness (HR30T) A4 Standard Rockwell Hardness (HRC) A5 Additional Surface Preparation A6 APPENDIX B Homogeneity Testing B1.1 Stability Testing B2.1 APPENDIX C Instructions to Participants C1.1 Results Sheet C2.1

-1-

1. FOREWORD

This report summarises the results of a proficiency testing program on the hardness properties of metals.

Proficiency Testing Australia conducted the testing program in December 2008 / January 2009. The Program Coordinator was Mark Bunt. The aim of the program was to assess laboratories' ability to competently perform the nominated tests.

2. FEATURES OF THE PROGRAM

(a) A total of 24 laboratories participated in the program, all of which returned results for inclusion in the final report. Laboratories from the following states and countries received samples:

7 NSW 6 VIC 4 WA 4 QLD 2 SA 1 SINGAPORE

To ensure confidential treatment of results, each laboratory was allocated a unique code number. All reference to participants in this report is by allocated code numbers.

(b) The results reported by participants are presented in Appendix A.

• an 8 mm thick hot rolled plate sample for both Brinell (preferably HBW 10/3000) and Vickers (preferably HV20) hardness testing; • a 2 mm thick, 50 mm diameter disc for both the Superficial Rockwell scale (HR30T) and the Standard Rockwell scale (HRB) hardness testing; and • a 1.5 mm thick, 55 mm diameter disc for the Standard Rockwell scale (HRC) hardness testing.

Laboratories were required to perform all tests for which they hold accreditation and were invited to report results for any of the other tests.

(d) Laboratories were requested to perform the tests according to the Instructions to Participants provided and to record the results on the accompanying Results Sheet , which was distributed with the samples. Copies of these documents appear in Appendix C.

-2-

(e) Prior to distribution, the samples were tested for homogeneity by BlueScope Steel Limited. Based on the results of this testing, the homogeneity of the samples was established (see Appendix B).

(f) A number of randomly selected samples were also tested for stability by BlueScope Steel Limited. The analysis of the stability testing results showed that the samples were sufficiently stable for testing for the duration of the program (see Appendix B).

3. FORMAT OF THE APPENDICES

(a) Appendix A is divided into 6 sections (A1-A6).

Sections A1-A5 contain the analysis of results reported by laboratories for Brinell Hardness (HBW), Vickers Hardness (HV), Standard Rockwell Hardness (HRB scale), Superficial Rockwell Hardness (HR30T scale) and Standard Rockwell Hardness (HRC scale). These sections contain, where appropriate:

i) a table of results reported by laboratories for each sample, and the calculated z-scores for these results; ii) a listing of the summary statistics; and iii) ordered z-score charts.

Section A6 contains comments on the additional surface preparations used by the participants.

(b) Appendix B contains details of the homogeneity and stability testing.

4. STATISTICAL DESIGN OF THE PROGRAM

For each statistically analysed test, robust statistical procedures were used to generate the z-scores and summary statistics for each hardness determination - number of results, median, normalised interquartile range (IQR), minimum, maximum and range.

For each participant, the robust z-score calculated for each hardness result was based on the average hardness value reported for each test.

-3-

5. EXTREME RESULTS

Robust z-scores have been used to assess each laboratory’s testing performance. These z-scores are used to detect excessively high or excessively low results in comparison to the consensus value (the median). Any result with an absolute z-score greater than three (i.e. <-3 or >3) is classified as an outlier.

For further details on the calculation and interpretation of robust z-scores, please see the Guide to Proficiency Testing Australia (2008).

The following table summarises the results submitted by participants for the program.

Table A: Summary Statistics for All Tests

Test Summary Statistics Average Result

No. of Results 18 Brinell Hardness (HBW) Median 271.5 Normalised IQR 5.9 No. of Results 19 Vickers Hardness Median 289.0 (HV) Normalised IQR 7.0 No. of Results 18 Standard Rockwell Hardness Median 80.35 (HRB) Normalised IQR 0.87 No. of Results 18 Standard Rockwell Hardness Median 31.75 (HRC) Normalised IQR 2.43

Notes:

1. Summary statistics were calculated for the average hardness value reported for each test.

2. There were not enough Superficial Rockwell Hardness (HR30T) results submitted to calculate summary statistics.

-4-

Table B: Summary of Statistical Outliers

Test Outliers (lab codes)

Brinell Hardness (HBW) 8

Vickers Hardness (HV) 20

Standard Rockwell Hardness (HRB) 7

Standard Rockwell Hardness (HRC) 5

Note:

There were not enough Superficial Rockwell Hardness (HR30T) results submitted to calculate z-scores.

6. PTA AND TECHNICAL ADVISER’S COMMENTS

The summary statistics and outliers identified for each of the tests are reported in Tables A and B above. Complete details of the statistical analyses appear in Appendix A.

6.1 Return rate

All of the 24 laboratories that participated in the program returned results. Of these 24 laboratories, three (13%) submitted results for all five tests. The return rate for all tests is as follows:

• Brinell Hardness (HBW) 18 out of 24 75% • Vickers Hardness (HV) 19 out of 24 79% • Standard Rockwell Hardness (HRB) 18 out of 24 75% • Superficial Rockwell Hardness (HR30T) 4 out of 24 17% • Standard Rockwell Hardness (HRC) 18 out of 24 75%

-5-

6.2 Performance summary

One or more statistical outliers were reported by 4 of the 24 laboratories (17%) that participated in this program. A total of 73 results were analysed in this program. Of these results, four (5%) were outlier results.

6.3 Brinell Hardness (HBW)

A total of 18 laboratories reported test results for Brinell Hardness. See Appendix A, Section A1.

The coefficient of variation (CV) for the Brinell Hardness results was considered to be low (2.2%).

One laboratory (code 8) reported an outlier result. For this laboratory, it was noted that one of the three tests performed to determine the average hardness was noticeably different to the other two (302 vs 285 HBW respectively). Further testing to establish the true hardness of this specimen should have been performed as a result of this variation. This also applies to the laboratories (code 4 and code 24) whose individual test results varied by 7 points HBW. The individual test results reported by all other laboratories were reasonably consistent.

Only 11 of the 18 laboratories reported the test temperature. All 11 reported temperatures that were within the prescribed limits.

It was also noted that two laboratories (codes 8 and 24) are still using steel ball indenters. The use of steel ball indenters at low hardness levels is no longer an option for laboratories testing to the Australian Standard AS 1816.1. (See Clause 5.2).

6.4 Vickers Hardness (HV)

A total of 19 laboratories reported test results for Vickers Hardness. See Appendix A, Section A2.

The CV for the Vickers Hardness results was 2.4%. This value is considered to be too high, considering that the Vickers method is the most accurate for determining hardness when compared with all the other methods employed in this program.

Laboratory 20 reported an outlier result. The average hardness reported by this laboratory was 138 HV points (47.8%) higher than the median hardness. It is difficult to speculate how such a massive error in hardness measurement can occur. Significant damage on the diamond indenter, incorrect load or forgetting to zero the microscope prior to measuring the diagonals are possible causes of this error. This laboratory should take urgent and immediate action to identify and remedy the cause of this non-conformance.

-6-

Laboratory 18 obtained an |z| score > 2. It was noted that this laboratory, along with laboratories 2, 8, 14, 15, 21 and 23 did not perform adequate preparation to the test surface. The surfaces of the specimens supplied for Vickers Hardness testing were too heavily cold worked and too rough for the accurate measurement of the diagonals. See Australian Standard AS1817.1, Clauses 6.1 and 6.2. These specimens should have been polished down to 1200 grit or finer finish, or to a rough diamond finish. The surface preparation practice reported by all other laboratories (see Appendix A, Section A6) complied with the requirements of the Standard.

Only 14 of the 19 laboratories reported the test temperature. All 14 reported temperatures that were within the prescribed limits.

6.5 Standard Rockwell Hardness (HRB)

A total of 18 laboratories reported results for Standard Rockwell B Hardness. See Appendix A, Section A3.

The CV for the Standard Rockwell B Hardness results was 1.1%, which is quite low (especially considering the test method is only accurate to ± 2 points HRB).

Again, only one laboratory reported an outlier result. Laboratory 7 reported an average hardness of 49.7 points HRB. The fact that this laboratory’s result was approximately 30 HRB points lower than the median (80.35 HRB) suggests that the hardness was read from the wrong scale. Standard Rockwell hardness machine dials usually have graduations on the inner scale for ball indenters and on the outer scale for diamond indenters. These scales differ by 30 ‘points’ which is the approximate size of the error.

In addition, laboratories 9 and 15 obtained |z| scores > 2.

It was noted that only three laboratories used the preferred carbide (hard metal) ball indenters for this test. Australian Standard AS 1815.1 states that “Steel balls may still be used subject to agreement between the purchaser and the supplier”. There is a slight difference in the results obtained with the different indenter materials. The carbide ball indenters give a slightly lower value than the steel balls. Comparison tables are provided in Appendix G of AS 1815.1.

Only 13 of the 18 laboratories reported the test temperature. All 13 reported temperatures that were within the prescribed limits.

6.6 Superficial Rockwell Hardness (HR30T)

Only 4 laboratories reported results for Superficial Rockwell 30T Hardness. There were insufficient results to calculate either summary statistics or z-scores for Superficial Rockwell Hardness.

-7-

6.7 Standard Rockwell Hardness (HRC)

A total of 18 laboratories reported results for Standard Rockwell C Hardness. See Appendix A, Section A5.

The CV for the Standard Rockwell C Hardness results was 7.7%. This value is higher than the CV values obtained for all of the other hardness tests in this program, which indicates that the results reported for Standard Rockwell C Hardness were the most variable. The accuracy of machines measuring Standard Rockwell C Hardness is expected to be ± 1.5 points HRC. It was noted that only 6 laboratories (codes 3, 4, 8, 18, 22 and 23) reported results that fell within 1.5 HRC points of the median.

Laboratory 5 reported an outlier result of 63.4 HRC. The fact that this laboratory’s result was approximately 30 HRC points higher than the median (31.75 HRC) suggests that the hardness was read from the wrong scale. As explained in Section 6.5, Standard Rockwell hardness machine dials usually have graduations on the inner scale for ball indenters and on the outer scale for diamond indenters. These scales differ by 30 ‘points’ which is the approximate size of the error.

Only 13 of the 18 laboratories reported the test temperature. All 13 reported temperatures were within the prescribed limits.

7. REFERENCES

1. Guide to Proficiency Testing Australia (2008) . (This document is located on the PTA website at www.pta.asn.au under Programs / Documents).

2. AS 1815.1-2007 Metallic materials – Rockwell hardness test Method 1: Test Method (scales A, B, C, D, E, F, G, H, K, N, T) .

3. AS 1816.1-2007 Metallic materials – Brinell hardness test Method 1: Test method (ISO 6506-1: 2005, MOD) .

4. AS 1817.1-2003 Metallic materials – Vickers hardness test Method 1: Test method (ISO 6507-1: 1997, MOD) .

APPENDIX A

Summary of Results

Section A1

Brinell Hardness (HBW) A1.1

Brinell Hardness (HBW) – Results and Z-Scores Lab Temp. Indenter Test 1 Test 2 Test 3 Average Z-Score Code (oC) Material 1 274 278 278 277 22 Carbide 0.93 2 272 272 272 272 22.3 - 0.08 3 279 280 280 280 25 Carbide 1.43 4 269 262 266 266 21 - -0.93 5 271 269 269 270 22.5 Carbide -0.25 7 277 277 277 277 21 - 0.93 8 285 302 285 291 - Steel 3.29 § 9 269 269 269 269 - Carbide -0.42 10 262 262 262 262 21.9 Carbide -1.60 11 277 277 272 275 - Carbide 0.59 13 272 272 272 272 - Carbide 0.08 14 272 271 271 271 22 - -0.08 15 269 269 269 269 21 Carbide -0.42 19 269 269 269 269 - Carbide -0.42 20 277 277 277 277 - Carbide 0.93 21 266 265 269 267 21 - -0.76 23 277 278 278 278 - - 1.10 24 266 262 269 266 25 Steel -0.93

Summary Statistics

Statistic Average No of Results 18 Median 271.5 Norm IQR 5.9 Robust CV 2.18% Minimum 262 Maximum 291 Range 29

Notes:

1. § denotes an outlier (i.e. |z-score| > 3). 2. Summary statistics and z-scores have been calculated for the average results reported. 3. The measuring microscope for laboratory 9 only estimates to within 0.05 mm ( i.e. within about 7 HBW at this hardness).

A1.2

Brinell Hardness (HBW)

8 3

2 3 23 1 1 7 20 11

2 13 0

5 14

9 -1 15 19 21 4 Robust Z-Score 24

-2 10

-3

Laboratory Code

Section A2

Vickers Hardness (HV) A2.1

Vickers Hardness (HV) – Results and Z-Scores Lab Temp. Indenter Test 1 Test 2 Test 3 Average Z-Score Code (oC) Material 1 293 297 297 296 22 Diamond 0.99 2 287 294 294 292 22.3 - 0.43 3 289 288 289 289 22 Diamond 0.00 4 287 287 286 287 21 - -0.28 6 288.5 292 288 290 25 - 0.14 7 289 289 289 289 21 - 0.00 8 293 289 298 293 - Diamond 0.57 10 294 298 298 297 21.9 Diamond 1.14 11 283 283 283 283 - Diamond -0.85 12 294 294 293 294 21 - 0.71 13 285 288 285 286 - Diamond -0.43 14 278 279 280 279 22 - -1.42 15 284 285 286 285 21 Diamond -0.57 18 304 303 306 304 24 Diamond 2.13 20 426 428 427 427 - Diamond 19.60 § 21 288 290 290 289 17 - 0.00 22 273 277 285 278 26 - -1.56 23 284 282 281 282 - - -0.99 24 277 281 283 280 25 Diamond -1.28

Summary Statistics

Statistic Average No of Results 19 Median 289.0 Norm IQR 7.0 Robust CV 2.44% Minimum 278 Maximum 427 Range 149

Notes:

1. § denotes an outlier (i.e. |z-score| > 3). 2. Summary statistics and z-scores have been calculated for the average results reported.

A2.2

Vickers Hardness (HV)

3 20

18 2

10 1

1 12 8

6 3 7 21 0

4 13 -1 15 Robust Robust Z-Score 11

24 14 -2 22

-3

Laboratory Code

Section A3

Standard Rockwell Hardness (HRB) A3.1

Standard Rockwell Hardness (HRB) – Results and Z-Scores Lab Temp. Indenter Test 1 Test 2 Test 3 Average Z-Score Code (oC) Material 3 80.5 80.6 80.8 80.6 22 Carbide 0.29 4 79.5 79.5 80.0 79.7 21 - -0.75 5 80.3 81.1 81.1 80.8 22.5 Carbide 0.52 7 50.3 49.0 49.7 49.7 28 - -35.19 § 8 82 82 83 82 - Steel 1.89 9 78 78 78 78 - Steel -2.70 12 81.8 81.9 81.8 81.8 21 - 1.66 13 79.9 79.9 80.1 80.0 22 Steel -0.40 14 79.0 79.0 79.0 79.0 22 - -1.55 15 82.1 82.9 82.1 82.4 21 Steel 2.35 16 81.4 80.9 81.0 81.10 22 Carbide 0.86 17 79.0 81.0 81.5 80.5 - Steel 0.17 18 80.0 80.2 80.0 80.1 24 Steel -0.29 20 81 81 81 81 - Steel 0.75 21 80.8 80.7 80.0 80.5 20 - 0.17 22 80.0 80.0 80.2 80.1 26 - -0.29 23 79.7 79.3 80.0 79.7 - - -0.75 24 80.0 80.5 80.0 80.2 25 Steel -0.17

Summary Statistics

Statistic Average No of Results 18 Median 80.35 Norm IQR 0.87 Robust CV 1.08% Minimum 49.7 Maximum 82.4 Range 32.7

Notes:

A3.2

Standard Rockwell Hardness (HRB)

15 2 8

1 20 5 3 17 21 0

24 18 22

13 4

-1 23 Robust Robust Z-Score

-2 14

-3 9 7 Laboratory Code

Section A4

Superficial Rockwell Hardness (HR30T)

A4.1

Superficial Rockwell Hardness (HR30T) – Results Lab Temp. Indenter Test 1 Test 2 Test 3 Average Code (oC) Material 3 70.3 70.2 69.8 70.1 22 Carbide 13 69.6 68.0 66.3 68.0 22 Steel 16 67.9 68.1 68.2 68.07 22 Carbide 24 69.5 69.0 69.0 69.2 25 Steel

Notes:

1. There were insufficient results to calculate either summary statistics or z-scores for Superficial Rockwell Hardness (HR30T).

Section A5

Standard Rockwell Hardness (HRC)

A5.1

Standard Rockwell Hardness (HRC) – Results and Z-Scores Lab Temp. Indenter Test 1 Test 2 Test 3 Average Z-Score Code (oC) Material 3 32.0 32.0 31.8 31.9 22 Diamond 0.06 4 32.0 31.7 31.7 31.8 21 - 0.02 5 63.3 63 63.8 63.4 22.5 Diamond 13.04 § 7 30.1 30.0 30.0 30.0 26 - -0.72 8 32 32 33 32 - Diamond 0.10 9 29.5 29.5 29.5 29.5 - Diamond -0.93 12 35.9 36.6 36.4 36.3 20 - 1.87 13 29.9 29.6 30.0 29.8 22 Diamond -0.80 14 36.0 35.5 35.5 35.6 22 - 1.59 15 34.1 33.8 32.9 33.6 21 Diamond 0.76 16 30.1 30.0 30.1 30.07 22 Diamond -0.69 17 33.5 34.0 33.5 33.7 - Diamond 0.80 18 32.0 31.8 32.0 31.9 24 Diamond 0.06 20 29.5 30 30 29.83 - Diamond -0.79 21 29.1 30.4 30.1 29.9 20 - -0.76 22 30.5 30.0 30.5 30.3 26 - -0.60 23 32.2 31.0 32.0 31.7 - - -0.02 24 29.5 29.5 30.0 29.7 25 Diamond -0.84

Summary Statistics

Statistic Average No of Results 18 Median 31.75 Norm IQR 2.43 Robust CV 7.65% Minimum 29.5 Maximum 63.4 Range 33.9

Notes:

1. § denotes an outlier (i.e. |z-score| > 3). 2. Summary statistics and z-scores have been calculated for the average results reported. 3. The Rockwell test machine for laboratory 9 can only estimate to within 0.5 HRC. 4. Laboratory 9 noted on their Results Sheet that the sample they received “was distorted and gave erroneously high results using a standard anvil. Point contact anvil was used”. It is noted that the average hardness result submitted by this laboratory was not an outlier.

A5.2

Standard Rockwell Hardness (HRC)

5 3

2 12 14

1 15

8 3 18 23 4 0

7 22 21 -1 16 9 Robust Robust Z-Score

20 24 13

-2

-3 Laboratory Code

Section A6

Additional Surface Preparation

A6.1

Additional Surface Preparation Lab Preparation Details Code 1 Test surface was ground to grit P1200 finishing. 2 Surface prep to 320 SiC abrasive paper for HV20 test. 3 Specimens for Vickers hardness testing were polished to a fine diamond finish. 4 For the 8 mm plate the sample was polished to a P1200 finish prior to testing. 5 Not performed. 6 8 mm plate Vickers – surface was taken down to a 1200 grit finish using 240 - 400 - 600 - 800 - 1200 grit papers before hardness was undertaken. 7 8 mm plate was linished with 240, 360, 400, 600, 800 & 1000 grit SiC paper flooded with water. 8 Not performed. 9 Not performed. 10 Polished part of 8 mm plate for HV20 Vickers test 1200 grit. 11 Surface finish on 8 mm test piece would be acceptable for Brinell but unacceptable for Vicker diamond. Preliminary hardness proved this - corners of diamond would vary approx 15 points. Preparation: opposite side was surface ground; surface to be tested was surface ground (soft wheel) and polished to P1200 grit. 12 1200 emery paper on 8 mm plate. 13 8 mm plate ground surface prepared metallographically to a P-1200 SiC finish prior to Vickers and Brinell testing. 14 8 mm plate was wet ground to P800. 15 8 mm plate surface was ground to P#400 grit. 16 Not performed. 17 Not performed. 18 8 mm plate had further polishing on a pre-grinder machine using 120 grit paper then 320 grit to a final polish finish of 600 grit. Sample washed off, dried then tested. 19 Not performed. 20 8 mm plate required extra surface preparation. Finish to P1200 conforming to AS1817.1 - 2003 - Clause 6.2 and to conform with our standard test procedures. 21 Not performed. 22 8 mm plate had a 6 µm diamond polish surface. 23 Not performed. 24 8 mm plate ground face was reground to finer finish.

APPENDIX B

Homogeneity and Stability Testing

B1.1

HOMOGENEITY TESTING

Before the samples were distributed to participants, they were tested for homogeneity by BlueScope Steel Limited, Port Kembla. Each sample was tested for homogeneity for Brinell Hardness (HBW), Standard Rockwell Hardness (HRB), Superficial Rockwell Hardness (HR30T) and Standard Rockwell Hardness (HRC). A number of samples were selected at random for Vickers Hardness (HV20) homogeneity testing. The results of the homogeneity testing are displayed below:

Homogeneity Testing Results

Brinell Scale (HBW)

Sample Sample Sample Sample Hardness Hardness Hardness Hardness Number Number Number Number 1 277 12 277 23 277 34 280 2 277 13 277 24 278 35 277 3 277 14 277 25 278 36 277 4 277 15 278 26 277 37 277 5 278 16 277 27 277 38 276 6 277 17 277 28 275 39 278 7 277 18 277 29 274 40 277 8 272 19 277 30 278 41 278 9 277 20 275 31 277 42 277 10 277 21 277 32 277 43 277 11 277 22 278 33 279 44 277

Homogeneity Testing Results

Vickers Scale (HV20)

Sample Result 1 Result 2 Result 3 Average Number 1 290 287 291 289 5 288 288 288 288 9 288 286 288 287 13 289 288 290 289 21 284 286 286 285 25 283 285 286 285 29 293 299 296 296 33 292 291 292 291 37 286 287 286 286

B1.2

Homogeneity Testing Results Standard Rockwell Scale (HRB) Sample Sample Result 1 Result 2 Average Result 1 Result 2 Average Number Number A1 80.1 80.1 80.1 A26 80.6 80.2 80.4 A3 80.9 80.7 80.8 A27 80.3 80.3 80.3 A4 80.5 80.1 80.3 A29 79.8 80.6 80.2 A5 80.2 80.3 80.3 A30 79.9 80.3 80.1 A6 80.2 80.4 80.3 A32 79.9 80.3 80.1 A7 80.3 81.0 80.7 A33 80.7 80.3 80.5 A8 80.4 80.0 80.2 A34 80.5 79.4 80.0 A9 80.5 80.2 80.4 A35 81.0 80.3 80.7 A10 80.3 80.4 80.4 A37 80.2 80.4 80.3 A11 80.6 80.0 80.3 A38 80.2 80.9 80.6 A12 80.2 80.1 80.2 A39 80.7 80.1 80.4 A13 79.6 79.3 79.5 A40 80.7 80.5 80.6 A14 80.3 80.2 80.3 A41 80.4 79.9 80.2 A15 80.5 80.9 80.7 A42 79.5 78.7 79.1 A16 80.8 80.0 80.4 A43 80.0 79.9 80.0 A17 80.8 80.3 80.6 A44 80.1 80.4 80.3 A18 80.5 80.4 80.5 A45 80.3 80.3 80.3 A19 80.3 80.1 80.2 A47 80.3 80.4 80.4 A20 80.5 80.5 80.5 A48 80.6 80.4 80.5 A21 79.9 80.3 80.1 A49 80.1 80.3 80.2 A22 80.3 80.4 80.4 A50 79.7 80.0 79.9 A23 80.0 79.8 79.9 A51 80.4 79.9 80.2 A24 80.5 79.9 80.2 A52 80.6 80.0 80.3 A25 80.3 80.6 80.5

Homogeneity Testing Results Standard Rockwell Scale (HRC)

Sample Sample Sample Sample Hardness Hardness Hardness Hardness Number Number Number Number 1 31.5 13 30.7 25 31.2 39 31.4 2 31.5 14 31.6 26 31.9 40 31.2 3 31 15 31.6 27 30.8 41 31 4 31.5 16 31.7 28 31.4 42 31 5 31.4 18 31.4 29 30.9 43 30.8 6 31 19 31.7 30 31.7 44 31.3 7 31 20 31.3 31 31.6 45 31 8 30.8 21 31.8 33 31.5 48 31 9 31.8 22 30.8 35 31.6 49 30.8 10 31 23 31.1 37 31 50 31.1 12 30.2 24 31 38 30.8 51 31.7

B1.3

Homogeneity Testing Results Superficial Rockwell Scale (HR30T) Sample Sample Result 1 Result 2 Average Result 1 Result 2 Average Number Number A1 69.6 68.4 69.0 A26 69.5 69.2 69.4 A3 69.7 69.4 69.6 A27 70.8 69.5 70.2 A4 69.6 70.2 69.9 A29 68.8 69.4 69.1 A5 70.1 68.7 69.4 A30 70.7 69.1 69.9 A6 68.5 69.6 69.1 A32 69.7 69.8 69.8 A7 69.9 69.9 69.9 A33 68.9 68.3 68.6 A8 71.3 69.7 70.5 A34 68.7 69.5 69.1 A9 68.8 69.9 69.4 A35 68.6 68.6 68.6 A10 70.6 69.0 69.8 A37 69.6 70.6 70.1 A11 70.2 69.1 69.7 A38 68.7 68.9 68.8 A12 69.7 69.1 69.4 A39 69.6 69.2 69.4 A13 70.0 70.3 70.2 A40 69.2 69.7 69.5 A14 70.3 69.4 69.9 A41 69.3 68.9 69.1 A15 69.7 69.9 69.8 A42 70.2 69.8 70.0 A16 69.4 69.4 69.4 A43 69.9 70.4 70.2 A17 69.4 70.1 69.8 A44 71.0 68.9 70.0 A18 68.8 70.4 69.6 A45 70.2 68.8 69.5 A19 70.1 68.9 69.5 A47 69.6 70.0 69.8 A20 70.2 69.2 69.7 A48 69.4 68.8 69.1 A21 69.7 69.6 69.7 A49 68.2 69.3 68.8 A22 69.0 68.7 68.9 A50 69.5 69.0 69.3 A23 70.0 70.2 70.1 A51 68.5 68.1 68.3 A24 69.2 69.5 69.4 A52 70.0 69.9 70.0 A25 69.7 69.8 69.8

Analysis of the homogeneity testing data indicated that the samples were sufficiently homogeneous for the program and, therefore, any participant results identified as extreme cannot be attributed to sample variability.

B2.1

STABILITY TESTING

A number of samples were selected at random by BlueScope Steel Limited, Port Kembla, for stability testing. This testing took place at the same time as the participants tested the samples. The results of the stability testing are displayed below:

Stability Testing Results Brinell Scale (HBW) & Vickers Scale (HV20)

Sample Hardness Hardness Number (HBW) (HV20) 5 280 285 13 280 284 21 279 - 25 278 281 37 280 287 42 280 -

Stability Testing Results Standard Rockwell Scale (HRB) & Superficial Rockwell Scale (HR30T)

Sample Hardness Hardness Number (HRB) (HR30T) A6 80.6 70.1 A8 80.5 69.7 A20 80.7 69.5 A32 80.7 69.6 A49 80.6 70.4

Stability Testing Results Standard Rockwell Scale (HRC)

Sample Hardness Number (HRC) 3 30.5 16 32.2 29 31.3 37 31.9 42 32.0

Analysis of these results showed that the samples were sufficiently stable for testing for the duration of the program.

APPENDIX C

Instructions to Participants

and

Results Sheet

C1.1 PROFICIENCY TESTING AUSTRALIA

Hardness Testing Of Metals Proficiency Testing Program Round 1, December 2008

Instructions To Participants

To ensure that the results of this program can be analysed correctly, participants are asked to adhere carefully to these instructions.

The three samples for this hardness testing program consist of:

1) An 8 mm thick hot rolled plate sample. This plate sample has been ground on one surface and is to be used for both Brinell (preferably HBW 10/3000) and Vickers (preferably HV20) hardness testing. Testing must be performed on the surface that has been ground. It is up to each participant to decide if the finish on this surface is suitable for the test being performed.

2) A 2 mm thick, 50 mm diameter disc. This specimen is identified by the prefix ‘A’ followed by a number. It is to be used for both the Superficial Rockwell scale HR30T and the Standard Rockwell scale HRB. Testing must be performed on the surface containing the identification number. The indentations from homogeneity testing will also be evident on this surface.

3) A 1.5 mm thick, 55 mm diameter disc. This sample is to be used for the Rockwell C scale (HRC). Again, testing must be performed on the numbered surface. This is the surface that was used for homogeneity testing.

4) All testing, recording and reporting is to be performed in accordance with the relevant Australian Standard. Please use the attached result sheet.

5) Participants are requested to perform tests for all the hardness scales for which they hold accreditation.

6) Do not discard the hardness test samples until you have received the final report. You may be asked to carry out a retest or to return the samples to Proficiency Testing Australia for retesting at the laboratory that performed the homogeneity tests.

7) For this program, your laboratory has been allocated the code number on the attached Results Sheet. All reference to your laboratory in reports associated with this program will be via this code number, thus ensuring the confidentiality of your results.

Hardness Testing of Metals, Round 1 December 2008 Page 1 of 3 C1.2

8) Return the Results Sheet, either by mail or facsimile, to:

Mark Bunt Proficiency Testing Australia PO Box 7507 Silverwater NSW 2128 AUSTRALIA

Telephone: + 61 2 9736 8397 (1300 782 867) Fax: +61 2 9743 6664

All results should arrive at the above address by no later than Friday 16 January 2009 . Results reported later than this date may not be analysed in the final report.

Hardness Testing of Metals, Round 1 December 2008 Page 2 of 3 C2.1

PROFICIENCY TESTING AUSTRALIA

Hardness Testing Of Metals Proficiency Testing Program Round 1, December 2008

RESULTS SHEET

Laboratory Code:

Report Test Results Sample Sample Hardness hardness Indenter Temp. No. Size Scale to Material Deg C nearest Test 1 Test 2 Test 3 Average

Steel 8 mm Brinell 1 BHN Carbide plate Diamond

Steel 8 mm Vickers 1 HV Carbide plate Diamond

Steel 50 mm 0.1 A HRB Carbide disc HRB Diamond

Steel 50 mm 0.1 A HR30T Carbide disc HR30T Diamond

Steel 55 mm HRC 0.1 HRC Carbide disc Diamond

Did you carry out any additional surface preparation for any of the hardness tests? Yes/No

If Yes, please give details of preparation.

………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………………

Print Name: ______Signature & Date: ______

Hardness Testing of Metals, Round 1 December 2008 Page 3 of 3

-----End of Report-----