Tensile Testing of Metals Proficiency Testing Program

REPORT NO. 1208

Tensile Testing of Metals

Proficiency Testing Program

Round 13

July 2020

ACKNOWLEDGMENTS

PTA wishes to gratefully acknowledge the technical assistance provided for this program by Mr S Sameem, ARL Laboratory Services Pty Ltd. Also our thanks go to ARL Laboratory Services Pty Ltd, for the supply and homogeneity testing of the samples.

© COPYRIGHT PROFICIENCY TESTING AUSTRALIA 2020

PO Box 7507 Silverwater NSW 2128 AUSTRALIA

CONTENTS

1. FOREWORD 1

2. FEATURES OF THE PROGRAM 1

3. FORMAT OF THE APPENDICES 2

4. DESIGN OF THE PROGRAM 3

5. OUTLIER RESULTS 4

Table A: Summary Statistics for All Tests 4

Table B: Summary of Statistical Outliers 5

6. PTA AND TECHNICAL ADVISER'S COMMENTS 5

7. REFERENCES 13 APPENDICES

APPENDIX A

Summary of Results

0.2% Proof Stress A1.1

Lower Yield A2.1

Upper Yield A3.1

Tensile Strength A4.1

Percentage Elongation after Fracture A5.1

Percentage Reduction in Area after Fracture A6.1

Method Information and Other Reported Results A7.1

APPENDIX B

Homogeneity Testing B1.1

APPENDIX C

Instructions to Participants C1.1

Results Sheet C2.1

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1. FOREWORD This report summarises the results of a proficiency testing program on the

tensile properties of metals. It constitutes the thirteenth round of an ongoing series of programs. This program is accredited to ISO/IEC 17043: 2010 “Conformity assessment – General requirements for proficiency testing” by International Accreditation New Zealand (IANZ).

Proficiency Testing Australia (PTA) conducted the testing program in April –

June 2020. The aim of the program was to assess laboratories' ability to competently perform the nominated tests.

The Program Coordinator was Dr M Bunt. The Technical Adviser was

Mr S Sameem, ARL Laboratory Services Pty Ltd. This report was authorised by Mrs K Cividin, PTA Quality Manager.

2. FEATURES OF THE PROGRAM (a) A total of 24 laboratories participated in the program, two of which did not

return results for inclusion in the final report. Laboratories from the following countries received samples:

7 NEW ZEALAND 4 AUSTRALIA 4 THAILAND 1 BOTSWANA 1 BRAZIL 1 COLOMBIA 1 ETHIOPIA 1 QATAR 1 SAUDI ARABIA 1 SINGAPORE 1 TAIWAN 1 TANZANIA

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. Please note that some laboratories submitted more than one set of results. The code numbers of these laboratories (with appended letters) could appear several times in the same data set.

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

(c) Laboratories were provided with a carbon steel round bar, labelled Sample 1, and an aluminium flat bar, labelled Sample 2. Both samples were approximately 450 mm in length. The carbon steel round bar was approximately 20 mm in diameter. The aluminium flat bar was approximately 40 mm in width and 6 mm in thickness.

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(d) Laboratories were asked to perform tests for:

0.2% Proof Stress (non-proportional elongation) (Rp0.2);

Lower and Upper Yield Strength (ReL and ReH), if applicable;

Tensile Strength (Rm);

Percentage Elongation after Fracture (A%); and

Percentage Reduction in Area after Fracture (Z%).

(e) All testing, recording and reporting was to be performed in accordance with the laboratory’s routine test methods, but testing in accordance with AS 1391 or ISO 6892-1 were the preferred test methods.

(f) Laboratories were requested to perform the tests according to the Instructions to Participants provided and to record the results, along with an estimate of their measurement uncertainty (MU) for each result, on the accompanying Results Sheet, which was distributed with the samples. Copies of these documents appear in Appendix C.

(g) Prior to distribution, the samples were tested for homogeneity by ARL

Laboratory Services Pty Ltd. Based on the results of this testing, the homogeneity of the samples was established (see Appendix B).

3. FORMAT OF THE APPENDICES (a) Appendix A is divided into seven sections (A1-A7).

Sections A1-A6 contain the analysis of results reported by laboratories for 0.2% Proof Stress (non-proportional elongation) (Rp0.2), Lower Yield (ReL), Upper Yield (ReH), Tensile Strength (Rm), Percentage Elongation after Fracture (A%) and Percentage Reduction in Area after Fracture (Z%). These sections contain, where appropriate: i) a table of results reported by laboratories for each test, with estimates of

their MUs and calculated z-scores; ii) a listing of the summary statistics; and iii) ordered z-score charts.

Section A7 contains information on the methods used by laboratories and the results reported by laboratories for Tensile Specimen Gauge Diameter, Tensile Specimen Gauge Thickness, Tensile Specimen Gauge Width, Tensile Specimen Gauge Length, Elastic Stress or Strain Rate and Plastic Strain Rate.

(b) Appendix B contains details of the homogeneity testing. (c) Appendix C contains copies of the Instructions to Participants and Results

Sheet.

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4. DESIGN OF THE PROGRAM

The summary statistics calculated for each test / sample consists of:

No. of Results: the total number of results for that test / sample;

Median: the middle value of the results;

Normalised IQR: the normalised interquartile range of the results;

Uncertainty of the Median: a robust estimate of the standard deviation of the Median;

Robust CV: the robust coefficient of variation expressed as a percentage, i.e. 100 x Normalised IQR / Median;

Minimum: the lowest laboratory result;

Maximum: the highest laboratory result; and

Range: the difference between the Maximum and Minimum. The median is a measure of the centre of the data. The normalised IQR is a measure of the spread of the results. It is calculated by multiplying the interquartile range (IQR) by a correction factor, which converts the IQR to an estimate of the standard deviation. The IQR is the difference between the upper and lower quartiles (i.e. the values above and below which a quarter of the results lie, respectively). For normally distributed data, the uncertainty of the median is approximated by:

n

normIQR

2

where normIQR is the normalised IQR and n is the number of results. In order to assess laboratories’ testing performance, a robust statistical approach, using z-scores, was utilised. Z-scores give a measure of how far a result is from the consensus value (i.e. the median), and gives a "score" to each result relative to the other results in the group. A z-score with an absolute value less than or equal to 2.0 is considered to be satisfactory, whereas, a z-score with an absolute value greater than or equal to 3.0 is considered to be an outlier and is marked by the symbol “§”. Laboratories are also encouraged to review results which have an absolute z-score value between 2.0 and 3.0 (i.e. 2.0 < |z-score| < 3.0). These results are considered to be questionable results. Ordered z-score charts indicate each laboratory's robust z-score, in order of magnitude, marked with its laboratory code number. From these charts, each laboratory can readily compare its performance relative to the other laboratories. The ordered z-score charts in Appendix A are limited on the vertical axis to +3.0 and -3.0, so that outliers are clearly identifiable as those laboratories whose "bar" extends beyond the chart boundary.

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For further details on the calculation and interpretation of robust z-scores and ordered z-score charts, please see the Guide to Proficiency Testing Australia (2019).

5. OUTLIER RESULTS

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

Table A: Summary Statistics for All Tests

Test Summary Statistics Sample 1 Sample 2

0.2% Proof Stress (non-proportional elongation) (Rp0.2)

(MPa)

Number of Results 22 20

Median 594.5 197.5

Normalised IQR 25.8 19.3

Uncertainty (Median) 6.9 5.4

Lower Yield (ReL) (MPa)


Median n/a n/a

Normalised IQR n/a n/a

Uncertainty (Median) n/a n/a

Upper Yield (ReH) (MPa)


Median n/a n/a

Normalised IQR n/a n/a

Uncertainty (Median) n/a n/a

Tensile Strength (Rm) (MPa)


Median 630.0 229.0



Percentage Elongation after Fracture

(A%)


Median 14.2 13.0



Percentage Reduction in Area after Fracture

(Z%)

Number of Results 19 n/a

Median 54.0 n/a

Normalised IQR 2.6 n/a

Uncertainty (Median) 0.8 n/a

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Table B: Summary of Statistical Outliers (by laboratory code number)

Test Sample 1 Sample 2

0.2% Proof Stress 1, 13, 17B, 18 11, 21

Lower Yield

Upper Yield

Tensile Strength 1, 13, 17B, 18 -


- 14, 20A, 20B


1, 17B

Notes: 1. For each test, the results for all test methods were pooled for analysis.

2. Summary statistics and z-scores for Percentage Elongation after Fracture

for Sample 1 were calculated by converting the results to a proportional gauge length.

3. There was an insufficient number of results submitted for Lower Yield and

Upper Yield to calculate summary statistics or z-scores. 4. The Percentage Reduction in Area after Fracture was only required to be

reported for Sample 1.

6. PTA AND TECHNICAL ADVISER’S COMMENTS

Consensus values (medians), derived from participants’ results, are used as the assigned values in this program. These values are not metrologically traceable to an external reference. The summary statistics, uncertainties of the assigned values and outliers, for each of the tests, are reported in Tables A and B, above and on the previous page. Complete details of the statistical analyses appear in Appendix A.

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6.1 Return rate

Twenty-two of the 24 laboratories (92%) that participated in the program returned results. Of the 22 laboratories that submitted results for the program, the return rate for all tests is as follows:

Test Sample 1 Sample 2

0.2% Proof Stress 20 out of 22 (91%) 19 out of 22 (86%)

Lower Yield 5 out of 22 (23%) 5 out of 22 (23%)

Upper Yield 4 out of 22 (18%) 4 out of 22 (18%)

Tensile Strength 19 out of 22 (86%) 20 out of 22 (91%)


18 out of 22 (82%) 18 out of 22 (82%)


17 out of 22 (77%)

Note that the numbers in the above table refer only to results returned that were able to be analysed. Some laboratories attempted some of the tests but were unable to report results for a variety of reasons (such as the sample failing outside the gauge length, for example).

6.2 Performance summary

One or more statistical outliers were reported by eight of the 22 laboratories (36%) that returned results for this round of the program. The last round of the Tensile Testing of Metals program where participants tested a round bar sample and a flat bar sample was Round 7. For comparison, 21% of the participants reported outlier results in Round 7 of the Tensile Testing of Metals program (see Report No. 901 for more details). A total of 143 results were analysed in this round of the program. Of these results, fifteen (10%) were outliers. For comparison, 5% of the results analysed in Round 7 of the Tensile Testing of Metals program were outliers (see Report No. 901 for more details).

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6.3 0.2% Proof Stress

A total of 22 laboratories reported results for 0.2% Proof Stress. Twenty of these laboratories reported results for Sample 1, while 19 of these laboratories reported results for Sample 2. Of these 22 laboratories, nine laboratories tested using AS 1391, including two laboratories that submitted two sets of results. Nine laboratories tested using ISO 6892-1. One laboratory tested using ASTM B557M. One laboratory tested using JIS Z 2241. Two laboratories did not specify the method that they used for testing (see Appendix A7 for more details). For the laboratories that used the AS 1391 method for Sample 1, the median and standard error of the 0.2% Proof Stress results was 589.0 ± 14.4 MPa. For all methods pooled, the median and standard error of the 0.2% Proof Stress results for Sample 1 was 594.5 ± 6.9 MPa. For the laboratories that used the AS 1391 method for Sample 2, the median and standard error of the 0.2% Proof Stress results was 197.0 ± 2.2 MPa. For all methods pooled, the median and standard error of the 0.2% Proof Stress results for Sample 2 was 197.5 ± 5.4 MPa. The methods were pooled when analysing the results for both samples. Four laboratories (codes 1, 13, 17B and 18) reported outlier results for Sample 1. Two laboratories (codes 11 and 21) reported outlier results for Sample 2. Two laboratories (codes 7 and 22) obtained absolute z-scores between 2.0 and 3.0 for Sample 1. The yield and proof strengths are very sensitive to loading conditions. If the test sample is subjected to higher load rates, the 0.2% Proof Stress results obtained may be slightly higher than normal. Another reason for high 0.2% Proof Stress results could be that the force measurements may not have been zeroed prior to testing and, as a result, higher strength values could be obtained. This may be the reason for the outlier results reported by laboratory codes 1, 13, 17B and 18, who each reported higher than normal strength values. These participants are highly encouraged to review their testing procedures to ensure correct loading conditions are employed during the tensile tests. The same can also be said for laboratory codes 11 and 21. When testing aluminium samples, or any other material, it is imperative to check and verify that the correct loading conditions are applied. Otherwise erroneous results will be obtained. The robust CV for the 0.2% Proof Stress results for Sample 1 (the round bar sample) was 4.3%, while the robust CV for Sample 2 (the flat bar sample) was 9.8%. The last round of this program where the 0.2% Proof Stress results for a round bar sample and a flat bar sample were analysed was Round 7. In Round 7 of this program the robust CV obtained for the round bar sample was 2.2%, while the robust CV for the flat bar sample was 12.2%. The robust CVs obtained for this round of the program compare well with the robust CVs obtained in Round 7 of the program (see Report No. 901 for more details).

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Fourteen laboratories reported measurement uncertainties associated with their 0.2% Proof Stress test results in this round.

6.4 Lower Yield

Only 5 laboratories determined values for the Lower Yield. Four of these laboratories tested using ISO 6892-1, while one laboratory tested using AS 1391 (see Appendix A7 for more details). There was an insufficient number of results submitted for Lower Yield to calculate summary statistics or z-scores. Two laboratories reported measurement uncertainties associated with their Lower Yield test results in this round.

6.5 Upper Yield

Only 4 laboratories determined values for the Upper Yield. Three of these laboratories tested using ISO 6892-1, while one laboratory tested using AS 1391 (see Appendix A7 for more details). There was an insufficient number of results submitted for Upper Yield to calculate summary statistics or z-scores. One laboratory reported measurement uncertainties associated with their Upper Yield test results in this round.

6.6 Tensile Strength

A total of 22 laboratories reported results for Tensile Strength. Nineteen of these laboratories reported results for Sample 1, while 20 of these laboratories reported results for Sample 2. Of these 22 laboratories, nine laboratories tested using AS 1391, including two laboratories that submitted two sets of results. Nine laboratories tested using ISO 6892-1. One laboratory tested using ASTM B557M. One laboratory tested using JIS Z 2241. Two laboratories did not specify the method that they used for testing (see Appendix A7 for more details). For the laboratories that used the AS 1391 method for Sample 1, the median and standard error of the Tensile Strength results was 631.5 ± 9.1 MPa. For all methods pooled, the median and standard error of the Tensile Strength results for Sample 1 was 630.0 ± 3.2 MPa. For the laboratories that used the AS 1391 method for Sample 2, the median and standard error of the Tensile Strength results was 227.0 ± 2.0 MPa. For all methods pooled, the median and standard error of the Tensile Strength results for Sample 2 was 229.0 ± 3.2 MPa. The methods were pooled when analysing the results for both samples.

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Four laboratories (codes 1, 13, 17B and 18) reported outlier results for Sample 1. There were no outlier results reported for Sample 2. One laboratory (code 6) obtained an absolute z-score between 2.0 and 3.0 for Sample 1. Four laboratories (codes 11, 14, 21 and 22) obtained absolute z-scores between 2.0 and 3.0 for Sample 2. The same comments regarding the high results reported by laboratory codes 1, 11, 13, 17B, 18 and 21 for 0.2% Proof Stress can also be applied to the high results that these laboratories reported for Tensile Strength. The robust CV for the Tensile Strength results for Sample 1 (the round bar sample) was 1.9%, while the robust CV for Sample 2 (the flat bar sample) was 5.2%. The last round of this program where the Tensile Strength results for a round bar sample and a flat bar sample were analysed was Round 7. In Round 7 of this program the robust CV obtained for the round bar sample was 1.4%, while the robust CV for the flat bar sample was 2.3%. The robust CVs obtained for this round of the program are higher than the robust CVs obtained in Round 7 of the program (see Report No. 901 for more details). Fourteen laboratories reported measurement uncertainties associated with their Tensile Strength test results in this round.

6.7 Percentage Elongation after Fracture

A total of 22 laboratories reported results for Percentage Elongation after Fracture. Eighteen of these laboratories reported results for Sample 1, while 18 of these laboratories reported results for Sample 2. Of these 22 laboratories, nine laboratories tested using AS 1391, including two laboratories that submitted two sets of results. Nine laboratories tested using ISO 6892-1. One laboratory tested using ASTM B557M. One laboratory tested using JIS Z 2241. Two laboratories did not specify the method that they used for testing (see Appendix A7 for more details). Participants were asked to use their routine methods for testing Sample 1. This means that the participants could employ different gauge diameters and different gauge lengths for their tensile testing of this sample. Therefore, it was necessary to convert the Percentage Elongation after Fracture results submitted by the participants for Sample 1 to a proportional gauge length of 5.65 √ S0 (5.65 times the square root of the original cross-sectional area). The results were converted to a proportional gauge length using the formula of ISO 2566-1. These results are displayed in Appendix A5. The exact formula used to convert the results is given on page A5.1 of Appendix A5. For the testing of Sample 2 there are currently no elongation conversion values established for aluminium alloys. This means that to evaluate, verify and compare Percentage Elongation after Fracture results for aluminium samples, it is important to use the same tensile test conditions, as supplied. Therefore, the participants were provided with instructions on how to machine Sample 2. These instructions can be found on page C1.3 of Appendix C.

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For the laboratories that used the AS 1391 method for Sample 1, the median and standard error of the Percentage Elongation after Fracture results (converted to a proportional gauge length) was 13.6 ± 0.9%. For all methods pooled, the median and standard error of the Percentage Elongation after Fracture results (converted to a proportional gauge length) for Sample 1 was 14.2 ± 0.6%. For the laboratories that used the AS 1391 method for Sample 2, the median and standard error of the Percentage Elongation after Fracture results was 13.1 ± 0.4%. For all methods pooled, the median and standard error of the Percentage Elongation after Fracture results for Sample 2 was 13.0 ± 0.4%. The methods were pooled when analysing the results for both samples. There were no outlier results reported for Sample 1. Three laboratories (codes 14, 20A and 20B) reported outlier results for Sample 2. One laboratory (code 4) obtained an absolute z-score between 2.0 and 3.0 for Sample 2. It was expected that there would be outlier results for Percentage Elongation after Fracture for Sample 2. That is because not all participants are expected to be familiar with aluminium material testing. The k-factor for laboratory code 14, being the lowest in this round, may suggest that the correct elongation values were not supplied for evaluation by this laboratory. The very high elongation values of 25%, reported by laboratory codes 20A and 20B, suggest the use of defective measuring equipment. The robust CV for the Percentage Elongation after Fracture results for Sample 1 (the round bar sample) was 14.1%, while the robust CV for Sample 2 (the flat bar sample) was 11.4%. The last round of this program where the Percentage Elongation after Fracture results for a round bar sample and a flat bar sample were analysed was Round 7. In Round 7 of this program the robust CV obtained for the round bar sample was 10.0%, while the robust CV for the flat bar sample was 6.4%. The robust CVs obtained for this round of the program are higher than the robust CVs obtained in Round 7 of the program (see Report No. 901 for more details). Fourteen laboratories reported measurement uncertainties associated with their Percentage Elongation after Fracture test results in this round.

6.8 Percentage Reduction in Area after Fracture

The Percentage Reduction in Area after Fracture was only required to be reported for Sample 1. A total of 17 laboratories reported results for Percentage Reduction in Area after Fracture. Of these 17 laboratories, eight laboratories tested using AS 1391, including two laboratories that submitted two sets of results. Eight laboratories tested using ISO 6892-1. One laboratory did not specify the method that they used for testing (see Appendix A7 for more details).

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For the laboratories that used the AS 1391 method for Sample 1, the median and standard error of the Percentage Reduction in Area after Fracture results was 55.0 ± 1.4%. For all methods pooled, the median and standard error of the Percentage Reduction in Area after Fracture results for Sample 1 was 54.0 ± 0.8%. The methods were pooled when analysing the results for Sample 1. Two laboratories (codes 1 and 17B) reported outlier results for Sample 1. For round samples, the Percentage Reduction in Area after Fracture is one of the most important tensile properties. If the correct cup and cone sections are not identified, reduction areas obtained could be incorrect. Usually, the Percentage Reduction in Area after Fracture can be calculated by measuring the smallest diameter of the tested bar in the cup section of the broken samples. This should be checked with the cone section of the tested sample and should be approximately the same value. The results reported by laboratory codes 1 and 17B suggest that these laboratories could not correctly identify the reduced area of the tested samples. The robust CV for the Percentage Reduction in Area after Fracture results for Sample 1 (the round bar sample) was 4.9%. In Round 7 of this program the robust CV obtained for the round bar sample was 4.1%. The robust CV obtained for this round of the program compares well with the robust CV obtained in Round 7 of the program (see Report No. 901 for more details). Ten laboratories reported measurement uncertainties associated with their Percentage Reduction in Area after Fracture test results in this round.

6.9 Measurement Uncertainty A lower percentage of participants in this round reported estimates of the measurement uncertainty associated with their results than those that reported measurement uncertainties in recent rounds of this program. The number and percentage of laboratories that reported estimates of their measurement uncertainty for each test is as follows:

0.2% Proof Stress 14 out of 22 64%

Lower Yield 2 out of 5 40%

Upper Yield 1 out of 4 25%

Tensile Strength 14 out of 22 64%

Percentage Elongation after Fracture 14 out of 22 64%

Percentage Reduction in Area after Fracture 10 out of 17 59%

Any laboratories that reported a measurement uncertainty less than two times the uncertainty of the median may have underestimated their measurement uncertainty.

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Any laboratories that reported a measurement uncertainty greater than three times the normalised IQR may have overestimated their measurement uncertainty. All the participants are highly encouraged to report and use measurement uncertainty, so that the program analysis can provide a better outlook of the overall performance for this program. An approach, such as that described in AS 1391 Appendix H, “An Error Budget”, to the estimation of the measurement uncertainty in tensile testing is an example of an approach that could be followed.

6.10 Other Reported Results

In addition to reporting results for 0.2% Proof Stress, Lower Yield, Upper Yield, Tensile Strength, Percentage Elongation after Fracture and Percentage Reduction in Area after Fracture, participants were also asked to report the Tensile Specimen Gauge Diameter, Tensile Specimen Gauge Thickness, Tensile Specimen Gauge Width, Tensile Specimen Gauge Length, Elastic Stress or Strain Rate and Plastic Strain Rate. The details reported by each of the participants are displayed in Appendix A7. It is highly recommended that all of the participants report all of this necessary information, in order to better analyse the test results. The Tensile Specimen Diameter and Tensile Specimen Gauge Length were required in order to convert the Percentage Elongation after Fracture results to a proportional gauge length for Sample 1. The Tensile Specimen Gauge Thickness, Tensile Specimen Gauge Width and Tensile Specimen Gauge Length can be used to check if the participants machined Sample 2 according to the Instructions to Participants. The loading rates (both stress and strain rates) can be reviewed for any abnormal test results. The loading rates are particularly important when comparing test results for elongation and yield strength, as the loading rates can affect these properties.

6.11 General Comments The aim of this round of the program was to determine the capabilities and proficiency of the participating laboratories in comparing and understanding the role of specimen geometry and material type on the tensile properties of the materials. The overall performance of the participating laboratories in this round has been very interesting. There were numerous outlier results for various tensile properties and from different participants. Surprisingly, there were more outlier results for the carbon steel sample than the aluminium sample (ten versus five, respectively). These tensile proficiency testing programs can greatly help the participants with outlier results to identify deficiencies that may be present in their methodologies and address them. This will help in improving the overall technical competency and proficiency of the participants.

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All the participating laboratories that reported results that have an absolute z-score of more than 2.0 are highly encouraged to use these proficiency testing programs to evaluate their testing methods, loading conditions, preparation procedures, equipment management and training details. It is expected of each participant to analyse their own proficiency testing results and evaluate any trends.

7. REFERENCES

1. Guide to Proficiency Testing Australia (2019). (This document is located on the PTA website at www.pta.asn.au under Programs / Documents).

2. ISO/IEC 17043: 2010 Conformity assessment – General requirements for proficiency testing.

3. AS 1391 (2007) – Metallic materials – Tensile testing at ambient

temperature.

4. ISO 6892-1 (2016) – Metallic materials – Tensile testing – Part 1: Method of test at room temperature.

5. ISO 2566-1 (1984) – Steel – Conversion of elongation values – Part 1:

Carbon and low alloy steels.

6. ASTM B557M – Standard Test Methods for Tension Testing Wrought and Cast Aluminum and Magnesium-Alloy Products (Metric).

7. JIS Z 2241 (2011) – Metallic materials – Tensile testing – Method of test at room temperature. .

.

APPENDIX A

Summary of Results

Section A1

0.2% Proof Stress

A1.1

0.2% Proof Stress (non-proportional elongation) (Rp0.2) (MPa) – Results and Z-Scores

Lab Code Sample 1 Sample 2

Result MU (±) Z-Score Result MU (±) Z-Score

1 702 - 4.17 § 230 - 1.69

2 593 - -0.06 - - -

4 577 17.3 -0.68 201 19.2 0.18

5 596 7 0.06 - - -

6 625 5% 1.18 210 5% 0.65

7 652 4 2.23 196 3 -0.08

8 602.86 - 0.32 176.05 - -1.11

9 578 4.5 -0.64 176 4 -1.12

11 562 8 -1.26 107 8 -4.70 §

12 586 6 -0.33 198 6 0.03

13 690 - 3.71 § 189 - -0.44

14 605 - 0.41 172 - -1.32

15 596 - 0.06 - - -

16 - - - 209 1 0.60

17A 588 3% -0.25 197 3% -0.03

17B 700 3% 4.10 § - - -

18 698 10 4.02 § 199 3 0.08

19 585 2% -0.37 193 2% -0.23

20A 589 6 -0.21 179 2 -0.96

20B 588 6 -0.25 203 2 0.29

21 597 - 0.10 256 - 3.04 §

22 528 - -2.58 172 - -1.32

23 - - - 208 13 0.55

24 571 5 -0.91 201 2 0.18

Summary Statistics

Statistic Sample 1 Sample 2


Median 594.5 197.5



Robust CV 4.3% 9.8%

Minimum 528 107

Maximum 702 256

Range 174 149

A1.2

Notes:

1. § denotes an outlier (i.e. |z-score| ≥ 3.0). 2. Laboratory code 5 could not report a result for 0.2% Proof Stress for Sample 2

because their extensometer failed. 3. The samples for laboratory code 12 were machined by another laboratory.

22

11 2

4

4

9 19 12

17A

20B

20A

2

5 15 21 8 1

4

6

7

13

18

17B

1

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

0.2% Proof Stress (non-proportional elongation) (Rp0.2) - Sample 1

11

14

22

9 8

20A

13 1

9 7

17A

12

18 4 24 20B 23 16 6

1

21

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

0.2% Proof Stress (non-proportional elongation) (Rp0.2) - Sample 2

Section A2

Lower Yield

A2.1

Lower Yield (ReL) (MPa) – Results


Result MU (±) Result MU (±)

1 700 - 230 -

4 578 17.3 224 19.2

18 722 11 205 3

21 573 - 230 -

22 528 - 171 -

Notes:

1. There was an insufficient number of results submitted for Lower Yield to

calculate summary statistics or z-scores.

Section A3

Upper Yield

A3.1

Upper Yield (ReH) (MPa) – Results



1 702 - 230 -

18 727 11 207 3

21 577 - 237 -

22 528 - 172 -

Notes:

1. There was an insufficient number of results submitted for Upper Yield to

calculate summary statistics or z-scores.

Section A4

Tensile Strength

A4.1

Tensile Strength (Rm) (MPa) – Results and Z-Scores


Result MU (±) Z-Score Result MU (±) Z-Score

1 743 - 9.53 § 235 - 0.51

2 630 - 0.00 - - -

4 622 17.3 -0.67 252 19.2 1.94

5 633 7 0.25 229 3 0.00

6 655 5% 2.11 235 5% 0.51

7 - - - 225 2 -0.34

8 639.92 - 0.84 208.87 - -1.70

9 618 5 -1.01 210 5 -1.60

11 640 0.14 0.84 258 0.14 2.45

12 627 6 -0.25 229 6 0.00

13 734 - 8.77 § 218 - -0.93

14 628 - -0.17 203 - -2.19

15 631 - 0.08 - - -

16 - - - 236 1 0.59

17A 623 2% -0.59 227 2% -0.17

17B 740 2% 9.27 § 232 2% 0.25

18 741 8 9.36 § 226 3 -0.25

19 618 2% -1.01 222 2% -0.59

20A 630 6 0.00 211 2 -1.52

20B 639 6 0.76 234 2 0.42

21 624 - -0.51 264 - 2.95

22 626 - -0.34 202 - -2.28

23 - - - 236 13 0.59

24 621 5 -0.76 232 2 0.25

Summary Statistics



Median 630.0 229.0



Robust CV 1.9% 5.2%

Minimum 618 202

Maximum 743 264

Range 125 62

A4.2

Notes:

1. § denotes an outlier (i.e. |z-score| ≥ 3.0). 2. Laboratory code 7 machined Sample 1 at full section. The sample failed within

the jaws and so the Tensile Strength could not be reported for Sample 1. 3. The samples for laboratory code 12 were machined by another laboratory.

9

19 2

4 4

17A

21 2

2 12 14

2 20A

15 5

20B

8 11

6

13

17B

18

1

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

Tensile Strength (Rm) - Sample 1

22 14

8 9

20A

13

19

7

18

17A

5 12 17B

24 2

0B

1 6 16

23

4

11

21

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

Tensile Strength (Rm) - Sample 2

Section A5


A5.1

Percentage Elongation after Fracture (A%) – Results and Proportional Gauge Length (PGL) Results


Result MU (±) PGL Result Result MU (±)

1 12 - 13 * -

2 14 - 14 - -

4 15 0.47 15 9 0.73

5 15.72 1 16 15.12 1

6 13 5% 13 12 5%

7 - - - 13 1

8 13.80 - 14 11.04 -

9 14 1 14 14 1

11 18.0 1 18 13.8 1

12 11 0.02 12 12 0.02

13 13.1 - 13 12.2 -

14 20 - 18 18 -

15 17 - 17 - -

16 - - - 12 1

17A 14 2% 14 13 2%

17B 11.7 2% 12 13.1 2%

18 12 1 12 14 1

19 15 2% 15 13 2%

20A 6* 1 - 25 1

20B 6* 1 - 25 1

21 15.4 - 18 13.4 -

22 14 - 15 * -

23 - - - 12 1

24 16 0.03 16 13 0.03 Notes:

1. To analyse the Percentage Elongation after Fracture results for Sample 1, the

results submitted by participants were converted to a proportional gauge length (PGL) using the following formula:

2. To analyse the Percentage Elongation after Fracture results for Sample 2, the participants were provided with instructions on how to machine the sample (see Appendix C).

0.4

2

.

Result Tensile Specimen Gauge LengthPGL Result =

2 Tensile Specimen Diameter

2

A5.2

Percentage Elongation after Fracture (A%) – Results, Proportional Gauge Length (PGL) Results and Z-Scores


PGL Result Z-Score Result Z-Score

1 13 -0.83 * -

2 14 -0.12 - -

4 15 0.38 9 -2.70

5 16 0.71 15.12 1.43

6 13 -0.54 12 -0.67

7 - - 13 0.00

8 14 -0.22 11.04 -1.32

9 14 -0.13 14 0.67

11 18 1.86 13.8 0.54

12 12 -1.00 12 -0.67

13 13 -0.57 12.2 -0.54

14 18 1.93 18 3.37 §

15 17 1.37 - -

16 - - 12 -0.67

17A 14 0.00 13 0.00

17B 12 -1.19 13.1 0.07

18 12 -1.14 14 0.67

19 15 0.26 13 0.00

20A - - 25 8.09 §

20B - - 25 8.09 §

21 18 1.87 13.4 0.27

22 15 0.24 * -

23 - - 12 -0.67

24 16 0.87 13 0.00

Summary Statistics



Median 14.2 13.0



Robust CV 14.1% 11.4%

Minimum 12 9

Maximum 18 25

Range 6 16

A5.3

Notes:

1. § denotes an outlier (i.e. |z-score| ≥ 3.0). 2. * The sample failed outside of gauge length. 3. Laboratory code 7 machined Sample 1 at full section. The sample failed within

the jaws and so the Percentage Elongation after Fracture could not be reported for Sample 1.

4. The samples for laboratory code 12 were machined by another laboratory.

17B 18 12

1 13 6

8 9 2

17A 22

19 4

5

24

15

11

21 14

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

Percentage Elongation after Fracture (A%) - Sample 1

4

8

6 12 16

23 1

3

7 17A

19

24 17B 21 1

1 9 18

5

14

20A

20B

-3

-2

-1

0

1

2

3

Ro

bust

Z-S

co

re

Laboratory Code

Percentage Elongation after Fracture (A%) - Sample 2

Section A6


A6.1

Percentage Reduction in Area after Fracture (Z%) – Results and Z-Scores

Lab Code Sample 1

Result MU (±) Z-Score

1 46 - -3.04 §

2 55 - 0.38

4 54 0.91 0.00

5 58 2 1.52

6 55 5% 0.38

7 - - -

8 53.69 - -0.12

9 57 1 1.14

11 55.11 - 0.42

12 53 0.02 -0.38

13 51 - -1.14

14 54 - 0.00

17A 55 2% 0.38

17B 66 2% 4.55 §

18 50 2 -1.52

19 55 2% 0.38

20A 52 3 -0.76

20B 50 3 -1.52

22 56 - 0.76

24 50 0.1 -1.52

Summary Statistics

Statistic Sample 1

Number of Results 19

Median 54.0

Normalised IQR 2.6

Uncertainty (Median) 0.8

Robust CV 4.9%

Minimum 46

Maximum 66

Range 20

A6.2

Notes:

1. § denotes an outlier (i.e. |z-score| ≥ 3.0). 2. Laboratory code 7 machined Sample 1 at full section. The sample failed within

the jaws and so the Percentage Reduction in Area after Fracture could not be reported for Sample 1.

3. The samples for laboratory code 12 were machined by another laboratory. 4. The Percentage Reduction in Area after Fracture was only required to be

reported for Sample 1.

1

18

20B 24

13 2

0A

12

8

4 14

2 6 17A

19 11

22

9

5

17B

-3

-2

-1

0

1

2

3

Robust

Z-S

core

Laboratory Code

Percentage Reduction in Area after Fracture (Z%) - Sample 1

Section A7

Method Information and Other Reported Results

A7.1

Method Information

Lab Code

0.2% Proof Stress Lower Yield Upper Yield

1 ISO 6892-1: 2019 ISO 6892-1: 2019 ISO 6892-1: 2019

2 BS EN ISO 6892-1: 2016 - -

4 BS 6892-1 BS 6892-1 -

5 AS 1391 - -

6 AS 1391 - -

7 AS 1391 - -

8 ISO 6892-1 - -

9 AS 1391 - 2007 (R2017) - -

11 ISO 6892-1: 2016 - -

12 AS 1391: 2007 - -

13 ISO 6892 - -

14 - - -

15 - - -

16 JIS Z 2241: 2011 - -

17A AS 1391 - -

17B AS 1391 - -

18 AS 1391 AS 1391 AS 1391

19 AS 1391 - -

20A AS 1391 - 2007 (R2017) - -

20B AS 1391 - 2007 (R2017) - -

21 ISO 6892-1 ISO 6892-1 ISO 6892-1

22 ISO 6892-1: 2019 ISO 6892-1: 2019 ISO 6892-1: 2019

23 ASTM B557M - -

24 ISO 6892-1 (2016) - -

Note: Method information for Lower Yield and Upper Yield has only been reported for those laboratories that determined values for these tests.

A7.2

Method Information

Lab Code

Tensile Strength Percentage Elongation

after Fracture Percentage Reduction in

Area after Fracture

1 ISO 6892-1: 2019 ISO 6892-1: 2019 ISO 6892-1: 2019

2 BS EN ISO 6892-1: 2016 BS EN ISO 6892-1: 2016 BS EN ISO 6892-1: 2016

4 BS 6892-1 BS 6892-1 BS 6892-1

5 AS 1391 AS 1391 AS 1391

6 AS 1391 AS 1391 AS 1391

7 AS 1391 AS 1391 -

8 ISO 6892-1 ISO 6892-1 ISO 6892-1

9 AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017)

11 ISO 6892-1: 2016 ISO 6892-1: 2016 ISO 6892-1: 2016

12 AS 1391: 2007 AS 1391: 2007 AS 1391: 2007

13 ISO 6892 ISO 6892 ISO 6892

14 - - -

15 - - -

16 JIS Z 2241: 2011 JIS Z 2241: 2011 -

17A AS 1391 AS 1391 AS 1391

17B AS 1391 AS 1391 AS 1391

18 AS 1391 AS 1391 AS 1391

19 AS 1391 AS 1391 AS 1391

20A AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017)

20B AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017) AS 1391 - 2007 (R2017)

21 ISO 6892-1 ISO 6892-1 -

22 ISO 6892-1: 2019 ISO 6892-1: 2019 ISO 6892-1: 2019

23 ASTM B557M ASTM B557M -

24 ISO 6892-1 (2016) ISO 6892-1 (2016) ISO 6892-1 (2016)

A7.3

Tensile Specimen Gauge Diameter and Tensile Specimen Gauge Thickness

Lab Code

Tensile Specimen Gauge Diameter (mm) Tensile Specimen Gauge Thickness (mm)

Sample 1 Sample 2


1 14.01 - 6.00 -

2 13.96 - - -

4 19.94 0.04 5.90 0.02

5 13.87 0.01 5 0.5

6 9.70 5% 5.8 5%

7 19.95 0.02 6.00 0.02

8 19.97 - 6.01 -

9 10.01 0.1 5.96 0.1

11 20.02 0.01 5.97 0.01

12 7.65 0.01 6.0 0.01

13 9.98 - 6.02 -

14 12.80 - 6.01 -

15 20.00 - - -

16 - - 6.01 0.05

17A 12.43 1% 6.00 1%

17B 12.54 1% 6.00 1%

18 10.06 0.01 5.99 0.01

19 12.47 1% 6.02 1%

20A 10.00 0.05 6.00 0.03

20B 10.00 0.03 6.00 0.03

21 20 - 6 -

22 14.07 - 5.96 -

23 - - 6.01 0.02

24 14.00 0.03 6.04 0.01

A7.4

Tensile Specimen Gauge Width and Tensile Specimen Gauge Length

Lab Code

Tensile Specimen Gauge Width (mm)

Tensile Specimen Gauge Length (mm)

Sample 2 Sample 1 Sample 2

Result MU (±) Result MU (±) Result MU (±)

1 20.59 - 79 - 86 -

2 - - 70 - - -

4 20.24 0.01 100 - 80 -

5 20 0.5 69 0.5 80 0.5

6 20 5% 50 5% 80 5%

7 20.00 0.04 100 1% 80 1%

8 19.39 - 99.97 - 80.05 -

9 20.0 0.1 50 0.1 80 0.1

11 20.53 0.01 100.0 0.6 80.0 0.6

12 8.1 0.01 50 0.01 50 0.01

13 19.93 - 50 - 80 -

14 25 - 50 - 69 -

15 - - 100 - - -

16 20.05 0.05 - - 80 1

17A 20.1 1% 65 1% 80 1%

17B 20.10 1% 65 1% 80 1%

18 12.53 0.01 50 1 50 1

19 19.94 1% 60 1% 75 1%

20A 20.00 0.02 50 1 80 1

20B 20.00 0.02 50 1 80 1

21 40 - 148 - 106 -

22 20.53 - 80 - 81 -

23 19.98 0.02 - - 80 0.02

24 20.05 0.04 70 0.7 80 0.8

A7.5

Elastic Stress or Strain Rate (number / sec)

Lab Code

Sample 1 Sample 2


1 6 MPa s-1 - - -

2 0.00025 (Method A) - - -

4 6 MPa s-1 - 6 MPa s-1 -

5 0.00006207 - - -

6 - - - -

7 30.0 MPa 0.2 MPa 15.0 MPa 0.1 MPa

8 10 MPa / sec - 3 mm / min -

9 0.00025 - 0.00025 -

11 - - - -

12 12 MPa / sec - 12 MPa / sec -

13 - - - -

14 - - - -

15 - - - -

16 - - 0.025 -

17A 0.00032 - 0.000359 -

17B 0.00032 - - -

18 - - - -

19 0.0025 2% 0.0025 2%

20A 12 MPa / s 1 12 MPa / s 1

20B 12 MPa / s 1 12 MPa / s 1

21 - - - -

22 6 MPa s-1 - - -

23 - - 10 MPa / sec -

24 0.0016 - 0.0016 -

A7.6

Plastic Strain Rate (number / sec)

Lab Code

Sample 1 Sample 2


1 0.005 - - -

2 0.0067 (Method A) - - -

4 6 MPa s-1 - 6 MPa s-1 -

5 0.0006000 - - -

6 - - - -

7 0.0067 0.0002 0.0067 0.0002

8 10 MPa / sec - 3 mm / min -

9 0.008 - 0.008 -

11 - - - -

12 0.004 - 0.004 -

13 - - - -

14 - - - -

15 - - - -

16 - - 0.173 -

17A 0.00362 - 0.00319 -

17B 0.00362 - - -

18 - - - -

19 0.0025 2% 0.0025 2%

20A - - - -

20B - - - -

21 - - - -

22 0.005 - - -

23 - - 0.5% / sec -

24 - - - -

APPENDIX B

Homogeneity

Testing

B1.1

HOMOGENEITY TESTING Before the test pieces were distributed to participants, eight specimens from each sample were selected at random and tested by ARL Laboratory Services Pty Ltd. This was done to assess the variability of the samples to be used in the program. The results of this testing appear in the following tables.

Homogeneity Testing Results

Sample 1 – Steel Round Bar Sample

Sample Number

Cross-sectional

Area (mm2)

Tensile Strength (MPa)

0.2% Proof Stress (MPa)

Gauge Length (mm)

Elongation After

Fracture (%)

Reduction in Area after

Fracture (%)

1-2 72.38 645 620 50 14 57

1-9 72.38 650 625 50 14 56

1-11 76.98 675 640 50 13 54

1-13 75.43 645 620 50 14 57

1-24 75.43 650 625 50 14 57

1-26 76.98 645 625 50 14 54

1-35 75.43 645 630 50 13 56

1-39 75.90 650 630 50 13 55

Homogeneity Testing Results

Sample 2 – Aluminium Flat Bar Sample

Sample Number

Cross-sectional

Area (mm2)

Tensile Strength (MPa)

0.2% Proof Stress (MPa)

Gauge Length (mm)

Elongation After

Fracture (%)

2-2 120 240 210 80 11

2-10 119 235 210 80 11

2-12 119 230 205 80 11

2-20 119 230 200 80 11

2-25 121 250 220 80 11

2-27 119 225 200 80 10

2-31 120 245 220 80 11

2-40 120 225 200 80 12

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

APPENDIX C

Instructions to Participants

and

Results Sheet

C1.1

Tensile Testing of Metals, Round 13 March 2020 Page 1 of 4

PROFICIENCY TESTING AUSTRALIA

Tensile Testing Of Metals Proficiency Testing Program

Round 13, March 2020

Instructions To Participants

To ensure that the results of this program can be analysed correctly, participants are asked to note carefully: 1) The samples for this tensile testing program comprise of a carbon steel round

bar, labelled 1-x for Sample 1, and an aluminium flat bar, labelled 2-x for Sample 2.

2) The tests to be performed in this program are:

0.2% Proof Stress (non-proportional elongation) (Rp0.2), if applicable;

Lower Yield Strength (ReL), if applicable;

Upper Yield Strength (ReH), if applicable;

Tensile Strength (Rm);

Percentage Elongation after Fracture (A%); and

Percentage Reduction in Area after Fracture (Z%), if applicable.

3) Tests may commence as soon as samples are received. The carbon steel sample (Sample 1) is to be treated in the same manner as your routinely tested samples. For the aluminium sample (Sample 2), a Tensile Specimen Gauge Length of 80 mm, Tensile Specimen Gauge Width of 20 mm, Parallel Length of 90 mm and Minimum Radius of Transition of 20 mm must be used (please see the diagram on page 3 of these Instructions).

4) All testing, recording and reporting is to be performed in accordance with your routine test methods, but testing in accordance with AS 1391 – Metallic materials – Tensile testing at ambient temperature (2007) or ISO 6892-1 – Metallic materials – Tensile testing – Part 1: Method of test at room temperature (2016) are the preferred test methods.

5) Report only one result per sample, based on the determination for each

property. For each determination, results are to be reported to the accuracy and in the units indicated on the Results Sheet.

6) The method of testing used should also be reported on the Results Sheet (e.g.

AS 1391, ISO 6892-1, etc.)

C1.2


7) The Percentage Elongation after Fracture (A%) results will be converted to a proportional gauge length before analysis for Sample 1. Participants should therefore report the Tensile Specimen Gauge Diameter and Tensile Specimen Gauge Length for this sample on the Results Sheet. For Sample 2, please report the Tensile Specimen Gauge Width, Tensile Specimen Thickness and Tensile Specimen Gauge Length used on the Results Sheet.

8) Participants are also requested to calculate and report an estimate of

uncertainty of measurement for each reported measurement result. All estimates of uncertainty of measurement must be given as a 95% confidence

interval (coverage factor k 2). 9) 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, ensuring the confidentiality of your results.

10) Return the Results Sheet, either by mail, email or facsimile, to: All results should arrive at the above address by no later than Wednesday 20

May 2020. Results reported later than this date may not be analysed in the final report.

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 Email: [email protected]

C1.3



Tensile Testing Of Metals Proficiency Testing Program Round 13, March 2020

Aluminium Sample Tensile Sizing

C2.1



Tensile Testing Of Metals Proficiency Testing Program

Round 13, March 2020

RESULTS SHEET

Laboratory Code:

Test Report

results to nearest

Sample 1 Sample 2 Method


0.2% Proof Stress (non-proportional elongation) (Rp0.2)

1 MPa

Lower Yield Strength (ReL) 1 MPa

Upper Yield Strength (ReH) 1 MPa

Tensile Strength (Rm) 1 MPa

Percentage Elongation after Fracture (A%)

1%

Percentage Reduction in Area after Fracture (Z%)

1%

Where possible, please also report the values for the following:

Test Report

results to nearest

Sample 1 Sample 2


Tensile Specimen Gauge Diameter 0.01 mm

Tensile Specimen Thickness 0.01 mm

Tensile Specimen Gauge Width 0.01 mm

Tensile Specimen Gauge Length 1 mm

Elastic Stress or Strain Rate number / sec

Plastic Strain Rate number / sec

All estimates of measurement uncertainty (MU) must be given as a 95% confidence

interval (coverage factor k 2). Print Name: _____________________ Signature & Date: ____________________

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