tensile testing of metals proficiency testing program · discussion of the final report, ......

y

REPORT NO. 558

Tensile Testing of Metals

Proficiency Testing Program

November 2007

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.

© COPYRIGHT PROFICIENCY TESTING AUSTRALIA 2007

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 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 9 APPENDICES

APPENDIX A

Summary of Results

Thickness A1

0.2% Proof Strength A2

Upper Yield Strength A3

Lower Yield Strength A4

Tensile Strength A5

Percentage Elongation After Fracture A6

Other Reported Results A7

APPENDIX B

Homogeneity Testing B1

APPENDIX C

Instructions to Participants C1

Results Sheet C2

-1-

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

properties of metals. Proficiency Testing Australia conducted the testing program in September and

October 2007. 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 16 laboratories participated in the program, 3 of which did not return

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

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

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.

(c) Laboratories were provided with four steel strip samples and were asked to perform tests for:

• thickness; • 0.2% proof stress (non-proportional elongation) (Rp0.2); • upper yield (ReH); • lower yield (ReL); • tensile strength (Rm); and • percentage elongation after fracture (A%). Laboratories were required to perform all tests for which they hold NATA accreditation and were invited to report results for any of the other tests.

(d) All testing, recording and reporting was to be performed in accordance with

AS1391 – Metallic materials – Tensile testing at ambient temperature (2005).

-2-

(e) 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.

(f) Ten randomly selected specimens from each of the four samples were tested

and analysed for homogeneity by BlueScope Steel Limited. 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 7 sections (A1-A7).

Sections A1-A6 contain the analysis of results reported by laboratories for thickness, 0.2% proof stress (non-proportional elongation) (Rp0.2), upper yield (ReH), lower yield (ReL), tensile strength (Rm) and percentage elongation after fracture (A%). These sections contain: 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; iii) ordered z-score charts.

Section A7 contains the results reported by laboratories for tensile specimen 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. 4. DESIGN OF THE PROGRAM

The samples for this program comprised of three cold rolled steel strip samples and one hot rolled pickled strip sample. Samples 1 and 3 were continuous yielding steel grades, while samples 2 and 4 were discontinuous yielding steel grades. All four samples differed for thickness, 0.2% proof strength, upper yield strength, lower yield strength, tensile strength and percentage elongation after fracture.

-3-

5. EXTREME RESULTS

Robust z-scores have been used to assess each laboratory’s testing performance. When calculated from single results, 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 (2006).

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

Table A: Summary Statistics for All Tests

Test Summary Statistics Sample 1 Sample 2 Sample 3 Sample 4

No. of Results 13 12 12 13

Median 1.4100 0.8775 0.8065 2.1540 Thickness

(mm) Normalised IQR 0.0030 0.0085 0.0039 0.0059

No. of Results 12 10

Median 272.0 141.0 0.2% proof stress (non- proportional elongation)

(Rp0.2) (MPa) Normalised IQR 4.3 3.3

No. of Results 11 11

Median 325.0 239.0 Upper yield

(ReH) (MPa)

Normalised IQR 13.2 13.0

No. of Results 9 10

Median 305.0 218.5 Lower yield

(ReL) (MPa)

Normalised IQR 5.2 9.3


Median 404.0 375.0 302.8 337.0 Tensile strength

(Rm) (MPa)

Normalised IQR 5.9 7.7 5.4 4.6


Median 48.0 55.0 71.0 53.0 Percentage elongation

after fracture (A%) Normalised IQR 3.7 3.0 5.2 6.7

-4-

Note: Summary statistics for percentage elongation after fracture were calculated by converting the results to the proportional gauge length 5.65√So.

Table B: Summary of Statistical Outliers

Test Sample 1 Sample 2 Sample 3 Sample 4

Thickness 1, 10, 13, 18 4, 18 10, 13, 18 10, 18

0.2% proof strength 2 -

Upper yield strength 2 4

Lower yield strength 2, 8, 18 -

Tensile strength 10 2 2, 8, 10 2, 13

Percentage elongation after fracture 1 2 - -

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

Thirteen of the 16 laboratories (81%) that participated in the program returned results. Of the 13 laboratories that submitted results for the program, the return rate for all tests is as follows:

• Thickness 13 out of 13 100% • 0.2% proof strength 12 out of 13 92% • Upper yield strength 12 out of 13 92% • Lower yield strength 10 out of 13 77% • Tensile strength 13 out of 13 100% • Percentage elongation after fracture 13 out of 13 100%

-5-

6.2 Performance summary

One or more statistical outliers were reported by 7 of the 13 laboratories (54%) that returned results for this program. A total of 213 results were analysed in this program. Of these results, 26 (12%) were outlier results.

6.3 Thickness

Five laboratories reported outliers for thickness. This was very disappointing, as an accurate thickness measurement is essential for the accurate determination of the proof, upper yield, lower yield and tensile strength properties. Laboratory 18 reported outliers for all 4 samples. There was no obvious reason for these thickness measurement errors, as there was no pattern to the error percent or to the absolute value of the error. It was also noted that the thickness measurements performed by this laboratory and laboratories 1 and 10 were made to only two decimal places. For accurate determination of tensile properties on material less than 1.5 mm thick, it is essential to measure thickness accurately to the third decimal place. Laboratory 10 reported outliers for samples 1, 3 and 4 and also obtained an |z| score > 2 for sample 2. For this laboratory, the outliers for thickness measurement on samples 1 and 3 have led to corresponding outliers for the reported tensile strength on the same samples. Laboratory 13 reported outliers for samples 1 and 3. Laboratory 1 reported an outlier for sample 1 and also obtained an |z| score > 2 for sample 4. Laboratory 4 reported an outlier for sample 2. It appears that this laboratory measured the coated thickness instead of the base metal thickness as per the instructions. This laboratory also obtained an |z| score > 2 for sample 3. In addition, |z| scores > 2 were also obtained by laboratory 14 (for sample 2) and laboratory 8 (for sample 4). All laboratories, particularly those with outlier results, are reminded that they must check their micrometers with a standard block each day before use.

-6-

6.4 0.2% Proof Strength

The range in proof strength values reported by the participating laboratories was larger than expected. This is believed to be due, in part, to the differences in the stress and strain rates employed. These rates ranged from 0.000016/sec to 0.0025/sec for the elastic rates and 0.00014/sec to 0.008/sec for the plastic rates. (It was assumed that rates expressed as 85, 120 and 250/sec were to a power of 10 to the minus 6. i.e. 250 x 10-6/ sec or 0.00025/sec). Only one laboratory reported an outlier for 0.2% proof strength. Laboratory 2 reported an outlier for sample 1. In addition, laboratory 14 obtained an |z| score > 2 for sample 1. There were no outliers reported for sample 3, although laboratories 5 and 18 obtained |z| scores > 2 for this sample. One result, reported by laboratory 8 for sample 3, was not analysed because the laboratory indicated this result was uncertain, as the sample was bending with the extensometer attached. Laboratory 18 quoted all of the strength properties to the second decimal place despite the instruction to report the values to the nearest whole number. Given that the uncertainty in the result is in the order of 2 to 2.5%, reporting strength properties to the second decimal place suggests an accuracy that is approximately 1000 times better than the uncertainty of the result.

6.5 Upper Yield Strength

The wide range in the reported upper yield strengths, for samples 2 and 4, was to be expected. Upper yield strength measurements are very sensitive to sample preparation, alignment of the specimen in the tensile machine, straining rate and machine stiffness. It is therefore pleasing to see that only two laboratories reported outliers for upper yield strength. Laboratory 2 reported an outlier for sample 2 and laboratory 4 reported an outlier for sample 4. In addition, laboratory 13 obtained an |z| score > 2 for sample 2. Laboratory 14 could not determine a result for sample 4 because the test equipment for this laboratory did not show sufficient resolution to determine an upper yield for this sample.

-7-

6.6 Lower Yield Strength

The range in lower yield strength values reported by the participating laboratories was smaller than it was for upper yield strength (62 MPa versus 91 MPa.) This was to be expected, as the lower yield strength is less sensitive to the conditions that affect the measurement of the upper yield strength. Three laboratories reported outliers for lower yield strength. Laboratories 2, 8 and 18 reported outliers for sample 2. There were no outliers reported for sample 4, although laboratory 8 obtained an |z| score > 2 for this sample.

6.7 Tensile Strength

It was disappointing to see four laboratories report outliers for tensile strength. Tensile strength is the easiest of the strength properties to measure, as it is the least sensitive to sample preparation, alignment, machine stiffness and strain rate (0.008/sec max). With the exception of laboratory 10 and, to a lesser extent, laboratories 2, 4 and 13, there was good agreement on the tensile strengths reported for sample 1. The results for laboratory 10 were out due to a thickness measurement error. Adjusting for this error, the result for laboratory 10 becomes 399 MPa, which falls well within one normalised IQR of the group median. Laboratory 2 reported the only outlier on sample 2, but the value reported by laboratory 4 (z-score -2.74) and laboratory 8 were also significantly different from the group median, having |z| scores > 2. There was otherwise good agreement between laboratories on this sample. Three laboratories (2, 8 and 10) reported outliers for tensile strength on sample 3. There is no obvious reason for the outliers reported by laboratories 2 and 8, but the outlier for laboratory 10 is due to a thickness measurement error. The value reported by laboratory 13 on this sample was also significantly different to the median, having an |z| score > 2. Two laboratories (2 and 13) reported outliers on sample 4 and four other laboratories (3, 5, 10 and 14) reported tensile strengths that differed significantly from the group median. It has been noted that all of the proof, upper and lower yield strength values reported by laboratory 2 were lower than the median, while all of the tensile strength values were significantly higher than the median. Some investigative work is needed to determine the cause of this anomaly.

-8-

6.8 Percentage Elongation After Fracture

Three laboratories (4, 9 and 14) employed a 12.5 mm wide specimen with a 50 mm gauge length for their tensile testing in this program, while the other laboratories all used a 20 mm wide specimen with a 80 mm gauge length. In order to be able to compare the results for percentage elongation after fracture, all of the results were converted to a proportional gauge length of 5.65 √So (5.65 times the square root of the cross-sectional area). The conversion factors in International Standard ISO 2566/1 were used for this purpose. These conversion factors are as follows: • For sample 1, divide the 50 mm gauge length results by 0.76 and divide the

80 mm gauge length results by 0.68. • For sample 2, divide the 50 mm gauge length results by 0.66 and divide the



80 mm gauge length results by 0.74.

The results, converted to a proportional gauge length, are displayed in Appendix A6. Only two laboratories reported outliers for percentage elongation after fracture. Laboratory 1 reported an elongation of 63% for sample 1. This is almost double the value reported by the other laboratories and was probably due to a gross error in the measurement of the final gauge length, as the same laboratory reported a value that was close to the median on sample 4. Errors such as this should have been detected when the report was checked and / or authorised. Laboratory 2 reported an outlier for sample 2. In addition, laboratory 9 obtained an |z| score > 2 for sample 2. There were no outliers reported for sample 3 or sample 4.

6.9 Other Reported Results

In addition to reporting results for thickness, 0.2% proof stress, upper yield, lower yield, tensile strength and percentage elongation after fracture, participants were also asked to report the tensile specimen width, gauge length, elastic stress or strain rate and plastic strain rate. The details reported by each of the laboratories are displayed in Appendix A7.

-9-

The information reported is limited, but it was requested in the hope that it would assist in the analysis of the results. In some instances, it was possible to explain the variation in reported properties using this data. In other instances, there was no obvious reason. It is the responsibility of the participating laboratories that reported outliers to review their procedures, determine the cause of the non-conformance and take effective corrective action.

7. REFERENCES

Guide to Proficiency Testing Australia (2006). This document is located on the PTA website at www.pta.asn.au, under “Documents”.

APPENDIX A

Summary of Results

Section A1

Thickness

A1.1

Thickness (mm) – Results and Z-Scores

Sample 1 Sample 2 Sample 3 Sample 4 Lab Code Result Z-Score Result Z-Score Result Z-Score Result Z-Score

1 1.42 3.37 § - - - - 2.17 2.70 2 1.412 0.67 0.876 -0.18 0.806 -0.13 2.160 1.01 3 1.408 -0.67 0.879 0.18 0.807 0.13 2.157 0.51 4 1.411 0.34 0.918 4.75 § 0.818 2.95 2.160 1.01 5 1.411 0.34 0.879 0.18 0.807 0.13 2.154 0.00 8 1.410 0.00 0.870 -0.88 0.800 -1.67 2.140 -2.36 9 1.410 0.00 0.874 -0.41 0.807 0.13 2.153 -0.17 10 1.50 30.35 § 0.90 2.64 0.94 34.30 § 2.18 4.38 § 13 1.424 4.72 § 0.864 -1.58 0.820 3.47 § 2.157 0.51 14 1.408 -0.67 0.898 2.40 0.803 -0.90 2.152 -0.34 15 1.410 0.00 0.880 0.29 0.805 -0.39 2.150 -0.67 17 1.405 -1.69 0.876 -0.18 0.805 -0.39 2.154 0.00 18 1.40 -3.37 § 0.85 -3.23 § 0.78 -6.81 § 2.10 -9.11 §

Summary Statistics

Statistic Sample 1 Sample 2 Sample 3 Sample 4

No of Results 13 12 12 13 Median 1.4100 0.8775 0.8065 2.1540 Norm IQR 0.0030 0.0085 0.0039 0.0059 Robust CV 0.21% 0.97% 0.48% 0.28% Minimum 1.400 0.850 0.780 2.100 Maximum 1.500 0.918 0.940 2.180 Range 0.100 0.068 0.160 0.080

Notes:

1. § denotes an outlier (i.e. |z-score| > 3).

2. Laboratory 1 did not test samples 2 and 3, as they were below the minimum

thickness tested by the laboratory.

A1.2

Thickness - Sample 1

3 14

8 9 15

4 5

2

1 13 10

18

17

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


8

9

2 17

3 5 15

14

10

4

13

18

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

A1.3


14

15 17

2

3 5 9

4 13 10

18

8

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


15

14

9

5 17

3 13

2 4

1

10

18

8

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A2

0.2% Proof Strength

A2.1

0.2% proof stress (non-proportional elongation) (R p0.2) (MPa) – Results and Z-Scores

Sample 1 Sample 3 Lab Code Result Z-Score Result Z-Score

1 272 0.00 - - 2 247 -5.77 § 139 -0.60 3 272 0.00 141 0.00 4 266 -1.39 146 1.50 5 269 -0.69 131 -3.00 8 275 0.69 177* - 9 271 -0.23 141 0.00 13 272 0.00 144 0.90 14 282 2.31 141 0.00 15 280 1.85 137 -1.20 17 276 0.92 144 0.90 18 277.37 1.24 150.03 2.71

Summary Statistics

Statistic Sample 1 Sample 3

No of Results 12 10 Median 272.0 141.0 Norm IQR 4.3 3.3 Robust CV 1.59% 2.37% Minimum 247 131 Maximum 282 150 Range 35 19

Notes:


2. Laboratory 1 did not test sample 3, as it was below the minimum thickness tested

by the laboratory.

3. The result for sample 3 for laboratory 8 is uncertain because the sample was bending with the extensometer attached.

A2.2

0.2% proof stress (non-proportional elongation) (Rp0.2) - Sample 1

4

5

9

3 13

8

17

18

15

14

1

2-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

0.2% proof stress (non-proportional elongation) (Rp0.2) -Sample 3

14

13 17

4

18

9

2

3

5

15

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A3

Upper Yield Strength

A3.1

Upper yield (ReH) (MPa) – Results and Z-Scores


1 - - 239 0.00 2 270 -4.18 § 225 -1.08 3 338 0.99 227 -0.93 4 325 0.00 285 3.55 § 5 326 0.08 232 -0.54 8 315 -0.76 250 0.85 9 319 -0.46 231 -0.62 13 361 2.73 256 1.31 14 306 -1.44 ND - 15 324 -0.08 248 0.69 17 335 0.76 238 -0.08 18 334.53 0.72 246.55 0.58

Summary Statistics



Notes:



by the laboratory. 3. ND denotes not determined. The test equipment for laboratory 14 did not show

sufficient resolution to determine an upper yield for sample 4.

A3.2

Upper yield (ReH) - Sample 2

14

8

9

4 5

18

3

13

17

15

2-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Upper yield (ReH) - Sample 4

17

1

18 15

13

4

8

9 5

2 3

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A4

Lower Yield Strength

A4.1

Lower yield (ReL) (MPa) – Results and Z-Scores


1 - - 228 1.03 2 261 -8.48 § 218 -0.05 3 300 -0.96 218 -0.05 5 306 0.19 212 -0.70 8 288 -3.28 § 241 2.43 9 305 0.00 206 -1.35 13 309 0.77 201 -1.89 14 301 -0.77 219 0.05 17 307 0.39 220 0.16 18 322.58 3.39 § 229.63 1.20

Summary Statistics



Notes:



by the laboratory.

A4.2

Lower yield (ReL) - Sample 2

8

3 14

9

5

17

13

18

2-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Lower yield (ReL) - Sample 4

9

5

2 3

14 17

1 18

8

13

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A5

Tensile Strength

A5.1

Tensile strength (R m) (MPa) – Results and Z-Scores

Sample 1 Sample 2 Sample 3 Sample 4 Lab Code Result Z-Score Result Z-Score Result Z-Score Result Z-Score

1 405 0.17 - - - - 337 0.00 2 414 1.69 491 15.16 § 403 18.64 § 372 7.62 § 3 400 -0.68 373 -0.26 298 -0.90 328 -1.96 4 392 -2.03 354 -2.74 297 -1.09 337 0.00 5 404 0.00 374 -0.13 298 -0.90 325 -2.61 8 409 0.85 391 2.09 321 3.38 § 342 1.09 9 404 0.00 374 -0.13 305 0.40 337 0.00 10 375 -4.90 § 371 -0.52 257 -8.53 § 331 -1.31 13 391 -2.20 380 0.65 289 -2.57 322 -3.26 § 14 405 0.17 365 -1.31 303 0.03 331 -1.31 15 403 -0.17 376 0.13 303 0.03 335 -0.44 17 404 0.00 381 0.78 305 0.40 338 0.22 18 397.02 -1.18 388.29 1.74 302.67 -0.03 337.20 0.04

Summary Statistics


No of Results 13 12 12 13 Median 404.0 375.0 302.8 337.0 Norm IQR 5.9 7.7 5.4 4.6 Robust CV 1.46% 2.04% 1.77% 1.36% Minimum 375 354 257 322 Maximum 414 491 403 372 Range 39 137 146 50

Notes:


2. Laboratory 1 did not test samples 2 and 3, as they were below the minimum

thickness tested by the laboratory.

A5.2

Tensile strength (Rm) - Sample 1

18

15

5 9 1 14

8

2

10

13

4

3

17

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


9

15

13

3

10

14

4

5

17

18

8

2

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

A5.3


18 14 15

34

13

10

5

9 17

8 2

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


15

1 4

2

10

3

5

13

14

9 18

17

8

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A6

Percentage Elongation After Fracture

A6.1

Percentage elongation after fracture (A%) – Results and Proportional Gauge Length (PGL) Results

Sample 1 Sample 2 Sample 3 Sample 4 Lab Code Result PGL

Result Result PGL Result Result PGL

Result Result PGL Result

1 63 93 - - - - 43 58 2 32 47 29 46 41 68 35 47 3 35 51 35 56 43 72 40 54 4 34 45 34 52 46 70 38 48 5 35 51 35 56 45 75 45 61 8 33 49 35 56 42 70 42 57 9 35 46 40 61 45 68 38 48 10 31 46 32 51 38 63 39 53 13 35 51 34 54 45 75 43 58 14 35 46 34 52 43 65 42 53 15 36 53 36 57 43 72 42 57 17 32 47 35 56 47 78 39 53 18 32.68 48 33.72 53 45.58 76 34.48 47

Note:

To analyse the percentage elongation after fracture results, the results submitted by participants were converted to a proportional gauge length. The proportional gauge length used was 5.65 times the square root of the cross-sectional area. The International Standard ISO 2566/1 was used for this conversion.

A6.2

Percentage elongation after fracture (A%) – Proportional Gauge Length (PGL) Results and Z-Score s

Sample 1 Sample 2 Sample 3 Sample 4 Lab Code PGL

Result Z-Score PGL Result Z-Score PGL

Result Z-Score PGL Result Z-Score

1 93 12.14 § - - - - 58 0.75 2 47 -0.27 46 -3.04 § 68 -0.58 47 -0.90 3 51 0.81 56 0.34 72 0.19 54 0.15 4 45 -0.81 52 -1.01 70 -0.19 48 -0.75 5 51 0.81 56 0.34 75 0.77 61 1.20 8 49 0.27 56 0.34 70 -0.19 57 0.60 9 46 -0.54 61 2.02 68 -0.58 48 -0.75 10 46 -0.54 51 -1.35 63 -1.54 53 0.00 13 51 0.81 54 -0.34 75 0.77 58 0.75 14 46 -0.54 52 -1.01 65 -1.16 53 0.00 15 53 1.35 57 0.67 72 0.19 57 0.60 17 47 -0.27 56 0.34 78 1.35 53 0.00 18 48 0.00 53 -0.67 76 0.96 47 -0.90

Summary Statistics


No of Results 13 12 12 13 Median 48.0 55.0 71.0 53.0 Norm IQR 3.7 3.0 5.2 6.7 Robust CV 7.72% 5.39% 7.31% 12.59% Minimum 45 46 63 47 Maximum 93 61 78 61 Range 48 15 15 14

Notes:


2. Laboratory 1 did not test samples 2 and 3, as they were below the minimum thickness tested by the laboratory.

A6.3

Percentage elongation after fracture (A%) -Sample 1

2 17

18

8

3 5 13

15

1

4

9 10 14

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


17

15

9

5 83

13

18

144

10

2

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

A6.4


15

13

18

17

10

14

2 9

4 8

3

5

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core


3

15 1 13

5

2 18

4 9

10 14 17

8

-3

-2

-1

0

1

2

3

Laboratory Code

Rob

ust

Z-S

core

Section A7

Other Reported Results

A7.1

Tensile specimen width and tensile specimen gauge l ength

Tensile specimen width (mm) Tensile specimen gauge length (mm) Lab Code Sample 1 Sample 2 Sample 3 Sample 4 Sample 1 Sample 2 Sample 3 Sample 4

1 20.18 - - 20.22 80 - - 80 2 20.33 20.29 20.36 20.30 80 80 80 80 3 20.30 20.34 20.34 20.23 80 80 80 80 4 12.53 12.42 12.53 12.53 50 50 50 50 5 19.98 19.97 19.97 19.97 80.00 80.00 80.00 80.00 8 20.08 20.09 20.08 20.08 80 80 80 80 9 12.49 12.41 12.34 12.60 50 50 50 50

10 20.09 19.75 19.84 20.03 80 80 80 80 13 20.55 20.55 20.55 20.50 80 80 80 80 14 12.81 12.68 12.67 12.83 50 50 50 50 15 20.04 20.04 20.04 20.03 80.0 80.0 80.0 80.0 17 20.00 19.99 20.01 20.01 80 80 80 80 18 19.70 19.70 19.65 19.70 79.89 79.90 79.75 79.45

Elastic stress or strain rate and plastic strain ra te

Elastic stress or strain rate (number / sec)

Plastic strain rate (number / sec) Lab

Code Sample 1 Sample 2 Sample 3 Sample 4 Sample 1 Sample 2 Sample 3 Sample 4

1 250 - - 250 2500 - - 2500 2 0.0025 0.0025 0.0025 0.0025 0.006 0.006 0.006 0.006 3 0.0004 0.0004 0.0004 0.0004 0.003 0.003 0.003 0.003 5 - 0.000037 - 0.000037 0.00014 - 0.00015 - 8 120 120 120 120 - - - -

13 0.0003 0.0003 0.0003 0.0003 0.001 0.001 0.001 0.001 14 0.000016 0.000019 0.000013 0.000011 - - - - 15 85 85 85 85 30 30 30 30 17 50 50 50 50 0.008 0.008 0.008 0.008

A7.2

Notes:

1. Laboratory 1 did not test samples 2 and 3, as they were below the minimum thickness tested by the laboratory.

2. Laboratory 15 reported elastic strain rate as aE / sec and plastic strain rate as

mm / min. 3. The results for laboratory 17 for elastic stress or strain rate are expressed in

MPa / sec.

APPENDIX B

Homogeneity Testing

B1.1

HOMOGENEITY TESTING

Before the test pieces were distributed to participants, ten specimens from each sample were selected at random and tested by BlueScope Steel Limited, Port Kembla. This was done to assess the variability of the four samples to be used in the program. Results for thickness, 0.2% proof stress, tensile strength and percentage elongation after fracture were obtained for samples 1 and 3. Results for thickness, upper yield, lower yield, tensile strength and percentage elongation after fracture were obtained for samples 2 and 4. The results of this testing appear in the following tables.

Homogeneity Testing Results

Sample 1

Sample Number

Thickness (mm)

0.2% proof stress (MPa)

Tensile strength (MPa)

% elongation after fracture

PT101 1.408 272 404 51 PT102 1.408 276 401 54 PT104 1.410 272 403 55 PT115 1.408 279 410 55 PT126 1.406 277 410 49 PT129 1.411 276 408 50 PT131 1.408 273 406 51 PT133 1.402 274 405 52 PT141 1.405 278 408 50 PT142 1.401 279 404 52


Sample 2

Sample Number

Thickness (mm)

Upper yield (MPa)

Lower yield (MPa)



PT204 0.873 331 309 381 60 PT209 0.871 333 310 391 59 PT211 0.874 336 308 386 59 PT212 0.871 335 310 384 60 PT215 0.874 334 309 390 58 PT223 0.873 336 310 391 60 PT226 0.870 338 309 381 64 PT228 0.872 332 311 391 62 PT229 0.875 325 305 389 58 PT241 0.871 340 309 391 59

B1.2


Sample 3

Sample Number

Thickness (mm)

0.2% proof stress (MPa)



PT302 0.810 144 305 73 PT312 0.809 144 304 73 PT317 0.809 140 304 75 PT318 0.808 140 305 78 PT319 0.808 140 305 72 PT320 0.809 139 304 77 PT330 0.811 140 305 75 PT333 0.809 140 305 75 PT335 0.808 141 305 74 PT338 0.810 141 304 72


Sample 4

Sample Number

Thickness (mm)

Upper yield (MPa)

Lower yield (MPa)



PT405 2.154 238 223 333 53 PT410 2.152 244 225 334 53 PT415 2.154 239 222 334 53 PT416 2.157 225 215 333 54 PT427 2.154 240 219 333 56 PT431 2.156 238 219 332 55 PT435 2.154 243 223 338 55 PT436 2.152 250 224 338 52 PT437 2.152 230 216 338 53 PT444 2.153 240 222 337 52

Please note that the percentage elongation after fracture results reported in the tables above have been converted to the proportional gauge length 5.65 √So. 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.

APPENDIX C

Instructions to Participants

and

Results Sheet

C1.1

Tensile Testing of Metals September 2007 Page 1 of 3

PROFICIENCY TESTING AUSTRALIA

Tensile Testing Of Metals Proficiency Testing Progr am

Instructions To Participants - September 2007

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 three cold rolled steel

strip samples and one hot rolled pickled strip sample. They are labeled 1-x, 2-x, 3-x and 4-x. The set of samples includes both continuous (Samples 1-x and 3-x) and discontinuous (2-x and 4-x) yielding steel grades.

The zincalume coat has been removed from one end of sample number 2-x to allow participants to measure and calculate the tensile properties using the base metal thickness.

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

• Thickness; • 0.2% proof stress (non-proportional elongation) (Rp0.2); • Upper yield (ReH); • Lower yield (ReL); • Tensile strength (Rm); and • Percentage elongation after fracture (A%).

3) All of the samples have been aged and the tests may commence as soon as samples are received.

4) All testing, recording and reporting is to be performed in accordance with

AS1391 – Metallic materials – Tensile testing at ambient temperature (2005). 5) Participants are requested to perform all tests listed above for which NATA

accreditation is held. Participants are welcome to report results for any other tests for which NATA accreditation is not held, however, please note this on the Results Sheet.

6) 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.

7) Testing for 0.2% proof stress (non-proportional elongation) is to be performed

on samples 1-x and 3-x only. Testing for upper yield (ReH) and lower yield (ReL) are to be performed on samples 2-x and 4-x.

C1.2


8) 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.

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

All results should arrive at the above address by no later than Monday 8

October 2007 . 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

C2.1


PROFICIENCY TESTING AUSTRALIA

Tensile Testing Of Metals Proficiency Testing Progr am

September 2007

RESULTS SHEET

Laboratory Code:

Results Test

Report results to nearest Sample 1 Sample 2 Sample 3 Sample 4

Thickness 0.001 mm

0.2% proof stress (non-proportional elongation) (Rp0.2)

1 MPa

Upper yield (ReH) 1 MPa

Lower yield (ReL) 1 MPa

Tensile strength (Rm) 1 MPa

Percentage elongation after fracture (A%) 1 %

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

Results Test

Report results to nearest Sample 1 Sample 2 Sample 3 Sample 4

Tensile specimen width 0.01 mm

Tensile specimen gauge length 1 mm

Elastic stress or strain rate number / sec

Plastic strain rate number / sec

Print Name: _____________________ Signature & Date: ____________________