TPT January 2010

A rticle

strength, yield strength and elongation for all specimens in the appropriate places of Table 1. So now we have the recorded results of the two (2) special tests and the three (3) full thickness tests, how are the results of these tests to be evaluated so as to be meaningful and useful? A bronze plaque on the wall of my office reads like this: “One test is worth a thousand experts opinions”. This is true, if you have collaborating data to compare the results of this one test with so that the results of the one test are both meaningful and useful. For the test results data from the two (2) special half thickness specimens and the standard tensile test from the finished pipe ring specimen to be useful we must collect additional data to compare them with. This additional data will be obtained from the incoming material, specimens marked 5E and 6F and specimens marked 1A, 2B and 3C and from the tensile test obtained from the flat skelp in the transverse direction, taken from the same heat, to determine the ultimate strength, yield strength and elongation.

Test specimen as illustrated here are to be machined and tested according with ASTM-A370 procedures. Test rings/specimen are to be marked as following: A, B, C, D, E, F Test specimen marked A and B require additional machining as per figures 3 and 4. All test specimen listed here are to be punched on the flat surface within the reduced width area for measuring and recording the elongation value after fracture. Test specimen 3A to specimen 5C c. Test specimen 3A to specimen 6D d. Compare test results of all three elements of specimens 3A e. and 4B If the test results of specimen 1T exceeds the test results of specimen 3A this indicates the loss of physical properties in the finished product due to the manufacturing process, Bauschinger effect. If, and when, the test results of specimen 3A exceeds the test results of specimen 1T this indicates an increases in the physical properties of the finished product. This increase is due to the manufacturing process. If the test results of specimen 1T exceeds the test results of specimens 4B and 5C it indicates a loss of physical properties in the finished product due to the Bauschinger effect. If the ring expansion test of specimen 6D results exceed the value of the yield strength test results from specimen 3A it indicates the yield loss when the pipe ring specimen is flattened, made straight, so as to machine a standard tensile specimen. The test results from specimen 2L indicates the ability of the individual pipe sections to contain the longitudinal stresses imposed on the installed pipe line.  Figure 5

Evaluation of Test Results In Table 1 record the following:

In column 1 record the test results of specimen No. 1T a. In column 3 record the test results of specimen No. 3A b. c. In column 4 record the test results of specimen No. 4B d. In column 5 record the test results of specimen No. 5C e. In column 6 record the test results of specimen No. 6, yield results only Mathematically compare, percentage wise, the test results of the following specimens, recording the three elements of each test

results in the positive or negative column. Test specimen 1T to specimen 3A a. Test specimen 3A to specimen 4B b.

 Table 1 : Testing and evaluation protocol

Changes from test 1-T + -

Position test taken from

Specimen to be tested as:

Specimen to be machined:

Test No.

Specimen designation

Yield strength

Ultimate strength Elongation

Flat coil head end Flat coil tail end

Full thick tensile test Full thick tensile test Full thick tensile test Half thick tensile test Half thick tensile test

1

T

As is

2

L

As is

Cut pipe ring & flatten Cut pipe ring & flatten Cut pipe ring & flatten Save pipe ring

Finished pipe

3

A

Warren Consulting Inc – USA Lew Warren, P. Eng

Finished pipe

4

B

Consultant specialist; manufacturing, testing and quality assessment of steel tube and pipe 621 South 350 West Orem, Utah, 84058-6105 Email: luwarren@mstarmetro.net

Finished pipe

5

C

Save pipe ring

Do not machine

6

D

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J anuary 2010

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