Manufacture and testing of welds — Production test

[mrmalcolm]

EN 13445-4:2021
Quote
9.3 Extent of testing
……
Prior to cutting the test pieces, the test plate shall be non-destructively tested in order to ensure that the test specimens are taken from sound areas.
Unquote
The test plate of pressure vessel welding products is an important means to ensure welding quality. Testing of mechanical properties of the test plate effectively prevents welding defects and ensure the safe operation of pressure vessels.
However, why take the test plates could be non-destructively tested and the test specimens can be taken from sound areas?

Best Regards

 

[mfgenggear]

EN 13445-4:2021
Quote
9.3 Extent of testing
……
Prior to cutting the test pieces, the test plate shall be non-destructively tested in order to ensure that the test specimens are taken from sound areas.
Unquote
The test plate of pressure vessel welding products is an important means to ensure welding quality. Testing of mechanical properties of the test plate effectively prevents welding defects and ensure the safe operation of pressure vessels.
However, why take the test plates could be non-destructively tested and the test specimens can be taken from sound areas?

Best Regards

to qualify weld schedule and prior to welding
production parts the test parts are NDT to ensure there are no welding defects.
what type of destructive testing?
does the specification depict tensile properties, and what else?
the requirements for NDTof pressure vessel
welds should NDT as well.

 

[DekDee]

mrmalcolm,
The purpose of destructive testing is to ascertain the mechanical properties of the weld.
If you do 2 x tensile tests on the same weld - one sound and one with lack of fusion you will have different results.
That is why you NDT first to find sound areas to test.
A welder induced defect is not relevant to a test coupons mechanical acceptability.

 

[mfgenggear]

a defect in a weld will result in premature failure in the test. I done it.
what if there are cracks present, it happens.
even with qualified WPS

 

[mrmalcolm]

Thank you, noting that this requirement is not a requirement for Welding Process Qualification Test Plate or for NDT of the pressure vessel product.
This requirement is appied to production test plates.
In order to control the continuing quality of the manufacture and the compliance of the mechanical properties of the welds with the specification, production test plates shall be welded and tested.
The production test plates were attached to the shell plate on one end of the weld so that the edges to be welded in the test plate are a continuation and duplication of the corresponding edges of the longitudinal welds.
Best Regards

 

[r6155]

If the production weld test fails, the previously performed weld will not be approved.

 

[mrmalcolm]

The point is why the test specimens can be taken from sound areas?

 

[r6155]

You are confused

"Prior to cutting the test pieces, the test plate shall be non-destructively tested in order to ensure that the test specimens are taken from sound areas"

The text is ..............ARE taken from sound areas not CAN BE taken from sound areas.

 

[gtaw]

What welding standard are you folks quoting from? It makes a difference.

 

[mrmalcolm]

What welding standard are you folks quoting from? It makes a difference.

EN 13445-4, thanks.

 

[mrmalcolm]

You are confused

"Prior to cutting the test pieces, the test plate shall be non-destructively tested in order to ensure that the test specimens are taken from sound areas"

The text is ..............ARE taken from sound areas not CAN BE taken from sound areas.

The understanding of this sentence is that the mechanical properties test plate shall be non-destructively tested and the test specimen will be taken from sound areas and will not be taken from the defective location of the test plate.
Thanks.

 

[DekDee]

As R6155 stated if the test plate has defects what do you do about the vessel weld ?
Seems a very weird scenario.
If you were doing test plates as run off plates it is common sense that the whole plate must be code compliant (NDT) before performing mechanical tests.
Not ignoring the defective areas and only testing in "sound" areas.

 

[mrmalcolm]

As R6155 stated if the test plate has defects what do you do about the vessel weld ?
Seems a very weird scenario.
If you were doing test plates as run off plates it is common sense that the whole plate must be code compliant (NDT) before performing mechanical tests.
The level of acceptance for NDT of test specimens for mechanical property tests should then not be more stringent than the level of acceptance for NDT of production welds. Right?

So, the acceptance level of NDT of mechanical property tests should not be stricter than that of non-destructive testing for production welds. Am I right? Thank you.