Weld tests on Lifting/Spreader Beams.

[truckdesigner]

We are currently building a number of beams that are then obviously proof load tested.

My boss insists on having the lug welds UT (Ultrasonic Tested) prior to proof load test, then MPI (Magnetic Particle Tested) after proof load test.

Other than as a health and safety concern I do not see the point of the test prior to proof load testing, and no-one is allowed near the beams whilst under test anyway.

AS (Australian Standard)4991 Lifting Devices mentions nothing, nor does AS1554 Structural Steel Welding.

Can anyone offer some insight, opinion?


Regards.

 

[MikeHalloran]

See Rule 1.


Mike Halloran
Pembroke Pines, FL, USA

 

[truckdesigner]

Rule 1 of...?

 

[MikeHalloran]

There are only two rules:
1. The Boss is always right.
2. When The Boss is not right, see Rule 1.



Seriously, can you conjecture some flaws that would not be detected by one proof load test? The Boss probably has.




Mike Halloran
Pembroke Pines, FL, USA

 

[Ron]

First, wouldn't the lug welds be fillet welds? If so, UT is difficult to interpret correctly on fillets.

Second, if you are going to test before and after, use the same test protocol. Using two different test methods with two different purposes might only serve to confuse you by their results.

Based on your handle, is there any chance that these beams will see repetitive loading? If so, the single proof test will show little other than a capability to hold the load once (though I assume you will proof test to some multiple of the design load).

 

[DWHA]

Have you taken a look at ASME BTH? If my memory is correct it discusses spreaderbeams.

 

[dhengr]

How big are these spreader beams and what exactly are the weld and structural details that you intend to inspect, and what are you expecting to see? As Ron suggested UT inspection may not actually show much on the kinds of weld details I’m imagining. And, they may not all have to be full pen. welds either. Proper weld design, good clean weld details and proper weld procedures may be just as important as that first inspection, because a poorly designed weld may still not show any defects, at this stage. Then a good visual inspection after fabrication for any deficiencies, such as notches, undercuts, craters and the like, all stress raisers, may be just as effective. Although, the boss is always right, I would discuss those first inspection methods and what is intended to be accomplished with them. The after load testing, by whatever test method is appropriate for what you want to see, and the final test results report might be interesting if they are made the first step in an ongoing, in-use, periodic inspection program for the spreader beams and associated lifting equipment.

 

[johg]

We fabricate our own lifting beams up to 200 tonnes. We fabricate to the European rules.
Guidelines to EC. We have a lot of experience welding for offshore structures. Only qualified welders are selected for welding on lifting equipment.
Partial welds and fillet welds are only checked visual and MPI. Full pen welds visual, MPI and UT.
The NDT testing is performed before test load the lifting equipment and after the testing. You want to find out if the test load, which is higher then the SWL, has some influence on your welds.
Additional we check the dimensions before the test and after. Looking for any plastic deformation. Always expect some force which you did not have taken into account. Better safe then sorry. European goverment rules only say it has to be safe. Specs are your guidelines to help you.

 

[truckdesigner]

The Spreader Beams vary from 100 kg WLL anywhere up to 50 Tonne. The computations are completed by myself and all welds are completed by DNV qualified welders.

The current beam we are fabricating has 6 mm fillet welds specified.

Thank you all for your insight.

I take it there is no definitive answer to this in any rules, codes etc?


Regards.