NDE for fillet weld 6

[EngMan40]

Base metals: 10" thick A36 bearing Plate with 6" A36 plate (part of box column). weld size 1/2" done using SMAW with E7018. 225F preheat was applied but only 3" depth into the metal not the the whole 10" from point of welding. Also was not maintained during welding. I want to check the whole weld not just the surface. any suggestions/ NDE method work best.

 

[metengr]

I would settle for a surface NDT using wet fluorescent MT.

 

[EngMan40]

is it comparable to the Circlesafe Water Based Aerosol #778A?

 

[yaschief]

Define "I want to check the whole weld"...what exactly are you looking for?"
a) Inclusions
b) To define the HAZ boundary
c) Cracking
d) ??

A combo of UT and MP can be done or RT if available but UT/MP is faster cheaper safer

 

[metengr]

First, I believe the concern was lack of preheat and preheat maintenance. Despite the conditions in the OP, performing volumetric examination of a fillet weld is difficult at best, and in my opinion, would serve no useful purpose. Most defects associated with lack of preheat would show as surface defects either in the weld face or in the base metal heat affected zone, which is why I believe surface NDT would be most efficient.

 

[gtaw]

How do you know the preheat only extended 3 inches into the base plate?

Best regards - Al

 

[valleytank]

100% Visual (Clear everything visually before you waste time calling in the mag crew) Black & White Contrast MPI should be more then sufficient for examining your weld and associated haz.

Is this for your info only...or? What code is this and what does your WPS say about pre-heat?

 

[gtaw]

If insufficient preheat was employed, the concern would be whether delayed cracking due to hydrogen introduced by the welding process and rapid cooling. Should hydrogen cracks develop, they most likely formed during the first 24 to 48 hours after welding. Since that time has long lapsed, magnetic particle testing would detect any cracks that have propagated to the surface. While dry MT would work if the cracks are relatively large, MT using wet fluorescent particles would detect cracks that may be missed by dry particles.

Fluorescent magnetic particle testing must be conducted in a darkened area to permit the inspector to see the fluorescent magnetic particles glow when stimulated by black light (ultraviolet light with a wavelength of 365 nanometers). This test method is very sensitive to very small cracks that are typically not detected with dry contrast magnetic particles. While working in a darkened environment can be a detraction, the effort is worthwhile. I use this technique on a regular basis to detect small fatigue cracks long before they can be detected with dry MY. A tarp may be all that is needed to provide a darkened work space to conduct the actual test.

Best regards - Al

 

[valleytank]

gtaw through your experience where do you make the decision to switch from Fluorescent Wet MPI vs Black Contrast Wet MPI?(No Dry Powder) Is this strictly a case by case basis as the black light method is more sensitive?

 

[gtaw]

One must consider the nature of the discontinuities that are of interest and the environment. For instance, if inspecting the welds in a fuel storage tank that has surfaces that will always be damp with residue, wet magnetic particle testing using a light petroleum distillate makes sense. Likewise, because it is dark already, fluorescent magnetic particles works nicely.

If one is looking for overlap, incomplete fusion, or other surface breaking linear discontinuities, dry contrast magnetic particles work well.

In this case, small hydrogen cracks are the most likely discontinuity that would result if hydrogen cracking is suspected. Wet fluorescent magnetic particles is the way to go if one is interested in detecting small hydrogen cracks that have not had an opportunity or time to propagate into large cracks.

Best regards - Al

 

[Ron]

As a former ASNT Level III, I agree with gtaw. Good advice.

 

[Tmoose]

I envision having to magnetize each part at least 2 different ways to detect cracks with different orientations in each region, and re-inspecting the part after each magnetization.

 

[SPDL310]

Ron/GTAW what do think of using of dye penetrant testing to replace florescent wet mag on large parts where it is hard to provide the low light environment needed like the OP seems to be describing?

 

[gtaw]

It is an option that requires more time to preclean, allow for sufficient dwell time, removal of excess surface penetrant, development time, and post test cleaning. The use of nonfluorescing dye is not as sensitive and the fluorescent dye, but adequate for the discontinuity you are looking for.

Best regards - Al

 

[EngMan40]

Thanks for the advice, I ended up using wet fluorescent MT and dry MT. Both showed linear face crack (wet showed longer crack than dry). There was a grout hole about 4" off the face of the column which I point my laser temp gauge to.