hey everyone dana bushcretter here with weld.com um today i'm going to be welding some 10 inch
schedule 80 pipe and once i weld it we're going to do several different ndt tests on it
so i'm going to get my land on here because right now i just have a bevel
and then i'll weld it out and we'll do a mag particle testing on it
what we're going to do is just a quick demonstration this is a electromagnetic yoke and
this produces what we call a longitudinal magnetic field so what you're going to see is two poles we
call these legs so this is a ferromagnetic plate so that magnetic field is going to exist very
nicely in there what we're going to do is we're going to see this kind of pattern start to build
and by doing that you can actually see that north and south kind of pull if you think about
two magnets and trying to stick them together like poles don't like each other posing poles do
now when we do this we're going to do it in two directions approximately 90 degrees apart
if you're trying to picture what's going on our field is creating a loop on either
side of this yoke so just kind of picture a little semi-circle so when we do this we want
to make sure that we turn this and that field is created 90 degrees or perpendicular to each other
by doing that it ensures that we will be able to find any flaws regardless of the orientation
so that's normal it's just going to build up where the weld metal meets our parent metal
has to be expected all right other than the the obvious stuff that we already discussed she looks
good i don't see any sort of cracks or anything to really be concerned about no laminations in
the base metals so as we filled this thing up we shouldn't really be getting any surprises alrighty
so i've got andrew with me here today to explain some of the ndt stuff and the industry and some
general questions of ndt um so first off can you kind of explain what ndt is yeah so ndt stands for
non-destructive testing as you can see uh ocean core logo i'm an instructor so that has been my
life you really could think of ndt as that it is a very very unknown trade but it's used everywhere
literally everywhere and a lot of ways people probably don't even think about and so uh you
know ndt is broken down into six key elements of various methods of inspection but i mean really
it is used in every single aspect of uh just our industrial world now for someone wanting to get
into the industry how long does schooling usually take well that that's a kind of a complicated
question now in the grand scheme of things with ndt we we break ourselves up in two levels so you
have a entry level level one level two level three entry level really you don't need a whole lot you
just need to get in with a business now that being said you do have to accrue experience or what we
call on-the-job training and our classroom uh there there's a lot of different methods and
they all require different extensive classroom training uh here at the ocean corps program is
seven and a half months and that meets all of our requirements for the classroom training portion so
our students they go out they start working and it's just a matter of a few months before these
start getting certified so in that seven months they learn every type of ndt testing uh for for
the basic six methods so that's going to be visual uh penetrant testing or liquid penetrate magnetic
particle eddy current or electromagnetic testing ultrasonics as well as radiograph
now if you guys can see there's a little line right there another start stop probably
something we want to address just right there so again uh anytime we're looking for indications
we're looking for something that stands out we can see the profile we know what that is
that's kind of an isolated indication by itself that something as you know an inspector anytime
you're looking at something your eyes are going to be drawn to that detail a detail that this
particular method is able to find whereas we really couldn't do that when we were outside using
the the dry powder method so trying to put it into layman's terms or welders terms i guess you should
say um so like say if one person knows like one process so putting that in perspective with ndt
what type of ndt testing would they possibly know and that's kind of the beauty of it you
do not have to know all six methods so there's a lot of pipeline welders for example and they are
very very good pipeline welders now they generally are only working in one or two positions when they
do that so that is a very specific practice now just the same way welders have to become
qualified right they they show up to a job site to do their welders call they pass all their tests
bend test x-ray whatever and then they can go and do that particular method for that employer
definitely correlates to us just instead of you know different welding processes they're different
ndt methods so i ran my root pass then we went and did some magnet particle testing on it um we came
back with a couple of spots that i know my hot pass is gonna fix however keep in mind i am making
errors on purpose because i want those to show up in those tests now um before i started videoing
um i went and ground down what i call wagon tracks so those are the so that would be our root
pass here then those edges i like to grind down because that's where you're going to trap slag at
so ground that down and now i'm going to run my hot pass hopefully that hot patch if i have any
issues um with my root pass that would burn in a little bit nicer to make my root more sound so
a little recap when i did my root we did dry powder uh that was visible and then we took it
into a room and did a fluorescent test yep and now we're gonna do what variation uh this is also a
wet method just like the fluorescent was but it is going to be visible now uh the big difference here
is this is a two-part system we put a white contrast paint down and then we use a black
uh colored iron shaving that's in an oil bath basically now really the whole difference will why
would i use one versus the other for the visible method so comparing this to like the red powder
this is going to be much more sensitive just the way we compared the fluorescent to the red
previously now what makes one more sensitive than the other um is really it comes down to the size
of the shavings the the dry powder is roughly about really ten times as large as these uh wet
methods are now with the fluorescent we get the the eight of that fluorescent light that jumps off
to us but um this is about as good as you're gonna get without having to go into a darkened area
i undercut
it's really not too bad
good indication under fill especially right there with that undercut
that very dark dark spot yeah it's really just pulling there yep all right cool okay we do have
advanced services as well or advanced techniques and so we have our base six and then we can
go from there so the big most common one is ultrasonics ultrasonics we start off with just a
very very base level what we call just a straight beam and a sheer wave examination and that's
uh stereo wave is pretty much what's commonly used for weld examination all right so what
we have is a standard conventional ultrasonic testing flaw detector if you want to call it
that um what we'll be doing today is we will be inspecting this with a 60 degree angle and just a
very very basic understanding we are just sending sound and bouncing it through this pipe
um it travels at a consistent angle until we strike something and really what we're going
to be seeing here is a response of whatever our sound wave strikes now this is uh similar in the
sense that you can hear people's voices speak when they're in the room with you and depending
if they're around the corner or not in a direct line of sight is harder to hear so this is our
first indicator you can see the reflection that it's giving us as it's bouncing back so this would
be the bottom of the material that green line yep green line red line would be top and then bottom
again so as you can see it's definitely towards our roots because it's closer to that bottom
maybe in between hot pass and yeah you know if you look at the bottom where there's a downward
arrow to actually tell you exactly how deep that spike is so it's 0.290 deep and we're what
0.4 0.4 on material thickness so yeah definitely towards the bottom of that material for sure
we can go further than that though we can have phased array which is just built off
of those fundamentals but it is definitely a more informative inspection we have time
of flight diffraction that's another one that can be used in addition to that and what we're doing
is we're giving ourselves more information and ultimately from a welder's standpoint
it makes the calls much much more accurate so it's all as close to an x-ray as we're gonna get
um and speaking of x-ray you know the dreaded x-ray crew that shows up
all right so as you can see i'm behind the uh good old rope here
um they're getting ready to shoot my x-ray so i guess let's watch them do that
so my x-ray had a two-minute shot time so they started it and now we've got to wait that two
minutes before the film's fully developed so we made our first exposure as we approach the
camera seth here is going to survey the camera ensuring that the radiation area is safe to come
back into we made our first exposure one to two we're gonna move on to two to three
last shot exposure hasn't been made now we want
to take it into the dark room and develop our film all right let's go
and then here's where you want to bring so now depending on the code right in here you can see
there's slag indications yep the accumulation across that section right there there's really
not a whole lot of codes out there that are going to have that you can see right here that's some
contour maybe a little bit of supplex okay um that is clearly sucked back right there yep
so and the way you would grade that is dance out the bass metal okay then you would dance out that
indication if that indication is darker than the base metal it's going to be a reject yeah
so i hope you learned something today maybe you learned a non-destructive testing method you've
never even heard of i know a couple of the methods i haven't actually had been able to see in person
so i was learning a little bit today as well if you have any more questions you can drop them down
below in the comments section i hope you learned something today and we'll see in the next video