The
only way you know you are making sound welds is to see if they pass tests.
Save
on Discounted Welding Rod Ovens
Besides
the possibility of getting hurt while welding using unsafe practices, there is
also the possibility of getting hurt when a home hobby project fails. A prime
example is when someone has an unsound weld fail on a trailer going down the highway
at 70mph. I've actually seen a spare tire rack break shooting the tire down the
road like a missile. Luckily that time no one was hurt, but I've heard of people
getting hurt and killed by similar incidents, including a one-year recovery from
a fall from a faulty deer stand!
New
welders should learn about testing, and be able to pass weld tests before taking
on projects that could affect public safety.
Anyone
can go out and buy a welder for a couple hundred bucks and start building projects.
But without their welds being tested, there's no telling how sound they are. A
good comparison is a teenager buying one of the new 600 cc sport bikes with over
100 horsepower. Just because they can afford to buy one, does not mean they are
qualified to operate one. Just because you can run a bead, that does not mean
you are putting down a sound weld unless your welds have been previously tested
and consistently passed.
There
are three different types of weld tests done in industry including visual,
destructive, and non-destructive.
A
visual weld test is using your eyes to examine the completed weld. You
are mainly looking for a smooth, uniform weld free from cracks, holes, concaveness,
lack of penetration, undercut (the cardinal sin of welding), and other defects.
Although a microscope or magnifying glass may be used, only the surface can be
examined when using visual weld tests. Therefore a visual weld test although being
the easiest, is also limited in its scope.
A
destructive weld test destroys the metal that has been welded on. There
are several different types of destructive tests including tensile shearing, breaking,
nicking, etching, impact, and acid. The most common structural weld test is the
guided bend test. Destructive tests show both the surface and inside of the weld.
Most
tests I took in the field working on high-rises, power houses and the like were
guided bend test.
Lastly
is the non-destructive weld test which does not tear up the welded metal
and includes liquid dye penetrant, radiographic, ultrasound, magnetic particle,
and eddy current testing. These are done on erected structures where it would
not be practical to destroy the metal.
