Stick
Welding - Shielded Metal Arc Welding The technical name for
stick welding is Shielded Metal Arc Welding, with the acronym SMAW. Mig welding
is now referred to as Gas Metal Arc Welding, or GMAW. Tig, or Heliarc welding
is now Gas Tungsten Arc Welding, or GTAW.
Out in the shop
or field it's Stick, Mig, and Tig. Stick welding uses
a consumable rod, or electrode. The rod is short circuited at the end causing
great heat, which in turn melts the end of the rod into tiny molten droplets.
These droplets form the weld pool which melts into the base, or parent metal.
Some rods penetrate, or fuse deeper into the metal than others.
Click here to view our welding ovens and to learn about the benefits of proper storage!
Fusion
is actually the correct word for how deep the weld pool goes into the surface
of the base metal. Penetrate means how far the weld pool goes into or through
a joint, although welders in the field usually use penetrate for both. When
doing any welding process, care must be taken to keep the harmful contaminants
in the atmosphere out of the weld pool. When hydrogen, oxygen, nitrogen, etc.
get into the weld pool they can cause porosity (worm holes in the weld), or cracking
in the weld once it solidifies. Porosity, cracking, and
slag inclusion (slag that hasn't been chipped/brushed welded over and becoming
part of the weld) are three major weld defects. Around
World War II, it was noticed that a rusty rod actually performed better than the
brand new bare rods used in welding. After experimenting with elements such as
silicon, potassium, and others, it was discovered that adding a flux coating to
the bare electrode formed a gas which kept the atmosphere out of the weld pool.
The slag would then solidify and form a protective coating around the weld which
would later be chipped off and brushed clean. Cleanliness
is of utmost importance in all welding processes! Although
aluminum and other metals can be stick welded, most common stick welding is done
on mild steel and stainless. Cast iron can be stick welded, but requires pre-heating
and post-heat cool down with a high degree of skill level. Some
advantages of stick welding are:- Very portable, welder needs only
to carry leads anywhere the weld needs to be done.
- Equipment is affordable.
- Can be used in all positions, and be used indoors our outside as wind
doesn't usually affect weld pool.
Some disadvantages
of stick welding are:- Only a few inches at a time can be welded before
another electrode is needed.
- Electrode ends (butts) are wasted.
- High
level of skill needed to produce sound welds.
- Many electrodes have
low penetration.
- Arc blow can occur with direct current. (Arc goes
everywhere EXCEPT where you want it to.)
In most structural
construction, stick welding is done with 7018 low hydrogen, and 6010 rods. An
easy rod to start out with is 6013. This is primarily
a rod used to stick weld thin surfaces such as sheet metal. It is a drag rod,
meaning that you need only to drag it on the surface of the steel as you weld.
Oscillation and manipulating the rod up and downwards slightly
as you weld will help wash the weld pool into the base metal, and produce a good
looking weld.
Learn More About Stick Electrodes!
|