MMA WELDING GUIDE
MMA (STICK) BASIC WELDING TECHNIQUES
Size of Electrode
The electrode size is determined by the thickness of metals being joined and
can also be governed by the type of welding machine available. Small welding
machines will only provide current (amperage) to run smaller sized electrodes.
For thin sections, it is necessary to use smaller electrodes otherwise the arc may
burn holes through the job. A little practice will soon establish the most suitable
electrode for a given application.
Storage of Electrodes
Always store electrodes in a dry place and in their original containers.
Electrode Polarity
Electrodes are generally connected to the ELECTRODE HOLDER with the
Electrode Holder connected positive polarity. The WORK LEAD is connected
negative polarity and is connected to the work piece. If in doubt consult the
electrode data sheet.
EFFECTS OF MMA (STICK) WELDING VARIOUS MATERIALS
High Tensile and Alloy Steels
The two most prominent effects of welding these steels are the formation of
a hardened zone in the weld area, and, if suitable precautions are not taken,
the occurrence in this zone of under-bead cracks. Hardened zone and under-
bead cracks in the weld area may be reduced by using the correct electrodes,
preheating, using higher current settings, using larger electrodes sizes, short
runs for larger electrode deposits or tempering in a furnace.
Manganese Steels
The effect on manganese steel of slow cooling from high temperatures causes
embrittlement. For this reason it is absolutely essential to keep manganese steel
cool during welding by quenching after each weld or skip welding to distribute
the heat.
Cast Iron
Most types of cast iron, except white iron, are weldable. White iron, because
of its extreme brittleness, generally cracks when attempts are made to weld it.
Trouble may also be experienced when welding white-heart malleable, due to
the porosity caused by gas held in this type of iron.
Copper and Alloys
The most important factor is the high rate of heat conductivity of copper, making
pre-heating of heavy sections necessary to give proper fusion of weld and base
metal.
Types of Electrodes
Arc Welding electrodes are classified into a number of groups depending on
their applications. There are a great number of electrodes used for specialized
industrial purposes which are not of particular interest for everyday general
work. These include some low hydrogen types for high tensile steel, cellulose
types for welding large diameter pipes, etc. The range of electrodes dealt
with in this publication will cover the vast majority of applications likely to be
encountered; are all easy to use.
Metal Being Joined
Electrode
Comments
Mild Steel
E6011
This electrode is used for all-position
welding or for welding on rusty, dirty, less-
than-new metal. It has a deep, penetrating
arc and is often the first choice for repair or
maintenance work.
Mild Steel
E6013
This all-position, electrode is used for weld-
ing clean, new sheet metal. Its soft arc has
minimal spatter, moderate penetration and
an easy-to-clean slag.
Mild Steel
E7014
All positional, ease to use electrode for use
on thicker steel than E6013. Especially suit-
able sheet metal lap joints and fillet welds,
general purpose plate welding.
Mild Steel
E7018
A low-hydrogen, all-position electrode used
when quality is an issue or for hard-to-weld
metals. It has the capability of producing
more uniform weld metal, which has better
impact properties at low temperatures.
Cast Iron
Eni-Cl
Suitable for joining all cast irons except
white cast iron.
Stainless Steel
E318L-16
High corrosion resistances. Ideal for dairy
work etc.
Flat Position, Down Hand Butt Weld (Fig 1-11)
Flat Position, Gravity Fillet Weld (Fig 1-12)
Horizontal Position, Butt Weld (Fig 1-13)
Horizontal-Vertical (HV) Position (Fig 1-14)
Vertical Position, Butt Weld (Fig 1-15)
Vertical Position, Fillet Weld (Fig 1-16)
Overhead Position, Butt Weld (Fig 1-17)
Overhead Position, Fillet Weld (Fig 1-18)
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