Mma (Stick) Basic Welding Guide - Weldclass WeldForce WF-200MST Operating Instructions Manual

by
MMA (Stick) Basic
Welding Guide
Size of Electrodes
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 to the negative polarity
and is connected to the work piece. If in doubt
consult the electrode data sheet.
Effects of MMA(Stick) Welding
on 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 underbead 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
steelcool 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
18
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)