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 sec ons, it is necessary to use smaller electrodes otherwise the arc may
burn holes through the job. A li le prac ce will soon establish the most suitable electrode for a given
applica on.
Always store electrodes in a dry place and in their original containers. If electrodes have been exposed to
moisture or moist air then they will need to be dried out using an electrode drying oven.
Electrodes are generally connected to the electrode holder with the electrode holder connected posi ve
polarity. This can change with different manufacturers.
The work lead is connected to the nega e polarity and is connected to the work piece. If in doubt consult
the electrode data sheet.
The two most prominent effects of welding these steels are the forma on of a hardened zone in the
weld area, and, if suitable precau ons 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,
prehea ng, using higher current se ngs, using larger electrodes sizes, short runs for larger electrode
deposits or tempering in a furnace.
The effect on manganese steel of slow cooling from high temperatures causes embri lement. For this
reason it is absolutely essen al to keep manganese steel cool during welding by quenching a er each
weld or skip welding to distribute the heat.
Most types of cast iron, except white iron, are weldable. White iron, because of its extreme bri leness,
generally cracks when a empts 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.
6. STICK (MMA) BASIC WELDING GUIDE
6.1 Size of Electrodes
6.2 Storage of Electrodes
6.3 Electrode Polarity
6.4 Effects of Stick (MMA) Welding on Various Materials
6.4.1 High Tensile and Alloy Steels
6.4. 2 Manganese Steels
6.4.3 Cast Iron
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EZIMIG185C
Summary of Contents for EZIMIG185C
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