CIGWELD 200i Instruction Manual download pdf (Page 41)

TRANSTIG 300 AC/DC

January 16, 2008

8-1

SECTION 8:

BASIC ARC WELDING GUIDE

8.01 Electrode Polarity

Stick electrodes are generally connected to the ‘+’ terminal and the work lead to the ‘-’ terminal but if in doubt

consult the electrode manufacturers literature.

8.02 Effects of Stick Welding Various Materials

High Tensile and Alloy Ateels

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 is to embrittle it. For this reason it is

absolutely essential to keep manganese steel cool during welding by quenching after each weld or skip weld-

ing 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 preheating of heavy sections

necessary to give proper fusion of weld and base metal.

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CIGWELD 200i Instruction Manual Page 41