Tweco 160 S Arcmaster - Manual (Page 33)

ARCMASTER ® 160 S
March 31, 2006 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 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 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 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 preheating of heavy
sections necessary to give proper fusion of weld and
base metal.
Types of Electrodes
Arc Welding electrodes are classifi ed 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 and all will
work on even the most basic of welding machines.
Metals being joined Electrode Comments
Mild steel 6013
Ideal electrodes for all general purpose work.
Features include out standing operator appeal,
easy arc starting and low spatter.
Mild steel 7014
All positional electrode for use on mild and
galvanized steel furniture, plates, fences,
gates, pipes and tanks etc. Especially suitable
for vertical-down welding.
Cast iron 99% Nickel
Suitable for joining all cast irons except white
cast iron.
Stainless steel 318L-16
High corrosion resistance. Ideal for dairy work,
etc. On stainless steels.
Copper, Bronze, Brass, etc.
Bronze
5.7 ERCUSI-A
Easy to use electrode for marine fi ttings, water
taps and valves, water trough fl oat arms, etc.
Also for joining copper to steel and for bronze
overlays on steel shafts.
High Alloy Steels,
Dissimilar Metals,
Crack Resistance.
All Hard-To-Weld Jobs.
312-16
It will weld most problematical jobs such as
springs, shafts, broken joins mild steel to
stainless and alloy steels.
Not suitable for Aluminum.
Table 10 - Types of Electrodes