Thermal Arc ARCMASTER 185 AC/DC, Operating Manual, Page: 43 / 74

ARCMASTER 185 AC/DC
Feb r ua r y 20, 2006
8-1
SECTION 8:
BASIC ARC WELDING GUIDE
8.01 Electrode Polarity
Stick elect r odes a r e gene r ally connected to the ‘+’ te r minal
and the wo r k lead to the ‘-’ te r minal but if in doubt consult
the elect r ode manufactu r e r s lite r atu r e.
8.02 Effects of Stick Welding Various
Materials
High Tensile and Alloy Ateels
The two most p r ominent effects of welding these steels
a r e the fo r mation of a ha r dened zone in the weld a r ea,
and, if suitable p r ecautions a r e not taken, the occu rr ence
in this zone of unde r -bead c r acks. Ha r dened zone and
unde r -bead c r acks in the weld a r ea may be r educed by
using the co rr ect elect r odes, p r eheating, using highe r
cu rr ent settings, using la r ge r elect r odes sizes, sho r t r uns
fo r la r ge r elect r ode deposits o r tempe r ing in a fu r nace.
Manganese Steels
The effect on manganese steel of slow cooling f r om high
tempe r atu r es is to emb r ittle it. Fo r this r eason it is abso-
lutely essential to keep manganese steel cool du r ing weld-
ing by quenching afte r each weld o r skip welding to dis-
t r ibute the heat.
Cast Iron
Most types of cast i r
on, except white i r on, a r e weldable.
White i r on, because of its ext r eme b r ittleness, gene r ally
c r acks when attempts a r e made to weld it. T r ouble may
also be expe r ienced when welding white-hea r t malleable,
due to the po r osity caused by gas held in this type of
i r on.
Copper and Alloys
The most impo r tant facto r is the high r ate of heat con-
ductivity of coppe r , making p r eheating of heavy sections
necessa r y to give p r ope r fusion of weld and base metal.
Types of Electrodes
A r c Welding elect r odes a r e classified into a numbe r of
g r oups depending on thei r applications. The r e a r e a g r eat
numbe r of elect r odes used fo r specialized indust r ial pu r -
poses, which a r e not of pa r ticula r inte r est fo r eve r yday
gene r al wo r k. These include some low hyd r ogen types
fo r high tensile steel, cellulose types fo r welding la r ge
diamete r pipes, etc. The r ange of elect r odes dealt with in
this publication will cove r the vast majo r ity of applica-
tions likely to be encounte r ed; a r e all easy to use and all
will wo r k on even the most basic of welding machines.