3.3 Welding technique
Successful welding depends on the following factors:
→
selection of the correct electrode
→
selection of the correct size of the electrode for the job
→
correct welding current
→
correct arc length
→
correct angle of electrode to work
→
correct travel speed
→
correct preparation of work to be welded.
3.4 Electrode selection
As a general rule the selection of an electrode is straight forward, in that
it is only a matter of selecting an electrode of similar composition to the
parent metal. It will be found, however, that for some metals there is a
choice of several electrodes, each of which has particular properties to
suit specific classes of work. Often, one electrode in the group will be
more suitable for general applications due to its all round qualities.
The table (on the next page) shows just a few of the wide range of
electrodes available from BOC with their typical areas of application.
For example, the average welder will carry out most fabrication using
mild steel and for this material has a choice of various standard BOC
electrodes, each of which will have qualities suited to particular tasks.
For general mild steel work, however, BOC Smootharc 13 electrodes
will handle virtually all applications. BOC Smootharc 13 is suitable for
welding mild steel in all positions using AC or DC power sources. Its easy-
striking characteristics and the tolerance it has for work where fit-up
and plate surfaces are not considered good make it the most attractive
electrode of its class. Continuous development and improvement of
BOC Smootharc 13 has provided in-built operating qualities which
appeals to the beginner and experienced operator alike. For further
recommendations on the selection of electrodes for specific applications,
see table on the next page.
Electrodes and typical applications
Name
AWS
Class.
Application
BOC Smootharc 13
E6013
A premium quality electrode for general
structural and sheet metal work in all
positions including vertical down using
low carbon steels
BOC Smootharc 24
E7024
An iron powder electrode for high
speed welding for H-V fillets and flat
butt joints. Medium to heavy structural
applications in low carbon steels
BOC Smootharc 18
E7018-1 A premium quality all positional
hydrogen controlled electrode for
carbon steels in pressure vessel
applications and where high integrity
welding is required and for free-
machining steels containing sulphur
BOC Smootharc S 308L E308L
Rutile basic coated low carbon
electrodes for welding austenitic
stainless steel and difficult to weld
material
BOC Smootharc S 316L E316L
BOC Smootharc S 309L E309L
Rutile basic coated low carbon electrode
for welding mild steel to stainless steel
and difficult to weld material
15
BOC Smootharc Advance II MIG 400R Operating manual
