10
So based on 3.2 mm material thickness amperage should be 125A if
using 1.0mm wire then the wire feed speed should be
0.04 X 125= 5m/min
Wire speed (amperage) controls weld penetration
4. Select Voltage. Voltage controls height and width of weld
bead.
Low Voltage: wire stubs into work
High Voltage: arc is unstable (spatter)
Set voltage midway between high/low voltages.
And then ne tune accordingly
6.2 MMA welding
Output Polarity Connections
Electrode polarity
MMA electrodes are generally connected to the ‘+’ terminal and the
work lead to the ‘-‘terminal
But if in doubt consult the electrode manufacturer’s literature.
MMA welding Operation
WARNING
When using an open arc process, it is necessary to use correct
eye, head, and body protection.
MMA Welding Guide
Using the selector button 13 toggle through the functions until the
MMA light is illuminated
You can adjust he welding amperage using the knob (5) and the arc
force using the knob (7)
Effects of MMA 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 enbrittlement. For this reason it is absolutely
CONTROLS
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 classied 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
outstanding 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.
vertical, lift the torch up from the work piece to draw out an arc. To
prevent melting of the end of the tungsten so this in a smoth rapid
movement
TIG welding guide ranges.
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