Safety Precautions - Lincoln Electric PRO 155 Operator's Manual

B-5
FIGURE B.6
Contact Tip
Wire Electrode
1. See "Process Guidelines" in this section for selec-
tion of welding wire and shielding gas and for
range of metal thicknesses that can be welded.
2. See the Application chart on the inside of the wire
feed compartment door for information on setting
the PRO 155 controls. Refer to Table B.1 for alu-
minum and stainless wire.
3. Set the Voltage ("V") and Wire Speed ("olo'") con-
trols to the settings suggested for the welding wire
and base metal thickness being used, refer to
Applications chart on the inside of the wire drive
compartment door.
4. Check that the polarity is correct for the welding
wire being used and that the gas supply, if
required, is turned on.
5. When using Innershield electrode, remove the gas
nozzle and install the gasless nozzle. This will
improve visibility of the arc and protect the gas dif-
fuser from weld spatter. Refer to the MAINTE-
NANCE section for details on nozzle replacement.
6. Refer to Figure B.7. Connect work clamp to metal
FIGURE B.7
WORKPIECE
WORK CLAMP
OPERATION
3/8" – 1/2" Electrical Stickout
GUN CABLE
ARC
PRO 155
to be welded. Work clamp must make good electrical
contact to the workpiece. The workpiece must also be
grounded as stated in "Arc Welding Safety
Precautions" in the beginning of this manual.
7. Position gun over joint. End of wire may be lightly
touching the work.
8. Lower welding helmet, close gun trigger, and
begin welding. Hold the gun so the contact tip to
work distance is about 3/8 inch (10 mm).
9. To stop welding, release the gun trigger and then
pull the gun away from the work after the arc goes
out.
10. When no more welding is to be done, close valve
on gas cylinder (if used), momentarily operate gun
trigger to release gas pressure, and turn off the
PRO 155.
Cleaning Tip And Nozzle
Clean the contact tip and nozzle to avoid arc bridging
between the nozzle and contact tip which can result in
a shorted nozzle, poor welds and an overheated gun.
Hint: Anti-stick spray or gel, available from a welding
supply distributor, may reduce buildup and aid in spat-
ter removal.
PROCESS GUIDELINES
The PRO 155 can be used for welding mild steel using
the self shielded, Innershield electrode process or it
can be used for the GMAW (MIG), single pass, process
which requires a supply of shielding gas, a KP665-035
drive roll and the K610-2 MIG Conversion Kit.
The recommended electrode for the self-shielded
process is 0.045" (1.2 mm) diameter Lincoln
Innershield NR-211-MP on 10 Ib (4.5 kg) spools. This
electrode can be used for all position welding of 20
gauge through 9 guage thick steel. The .045" (1.2
mm) NR-211-MP can also be used for welding galva-
nized sheet metal.
The recommended gas and electrode for GMAW is
welding grade CO gas and 0.025" (0.6 mm) diameter
2
Lincoln L-56 mild-steel welding wire [supplied on
2 lb. (.90 kg) spools]. For 14 gauge (2,0 mm) and thin-
ner, CO or blended gas is acceptable.
2
A mixed gas consisting of 75 to 80% Argon and 20 to
25% CO is recommended for welding on heavier
2
B-5