ESAB MT-400EHD User manual

INSTRUCTIONS for F-12-778-H
June, 1999
MT-200, MT-400 & MT-400EHD*
MIG WELDING GUN
WITH BAYONET CONNECTOR
Be sure this information reaches the operator.
You can get extra copies through your supplier.
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles of operation
and safe practices for arc welding equipment, we urge you to read our booklet, "Precautions and Safe Practices for
Arc Welding, Cutting and Gouging." Form 52-529. Do NOT permit untrained persons to install, operate, or maintain
this equipment. Do NOT attempt to install or operate this equipment until you have read and fully understand these
Instructions. If you do not fully understand these Instructions, contact your supplier for further information. Be
sure to read the Safety Precautions on page 3 before installing or operating this equipment.
*Extra Heavy Duty (EHD)

2
USER RESPONSIBILITY
This equipment will perform in conformity with the description thereof contained in this manual and accompany-
ing labels and/or inserts when installed, operated, maintained, and repaired in accordance with the instructions pro-
vided. This equipment must be checked periodically. Malfunctioning or poorly maintained equipment should not be
used. Parts that are broken, missing, worn, distorted, or contaminated should be replaced immediately. Should such
repair or replacement become necessary, the manufacturer recommends that a telephone or written request for
service advice be made to the Authorized Distributor from whom it was purchased.
This equipment or any of its parts should not be altered without the prior written approval of the manufacturer.
The user of this equipment shall have the sole responsibility for any malfunction which results from improper use,
faulty maintenance, damage, improper repair, or alteration by anyone other than the manufacturer or a service facility
designated by the manufacturer.
TABLE OF CONTENTS
I. INTRODUCTION .......................................................................................................... 5
1.1 Scope................................................................................................................. 5
1.2 Features/Benefits............................................................................................... 6
1.3 Required Equipment .......................................................................................... 6
1.4 Torch Accessory Guide & Selection ................................................................... 6
II. INSTALLATION ............................................................................................................ 8
2.1 Torch Connections ............................................................................................. 8
2.1.1 Air-Cooled Models ............................................................................................. 8
III. OPERATION................................................................................................................. 8
3.1 Operating Safety Precautions ............................................................................ 8
3.2 Pre-Weld Requirements .................................................................................... 9
3.3 Welding Procedures .......................................................................................... 9
3.4 Shutdown Procedure ......................................................................................... 9
V SERVICE ...................................................................................................................... 9
4.1 Service Procedure ............................................................................................. 9
4.2 Inspect and Service Torch Regularly ............................................................... 10
4.3 Nozzles ............................................................................................................ 10
4.4 Wire Feed Liner (except 0.023-in. liner) .......................................................... 10
4.5 0.023-in. Wire Feed Liner ................................................................................ 11
4.6 Curved Wire Guide .......................................................................................... 12
4.7 Torch Switch .................................................................................................... 13
4.8 Handle and Cable Assembly ............................................................................ 13
V. REPLACEMENT PARTS ............................................................................................ 13

3
SAFETY PRECAUTIONS
WARNING: These Safety Precautions are for
your protection. They summarize precaution-
ary information from the references listed in
Additional Safety Information section. Before
performing any installation or operating procedures, be
sure to read and follow the safety precautions listed below
as well as all other manuals, material safety data sheets,
labels,etc.FailuretoobserveSafetyPrecautionscanresult
in injury or death.
PROTECT YOURSELF AND OTHERS--
Some welding, cutting, and gouging
processes are noisy and require ear
protection. The arc, like the sun, emits
ultraviolet(UV)andotherradiationand
can injure skin and eyes. Hot metal can cause burns.
Training in the proper use of the processes and equip-
ment is essential to prevent accidents. Therefore:
1. Alwayswearsafetyglasseswithsideshields inanywork
area, even if welding helmets, face shields, and goggles
are also required.
2. Use a face shield fitted with the correct filter and cover
plates to protect your eyes, face, neck, and ears from
sparks and rays of the arc when operating or observing
operations. Warn bystanders not to watch the arc and
not to expose themselves to the rays of the electric-arc
or hot metal.
3. Wearflameproofgauntlettypegloves,heavylong-sleeve
shirt, cuffless trousers, high-topped shoes, and a weld-
ing helmet or cap for hair protection, to protect against
arcrays and hot sparksor hot metal. A flameproofapron
may also be desirable as protection against radiated
heat and sparks.
4. Hot sparks or metal can lodge in rolled up sleeves,
trouser cuffs, or pockets. Sleeves and collars should be
kept buttoned, and open pockets eliminated from the
front of clothing
5. Protect other personnel from arc rays and hot sparks
with a suitable nonflammable partition or curtains.
6. Use goggles over safety glasses when chipping slag or
grinding. Chipped slag may be hot and can fly far.
Bystandersshouldalsoweargogglesoversafetyglasses.
FIRES AND EXPLOSIONS -- Heat from
flamesandarcs canstartfires.Hotslag
or sparks can also cause fires and ex-
plosions. Therefore:
1. Remove all combustible materials well away from the
work area or cover the materials with a protective non-
flammablecovering.Combustiblematerialsincludewood,
cloth,sawdust, liquid and gasfuels, solvents, paints and
coatings, paper, etc.
2. Hot sparks or hot metal can fall through cracks or
crevices in floors or wall openings and cause a hidden
smoldering fire or fires on the floor below. Make certain
that such openings are protected from hot sparks and
metal.“
3. Do not weld, cut or perform other hot work until the
workpiece has been completely cleaned so that there
are no substances on the workpiece which might pro-
duce flammable or toxic vapors. Do not do hot work on
closed containers. They may explode.
4. Havefireextinguishingequipment handyforinstantuse,
such as a garden hose, water pail, sand bucket, or
portable fire extinguisher. Be sure you are trained in its
use. 10/98
5. Do not use equipment beyond its ratings. For example,
overloaded welding cable can overheat and create a fire
hazard.
6. After completing operations, inspect the work area to
make certain there are no hot sparks or hot metal which
could cause a later fire. Use fire watchers when neces-
sary.
7. For additional information, refer to NFPA Standard 51B,
"Fire Prevention in Use of Cutting and Welding Pro-
cesses",available fromthe NationalFire Protection Asso-
ciation, Batterymarch Park, Quincy, MA 02269.
ELECTRICALSHOCK--Contactwithlive
electrical parts and ground can cause
severe injury or death. DO NOT use AC
welding current in damp areas, if move-
ment is confined, or if there is danger of
falling.
1. Be sure the power source frame (chassis) is connected
to the ground system of the input power.
2. Connect the workpiece to a good electrical ground.
3. Connect the work cable to the workpiece. A poor or
missing connection can expose you or others to a fatal
shock.
4. Use well-maintained equipment. Replace worn or dam-
aged cables.
5. Keepeverythingdry,includingclothing,workarea,cables,
torch/electrode holder, and power source.
6. Make sure that all parts of your body are insulated from
work and from ground.
7. Do not stand directly on metal or the earth while working
in tight quarters or a damp area; stand on dry boards or
an insulating platform and wear rubber-soled shoes.
8. Puton dry,hole-freegloves beforeturning onthe power.
9. Turn off the power before removing your gloves.
10. RefertoANSI/ASCStandard Z49.1(listedonnextpage)
forspecificgroundingrecommendations.Donotmistake
the work lead for a ground cable.
ELECTRIC AND MAGNETIC FIELDS —
Maybedangerous.Electriccurrentflow-
ing through any conductor causes lo-
calized Electric and Magnetic Fields
(EMF). Welding and cutting current cre-
ates EMF around welding cables and
welding machines. Therefore:
1. Welders having pacemakers should consult their physi-
cian before welding. EMF may interfere with some pace-
makers.
2. Exposureto EMFmay haveother healtheffects whichare
unknown.
3. Welders should use the following procedures to minimize
exposure to EMF:
A. Route the electrode and work cables together. Secure
them with tape when possible.
B. Never coil the torch or work cable around your body.
C. Do not place your body between the torch and work
cables. Route cables on the same side of your body.
D. Connect the work cable to the workpiece as close as
possible to the area being welded.
E. Keep welding power source and cables as far away
from your body as possible.

4
FUMES AND GASES -- Fumes and
gases,cancausediscomfortorharm,
particularly in confined spaces. Do
notbreathefumesandgases.Shield-
ing gases can cause asphyxiation.
Therefore:
1. Always provide adequate ventilation in the work area by
naturalormechanical means.Donotweld, cut,orgouge
on materials such as galvanized steel, stainless steel,
copper,zinc,lead,beryllium,orcadmiumunlesspositive
mechanicalventilationisprovided.Donotbreathefumes
from these materials.
2. Do not operate near de-greasing and spraying opera-
tions. The heat or arc rays can react with chlorinated
hydrocarbon vapors to form phosgene, a highly toxic
gas, and other irritant gases.
3. If you develop momentary eye, nose, or throat irritation
whileoperating,thisisanindicationthatventilationisnot
adequate. Stop work and take necessary steps to im-
prove ventilation in the work area. Do not continue to
operate if physical discomfort persists.
4. Refer to ANSI/ASC Standard Z49.1 (see listing below)
for specific ventilation recommendations.
5. WARNING: This product, when used for welding or
cutting, produces fumes or gases which
contain chemicals known to the State of
California to cause birth defects and, in
some cases, cancer. (California Health &
Safety Code §25249.5 et seq.)
CYLINDER HANDLING -- Cylinders, if
mishandled, can rupture and violently
release gas. Sudden rupture of cylin-
der,valve,orreliefdevicecaninjureor
kill. Therefore:
1. Use the proper gas for the process and use the proper
pressure reducing regulator designed to operate from
the compressed gas cylinder. Do not use adaptors.
Maintain hoses and fittings in good condition. Follow
manufacturer'soperatinginstructionsformountingregu-
lator to a compressed gas cylinder.
2. Always secure cylinders in an upright position by chain
orstraptosuitablehandtrucks,undercarriages,benches,
walls, post, or racks. Never secure cylinders to work
tables or fixtures where they may become part of an
electrical circuit.
3. When not in use, keep cylinder valves closed. Have
valve protection cap in place if regulator is not con-
nected. Secure and move cylinders by using suitable
hand trucks. Avoid rough handling of cylinders.
4. Locate cylinders away from heat, sparks, and flames.
Never strike an arc on a cylinder.
5. For additional information, refer to CGA Standard P-1,
"PrecautionsforSafeHandling ofCompressedGasesin
Cylinders", which is available from Compressed Gas
Association, 1235 Jefferson Davis Highway, Arlington,
VA 22202.
EQUIPMENT MAINTENANCE -- Faulty or
improperly maintained equipment can
cause injury or death. Therefore:
1. Always have qualified personnel perform the installa-
tion, troubleshooting, and maintenance work. Do not
perform any electrical work unless you are qualified to
perform such work.
2. Beforeperforminganymaintenanceworkinsideapower
source, disconnect the power source from the incoming
electrical power.
3. Maintain cables, grounding wire, connections, power
cord, and power supply in safe working order. Do not
operate any equipment in faulty condition.
4. Do not abuse any equipment or accessories. Keep
equipment away from heat sources such as furnaces,
wet conditions such as water puddles, oil or grease,
corrosive atmospheres and inclement weather.
5. Keep all safety devices and cabinet covers in position
and in good repair.
6. Use equipment only for its intended purpose. Do not
modify it in any manner.
ADDITIONAL SAFETY INFORMATION -- For
more information on safe practices for elec-
tric arc welding and cutting equipment, ask
your supplier for a copy of "Precautions and
Safe Practices for Arc Welding, Cutting and
Gouging", Form 52-529.
The following publications, which are available from the
American Welding Society, 550 N.W. LeJuene Road, Mi-
ami, FL 33126, are recommended to you:
1. ANSI/ASC Z49.1 - "Safety in Welding and Cutting"
2. AWS C5.1 - "Recommended Practices for Plasma Arc
Welding"
3. AWS C5.2 - "Recommended Practices for Plasma Arc
Cutting"
4. AWS C5.3 - "Recommended Practices for Air Carbon
Arc Gouging and Cutting"
5. AWSC5.5-"RecommendedPracticesforGasTungsten
Arc Welding“
6. AWSC5.6-"RecommendedPracticesforGasMetalArc
Welding"“
7. AWS SP - "Safe Practices" - Reprint, Welding Hand-
book.
8. ANSI/AWS F4.1, "Recommended Safe Practices for
Welding and Cutting of Containers That Have Held
Hazardous Substances."
MEANING OF SYMBOLS - As used through-
out this manual: Means Attention! Be Alert!
Your safety is involved.
Means immediate hazards which, if
not avoided, will result in immediate,
serious personal injury or loss of life.
Means potential hazards which could
result in personal injury or loss of life.
Means hazards which could result in
minor personal injury.
SP98-10
SAFETY PRECAUTIONS

5
tibles du secteur où lon exécute des soudures ou des
coupes à larc, à moins de les recouvrir complètement
dune bâche non-inflammable. Ce type de matériaux
comprend notamment le bois, les vêtements, la sciure,
lessence, le kérosène, les peintures, les solvants, le
gaz naturel, lacétylène, le propane et autres sub-
stances combustibles semblables.
b. Les étincelles ou les projections de métal incandes-
cent peuvent tomber dans des fissures du plancher ou
dans des ouvertures des murs et y déclencher une
ignition lente cachée. Veiller à protéger ces ouvertures
des étincelles et des projections de métal.
c. Nexécutez pas de soudures, de coupes, dopérations
de gougeage ou autres travaux à chaud à la surface
de barils, bidons, réservoirs ou autres contenants
usagés, avant de les avoir nettoyés de toute trace de
substance susceptible de produire des vapeurs
inflammables ou toxiques.
d. En vue dassurer la prévention des incendies, il
convient de disposer dun matériel dextinction prêt à
servir immédiatement, tel quun tuyau darrosage, un
seau à eau, un seau de sable ou un extincteur portatif.
e. Une fois le travail à larc terminé, inspectez le secteur
de façon à vous assurer quaucune étincelle ou projec-
tion de métal incandescent ne risque de provoquer
ultérieurement un feu.
3. CHOC ÉLECTRIQUE-- Le gougeage à larc et à larc
au plasma exige lemploi de tensions à vide relativement
importantes; or, celles-ci risquent de causer des
dommages corporels graves et même mortels en cas
dutilisation inadéquate. La gravité du choc électrique
reçu dépend du chemin suivi par le courant à travers le
corps humain et de son intensité.
a. Ne laissez jamais de surfaces métalliques sous ten-
sion venir au contact direct de la peau ou de vêtements
humides. Veillez à porter des gants bien secs.
b. Si vous devez effectuer un travail sur une surface
métallique ou dans un secteur humide, veillez à assu-
rer votre isolation corporelle en portant des gants secs
et des chaussures à semelles de caoutchouc et en
vous tenant sur une planche ou une plate-forme
sèche.
c. Mettez toujours à la terre le poste de soudage/coupage
en le reliant par un câble à une bonne prise de terre.
d. Nutilisez jamais de câbles usés ou endommagés. Ne
surchargez jamais le câble. Utilisez toujours un
équipement correctement entretenu.
e. Mettez léquipement hors tension lorsquil nest pas en
service. une mise à la masse accidentelle peut en effet
provoquer une surchauffe de léquipement et un dan-
ger dincendie. Ne pas enrouler ou passer le câble
autour dune partie quelconque du corps.
f. Vérifiez si le câble de masse est bien relié à la pièce en
un point aussi proche que possible de la zone de
travail. Le branchement des câbles de masse à
lossature du bâtiment ou en un point éloigné de la
zone de travail augmente en effet le risque de pas-
sage dun courant de sortie par des chaînes de
PRÉCAUTIONS DE SÉCURITÉ
AVERTISSEMENT: Ces règles de sécurité ont pour objet
d assurer votre protection. Veillez à lire et à observer les
précautions énoncées ci-dessous avant de monter l
équipement ou de commercer à lutiliser. Tout défaut
dobservation de ces précautions risque dentraîner des
blessures graves ou mortelles.
1. PROTECTION INDIVIDUELLE-- Les brûlures de la
peau et des yeux dues au rayonnement de larc
électrique ou du métal incandescent, lors du soudage
au plasma ou à lélectrode ou lors du gougeage à
larc, peuvent savérer plus graves que celles résultant
dune exposition prolongée au soleil. Aussi convient-il
dobserver les précautions suivantes:
a. Portez un écran facial adéquat muni des plaques
protectrices et des verres filtrants appropriés afin de
vous protéger les yeux, le visage, le cou et les oreilles
des étincelles et du rayonnement de larc électrique
lorsque vous effectuez des soudures ou des coupes
ou lorsque vous en observez lexécution.
AVERTISSEZ les personnes se trouvant à proximité
de façon à ce quelles ne regardent pas larc et à ce
quelles ne sexposent pas à son rayonnement, ni à
celui du métal incandescent.
b. Portez des gants ignifugés à crispins, une tunique
épaisse à manches longues, des pantalons sans
rebord, des chaussures à embout dacier et un casque
de soudage ou une calotte de protection, afin déviter
dexposer la peau au rayonnement de larc électrique
ou du métal incandescent. ll est également souhaitable
dutiliser un tablier ininflammable de façon à se
protéger des étincelles et du rayonnement thermique.
c. Les étincelles ou les projections de métal incandes-
cent risquent de se loger dans des manches
retroussées, des bords relevés de pantalons ou dans
des poches. Aussi convient-il de garder boutonnés le
col et les manches et de porter des vêtements sans
poches à lavant.
d. Protégez des étincelles et du rayonnement de larc
électrique les autres personnes travaillant à proximité
à laide dun écran ininflammable adéquat.
e. Ne jamais omettre de porter des lunettes de sécurité
lorsque vous vous trouvez dans un secteur où lon
effectue des opérations de soudage ou de coupage à
larc. Utilisez des lunettes de sécurité à écrans ou
verres latéraux pour piquer ou meûler le laitier. Les
piquetures incandescentes de laitier peuvent être
projetées à des distances considérables. Les
personnes se trouvant à proximité doivent également
porter des lunettes de protection.
f. Le gougeage à larc et le soudage à larc au plasma
produisent un niveau de bruit extrêmement élevé (de
100 à 114 dB) et exigent par conséquent lemploi de
dispositifs appropriés de protection auditive.
2. PRÉVENTION DES INCENDES-- Les projections de
laitier incandescent ou détincelles peuvent provoquer
de graves incendies au contact de matériaux com-
bustibles solides, liquides ou gazeux. Aussi faut-il
observer les précautions suivantes:
a. Éloigner suffisamment tous les matériaux combus-
9/97