2. Topic
General Safety for all Metal works
Welding
Gas Welding
Arc Welding
MIG Welding
Other Welding
Types of Metal
Metal Forming
Tools – hand & power
Equipment
3. General Idea
Welding, cutting, and brazing are hazardous activities which pose both safety and
health risks to over 500,000 workers in a wide variety of industries.
The risk from fatal injuries is more than four deaths per thousand workers over a
working lifetime.
4. Health Hazard
There are numerous health hazards associated with exposure to fumes, gases and
ionizing radiation formed or released during welding, cutting and brazing,
including:
Heavy metal poisoning
Lung cancer
Metal fume fever
Flash burns, and others
5. Health Hazards
FUMES MAY PRODUCE METAL FUME FEVER
Symptoms:
1. Respiratory disturbances
2. Infection – Influenza
3. Fever – Acute Bronchitis
4. Pneumonia – Chills, Shivering, Trembling, Nausea, Vomiting
6. Use PPE (Personal Protection Equipment)
Welders should consider using appropriate protective clothing which should include:
1. Shield or helmet with a filtered lens
2. Fire resistant gloves (leather)
3. Fire resistant jacket (ex. Leather or 100% cotton)
4. Boots (ex. Leather, work boots that cover your ankles – preferably steel-toe)
5. 100 % cotton blue jeans with no holes or cuffs.
6. Organic Vapor Respirator mask = NIOSH 100 Respirator
7. Cap
8. Safety glasses
7. Check it before you start welding
Do you wear:
Safety glasses?
No pockets?
Full Sleeves?
Leather Apron, fire resistant jacket?
No cuffs?
Safety shoes?
Flameproof skullcap?
Helmet with Filter Lens?
Collar buttoned?
Fire Protection Gauntlet Gloves?
All Fire resistant Clothing?
8. Dangers
The arc itself – the temperature can reach
6,000 degrees Fahrenheit
The intense ultraviolet and infra –red rays can
be harmful to both the welder and anyone
else nearby
It is not unusual for welders who are not
wearing overalls to suffer symptoms similar
to extreme sunburn
* The picture on the right is “Arc Eye”
9. Volatile Combination
Of Heat and Gas:
Fatalities have resulted where drums and other
containers have exploded as a result of some
welding or cutting work.
Know the nature of the previous contents to
ensure any heating does not liberate toxic fumes
or cause an explosion.
10. Gas Cylinders
Transporting, moving and storing:
Valve protection caps in place and secure
Cylinders hoisted on cradle, sling board, or
pallet only
No magnets or choker slings!
Move by tilting and rolling on edge
Transport by powered vehicle: secured upright
only
11. Transporting, Moving,
Storing
Unless a special welding cart is provided
cylinders shall have their regulators
removed & valve protection caps in
place before cylinders are moved
12. Valve Protective Caps
No hoisting of cylinders via Valve Protection Caps!!!
No prying of VALVE CAPS with bars
13. Gas Cylinder Safety
When cylinders are in use, they shall be
secured by chain, cart, other steadying device
14. Gas Cylinder Safety
When work is finished, when cylinders are
empty, or when cylinders are moved at any
time, the cylinder valve shall be closed
15. Gas Cylinder Safety
Cylinders secured in upright position at
all times
Except for hoisting or carrying
16. Storing
Separation of 20 feet for storage
of oxygen / fuel cylinders
Or a 5 Foot high non-combustible
barrier with fire rating of ½ hour
Well Protected
Well Ventilated
Dry
20 feet from Flammable or
Combustible Materials.
17. Use Safety
If sparks or hot slag can reach the cylinders, INSTALL A
SHIED!!!!!
NO striking the electrode to the cylinder to strike an
arc
18. Use Safety
NEVER TAKE OXYGEN OR
ACETELYNE cylinder into
CONFINED SPACES!!!
19. Use Safety
Never crack the cylinder
in the presence of open
flames, or where the gas
could reach welding work
or sparks!
Always stand to the side
when cracking cylinders
20. Use Safety
The safe use of fuel gas as follows:
Pressure must be reduced through the use of regulators before fuel gas can be burned
Before connecting a regulator the cylinder must be opened slightly and closed (cracking the
cylinder) to clear the valve of dirt
This prevents dirt from entering the regulator
Always open the cylinder valve slowly to prevent damage to the regulator
Only open the cylinder 1 and ½ turns (so it can be quickly closed!)
Leave the valve wrench in place when the cylinder is in use
Close cylinder valve, and bleed the regulator before removing the regulator (Make sure all
pointers are on zero)
21. Regulators
Use of regulators
required
Before removing
regulator, close valve and
release gas from
regulator
24. Ferrous Metal
(Melts at degree)
Oxyace
tylene
Arc
TIG & MIG
Braze welding
and Brazing
Silver brazing Soft solder
Mild steel (2729) good All good good OK OK
Galvanized steel zinc
melts (785)
Poor No good No Good
Stainless steel (2760) Poor TIG & MIG Good Good OK
Cast Iron (2742) OK Poor Good OK OK
Non-Ferrous
Copper (1982) OK TIG Good Good Good
Bronze (1629) Good TIG & MIG Good Good OK
Yellow Brass (1700) Good Poor OK Good OK
Aluminum (1212) OK TIG & MIG OK No No
Silver (1760) OK No No No OK
Lead (620) Good No No No OK
Titanium (3135) No TIG & MIG Special No No
26. Gas Welding – General Knowledge
Gas Welding (Oxyacetylene Welding) welds or cuts with the hottest known flame
(6300 F) which is produced by the combustion of acetylene (C2H2) with an equal
amount of oxygen.
When acetylene gas is burned in air it is unable to get enough oxygen from the air
to achieve complete combustion. The result is a residue of black carbon smoke.
As oxygen is added to the acetylene flame, it becomes more and more luminous
and more concentrated.
When a neutral flame is achieved there is no smoke, and the flame has become an
intense white cone about the size of a pencil point. It is with this point that the
welder controls the continuous welding bead or rippled ridge that forms a welded
joint.
28. Fuel Gas/ Oxygen Manifolds
Manifold Hose Connections
Green hose for oxygen and
right-hand thread (can be
Black)
Red for acetylene and left-
hand thread
Hose couplings must be the type that
rotate to disconnect
Boxes used for hose storage must be
ventilated
Hose kept clear of passageways,
stairs and ladders
29. Welding Hose
Not more than four of twelve inches covered with tape
for fuel and oxygen hoses taped together
Fuel hose inspected prior to each shift
Defective hose removed from service
30. Pressure Settings
Clean the nozzle
Open regulator Oxygen and Acetylene
Set until the pressure is matching with what
you want or for acetylene 5 to 7 psi and
Oxygen 7 to 10 psi
31. Torches
Clogged tips cleaned with suitable devices
Torches inspected prior to each shift
Torches lit by strikers or other approved
methods
No matches
Don’t move it away from the hot work
32. Eye Protection
Gas flames produce
infrared radiation
Check the chart and wear
adequate eye protection
33. Oxygen
Cylinder valves, caps,
couplings, regulators,
hose and apparatus kept
free from oil at ALL TIMES
1
Never handle oxygen
with oily clothes, hands,
or gloves
2
Never direct oxygen at
any oily surface
3
Never use oxygen inside
a fuel oil, or other storage
tank or vessel
4
34. Arc Welding
Personal Protection -1
Manual electrode holders must be designed for that
purpose and capable of carrying the maximum rated
electrode current
Only fully insulated holders to contact hands
Arc Welding cables completely insulated and flexible
type.
Free of splices minimum ten feet from electrode cable
end
Cables in need of repair not allowed
36. Arc Welding – General Knowledge
In Arc Welding the source of heat and the source of filler metal are the same: a
consumable electrode or stick, that forms an electrically charged gap between its
tip and the metal to be welded.
Across this gap flows a plasma of vaporized metal at 7232 F to deposit itself on
the molten surface of the work.
Arc Welding produces a more intense and concentrated heat than the
oxyacetylene flame, and therefore is useful for welding heavy sections of metal
that would consume a great deal of time and gas by the oxyacetylene method.
When the weld is finished there is a slag to be removed.
37. Arc Welding
Personal Protection -2
Ground return cables must have sufficient current
carrying capacity for maximum voltage
No grounding on pipelines containing gases or
flammable liquid
When using pipelines for ground return, continuity of
ground must be verified for all joints
38. Arc Welding
Make sure:
Electrodes removed from holders when unattended
Do not dip hot electrodes in water
Machine power opened when leaving machine or stopping work
Faulty equipment reported to supervisor
Always shield operations with flameproof screens to protect eyes
39. Arc Welding
Before starting:
Move objects to be welded to safe locations, or
Remove fire hazards from the area, or
Confine the heat, sparks, and slag, and to protect the immovable fire hazards from them
Extinguishing equipment present and ready
No paint or dust hazards are present on the surface of the metal to weld
When welding over walls, floors, ceilings where sparks may travel precautions must be
taken in the adjacent areas
A coated surface whose flammability is not known scrapings must be taken and tested
If scrapings burn, coating(s) must be removed
40. Arc Setting
The source of electricity for the arc welding transformer is either a 220/ 440-volt
single-phase electrical outlet or direct-current generator driven by gasoline or
diesel engine.
Welding units of 150 and 200 amperes can deal with about the same range of
material sizes as a medium-size gas welding – ease in dealing with heavy materials
– a unit of 300 to 500 amperes in needed.
Always test welding before weld an actual metal and Adjust ampere.
42. Confined Space
When welding in confined spaces has ended, remove
torch and hose
This eliminates possibility of accumulation of
hazardous atmospheres in confined spaces
43. Welding Containers
Before welding on drum or hollow structures which
have contained toxic or flammable materials either:
Completely fill with water before proceeding, or
Thoroughly clean, ventilate, and TEST
Before applying heat to any container drum, or
hollow structure a vent or opening must be provided
44. Ventilation & Protection
General ventilation maintains welding smoke
and fumes within safe limits
When welding in confined spaces, use
mechanical ventilation or local exhaust
If ventilation blocks access/egress to confined
space, air line and attendant required
45. Eye Protection
Anyone performing welding cutting or heating
must have eye protection
Refer to requirement in Subpart E
48. MIG Welding – General Knowledge
Metal –Inert –as (MIG) welding is that the weld takes place within a shielding envelope
of inert gas. In the MIG process, the electrode is a consumable metal wire which
automatically feeds into the weld, providing filler material.
The MIG wire control, cooling passages, and current control are combined in a compact
welding gun. Once adjusted for the job at hand, the MIG outfit is relatively easy to
operate. The large coil of filler wire permits long, uninterrupted welds.
A further refinement of the MIG system called “short-arc” uses an adjustable shorting-
out process to produce heat at electrode. This allows great versatility in welding
different thickness of metal, from the thinnest to the thickest, and maximum linear
speed of welding.
49. DCEN / DCEP
Direct Current Electrode Positive “DCEP” (Reverse
Polarity) is the standard polarity for MIG and for Stick
welding. In MIG, if it uses gas only without a flux or
metal core, it will require electrode positive. Dual
shield and metal core can vary. This is because the
electrons flowing from the negative work to the
positive electrode help to deposit the metal at a
regular pace and, though it is counter-intuitive, it
actually helps to increase penetration.
Any MIG hard wire welding accidentally with DCEN
9Direct Current Electrode Negative), will result in
globby welds, with an unstable arc and frequent arc
outage.
53. Plasma Cutter – General Knowledge
The heat levels increase and the gases that make up the steam will become
ionized and electrically conductive, becoming plasma.
A plasma cutter uses this electrically conductive gas to transfer energy from a
power supply to any conductive material, resulting in a cleaner, faster cutting
process than with oxyfuel.
The plasma arc formation begins when a gas such as oxygen, nitrogen, argon, or
even shop air is forced through a small nozzle orifice inside the torch. An electric
arc generated from the external power supply is then introduced to this high-
pressured gas flow, resulting in what is commonly referred to as a “plasma jet”.
The plasma jet immediately reaches temperatures up to 40,000F, quickly through
the work piece and blowing away the molten material.
55. Setting ( for Lincoln Cut 55 at ATU)
Air pressure required to operate the torches is anywhere 55 to 70 psi
Thin Gauge Sheet: Output set below 45 amps: below the mid range
Thick Sections: Output set above 45 amps: above the mid range
56. How to operate
Place the torch near the work, make certain all safety precautions have been taken and pull the
trigger. *When the arc brought within ¼” from the work piece, the arc will transfer.
Pierce the work piece by slowly lowering the torch onto the metal at a 30-degree angle away
from the operator. This will blow the dross away from the torch tip. Slowly rotate the torch to
vertical position as the arc becomes deeper.
Hold the nozzle standoff 1/8” (3.2mm) to 3/16” (4.7mm) above the workpiece during cutting. Do
not let the torch nozzle touch the work or carry a long arc.
Keep moving while cutting. Cut at a steady speed without pausing. Maintain the cutting speed so
that the arc leg is 10-degree to 20-degree behind the travel direction.
Use a 5-15-degree leading angle in the direction of the cut.
Use the drag cup to maintain constant standoff for better cut quality and to protect the nozzle
from spatter.
When the trigger is released, the arc will stop.
Clean spatter and scale from the nozzle and drag cup frequently.
58. TIG Welding – General Knowledge
Tungsten-inert gas (TIG) welding uses a non-consumable tungsten electrode
barely protruding from a ceramic cup from which an inert gas, usually argon, flows
over the weld area, shielding it from the atmosphere.
Argon is commonly used today instead of helium because it is heavier and thus
forms a better cover over the weld area. The result is an unusually clean and fluid
weld.
The filler rod is introduced to the weld area by the left hand in a manner similar to
oxyacetylene welding. When the weld is finished there is no slag to be removed.
59. Stainless Steel - Approach
Gas - It is possible to weld stainless steel with oxyacetylene equipment and good technique, the right
flux, and the correct rod for the type of stainless.
MIG & TIG – Both weldings give better results, however, and are almost always employed for
thicknesses over 16-guage. Straight polarity is standard.
Braze – Braze welding provides a way to join stainless steel to other metals.
60. Stainless Steel - Techniques
Most stainless steels distort radically when heated, so shapes must be clamped and jigged carefully if
accurate results are to be achieved. Most stainless steels shrink upon cooling together than retain their
expansion as do mild steels. Careful planning of. The order in which welds are made can usually minimize
shrinkage distortions in the finished work. Skip-welds are recommended for all long seams. The welds
should be made with as little excess heat as possible.
Some discoloration will always be present around the weld area. This can be removed by brushing,
sanding, sandblasting, or scrubbing with oxalic acid. Light rust is liable to form around the weld even
after initial cleaning because of the free iron that dissociates from the alloying elements during the heat
of welding. This rest may be removed as above and should not reappear after a few cleanings unless the
area has been badly burned by welding heat.
Note that only stainless steel brushes should be used on stainless, and only clean abrasives that have
never been in contact with other steels or iron. Free iron ground into the surface of stainless steel by
contaminating abrasives is very difficult to remove and will cause rust.
61. Bronze and Brass - Approach
All copper alloys, and copper itself, may be welded and braze welded by gas,
TIG, and MIG.
Alloys containing considerable proportions of zinc, such as yellow brass, gun
metal, and cartridge brass, are best gas welded because of the zinc fumes
produced by electric welding.
62. Bronze and Brass - Techniques
A flux is always used for gas welding copper alloys.
The flame should be slightly oxidizing. Silicon bronze is the easiest of the bronzes to weld and can be handled
either with gas or shielded arc on straight polarity. Care should be taken to support sections of brass or
bronze being welded. Since these alloys conduct heat very readily, large areas around the weld can soften
and sag.
Copper can be welded and brazed by gas or shielded arc. Because of its high conductivity. Large sections
require a great amount of heat, making flame welding impractical for anything with a surface bronze makes
an excellent brazing rod for copper and is not far off in color. Phos-Copper rod also works well, melts at
about 1300F, and has nearly the same electrical conductivity as copper. Copper has been fabricated for
centuries by soldering.
63. Aluminum - Approach
It is easier to attain good looking welds in aluminum with TIG or MIG than with
gas.
It is possible to braze weld aluminum with the correct flux and filler rod. This
provides a method for joining aluminum to copper and its alloys. Aluminum and
steel are not usually joined by braze welding because the melting temperatures of
these two materials are so far part.
64. Aluminum - Technique
Aluminum, like copper, is very conductive, but its welding temperature is so low that it is easy weld once its
behavior is learned. One of aluminum’s characteristics is that it does not change color and glow red when it
approaches welding heat. It is also weakened greatly as it approaches welding temperature. This, combined with
the rapid spread of heat due to its conductivity, means that large areas around the weld will collapse without
warning if not adequately supported.
The work must be bright and clean before welding begins, as aluminum oxide forms a barrier to fusion and can
also find its way into the weld as brittle inclusions which weaken the weld. To further combat oxidation when
welding with gas, both the work and the rod should be generously coated with flux. A slightly reducing flame is
used and careful attention is directed to judging the temperature of the weld area to avoid overheating.
As there are many alloys of aluminum, care should be taken to select a rod which is compatible with the work.
When in doubt general purpose type 4043 will blend with most alloys and produce a satisfactory weld if ultimate
strength and color matching is not too important.
It is possible to braze weld aluminum with the correct flux and filler rod. This provides a method for joining
aluminum to copper and its alloys.
65. Metal Forming
Metal-working tools range from the simplest hand tools, virtually unchanged in
design for centuries, to the most advanced production machinery, guided by there
is always an edge or face of hardened steel, tungsten carbide, or an abrasive
material. The rest of the tool is a device to hold the cutting surface in contact with
the work.
68. Hack Saw
Metal can be cut swiftly with a sturdy hacksaw
and sharp alloy-steel blade.
Care must be taken to keep the blade straight
otherwise it will bind and be broken.
With a rod-type blade coated with particles of
carbide you can saw ceramcis and other hard
materials as well as metals.
Be sure that the teeth face forward.
Do not saw so fast that the blade becomes hot
or the teeth will lose their temper
69. Chisel &
Hammer
The cold chisel is used for cutting
sheet metal, shearing off bolts,
and cleaning up castings.
Punch/ Point is used for making
holes in sheet metal, making
reference marks, and making
indentations for drill starting.
The carbide-tipped chisel stays
sharp for a long time but chips
easily if used on steel. It is just
right for bronze.
70. Files
Filing is a fairly simple operation, but to do it
well requires skill and care. After selecting right
file for the job, you should clean any oil off the
work and clamp it firmly so it will not vibrate.
Files must be pushed evenly over the work. It
cuts only on the forward stroke; the return stroke
should be a light one.
When the file becomes clogged with material it
can be cleaned with a wire brush, or if available,
a rotary wire brush mounted on a stationary
grinder. Be sure to wear goggles.
71. Shear
A shear is a device for slicing metal, with
a sharp blade operated by a lever. The
small bench shear requires successive
shearing actions to make a long cut with
its short blade.
The shear is an excellent tool for cutting
metal up to around 3/16-inch thick
because it is fast and leaves a clean
edge.
72. Rod Cutters
These devices make a clean cut in rods up to
one inch thick.
Bolt clippers can also be used for cutting rod,
wire, cable, and chain.
Clippers are essentially large scissors.
Specially tempered and ground blades are
available for cutting hard materials such as
stain-less steel and tempered bolts.
73. Pliers
Pliers are used to hold
objects firmly for hot and
cold metal work.
They are also useful for
bending and
compressing a wide
range of materials.
74. Pipe bender
A moderate curve can be formed in small
sizes of pipe and tubing by hand bending.
After a point, however, the inner wall of the
pipe will start to collapse, forming a crimp.
Sharper bends may be formed with a pipe
bender because the bending shoe supports
the walls of the pipe and allows them to
stress without collapse.
75. Taps and Dies
Taps are used for cutting internal threads
such as those on the inside of a nut. Dies cut
external threads on rods or pipes.
Taps and dies are available to cut all types of
threads, the main ones being coarse bolt
threads, fine or “machine” threads, and pipe
threads.
76. Vises and Clamps
One of the most important aspects of all
shop procedures is the adequate holding
and positioning of the work. Only by
holding the work firmly in the right
position can you make the most of the
different processes that are available.
77. Power tools
In the shop or studio 110-volt power is commonly
available to drive power tools. If large stationary saws
and grinders are to be used, it is worthwhile to obtain
220-volt 3-phase service.
In the long run, pneumatic power is more efficient
for hand tools than is electric power. Though their
initial expense is higher, air tools last much longer
between repairs and can be used continuously on
long jobs because they do not heat up.
79. Jig Saw
With the proper blade,
jigsaw can cut through
wood with embedded
nails, 1/18”, mild steel,
no-iron pipe and sheet
metal up to 10 gauge
thick.
For cutting sheet metal,
choose a finer with 21 to
24 teeth per inch
81. Types of Disc –
Cutting Disc
Cutting discs are expendable tools used on angle
grinders for cutting steel, stainless steel,
aluminum and other metal alloys.
For standard everyday jobs choose a 1mm or
1.6mm thickness,
For thin metal such as sheet metal choose a
1.0mm or 0.8mm thinner cutting disc,
For heavier steel cutting jobs select a 1.6mm or
2.5mm thickness of cutting disc.
82. Types of Disc –
Flap Disc
Flap discs are generally the best abrasive /
grinding wheel for fast stock removal,
deburring welds and provide grinding,
blending and finishing with on product.
INOX grade Flap Disc using (blue/green)
Zirconia material are perfect for use on both
mild and stainless steel. This is in contrast to
other Flap Discs that use the significantly less
effective (brown/red) Aluminum Oxide
abrasive material, which is also not suitable
for work on stainless steel.
83. Types of Disc-
Strip Disc
Strip Discs are ideal angle grinder attachment
used to remove paint. These paint remover
discs will thoroughly remove paint, epoxy
and rust from surfaces.
Poly Clean and Strip discs are made of poly-
fibre impregnated with abrasive grain, which
provides a very fast strip removal of paint or
rust importantly without damaging the
original surface.
84. Types of Disc –
Grinding Disc
Depressed center grinding wheel are the
recommended grinder attachment for all
weld grinding, pipe notching, beveling and
general heavy stock removal – on mild steel.
These discs with an aluminum oxide bond are
most effective on mild steels, or softer metals
and are not suitable for use on stainless steel.
Be careful with mis-choosing with cutting
discs. Those look similar but cutting discs are
thinner and grinding discs are thicker.
85. Types of Disc –
Fibre Sanding Disc
Zirconia Fibre Discs are the recommended
abrasive wheels for medium to light stock
removal on both mild and stainless steel.
Used on a backing plate on an angle grinder,
resin fibre discs have an extensive scope of
applications ranging from fine and coarse
sanding, blending welds, deburring and de-
rusting.
