UNIT 4: OXYACETYLENE
WELDING AND CUTTING IN
AGRICULTURE
Objectives
4.1 Define terminology
4.2 Describe the oxyacetylene welding and cutting
processes in agriculture
4.3 Distinguish parts and functions of oxyacetylene
welding and cutting equipment and supplies
4.4 Describe safe practices in oxyacetylene welding
and cutting
4.5 Describe the process of using oxyacetylene
welding and cutting equipment
4.1 Define terminology
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1. Bleeding the lines – moving gas pressure from all lines
and equipment, as with oxyacetylene welding systems
2. Brazing – the process of joining metal with a filler rod
that melts at a temperature below the metal being joined
3. Carbonizing flame – a flame with excess acetylene;
adjustment is needed to achieve a neutral flame
4. Cutting tip – a special tip used in cutting metal with gas
systems such as oxyacetylene
5. Filler rod – a long, thin metal rod used in welding to add
to or fill joints when welding or brazing
4.1 Terms Cont.
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6. Flammable – the quality of a substance that is
capable of burning
7. Fusion – the process of joining by melting, as in fusion
welding
8. Gauge – a device used to measure certain
substances such as pressure in an oxyacetylene
welding/cutting system
9. Neutral flame – an oxyacetylene flame with a
balance of oxygen and acetylene
10. Oxidizing flame – an oxyacetylene flame with an
excess of oxygen; adjustment is needed to achieve a
neutral flame
4.1 Terms Cont.
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11. Regulator – a device that controls the flow amount of a
liquid or gas; with oxyacetylene welding systems, regulators
control the flow of oxygen and acetylene
12. Tip – the part of a welding or cutting torch with holes to
release fuel for combustion
13. Tip cleaner – small, round rod-like devices that remove
dirt from the holes in welding and cutting torch tips
14. Torch – the assembly in an oxyacetylene system that
mixes oxygen and acetylene to provide the desired flame
15. Valve – a device that controls the flow of gas in an
oxyacetylene system
4.2 Describe the oxyacetylene
welding and cutting processes in
agriculture
Uses of Oxy-fuel Cutting and Welding
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What are some
examples of cutting
torch uses on the farm?
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Have you ever used a
gas welder at home?
Relate welding and cutting processes to
different kinds of metal
4.3 Distinguish parts and functions of
oxyacetylene welding and cutting
equipment and supplies
Regulators
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Gauges - High and Low pressure
Bonnet - weakest point
Adjusting screw - Clockwise = On
Protector Cap
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Protects valve from being knocked off
Must be in place when Regulators are off
Backflash Arrestor
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Torch / Manifold
Regulator / torch
Hoses
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Acetylene = Red
 Notch
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Oxygen = Green
 RH
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around nut means LH thread
Thread
New Hoses have talc inside - Blow out before
connecting to torch
Needle valves
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What each does
Preheat / Cutting hole pressures
Tightening
Torch Body
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single stage / dual stage
Distinguish between welding and cutting
components of oxy-acetylene equipment
Cutting Head
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Preheat oxygen needle valve
Seat type / Graphite type - tightening
Body to head connection - tightening
Oxygen lever - regulator setting, #1 needle
valve setting
Welding Tip
Identify, compare, and select filler rods by
type and by metal to be welded
4.4 Describe safe practices in
oxyacetylene welding and cutting
Objective 4: Describe fire prevention and personal protection in welding and
Identify and properly use personal protection equipment in oxy-fuel cutting
and welding
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Identify fire protection equipment
List the practices to follow to prevent accidents
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Make sure you have all PPE on at all times!!
 This
includes your shade 4 glasses at all times while
looking at the flame.
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Make sure that you always shut off the acetylene
valve first then the oxygen.
Do not point the torch directly into the lighter. Never
use a match or cigarette lighter to light the torch.
Identify proper ways of handling hot
metal
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Once you have made a weld that you want looked
at use a pair of pliers to carry the hot metal. Take
the metal to the sink and cool it off. Then you can
bring it to me for a grade. Using this method will
save our gloves in the long run!!
Identify practices to follow in safely
storing and using compressed gas
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Acetylene Cylinders
Acetone - absorbs acetylene under pressure
Consumption rate = 1/7 content per hour
Fusible plug - 2120 F
Temperature has an extreme affect on pressure
Let stand upright at least 20 minutes before using
Protected valve or cylinder cap
Stored away from oxygen and combustibles
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5’ high wall
1/2 hour fire rating
Identify practices to follow in safely
storing and using compressed gas
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Oxygen Cylinders
Pressure is about 2200 psi at 700 F
Hydrostatic tested to 3300 psi
Forged from a single piece of steel - no
welding
Minimum of 1/4” thickness
Annealed periodically
Stored away from combustibles
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5’ high wall
1/2 hour fire rating
Acetylene safety Precautions
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Never call acetylene “gas”
Extremely explosive with air or oxygen
Leave wrench on tank
Oxygen Safety Precautions
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Never call oxygen “Air”
Never allow oxygen to come in contact with oil,
grease, or other petroleum bases
Never use oxygen for compressed air
Never move cylinders without caps
Always secure cylinders
4.5 Describe the process of using oxyacetylene
welding and cutting equipment
Lighting Procedure
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1. Place goggles or safety glasses and face shield
on your forehead.
 Must
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be shade 4 lenses.
2. Be sure regulator adjusting screws are turned out.
 The
screw should turn freely.
Lighting Procedure
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3. Standing to one side, not directly in front of the
regulator, open the oxygen cylinder valve slowly, then
open it all the way.
 Set
the regulator at the correct working pressure.
 Open the oxygen blowpipe valve and fine tune the operating
pressure.
 Cutting-
40 psi
 Welding- 15-20 psi
 Close
the oxygen blowpipe valve.
Lighting Procedure
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4. Standing to one side, not directly in front of the
regulator, open the acetylene cylinder valve slowly.
 Only
open the tank valve ½ to ¾ of a turn.
 Set the regulator at the correct working pressure.
 Open the acetylene blowpipe valve and fine tune
the operating pressure.
 Cutting-
7-10 psi
 Welding- 5-7 psi
 Close
the acetylene blowpipe valve.
Lighting Procedure
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5. Put on gloves, and lower goggles or face shield
over eyes.
Lighting Procedure
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6. With the friction lighter in the left hand at the tip
of the blowpipe, and the blowpipe in the right
hand, open acetylene blowpipe valve with the right
thumb and forefinger one-eighth to one-quarter
turn.
 Strike
the friction lighter and adjust the acetylene level.
Lighting Procedure
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7. Adjust the acetylene by opening the blowpipe valve
until the flame leaves the tip about ¼ inch.
 Close
the valve very slowly until the flame is pulled back to the
end of the tip.
 Open the valve slowly again, stopping just before the flame
leaves the tip.
 This is the proper adjustment for most welding.
Lighting Procedure
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8. Open oxygen blowpipe valve and set the
desired flame type.
The correct shutting down
procedure is as follows.
Shut Down Procedures
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1. Close the acetylene blowpipe valve.
2. Close the oxygen blowpipe valve.
3. Close acetylene tank valve.
4. Close oxygen tank valve.
Shut Down Procedures
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5. Open the acetylene blowpipe valve to drain the
hose and release all pressure from the hose and
regulator.
6. Turn out the pressure-adjusting screw on the
acetylene pressure regulator by turning it
counterclockwise.
Shut Down Procedures
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7. Close the acetylene blowpipe valve.
8. Open the oxygen blowpipe valve to drain the
hose and release all pressure from the hose and
regulator.
Shut Down Procedures
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9. Turn out the pressure-adjusting screw on the
oxygen pressure regulator by turning it
counterclockwise.
10. Close the oxygen blowpipe valve.
11. Wrap up hoses and put welding accessories in
their proper place.
Fuel Gas Welding Techniques
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setting the proper flame
preparing the pieces to be welded
knowing the common types of welds
holding and using the blowpipe and rod
completing the different types of welds.
Three types of oxyacetylene welding
flames.
1. The neutral flame is usually used for welding. A neutral
flame will produce a smooth, shiny bead of the best
quality.
Three types of oxyacetylene welding
flames.
2. The oxidizing flame is caused by an excessive
amount of oxygen, which produces a short white
inner cone and a short envelope flame.
 An
oxidizing flame will produce sparks that shower the
weld area with droplets of metal and slag, leaving the
weld zone weak and porous.
Three types of oxyacetylene welding
flames.
1. The carburizing flame is caused by an excessive
amount of acetylene and has a long, bluish outer flame.
A
carburizing flame will cause the puddle to foam and boil,
leaving a brittle, porous, and scaly weld area.
 The carburizing flame is used for hard-surfacing.
Flame types
Carborizing
Neutral
Oxidizing
Review
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Describe the oxyacetylene welding and cutting
processes in agriculture
Distinguish parts and functions of oxyacetylene
welding and cutting equipment and supplies
Describe safe practices in oxyacetylene welding
and cutting
Describe the process of using oxyacetylene welding
and cutting equipment