This document discusses the essential elements of oxy-fuel cutting. It explains that oxy-fuel cutting involves heating metal to its ignition point with a flame and then using high-pressure oxygen to burn and remove the metal. It provides details on equipment setup and inspection, selecting cutting tips, adjusting gas pressures, and maintaining a neutral flame for cutting. The document also outlines the advantages of oxy-fuel cutting, such as its ability to cut complex shapes and various metals, along with its disadvantages like slower speed and less accuracy compared to other cutting methods.

1. Three Essential Elements of Fire

2. CUT AND PREPARE EDGE OF
MATERIALS
LESSON: CUTTING OPERATION
PROCEDURES

3. Oxy-Fuel Cutting
Definition:
Burning is the rapid oxidation of a
material
Does Metal Burn?
• Virtually all materials will burn if
they are first heated to their ignition
temperature.
• Steel ignition temp is when it is
cherry red, 1300-1400° C
• Oxygen burns preheated metal and
blows it away from the work piece.

4. Oxyacetylene welding (OAW)
Oxygen and acetylene gas are mixed in the torch tip. The mixture burns at the torch tip.
The heat from this flame is used to melt the base metal and welding rod. This melted
material forms a weld joint.

5. Flame Cutting – How it works?
The Oxy-Fuel cutting
process is
accomplished by
bringing the base
metal to a molten
state, then
introducing a high-
pressure stream of
cutting oxygen.

6. Flame Cutting – How it works?
This will ignite and burn the
metal as well as carry away
the slag or oxidized residue.
Oxy-fuel cutting can be
applied to plain carbon
steels, low-alloy steels and
other ferrous metals.
Nonferrous metals, stainless
steels and cast iron are not
usually cut using oxy-fuel
equipment.
Ferrous Metals
Non-Ferrous Metals

7. Things to Consider before Getting Started
1. Inspect the cone end,
coupling nut, and torch
head for dirt, dust, oil,
grease, or damaged
parts. Dirt and dust can
be removed with a
clean cloth.
CAUTION: If oil, grease
or damaged parts are
detected, DO NOT USE!
Report it to the
instructor immediately!
Inspect the Equipment

8. Straight Cutting Torch
OFC Equipment
Combination Cutting Torch with Cutting Attachment

9. Inspect the “O”Rings
2. Inspect the cutting
attachment cone end
for missing or
damaged “O” rings.
Damaged or missing
“O” rings can allow
gases to mix and will
cause backfires or
backflash.

10. Inspect the Cutting Tips
3. Inspect the torch head.
The tapered seating
surfaces must be in good
condition.
If dents, burns or burned
seats are present, the seat
must be resurfaced.
If the torch is used with a
bad seat, backfire or
backflash may occur.

11. Setting up the Cutting Head
4. Connect the cutting
attachment to the
welding torch handle
and tighten the
coupling nut, using
hand pressure only.
Wrench tightening
may damage “O” rings
and create a faulty
seal.
HAND TIGHT ONLY

12. Tip Selection
5. Select the
required size and
type of cutting
tip.

13. 3690 Cutting Tip
3690-P Cutting Tip
Cutting Tips

14. Attaching the Cutting Tip
6. Insert the tip in
the cutting
attachment head
and tighten
securely with an
open-end
wrench.
Wrench Tight Connecting Nut

15. CUTTINGTIP SELECTION CHART
Thickness Tip Cutting Oxygen Acetylene Oxygen Acetylene
ofMetal Size Orifice Pressure Pressure Consumption Consumption
in Inches Number DrillSize (P.S.I.G.) (P.S.I.G.) (SCFH) (SCFH)
Lightgauge
to 3/16 000 #68 15-20 5-15 35-40 10-15
3/16 -3/8 00 #64 20-25 5-15 45-50 10-15
3/8 -5/8 0 #60 35-40 5-15 75-85 15-20
5/8-1 1 #56 35-40 5-15 97-107 15-20
1-2 2 #52 40-45 5-15 180-195 20-30
2-3 3 #48 45-50 5-15 270-290 20-35
3-6 4 #42 50-75 10-15 450-600 25-40
OFC Cutting Tip Information

16. Oxy-Fuel Cutting Set-up
All set up the same as
oxy-fuel welding
except:
• To set working
pressure for
oxygen must
open cutting
valve

17. Oxy-Fuel Cutting Process
•Clean metal
•Draw line
•Make jig to keep cut straight
•Hold tip 1/16-1/8” above metal
•Preheat metal to cherry red color
•Open oxygen valve and push torch through metal
(Angle tip slightly toward direction of cut)

18. Carburizing Flame
Neutral Flame
Oxidizing Flame
Neutral Flame with Oxygen Cutting Stream
Cutting Flame Types
Acetylene Burning in Atmosphere

19. Advantages
• Can cut complex shape
• Can cut carbon and low carbon steel
• Inexpensive process
• Can have multiple cutting torch
Disadvantages
• It is slower than other cutting systems
• Cut accuracy is not as good as plasma, water jet
,laser
• Creates heat affected zone