1. Oxy-Fuel Cutting:
Say what?

2. Oxy- cutting Some call people it Oxygen-Acetylene
Some people call it Oxygen-Fuel
Some call people it Oxy-Acetylene
Some people call it Oxy-Fuel
Some people call it gas
Some people call it torch
SO WHICH IS CORRECT?

3. Oxy-fuel
Oxyfuel is a group of processes that use heat generated as a result of the combustion of a mixture of oxygen and a combustible gas (a fuel gas).
Propane, Natural, MAPP, Propylene, and Acetylene are most common fuel gasses.
Each fuel gas has unique qualities and guidelines for use. Follow them!

4. Oxyfuel: the process of combining pure oxygen with a combustible fuel gas to produce a flame
Can be used for welding, brazing, cutting, and heating metals
Oxygen & fuel gases are stored under pressure in cylinders and are released as individual gases through valves, regulators, and hoses.
Mixed as they flow through torch assemblies then burned as they are discharged through special tips.

5. Ag Systems l Standard 8: Students will fabricate with metal.
Objective 4:
“Use manual oxy-fuel gas cutting processes.”

6. We will cover The Oxygen –Acetylene (oxy-fuel) Cutting process.
Information to help you better use this cutting process.

7. Cutting Equipment
The equipment is basically the same for both oxy-fuel gas cutting and oxy-fuel gas welding, except for the torch.
The cutting torch is a unique and invaluable tool that enables the operator to cut almost any thickness of steel to the required size and shape.

8. Oxy-Fuel Cutting
Oxy-fuel gas cutting is also referred to as flame cutting it is a process of cutting steel by removing material to form a slot, called the kerf.
The metal is actually removed from the kerf by burning it away.
Flame cutting is one of the fastest and most efficient methods for cutting thick metal.

9. Most widely used fuel gas for welding and cutting applications.
Less stable and more expensive than other fuel gases.
Performs most functions well and is widely available.

10. Oxy-acetylene is the most commonly used oxyfuel process for Cutting, Heating, or welding.
The flexibility and mobility provided by oxy-acetylene Cutting allow its use in all metalworking industries.

11. Oxy-fuel Cutting is primarily used for maintenance, general fabrication, and repair work.
To see more about it’s uses Click on button

12. (Oxy-Fuel Cutting or Burning)
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.

13. Oxygen/ Fuel Cutting
Welding and Cutting operations use fire or combustion as a basic tool. 
The process is very useful when properly controlled.
However, it can be extremely destructive if not performed correctly in the proper environment.
We will cover practices and procedures that will promote SAFETY.

14. Elements for Burning
To understand how metal can be cut quickly with a flame, you must first understand how burning takes place.
Three essential elements are needed for burning: Fuel, Oxygen, and Heat.

15. 1st Element for Burning = Fuel
Fuel can be any material that will chemically combine with oxygen.
In this case, the steel to be cut is the fuel.

16. 2nd Element for Burning = Oxygen
A large quantity of pure Oxygen is needed to combine with the fuel.
The more oxygen present, and the greater the oxygen’s force, the faster burning will take place.

17. Oxygen is needed for Burning
Therefore, flame cutting requires a jet stream of pure oxygen directed onto the steel.

18. 3rd Element for Burning - Heat
Heat is needed to raise the temperature of the steel until it reaches its ignition temperature.
Ignition temperature is the temperature at which the material will burn when oxygen is present.

19. The Ignition or kindling Temperature
Steel is 1500 degrees Fahrenheit.
Steel turns cherry red.
The stream of oxygen is directed onto the hot metal.
The steel burns rapidly, and a slot (kerf) is cut (burned) through the entire piece.

20. Flame Cutting – Review, How it works?
Oxy-Fuel cutting is Heating the base metal to a cherry red color then a jet stream of pure oxygen is directed onto the steel.
These combine to form a chemical reaction called oxidation.

21. Flame Cutting- How it Works? Cont.
This jet of oxygen will ignite and burn the steel 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 (Iron Based) metals.

22. FUEL+ OXYGEN+ HEAT
To see that Burn = Cut Click Picture

23. Cutting Torch Parts

24. Oxy-fuel equipment sets are available from your welding supplier.
Add the Fuel Gas & the Oxygen cylinders and you are ready for work.

25. Typical Portable Oxygen/ Fuel Cutting Rig
The Cart for portability.
Chained in for safety.

26. Acetylene Regulator The coupling threads into the valve.
It is LEFT hand threaded (see the notches).

27. Read the label to check which gas is the cylinder
Acetylene label on a cylinder.

28. Acetylene review
To see review click on button

29. Oxygen Regulator The coupling threads onto the valve
It is RIGHT hand threaded.

30. Read the label to check which gas is the cylinder
Oxygen label on cylinder.

31. Pressure Regulators Pressure of cylinder
Pressure of gas being supplied to the torch
Pressure of cylinder
Hand screw which adjusts working pressure
Union for attachment to cylinders
Outlet connection for hose leading to torch
Thermadyne Industries, Inc.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

32. Two Gauges Two pressure gauges mounted on body of each regulator:
One shows the pressure in Cylinder, (Tank Pressure) high pressure.
The other shows the pressure of gas being supplied to torch (Work Pressure) low pressure.

33. Pressure Regulators
Reduce high cylinder pressure to low pressures of 0 to 45 p.s.i. used for Welding, Heating, or Cutting.
Maintain pressure without variation during Welding, Heating, or Cutting so the Flame remains steady and uniform during use.
To see more about Regulators and gauges click button

34. Valve Protecting Caps
Should be kept in place (hand-tight) when the cylinder is not in use.
Must be threaded on the cylinder when ever the regulators are not.
Protects valve from being knocked (broken) off.

35. Oxygen & Fuel Gas Hose Colors
Green = Oxygen
Red = Fuel Gas
Oxygen & Fuel Gas Hose Colors

36. Hoses and fittings
Color-coded & specifically designed based on use

37. For safety reasons
Repair hoses with proper hose splices, not friction tape or duck tape or wire!!!!
NEVER use a leaking hose.

38. A Typical Cutting Torch
We will discuss two common types.
Straight cutting torch:
&
Combination cutting torch :

39. Straight Cutting Torch
This torch is useful but it can only be used for Cutting.

40. Used in the Steel & Iron recycling industry.
Long handle keeps the operator from the heat and flame.

41. Combination Cutting Torch
Can do Welding, Heating or Cutting by changing the Attachments on the handle
Do Not use a wrench to tighten the coupling nut.

42. Cutting Attachment Parts
Torch handle
Cutting tip
Multi-flame Heating tip
Welding tips

43. See more information Click on button

44. Spark Lighter or Friction lighter
Use friction spark lighter to light welding torch
Safety note:
Never use matches they Put the welder's hand too close to torch tip where it may be burned when gases ignite.
Gas lighters may explode in your hand or pocket.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

45. Flashback Arrestor
Used to limit damage from a flashback by allowing the gases to flow in only one direction, preventing the flame from burning back into the equipment.
Use on the torch handle, and the regulators.

46. Flashback Arrestor
Use at the torch or at the regulator

47. Reverse Flow Check Valves

48. Reverse Flow Check Valves
The purpose of an internal check valve is to reduce the possibility of reverse flow gas.
It is not intended to act as a fire stop or flashback arrestor!
Spring activated
Once flow pressure decreases, valve will closes preventing back flow of gas
Gas flow
Flow of gas keeps valve open

49. Tip Cleaner Like small round files.
Used to clean the slag and spatter from the holes in the Oxy-fuel Cutting, welding, or, heating tips.
Tip Cleaner
To see tip cleaning info click the drawing

50. Cutting Tip

51. Welding Tip

52. Heating Tip

53. Safety tips for tips
The oxy- Acetylene process consumes gases for combustion to do it’s work.
Different tips withdraw different amounts.
If it is removed too fast some liquid may get in the system which is VERY DANGEROUS!

54. 1/7th Rule
The Acetylene Gas should never be removed faster than 1/7th of the cylinder volume per hour of use.
More information about Acetylene withdraw from Victor.

55. OFC Cutting Tip Information
SCFM (Standard Cubic Feet per Minute) is the volumetric flow rate of a gas

56. Department of Labor Occupational Safety and Health Administration
“Guidelines not mandates”
1966 OSHA specified that the flow rate of Acetylene gas , should be one-seventh of the capacity of the cylinder per hour use. (the 1/7th rule).
In 2003 OSHA specified that the flow rate of Acetylene gas, should be one- tenth of the cylinder capacity per hour during intermittent use, and one-fifteenth of the cylinder capacity per hour during continuous use.

57. Margin for error
I have been using the 1/7th rule my whole life, I am not dead so it must be ok.
 I suppose the new recommendations are super safe, that doesn't necessarily make the old recommendations dangerous, just less margin for error.

58. Use the with draw worksheet.
A small group or individual activity:
Get a worksheet from your teacher.
Discuss it’s use.
Complete the assignment.
Hand it in for grading .

59. To see the federal document about acetylene withdraw rates.
It is a PDF. The information is about half way down.