Terms and Definitions

1
Terms and Definitions

• Base Metal metal to be welded
• Fusion Welding process that joins metals by
  heating them to a melting point and allowing them
  to fuse or flow together.

2
Terms and Definitions

• Penetration Distance from the original surface
  of the base metal to that depth at which fusion
  stops.

3
Terms and Definitions

• Backfire A short pop of the torch flame
  followed by extinguishing of the flame.
• Flashback when the torch flame moves into or
  beyond the mixing chamber.

4
Terms and Definitions

• Tack Weld A short weld used to hold the work
  pieces together.
• Preheating Heating prior to a welding or
  cutting operation.

5
Benefits of Learning Oxy-Fuel Welding and Cutting

• Teaches methods used in forming and controlling a
  weld puddle
• Teaches methods of using welding equipment and
  techniques that are useful in other welding
  processes

6
Benefits of Learning Oxy-Fuel Welding and Cutting

• Provides practice leading to good hand-eye
  coordination
• FUN and challenging for the welder.
• Sense of Accomplishment

7
Equipment required

• Oxygen cylinder
• Acetylene cylinder
• Pressure regulators

8
Equipment required

• Two hoses encased together
• Welding torch with tips
• Welding goggles and safety glasses

9
Equipment required

• Striker
• Check valves to prevent flashback

10
Safety Rules for Oxy-Acetylene Workplace

• Keep work area free of grease, oil, and flammable
  materials
• Cool or quench hot metal and extinguish all
  sparks before leaving

11
Safety Rules for Oxy-Acetylene Workplace

• Dont leave torches, tips or hot metal where
  someone will pick them up
• Never carry matches or lighters into any work area

12
Personal Safety

• Shirts
• keep collar and sleeves buttoned to keep out
  sparks and remove pockets or tape them shut

13
Personal Safety

• Pants
• full length required with no cuffs for spatter to
  catch in.
• shorts are not allowed in the welding area

14
Personal Safety

• Shoes
• leather preferred
• cover entire foot
• Gloves
• leather is best
• never used to pick up hot metal

15
Personal Safety

• Safety Glasses
• worn under helmets and goggles
• goggles do not serve as a replacement for safety
  glasses

16
Eye Protection

• wear safety glasses at all times in the shop
• wear welding goggles or a face shield with a lens
  4-6
• when in doubt start, with too dark of a lens and
  then switch to a lighter one.

17
Pressure Regulating Valves

• each regulator has two gauges mounted on a single
  manifold
• one indicates cylinder pressure
• the other indicates working pressure for the torch

18
Pressure Regulating Valves

• each regulator has an adjusting screw to regulate
  the working pressure to the torch.
• tightening the regulator screw increases the
  working pressure.

19
Welding hoses

• Colors of Welding Hoses
• Acetylene - red
• Oxygen - green

20
Welding hoses

• Connecting threads
• acetylene connectors have a V-groove and left
  handed threads
• oxygen connectors have plain surfaces and right
  handed threads

21
Parts of a welding torch

• the torch body is the part of the torch that is
  held like a pencil, it contains two needle valves
  to control flow of gas
• the welding head contains the mixer, mixing
  throat, and the welding tip

22
Basic Safety Rules

• Before you start make sure personal safety is
  followed.
• Make sure you have had instruction
• Release adjusting screw on regulators before
  opening valves

23
Basic Safety Rules

• Stand on the opposite side of the regulator when
  opening the cylinder valve
• Open cylinder valve slowly
• Oxygen - all the way open
• acetylene - 1 turn maximum

24
Basic Safety Rules

• Acetylene pressure should never exceed 15 psi.
• Set working pressures at 5 psi oxy 5 psi
  acetylene for welding.
• Light acetylene first, then add oxygen to obtain
  a neutral flame.

25
Basic Safety Rules

• Never use oil or grease on regulators or any
  equipment
• Never use oxygen as a substitute for compressed
  air
• Keep heat, flames and sparks away from
  combustibles.

26
Basic Safety Rules

• Keep hoses away from sparks or spatter to prevent
  leaks.
• Investigate your work area at all times.
• Be aware and prepared to prevent accidents before
  they happen.

27
Types of Flames

• Oxidizing
• Excess oxygen with no feather, makes hissing
  sound
• least used for any welding process

28
Types of Flames

• Neutral
• burns equal amounts of oxygen and acetylene and
  has a clear edged inner cone
• most used and creates a clean puddle when achieved

29
Types of Flames

• Carburizing
• Excess acetylene with an acetylene feather two to
  three times the length of the inner cone
• used some in hardsurfacing
• adds carbon to metal

30
Safely lighting a flame

• check the torch valves to make sure they are
  closed
• open the oxygen cylinder valve all the way open
• It is a double seated valve and should never be
  used partially opened

31
Safely lighting a flame

• open the acetylene a maximum of 1 turn
• This is a low-pressure gauge and can be closed
  quickly if need be
• set both oxygen acetylene line (working)
  pressures at 5 psi one each line

32
Safely lighting a flame

• open the acetylene torch valve 1/8 of a turn
• point the torch down away
• light the torch with a striker
• never use matches or a lighter

33
Safely lighting a flame

• open the valve until it jumps off the tip
• close the valve slightly to bring the flame back
  to the tip
• open the oxygen valve until a neutral flame is
  reached

34
Guidelines for Flame adjustment

• to get a neutral flame, always start with more
  acetylene
• increase oxygen until the acetylene feather
  disappears from the center cone
• excessive oxygen causes the molten metal to spark

35
Guidelines for Flame adjustment

• make sure regulators are set at the working
  pressures recommended for the tip size
• you want the acetylene flame adjusted just prior
  to jumping off the tip

36
Shutting down the unit

• close the acetylene valve first
• close the oxygen valve
• close the cylinder valves
• purge the acetylene line
• Observe the gauges reading to zero and close the
  valve

37
Shutting down the unit

• purge the oxygen valve
• When both gauges read zero, close the valve
• loosen the regulator adjusting screws to release
  the pressure
• coil hoses and put tools away