Oxyfuel Gas Welding

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Oxyfuel Gas Welding

• Safety

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TERMS AND DEFINITIONS

• Fusion Welding
• Joining of metal by heating the adjoining edges
  to the fusion or melting point and allowing them
  to flow or run together and then cool
• Penetration
• Distance from the original surface of the base
  metal to the point at which fusion ceases.
• Base Metal
• Metal to be welded

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TERMS AND DEFINITIONSContinued

• Alloy
• Mixture with metallic properties composed of two
  or more elements of which, at least one, is a
  metal.
• Inner Cone
• Inner white part of a neutral flame.
• Tack Weld
• Short weld used for temporarily holding metal in
  place.

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TERMS AND DEFINITIONSContinued

• Back Fire
• Momentary burning back of the flame into the tip.
• Flame goes out with a loud snap or pop.
• Flash Back
• Fire inside the torch.
• Indicated by a hissing or squealing sound
• (Caution this is a very dangerous condition.
  Shut down acetylene first and then the oxygen
  last.)
• Causes of flash backs are dirty tips or
  equipment, improper welding or cutting
  procedures.
• Check Valves
• Prevents the mixing of gases and removes the
  hazard of explosion.

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Safety rules for Oxygen, Acetylene, and
Oxy-acetylene welding equipment.

• Support oxygen and acetylene cylinders in an
  upright position so they cannot be tipped over.
• Note Acetylene gas is in a liquid form in the
  cylinder and should be used in the vertical
  position so the acetone will not be withdrawn.
  If the tank is on its side it must stand for at
  least twice the amount of time it was on its
  side.
• Before connecting regulators to the tanks, crack
  the valve in order to remove dust and dirt that
  may damage the regulators.
• Note Be sure to crack cylinder valves for a
  second before attaching regulators.

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Safety Rules Continued

• Release pressure-adjusting screws on regulator
  before opening the cylinder valve to prevent
  damage to the regulator and possible injury to
  the operator.
• Stand to the side of tank and regulator, keeping
  the cylinder valve between operator and
  regulator, while opening cylinder valve.

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Safety Rules Continued

• Open cylinder valve SLOWLY.
• Note The oxygen cylinder valve is opened to
  full capacity. The Acetylene valve is opened ¾
  of a turn only.
• Do not use acetylene (in free state) at pressures
  above 15 psi
• Note Acetylene becomes unstable at pressures
  above 15 psi and becomes highly explosive.
• Oxygen and Acetylene regulators should be set at
  a 7 to 3 ratio.
• Note Oxygen 20 psi, Acetylene 7 psi

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Safety Rules Continued

• Clear oxygen and acetylene passages individually
  before lighting torch.
• Crack torch valves for each one separately before
  you light the torch.
• Light Acetylene before opening oxygen torch
  valve.
• Use only a striker, never a match or lighter.

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Adjusting The Flame

• Adjust the flame to a neutral flame. This is the
  desired flame for most welding applications.
• There are 3 types of flames.
• A. Neutral Flame
• B. Oxidizing Flame
• Carburizing Flame

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Safety Rules Continued

• Never use oil or grease on regulators, torches,
  or fittings.
• Oil or grease has a high attraction to oxygen
  and will unit with explosive violence.
• Do not use oxygen as a substitute for compressed
  air
• Use safety goggles, gloves, and protective
  clothing.
• Keep gloves, hands, and clothing free from oil,
  grease, and fuels
• Have CO2 or dry chemical type fire extinguishers
  available.

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Safety Rules Continued

• Test connections for leaks with a non-oil-based
  soapsuds, paint brush, and water.
• Avoid lighting the torch or welding near
  combustible materials.

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Safety Rules Continued

• Never open the acetylene cylinder valve more than
  ¾ of a turn.
• Always operate torch in a well ventilated place.
• Never weld on containers that have been used for
  combustible materials.
• Avoid breathing toxic fumes when welding.

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Safety Rules Continued

• Place steel caps on all gas cylinders when they
  are being moved or stored, to protect the valves.
• Shut off cylinder valves when not in use for any
  length of time to reduce the possibility of
  leakage and strain on equipment.

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PPE (Personal Protective Equipment)

• Eye Ear Protection
• Welding Goggles with Proper Lens Shade Number
• Welding Gloves Optional Covering
• Proper Attire for OFW, OFC, OFB, AFS

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Eye Ear Protection
Ear Plugs
Goggles
Safety Glasses
Hearing Protection
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Headgear
Adjustable Head Gear
Spare Cover Lens
Cover Lens
Filter Lens
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AWS/ANSI Lens Shade Numbers
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Optional Covering
Leather Welding Apron
Leather Welding Jacket
Leather Welding Gloves
Leather Welding Cape Sleeves/Bib
Leather Welding Trousers
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Proper Attire
Cap with Visor Turned to the Back
Industrial Quality Safety Glasses
Long Sleeve Shirt
Gauntlet Leather Welding Gloves
High Top Leather Boots(Steel Toes)
Pants without Cuffs
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Fumes Gases

• Welding or Cutting May Produce Hazardous Fumes
  Gases
• Leaking Gases May Cause Injury or Death
• Use Ventilation To Keep Air Breathing Zone Clear
  Comfortable
• Use Special Care When Welding or Cutting In a
  Confined Area or on a Container
• Do Not Weld or Cut Near Flammables

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Radiation - UV, IR, Visible

• Oxyfuel UV/IR Rays Can Burn Eyes Skin
• Always Use Approved Eye Protection When Oxy
  FuelWelding or Cutting
• Select an Appropriate Filter Lens for the
  Process Application
• Wear Appropriate Clothing Which Protects the Skin
  
• Provide Non-Flammable Shielding to Protect Others

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Fire or Explosion

• Remove Flammable Materials From The Work Area
• Keep a Fire Extinguisher in the Work Area
• Wear Fire Retardant Clothing a Hat When
  Welding or Cutting
• Do Not Weld on Containers Which Have Held
  Combustible Materials or Closed Containers of Any
  Kind

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Compressed Gas Hazards

• Cylinders may Explode if Damaged
• Keep Cylinders Upright Chained to Support or
  Approved Carrier
• Keep Cylinder Free from Sparks Out of the Spark
  Zone
• Never Allow Flames from a Torch to Come in
  Contact with a Cylinder or Hose

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General Hazards in Work Area

• Keep Gas Hoses, Materials Tools Neatly
  Organized
• Never Use Leaking or Faulty Equipment
• Always Ensure ProperEnvironment Ventilation
• Do Not Weld or Cut in a Confined Area
• Remove All Flammable Materials From the Work
  Area, Etc.
• Keep All Equipment In Good Condition

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Equipment needed for OFW

• Oxygen Cylinder
• Acetylene Cylinder
• Regulators for both Acetylene and Oxygen
• Hoses
• Flash Arresters
• Torch body
• Torch Tip
• Tip Cleaners
• Striker

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Acetylene Cylinder

• Acetylene Cylinder
• The valve is opened ¾ of a turn.
• This is due to that acetylene can only be drawn
  off at a certain rate and any more is not needed.
• Also this allows for a quick shutdown if
  something wrong happens.
• Set the regulator pressure at 7 psi. Never let
  the pressure go over 15 psi. Acetylene becomes
  unstable at 15psi or higher.

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Oxygen Cylinder

• Oxygen cylinder
• The oxygen cylinder should be opened completely.
• This needs to happen due to the valve having a
  back seat valve.
• The pressure needs to be set at 20 psi

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What do the cylinders look like?
High Pressure Hazard
Safety Disc
Flammable
Monolithic Porous Filler Material
Fusible Plugs
Hollow
Vigorously Supports Combustion
1/7th Rule
Shock Sensitive
Oxygen Cylinder
Acetylene Cylinder
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Types Cylinder Valves

• Oxygen Cylinder Valve
• CGA 540
• Acetylene Cylinder Valve
• CGA 510 with hand knob
• CGA 510 with Tee Wrench or Tank Wrench
• CGA 300

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Oxygen Cylinder Valves
Handwheel

• CGA 540

Packing Nut
Upper Valve Seat
To Oxygen Regulator
Lower Valve Seat
Disc Ruptures If Pressure Goes Too High
From Oxygen Cylinder
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Acetylene Cylinder Valves

• CGA 510 CGA 300

Handwheel
Packing Nut
Upper Valve Seat
To Acetylene Regulator
To Acetylene Regulator
Lower ValveSeat
From Acetylene Cylinder
From Acetylene Cylinder
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Acetylene Cylinder Valves - Linde (Presti-Lite)

• CGA 510

To Acetylene Regulator
Tank Wrench
Tee Wrench
Valve Stem
Packing Nut
Upper Valve Seat
Lower Valve Seat
From Acetylene Cylinder
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Regulators
Oxygen Regulator
Fuel Gas Regulator
20 psi
7 psi
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Which Regulator?

• Single Stage Regulator
• Use When Slight Rise in Delivery Pressure from
  Full to Empty Cylinder Condition Can Be Tolerated
• Two Stage Regulator
• Use When a Constant Delivery Pressure from Full
  to Empty Cylinder Condition is Required

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Single Stage Regulator
Adjusting Screw
Bonnet
Flexible Diaphragm
Primary Spring
Gas To Torch
Gas From Cylinder
Regulator Body
Secondary Spring
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Cutaway
Bonnet
Gas From Cylinder
Cylinder Pressure Gauge
Adjusting Screw
Secondary Spring
Primary Spring
Capsule
Flexible Diaphragm
Working Pressure Gauge
Regulator Body
Gas To Torch
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Two Stage Regulator

Adjusting Screw
Primary Spring Second Stage
Regulator Body
Bonnet
Adjustable Second Stage
Gas To Torch
Gas From Cylinder
Flexible Diaphragm
Secondary Spring
Primary Spring First Stage
Pre-Set First Stage
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Cutaway
Gas From Cylinder
Regulator Body
Secondary Spring
Cylinder Pressure Gage
Bonnet
Adjusting Screw
Capsule
Primary Spring
Primary Spring
Capsule
Bonnet
Flexible Diaphragm
Working Pressure Gage
Gas To Torch