Download - Welding, Cutting and Brazing
Welding, Cutting, And Brazing
© Business & Legal Reports, Inc. 0507
Session ObjectivesYou will be able to:• Identify major safety and health hazards of
welding• Select appropriate PPE for welding, cutting,
and brazing• Implement controls to prevent or control
fires
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Types of Welding• Welding includes 60 or
more process variations• Electric welding and
oxy-fuel gas welding• Welding/cutting occurs
at most businesses at some point
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Welding Hazards• Fires—caused by
unsafe welding or cutting operations• Burns• Electric Shock• Light radiation—
ultraviolet, infrared, and intense visible light• Air Contaminants
(gases, fumes, smoke)
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Basic Fire Prevention• Inspect welding area before starting• Remove fire hazards• Install guards•Welding or cutting must NOT take place
unless hazards removed or guards installed• Obtain a hot work permit before starting
operations to ensure that all fire hazards are controlled• Post a fire watch person 1/2 hour after
operation ceases
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Fire Prevention (cont.)
• Never weld in explosive atmospheres• Do not weld on used
containers• Test potentially
explosive containers for flammable atmospheres• Shut off cylinder valves
when not in use
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Ventilation• Three factors govern the amount of
contamination to which welders may be exposed:• Dimensions of the space• Number of welders• Possible evolution of hazardous fumes
•Management must ensure welders have proper protection and ventilation
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Oxygen-Fuel Gas Welding• Acetylene
• Flammable• Unstable• Cannot be used above 15 psi
• Oxygen• Added to support fuel gas flame and obtain high temperature for melting steel (welding)
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Basic Rules for Oxy-acetylene Welding• Ensure the safety fuse plug or disk is
functional• Attach regulator• Stand to one side of regulator• Open cylinder valve slowly• Not more than 15 psi
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Basic Rules for Oxy-acetylene Welding (cont.)
• Purge oxygen and acetylene lines • Light the acetylene • Never use oil or grease near oxygen• Do not use oxygen to clean or blow off dirt
or clothing• Keep your work area clean
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Store Gas Cylinders Safely• The storage area must be well ventilated• Keep fuel cylinders 20 feet or more from
combustibles• Close valves, ensure valves are protected• Limit inside storage to 2,000 cubic feet• Store cylinders in the upright position and
secured from falling• Separate oxygen from fuel gas
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Follow Gas Cylinder Precautions• Never lift cylinders by the service valve or
valve protection (use slings, net, or other approved means)• Keys, handles, and hand wheels must be
present• Use the proper regulator• Open acetylene valve no more than 11/2
turns• If in doubt about a cylinder, don’t use it
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Use Protective Devices• Pressure relief valves,
backflow preventers or check valves• Flash back arrestors• Fuel gas hose—red
(sometimes black)• Oxygen hose—green• Hose protection
required• Pressure-reducing
regulators
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Protect Yourself• Keep working surfaces clean and clear• Light torches with a striker, not a lighter!•Wear face and eye protection
• Use safety glasses under welding hood and burning goggles with proper shading
•Wear protective body clothing• Avoid synthetic clothing• Use leather gloves with gauntlet
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Lens Shades Generally, use a 4–5 shade for:• Torch brazing• Oxy-fuel gas
cutting/welding
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Oxy-Acetylene Welding—Any Questions?• Any questions about oxy-acetylene welding
safety?
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Arc Welding—Common Processes• Shielded metal arc
welding (stick welding)• Gas metal arc welding
(MIG welding)• Gas tungsten arc
welding (TIG welding)• Flux cored arc welding• Submerged arc
welding• Arc cutting• Plasma arc cutting
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Arc Welding Hazards and Safety Measures• Hazards
• Arc gives off ultraviolet and infrared rays the same as those causing sunburn
• Exposure within several inches to a few feet can cause flash burn to eyes and skin
• Safety measures• Avoid wet or damp areas—promotes electric shock hazard
• Avoid oil, grease, and flammables as they pose a fire hazard
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Shielding and Flash Screens• Air must be kept away
from weld area• Shielding protects the
integrity of the weld joint• Flux or gas mixture is
used as a “shield”• Welders need to erect
flash screens around them to protect others in area
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•Welding machines must be grounded•Work area must be dry and free of hazards• Connections must be tightly made• Cable splices within 10 feet of holder are
prohibited• Cables must be maintained and conductors
well insulated
Maintain Equipment Properly
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Protect Yourself•Wear welding helmets with proper shading
depending on type of arc• DO NOT use brazing goggles•Wear safety glasses under helmet•Wear leather gloves with gauntlets• Use ventilation or respirators•Wear leather bibs, sleeves, or jackets to
prevent burns from slag, sparks, and ultraviolet
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Lens Shades Generally, use a 10–14 shade for:• Shielded metal arc• Gas metal arc• Gas tungsten arc
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Arc Welding—Any Questions?• Any questions about arc welding?
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Key Points to Remember•Major hazards include:
• Fire• Burns• Shock• Toxic exposures
• Follow proper procedures to prevent fires • Use appropriate engineering controls•Wear appropriate PPE