Z34-GasWelding-4

8/7/2019 Z34-GasWelding-4

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GAS WELDING


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Work Area

Area Should be Clear and Free of Combustibles

Area Should Be well Ventilated

Fire Extinguishers Should Be Available

Area Should Be Free of Open Arcs or Flames

Fireproof Blankets and/or Screens Are Suggested

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Personnel Protection

Wear Approved Eye

P

rotection

Wear Flame Resistant Clothing

Wear Long Sleeves, Pocket Flaps and No Cuffs

Wear Approved Foot Gear

Wear Approved Hand Protection

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Proper Eye Protection

2A

*As a rule of thumb, start with a shade that is too dark to see the weld or cutting zone.

Then go to a lighter shade, which gives sufficient view of the weld or cutting zone without going below the minimum.

3-4

4-5

5-6

3

4

5

< 1

1 to 6

6

Oxygen Fuel Gas Cutting

2-42Air Fuel Gas Soldering

3-53Oxygen Fuel Gas Brazing

4-5

5-6

6-8

4

5

6

< 1/8

1/8 to

>

Oxygen Fuel Gas Welding

Recommended ShadeNumber*

Minimum Protective

Shade number

Material Size

(inches)Operation

LENS SHADES SELECTION FOR OXYGEN FUEL GAS APPLICATIONS


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Oxygen Gas

Considered by Many as The Most Dangerous Gas

Know the Difference Between Oxygen and Air

Does Not Burn Itself, But Causes Other Materials

To Burn More Vigorously

Heat of Recompression Open Valve Slowly

Keep Away From Combustibles Especially Oil

Do Not Saturate Clothing, etc.

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Combustion Theory

EQUILIBRIUM

3A


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Oxygen Cylinder

High Pressure Cylinder 2200 PSIG or

Higher

Hollow, Seamless Steel Construction

Do Not Abuse Cylinder

Never Use For Other Than Intended Use

Report Any Damage to Supplier

Oxygen Cylinder

High Pressure

Hazard

CapValve

Contents

Vigourously

Supports

Combustion

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4A


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Oxygen Cylinder Valve

Compressed Gas Association(CGA) 540

Stuck Valve Valve WrenchOnly/Call Supplier

High Pressure Safety- Do Not Hang Objects On Cylinder

- Never Tamper With Valve Construction

- Heat Source Can Blow Safety

Only Fully Open or Fully Closed

Report Any Leaking or Damaged

Valve to Supplier

To Oxygen

Regulator

From Oxygen Cylinder

Upper Valve

Seat

Lower Valve

Seat

Burst Disc

Safety

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Moving Oxygen or OtherHigh Pressure Cylinders

Moving Cylinders Not In use:

Must Have Caps On

Do Not Lift Roll on Bottom Edge

Use An Approved Carrier

Moving Cylinders That Are In Use

(Regulators Attached) Must Be In An Approved Carrier!

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NEVER REMOVE THEVALVE PROTECTION

CAP UNTIL

CYLINDER IS

SECURED PROPERLY

6A


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Using Oxygen And Other

High Pressure Cylinder

Gases Secure Cylinder In A Cart Or to Strong

Permanent Structure

Do Not Use Near Flame, Flammables,

Open Arc, Etc.

Use Only In An Upright Position

Use Only In A Well Ventilated Area

Always Inspect Cylinders For Damage

Valve Fully Opened or Closed

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Acetylene Gas

Calcium Carbide and Water

Unstable and Highly Flammable

Shock Sensitive

Lighter Than Air

Not to be used above 15 PSIG

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LiquidPetroleum Gases (LPG)

Propane, Propylene Mapp, Etc.

Liquid UnderPressure

Heavier Than Air

Not Shock Sensitive

Can Be Used Up To Full CylinderPressure

Limited Withdrawal Rate Cylinder Size, % Full, ,and Ambient

Temperature

8A


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Liquid Petroleum Gas (LPG)Cylinder

Hollow Welded Thin Wall Cylinder

Vapor Space Above Liquid

Use Only While Standing Up

Low Pressure Less Than 500 PSIG

Has Fast Acting Valve

Open to 1 Full Turn

Valve Safety Relieves and Resets

Never Use A Damaged Cylinder

CGA #510 Valve

From LPG

Cylinder

To LPG

Regulator

Valve Seat

Packing Nut

Handwheel

Valve Safety

9A


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Acetylene Cylinder

Low Pressure 250 PSIG @ 70o F

Thin Walls, Welded And Easily Damaged

Do Not Abuse Can Explode Because of Abuse

Do Not Use For Other Than The Intended Use

Never Use A Damaged Cylinder Report Damages To Supplier

Do Not Attempt To Repair Leaks

Move Leakers Outside IfPermitted

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Acetylene Cylinder

Fusible

Plug

Monolithic

Porous Filler

Material

FusiblePlug


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Using Acetylene

Flammable Keep Away From Sources of Ignition or Heat

Shock Sensitive May Decompose Violently

Limited Withdrawal Rate 1/7th Rule

Asphyxiation

15 PSIG Maximum Use Pressure

Do Not Use CopperPiping

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Acetylene Fires

Most Fires Start In Valve Area Check for Leaks

Fusible Metal Plugs Melt At 212o F

Flames 5 x 3

Very Difficult To Extinguish

Evacuate Area

Call Fire Department

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Oxy/Fuel EquipmentEquipment Set Up

Secure Cylinders Before Removing Caps

Crack Oxygen Valve and Wipe Fuel Gas Valve With a Clean Cloth

Attach Regulators With Smooth Jawed Wrench

Back Out Adjusting Screws

Torch Valves Must Be Closed

Tighten Wrench Connections According To Manufacturers Instructions

Inspect and Test Equipment

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Secured Cylinders

13A


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Tighten all connections withsmooth jaw wrench

13B


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Equipment Inspection

Look For Any Physical Damage

Look For Signs of Abuse or Improper Use

Look For Contamination Oil, Dirt, etc.

Clean, Replace Or Repair Before Use

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Equipment Testing

Properly Tighten All Connections and Check To See If All Valves Are

Closed

Stand To The side And Open Valves Slowly

Check For Leaks

Use Approved Bubble Solution orP

ressure Test Fix Any And All Leaks Before Proceeding

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Before Lighting Oxy/Fuel GasTorches

Make Sure All Valves Are Closed And Regulator Adjusting Screws Are

Backed Out

Set Gas Pressures According to the Manufacturers Tip Charts

Open Then Close Each Gas Valve Independently To Bleed

The System

Set Pressures At Flow

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OFW Welding Tip

Information

1515151

13133/1613

10103/16101/2

995/3293/8

885/3285/16

771/87

661/863/16

553/3251/8

443/3243/32

331/1631/16

221/1623/64

11--11/32

11--01/64

ACETYLENE

P.S.I.G.

OXYGEN

PSIG

DIA. OF

WELDING ROD

TIP

SIZE

THICKNESS OF METAL

(Inches)

16A


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Lighting An Oxy/AcetyleneTorch

Slightly Open Acetylene Valve And Light With An Approved Device

Root Flame and Clear Smoke

Open Oxygen Valve And Set Flame To Neutral

Sharp, Defined Inner Cone

Never Light Torch With Both Oxygen And Acetylene Flowing

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Welding Flame Types

17A

Carburizing Flame

Neutral Flame

Oxidizing Flame


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Lighting Equal Pressure

Torches Using Alternate

Fuel Gases Open Torch Valves 1/8 to Turn

Ignite Fuel Gas With Approved Igniter and Adjust Flame

Introduce Oxygen And Adjust To The Desired Flame

Tip Edge Touching Plate

StarPattern or Sound

It is Permissible To Light The Flame With Both Gases Flowing

Sometimes Necessary

Adjusting For Large or Heating Tips:

Increase Fuel Then Oxygen In Successive Steps

17B


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Lighting Low PressureInjector Torches

It is Permissible To Light Torch With Both Gases Flowing

Use Special Purge Sequence To Clear The System of Mixed Gases

Open Fuel Gas Valve to Turn

Open Oxygen Valve Slightly 1/8 to Turn

Ignite Flame With An Approved Igniter

Adjust To Desired Flame

Tip Edge Touching Plate StarPattern or Sound

Adjusting For Large or Heating Tips: Increase Fuel Then Oxygen In Successive Steps

17C


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Turning Off An Oxy/AcetyleneTorch

Proper Sequence Checks Integrity of Torch Valves

Close Oxygen Valve First Close Acetylene Valve Second

If Acetylene Valve is Leaking a Small Flame Will Continue Burning

If Oxygen Valve is Leaking, Torch Will Pop as Acetylene Valve IsClosed

If Either Valve Is Leaking, Repair Before Further Use

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Turning Off Alternate FuelTorches

Close Fuel Gas Valve First

Close Oxygen Valve Second

This Sequence Can Prevent The Operator From Being Burned

If Fuel Pressure is Great Enough - Check Valves At Initial Light Up By

Turning Oxygen Off First

18A


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Shutting Down An Oxy/FuelTorch

Overnight Or For An Extended Period of Time

Turn Off Torch Close Cylinder Valves

Open Then Close Each Torch Valve Independently To Bleed Pressure

Back Regulator Adjusting Screw Out Until Loose

Store Hose and Equipment In a Clean Area Away From Potential Damage

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Check Valves andFlashback Arrestors

CHECK VALVES

Are a one way valve that stops the reverse flow of gases

FLASHBACK ARRESTORS

Have a special element that can quench a flame

Usually also include a check valve

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20A


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CHECK VALVES

Are the basic safety device Prevents flash back accidents caused by reverse flow

-Flashbacks can cause the most serious accidents

Check valves can fail because of dirt or othercontamination

-Keep equipment clean

-Check them periodically

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Checkvalves

21A

HOW THEY WORK

CORRECT FLOW REVERSE FLOW


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FLASHBACK ARRESTORS

Flashback arrestors are the ultimate safety device

Usually have a check valve built into it, but, can also stop a flame

-The check valve can fail because of contamination

The Heat sink element will absorb heat from a fire

The element should also be kept free of contamination and checkedperiodically

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Z34-GasWelding-4