AY Honors/Welding/Answer Key

(Instructor Required)

The Welding Honor is perhaps of all the AY honors, the one with the greatest potential to cause injury. Do not attempt to teach yourself how to weld. An experienced instructor is absolutely required for this honor.

1. Identify all parts of the following:

a. Welding and cutting torches

A welding torch has a nozzle with one hole, the torch body mixes oxy and acet, and you get your flame.

A cutting torch has a bunch of nozzles in a circle, with an oxy/acet mix (like the welding torch), and a bigger hole in the middle where oxygen comes out.

The outer holes heat the steel, the inner hole cuts.

b. Oxygen and acetylene gauges and their differences

The pressure regulators enable the user to reduce the high pressure contained in the cylinder to a usable working pressure. There are several handling and set up procedures that are important to the overall operation of the pressure regulator. The pressure regulator on each tank shows two things:

• Cylinder pressure (How much gas is in the cylinder) • Working or line pressure

Installing the regulators

• Before installing the regulator Crack the cylinder valve to clean out any dirt or dust • Mount the regulator onto the cylinder o Ensure that the oxygen pressure regulator is on the oxygen tank • Do Not over tighten regulator nut • Before opening the cylinder valve ensure that the pressure regulator screws are released (turned out) • Never use oil or grease on the regulators o Frictional heat as a result of high pressures can cause oil to ignite and possibly cause an explosion

c. Oxygen and acetylene hoses and their differences

Oxygen hoses are green. Acetylene hoses are red.

HOSES: The oxy acetylene welding hoses are made out of a durable rubber that is designed to withstand different pressures. There are several things to remember about the hoses:

• Red = Fuel • Green = Oxygen • Do not kink hoses • Keep hoses away from work area • Wrap hoses when not in use • Keep hoses away from sparks and hot metal

Hose fittings

• Acetylene fitting are notched • Acetylene fittings are left hand thread • Oxygen fittings are smooth • Oxygen fittings are right hand thread • Both tanks should always be fitted with anti flash back arrestors

d. Oxygen and acetylene tanks and their differences

The oxygen and acetylene cylinders are designed to hold high-pressure gases. There are some important things to remember when using these cylinders:

• Cylinders must always be stood upright and be secured by a chain • When not in use (regulator mounted) they must always have a valve protection cap in place • Cylinders should be stored in a cool dry place away from direct sunlight or extreme cold

Oxygen Cylinders

• Usually red in colour, smaller in diameter and taller than Acetylene • 2200 PSI when full • The cylinder valve must be opened fully (double seated valve) or it could leak! • You should not run an oxygen tank below 50 PSI.

Acetylene Cylinders

• Usually black, large in diameter and short • 250 PSI when full • The cylinder valve should only be opened ¼ of a turn. • The acetylene cylinder should never be laid down as this will result in the gas becoming unstable. • You should not run an acetylene tank below 50 PSI.

2. Explain the safe working pressures of oxygen and acetylene, as per your instruc­tor's directions, for various procedures.

When welding and brazing with an oxy-acetylene torch, acetylene should be set at 5psi. Oxygen should be set at 5 or 6psi, but no more.

When cutting with an oxy-acetylene torch, acetylene should again be set at about 5psi. Oxygen, however is set much higher, about 25psi, when cutting.

OXY ACETYLENE START UP PROCEDURE:

These steps must be followed to ensure safe usage of this equipment.

1. Make sure pressure regulator screws are released (turned out) on both tanks. 2. Standing to the side of the regulator, Slowly open the oxygen cylinder valve fully 3. Standing to the side of the regulator, Slowly open the Acetylene cylinder valve ¼ turn 4. With the welding or cutting adjustment valves open, quickly adjust the working pressure to the desired amount

OXY ACETYLENE SHUT DOWN PROCEDURE:

After the equipment has been used these steps must be followed to ensure safe storage:

• Close both cylinder valves • Open the welding or cutting attachment valves to release regulator pressure • Release pressure regulator adjustment screws • Wrap up hoses

10. There will be no horseplay.

7. Explain the safety precautions and safety equipment normally used in electric welding in relation to eyes, hands, and exposed skin areas. Why should the tank valves never be oiled?

SAFETY EQUIPMENT:

The correct safety equipment must be used when using the oxy acetylene equipment or electric welding.

• Wear shaded safety glasses • Use gloves during torch operation and when handling hot metals • Follow all safety rules for this and all other equipment

OXY-ACETYLENE SAFETY

 You must be trained and authorized before using the oxy-acetylene torch

 Make sure you do not have a lighter in your pocket – they can explode!

 Ensure gas bottles are upright and secure at all times

 Do not allow oil or grease to come in contact with hoses or equipment

 Perform all welding and cutting in the welding area – ventilation must be turned on

 Approved goggles and spark resistant clothing must be worn when using the oxy-acetylene torch

 Do not weld or cut a closed container

 Make sure the work area is clear

 Open the cylinder valves slowly – stand to the side!

 Light the torch with the striker – do not use a match or a lighter

 When welding, bend the end of the rod to identify the hot end and to prevent eye injury

 When finished turn off the torch valves, turn off cylinder valves, then go back to the torch and bleed both lines

 Keep the cylinder caps on when not in use

8. Explain the difference between oxyacetylene and electric arc welding.

Oxy-acetylene welding uses two gases in the process of producing a weld. Acetylene, which is the fuel and is the main source of heat, and oxygen, which is a propellant.

Electric arc welding does not use gas to produce a weld like oxy-acetylene welding does. Electric arc welding uses an electric current to produce its welds. A clamp, with the one side of the current flowing through it, is attached to a base plate. Then the another clamp/nozzle, with the other side of the current flowing through it, is held in a hand. A filler rod is then used to complete the circuit and create the heat needed to heat the pieces of metal being joined and melt the filler rod (used to bind the pieces of metal together).

References

• Steelworker, Volume 1, A U.S. Navy Training Manual. As an original document produced by the U.S. government, this publication is in the public domain and has a lot of information that should be incorporated into this text.