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.
1. Always use goggles when welding or cutting
2. Use aprons and gloves.
3. Do not point the flame towards the regulators and another person.
4. When finished welding shut off the main valves , bleed the lines and loosen the regulator adjusting screws.
5. Wind up the hoses when finished shutting everything off.
6. Do not turn acetylene valve more than 1 ½ turns.
7. Never use oil near oxygen equipment
8. Threads used for acetylene are LEFT-HANDED.
9. Threads used for oxygen are RIGHT HANDED.
10. There will be no horseplay.
3. While blindfolded, demonstrate ability to hook up an entire oxyacetylene kit, including tanks, gauges, hoses, and torches, and light the same.**
4. As per your instructor's directions, weld two mild steel test plates (1/8 inch x 1 inch x 8 inches) (0.3 cm x 2.5 cm x 20.3 cm) in horizontal, and vertical positions.
5. Use a cutting torch and demonstrate your skill by making one 12 inches (30.5 cm) straight-line cut, one circle cut of at least 3 inches (7.6 cm) in diameter and one 3 inch (7.6 cm) star cut. The cuts are to be made on mild steel plate at least 1/4 inch (0.6 cm) thick.
6. Demonstrate your ability to braze a cast-iron object with at least 1/4 inch (0.6 cm) double bevel butt weld 2 inches (5 cm) long.
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?
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).
9. Demonstrate ability to select from an electrode guide the proper amperage and electrode for various types and thicknesses of metal.
10. Demonstrate ability to weld flat, vertical, horizontal, and overhead on (1/8 inch x 1 inch x 8 inches) (0.3 cm x 2.5 cm x 20.3 cm) mild steel test plates.
Note: An instructor is a must. Welding is a very critical and serious skill to learn and is not a home-type course. Welding essentially takes the place of bolts and rivets, and if not properly done, is most dangerous. Example: A trailer hitch not properly bonded, or machinery exposed to the strain of pull or weight, is an invitation to disaster.
Note: ** This requirement demonstrates one's skill in working in darkness, such as in an emergency. All acetylene connection threads are left-handed, while all oxygen connection threads are right-handed.
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.
