Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Unit 23 Using Gas Welding Equipment

Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED.

Unit 23

Using Gas Welding Equipment


Gas Welding

• The burning qualities of a gas are used to heat, cut, and weld metals

• Compressed gases can be very dangerous

• The most popular fuel gases for welding are propane and acetylene

• Fuel gases must be mixed with oxygen before they will burn


Safety Precautions• Wear safety goggles and face shield at all times• Obtain instructor’s permission before using any gas• Store fuel gas cylinders and oxygen cylinders separately• Keep cylinders upright and chained at all times• Store cylinders in well-ventilated areas• Do not put pressure on the hoses or equipment connected

to cylinders• Always check for leaks before using• Never use equipment exposed to grease or oil• Follow specific on/off procedures


Safety Precautions (continued)

• Work only in areas free of flammable materials• Always have fire extinguishers nearby• Wear leather gloves and apron• Always screw on caps when cylinder is not in use• Always point equipment away from people and clothing• Never leave clothing where it can be saturated by fuel

gases or oxygen• Learn to recognize combustible fuel odors• Protect gas cylinder storage areas with locked fences or

concrete enclosures


Oxyacetylene Equipment

• Cart

• Cylinders

• Valves

• Regulators

• Gauges

• Hoses

• Torch assemblies


Set Up

• Cylinder design features– Acetylene cylinder valve protected by a high collar

– Acetylene valve turned on or off with a handle

– Acetylene equipment color-coded red

– Acetylene couplings have left-hand threads and notched fittings

– Oxygen cylinder valve protected by a heavy cap

– Oxygen color-coded green

– Oxygen couplings have right-hand threads


Leak Tests

• Leak tests should be performed when– equipment is first set up– cylinders are changed– odor of acetylene is present

• To test– Put a small amount of water in a jar or can– Add a drop or two of non-detergent hand soap– Use a 1'' paintbrush to get a soapy lather and apply gently around

each fitting or any connection where gas can escape– Bubbles will form if there is a leak


Torches

• Two types– welding– cutting

• Both types include a body/handle with hose connections and valves

• Tips are screwed onto the body• Tips are available in different sizes• A cutting assembly can also be attached to the

handle


Important Terms

• Weld: to join by fusion• Fusion: to melt together• Gas: any fluid substance that expands without

limit• Compress: to reduce in volume by applying

pressure• Flammable: burns easily• Apparatus: objects necessary to carry out a

function


Important Terms (continued)

• Manifold: a pipe with two or more outlets• Rig: a self-contained piece of apparatus assembled

to conduct a specific operation• Oxyacetylene: oxygen and acetylene• Torch: assembly that mixes gases and discharges

them to support a controllable flame• Cylinder: long, round tank with extremely thick

walls built to contain gases under great pressure



• Valves and regulators: devices that control or regulate the flow of a gas

• Gauge: measures the gas pressure in a hose, tank, or manifold

• Hoses: flexible lines that carry gases• Crack the cylinder: turning the gas on and off

quickly to blow away any dust from the opening• Purge the lines: remove undesirable/leftover

gases in the welding hoses



• Carbonizing flame: excess acetylene present in the flame

• Neutral flame: correct balance of acetylene and oxygen in the flame

• Oxidizing flame: excess oxygen in the flame• Tip cleaners: rods with rough edges designed to

clean the hole in the welding tip• Bleeding the lines: removing gases from all lines

and equipment

Documents

Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Unit 23 Using Gas Welding Equipment