Welding Flashcards
What type of well joint must be used to weld magnesium
Only butt welds are used to weld magnesium.
This is to prevent possibility of trapping contaminants
Why must of flux be removed from the metal after welding magnesium
Any flux left on the metal will result in severe corrosion
What must be done in order to successfully weld titanium
The weld zone must be shielded within an inert gas such as helium or argon
What is gas shielded arc welding
Gas is used as a covering shield around the ark to prevent the atmosphere from Contaminating the weld
What are the advantages of gas shielded arc welding
It results in a stronger, More ductile, and more corrosion resistant weld
What shielding gases are used for gas tungsten arc welding
Helium and argon
What is an advantage of electric arc welding over gas welding
It causes less buckling and warping of the welded material
What determines the amount of heat that will be applied to the work when welding by the Oxy-acetylene method
The torch tip office size or diameter
What is meant by a soft flame
When the torch is adjusted so the flame makes no noise, and doesn’t push the weld puddle
When gas welding, what should be turned off first
First shut off the acetylene, then the oxygen source
What will be the result of using a torch tip that is too large or to small
If two large, the heat will be too great and holes may be burned in the metal
It’s too small the heat provided may be in efficient to produce penetration to the proper depth causing a low strength weld
How do you determine the correct size filler rod to be used in welding
The thickness of the metal being joined. Rods are made and 36 inch Lengths, and diameters from 1/16 to 3/8 in.
If the rod is too small, it will not contact heat away from the puddle rapidly enough, and a burned weld will result. A filler rod that is too large for cool the puddle too quickly and not allow for proper penetration
What is the function of flux when used in soldering
Flux erodes corrosion from the surface of the metal when it is heated so the solder can form a strong bond
Why must acid core solder never be used in electrical wires
Any acid flux that is left over will cause severe corrosion to the wire
What is brazing
A joining process in which bonding material is a nonferrous metal with a melting point lower than of the metals being used. It includes silver soldering, copper brazing, and aluminum brazing. It can be used to join metals that are damaged by high heat
What is one method of controlling expansion when welding a joint
By track welding at intervals along the joint
Why is it especially desirable to use a soft flame when welding aluminum
To avoid blowing holes in the metal when the puddle is formed
What fuel is used for gas welding aluminum
Oxygen and hydrogen
What is the purpose of using flux when welding aluminum
Aluminum and it’s alloys combined with air and form oxides very rapidly, and oxides form doubly fast if the metal is hot.
aluminum weld flux is designed to remove the aluminum oxide by Chemically combining With it.
Aluminum flexes dissolve below the surface of the puddle and float the oxides to the surface where they can be removed
What is the maximum safe pressure for acetylene gas When welding
No more than 15 psi
How can dents at a steel tube cluster joint be repaired
Weld a specially formed steel patch over the dented area and surrounding tubes
What type of flame should be used when silver soldering
The flame should be neutral
What are the procedures for preparing a metal fuel tank for welding
The tank should be washed with hot water and detergent, then steamed for 30 minutes. Then fill the tank with CO2 gas from a fire extinguisher and seal the tank except for a small vent hole
When splicing tubing by the inner sleeve method, what method can be used to insert a tight fitting inner sleeve into the replacement tube
The inner sleeve can be chilled with dry ice or cold water, and the outer sleeve can be heated
Why is flux used on silver solder
It cleans the base metal of oxide to ensure good bond
Name three types of welding
Resistance, arc, gas
