Welding

Question 1

What type of well joint must be used to weld magnesium

Answer 1

Only butt welds are used to weld magnesium.

This is to prevent possibility of trapping contaminants

Question 2

Why must of flux be removed from the metal after welding magnesium

Answer 2

Any flux left on the metal will result in severe corrosion

Question 3

What must be done in order to successfully weld titanium

Answer 3

The weld zone must be shielded within an inert gas such as helium or argon

Question 4

What is gas shielded arc welding

Answer 4

Gas is used as a covering shield around the ark to prevent the atmosphere from Contaminating the weld

Question 5

What are the advantages of gas shielded arc welding

Answer 5

It results in a stronger, More ductile, and more corrosion resistant weld

Question 6

What shielding gases are used for gas tungsten arc welding

Answer 6

Helium and argon

Question 7

What is an advantage of electric arc welding over gas welding

Answer 7

It causes less buckling and warping of the welded material

Question 8

What determines the amount of heat that will be applied to the work when welding by the Oxy-acetylene method

Answer 8

The torch tip office size or diameter

Question 9

What is meant by a soft flame

Answer 9

When the torch is adjusted so the flame makes no noise, and doesn’t push the weld puddle

Question 10

When gas welding, what should be turned off first

Answer 10

First shut off the acetylene, then the oxygen source

Question 11

What will be the result of using a torch tip that is too large or to small

Answer 11

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

Question 12

How do you determine the correct size filler rod to be used in welding

Answer 12

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

Question 13

What is the function of flux when used in soldering

Answer 13

Flux erodes corrosion from the surface of the metal when it is heated so the solder can form a strong bond

Question 14

Why must acid core solder never be used in electrical wires

Answer 14

Any acid flux that is left over will cause severe corrosion to the wire

Question 15

What is brazing

Answer 15

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

Question 16

What is one method of controlling expansion when welding a joint

Answer 16

By track welding at intervals along the joint

Question 17

Why is it especially desirable to use a soft flame when welding aluminum

Answer 17

To avoid blowing holes in the metal when the puddle is formed

Question 18

What fuel is used for gas welding aluminum

Answer 18

Oxygen and hydrogen

Question 19

What is the purpose of using flux when welding aluminum

Answer 19

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

Question 20

What is the maximum safe pressure for acetylene gas When welding

Answer 20

No more than 15 psi

Question 21

How can dents at a steel tube cluster joint be repaired

Answer 21

Weld a specially formed steel patch over the dented area and surrounding tubes

Question 22

What type of flame should be used when silver soldering

Answer 22

The flame should be neutral

Question 23

What are the procedures for preparing a metal fuel tank for welding

Answer 23

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

Question 24

When splicing tubing by the inner sleeve method, what method can be used to insert a tight fitting inner sleeve into the replacement tube

Answer 24

The inner sleeve can be chilled with dry ice or cold water, and the outer sleeve can be heated

Question 25

Why is flux used on silver solder

Answer 25

It cleans the base metal of oxide to ensure good bond

Question 26

Name three types of welding

Answer 26

Resistance, arc, gas