Welding Flashcards
What type weld joint must be used to weld magnesium?
Only butt welds are used to weld magnesium. This is to prevent the possibility of trapping the flux
Why must all 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 with an inert gas such as helium or argon.
What is gas shielded arc welding?
A gas is used as a covering shield around the arc to prevent 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 is an advantage of electric arc welding over gas welding?
It causes less buckling and warping of the welded material.
What will be the result of using a torch tip that is too large or too small?
If the torch tip is too large the heat will be too great and holes may be burned in the metal. If the torch tip is too small, the heat provided may be insufficient 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?
Welding rods are made in standard 36”lengths, and in diameters from 1/16 inch to 3/8 inch. The diameter of the rod to be used is governed by the thickness of the metals being joined. If the rod is too small, it will not conduct heat away from the puddle rapidly enough, and a burned weld will result. A filler rod that is too large will chill the puddle. As in selecting the proper size torch tip, experience enables the welder to select the proper diameter welding rod.
What is brazing?
Brazing is a metal joining process in which the bonding material is a non-ferrous metal with a melting point lower than that of the metals being welded. 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 tack 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 is the purpose of using flux when welding aluminum?
Aluminum and its alloys combine with air and form oxides very rapidly, and oxides form doubly fast if the metal is hot. Aluminum welding flux is designed to remove the aluminum oxide by chemically combining with it. Aluminum fluxes 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?
When acetylene gas is compressed in a container to a pressure greater that 15 psi it becomes dangerously unstable. At 29.4 psi acetylene is self-explosive and only a slight shock can cause it to explode.
How can dents at a steel tube cluster joint be repaired?
Weld a specially formed steel patch plate over the dented area and surrounding tubes.
What type of flame should be used when silver soldering?
The flame should be neutral
