Welding Flashcards
What type of weld joint must be used to weld magnesium?
Butt welds, in order to prevent trapping of contaminates.
Why must all flux be removed from the metal after welding magnesium?
To prevent severe corrosion.
What must be done in order to successfully weld titanium?
Welded in an inert gas such as Helium or Argon.
What is gas shielded arc welding?
A gas is used as a cover shield around the arc to prevent oxidation and contamination from the atmosphere during the weld.
What are the advantages of gas-shielded arc welding?
Stronger, more ductile, more corrosion-resistant weld.
What is an advantage of electric arc welding over gas welding?
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 diameter or orifice size of the torch tip.
What will be the result of using a torch tip that is too large or too small?
Too large and you may burn the material (too hot). Too small and you may have insufficient penetration (too cold).
How do you determine the correct size rod to be used in welding?
Rod size is determined by the thickness of the metals being joined. Too small, and a burned weld will result. Too big, and the weld will become cold (chill the puddle). Rods are from 1/16” to 3/8”
What is brazing?
A metal joining process using a non-ferrous metal as bonding material. The joining metal has a melting point lower than the metals being joined, preventing damage to the metals being joined 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 creating cavities (“blowing holes”) through the metal when the puddle is formed.
What is the purpose of using flux when welding aluminum?
Using flux helps prevent the buildup of oxides during welding. Flux forces oxides to float to the surface where they can be removed.
What is the maximum safe pressure for acetylene gas when welding?
Less than 15 psi when compressed in a container. At 16 psi, acetylene becomes unstable and at 29.4 psi, a slight shock can cause an explosion (self-explosive).
How can dents on a steel tube cluster joint be repaired?
Weld a specially formed steel patch over the dented area.
