Welding Skills Chapter 42

What are 2 common applications for magnesium and why?

Aerospace components and auto racing parts because of it's high strength to weight ratio

What shielding gas is typically used to weld aluminum and why?

Argon-helium for maximum penetration must most of the time argon

What are the major factors the affect the weld-ability of aluminum?

Cleanliness of the weld area, ability to heat treat, and desired appearance after welding

What are 2 categories of aluminum?

Heat-treatable and non heat-treatable

How does the welding of non heat-treatable alloys effect the HAZ?

It causes a loss of strength in the HAZ

What must the oxide film on aluminum be removed?

It melts at 3X the melting temperature of the base metal and will prevent molten aluminum from fusing properly

Why is AC current used to weld aluminum?

It removes oxide film by breaking it apart during the cycle when the electrode is positive

What problems can titanium oxide cause if not removed before welding?

It will cause problems with fusion, contamination of the weld, and weld bead embrittlement

What is most important for welding nickel alloys?

Joint cleanliness, because they will crack from contamination

what types of applications is nickel typically used?

Nickel alloys are used for: high-temp strength and extreme corrosion resistance

What are two means by which non ferrous metals are strengthened?

Strain hardening (work hardening) and precipitation hardening (age hardening)

Why does aluminum require more heat input than steel?

aluminum conducts heat 3-5 times faster than steel, more heat is needed to compensate for the rapid cooling

Why are jigs in fixtures require for welding copper?

because of it's very high coefficient of thermal expansion