Setting expansion is advantageous in__________________?
A. Casts
B. Models
C. Investment
D. Dies
Metallurgy
Back pressure porosity can be avoided by________________?
Back pressure porosity can be avoided by________________?
A. Using asbestos linear
B. Placing the sprue at least one quarter inch away form the end of casting ring
C. Preventing rapid heating the investment in burnout oven
D. Using a short and wide sprue
Which of the following zones is used for melting alloy during casting______________?
Which of the following zones is used for melting alloy during casting______________?
A. Reducing flame
B. Oxidizing flame
C. Green flame
D. All of the above
Cleaning of base metal alloy is done by______________?
Cleaning of base metal alloy is done by______________?
A. Warm HCI
B. Cold HF
C. Cold H2SO4
D. Sand blasting with aluminium oxide
Which one of the following is most elastic ?
Which one of the following is most elastic ?
A. a titanium
B. B titanium
C. Chrome-cobalt-nickel
D. Nickel-titanium
A thinner mix of a gypsum bonded investment will_______________?
A thinner mix of a gypsum bonded investment will_______________?
A. Produce a smoother casting
B. Decrease setting expansion
C. Increase setting expansion
D. Increase thermal expansion
Stainless steel orthodontic wire can be hardened by________________?
Stainless steel orthodontic wire can be hardened by________________?
A. Tempering
B. Work hardening
C. Age hardening
D. Precipitation hardening
Pickling________________?
Pickling________________?
A. Is accomplished by soaking the casting in baking soda
B. Causes porosity in gold
C. Removes surface oxides from gold castings
D. Remove investment from gold casting
NiTi alloy have_______________?
NiTi alloy have_______________?
A. Shape memory
B. Hyper rigidity
C. Corrosion resistance
D. Weldable properties
The main form of iron carbide found in 18-8 steel________________?
The main form of iron carbide found in 18-8 steel________________?
A. Martensite
B. Ferrite
C. Austenite
D. Pearlite