MMET 207 EXAM 3 QUESTIONS AND ANSWERS
What are the techiques for corrosion control: Design - Answers :Crevice control
No metal mixes
Corrosion allowace
Anodic protection
Cathodic protection
Welding Practice
Stagnant Areas
Hot spots
What are the techniques for corrosion control: Environment control - Answers :pH
Temperature
Velocity
Concentration
Inhibitors
Cleaning
Aeration
What is cladding and how does it help? - Answers :Bonding a surface layer of a metal or
an alloy with good corrosion resistance and anodic to the core alloy to the core alloy to
improve corrosion resistance
What is the difference between cladding and coating? - Answers :
Types of Cast irons - Answers :Alloy Cast Irons
Gray Cast Iron
Malleable Cast Iron
White Cast Iron
Ductile Cast Iron
Alloy Cast Iron:
Process - Answers :
Malleable Cast Iron:
Process - Answers :Made by converting a white iron to either a ferrite or a pearlite
matrix with the excess carbon present in the form of a small flowerike nodules called
temper
Gray Cast Iron: Properties - Answers :Good Damping Capacity
Corrosion Resistance
Increasing Tensile and Yield strength
Increasing Resistance to Wear
Increasing Modulus of Elasticity
Increasing Quality of finish for machined surfaces Decreasing ability to Dampen
vibration
, Decreasing resistance to thermal shock
Decreasing Machinability
Decreasing Castability
Ductile Cast Iron:
Process - Answers :Convert White iron to either ferrite or pearlite matrix with excess
carbon present as flowerlike nodules called temper carbon.
First stage of graphitization - Free cementite and pearlite dissolve in austenite
Second stage of graphitization - Temper carbon and ferrite/pearlite forms
White Cast Iron:
Process - Answers :Gray iron will form a white-iron structure when rapidly cooled from
the casting temperature. Nade by casting in metal or graphite molds or by using metal
inserts in sand molds.
Gray Cast Iron: Can they be machined or welded? - Answers :Machined yes but they
are prone to cracking during welding
Gray Cast Iron:
Process - Answers :
Gray Cast Iron: Chemistry - Answers :2% to 4% Carbon
1% Silicon
Gray Cast Iron: What are they used for? - Answers :General Purpose
White Cast Iron
Chemistry - Answers :2% to 4% carbon
0.5% to 2% Silicon
0.5% manganese
White Cast Iron
Can they be machined or welded? - Answers :No
White Cast iron
Properties - Answers :High hardness
High compressive strength
Excellent wear resistance
White Cast Iron
What are they used for? - Answers :Mining and Agriculture
Ductile Cast Iron
Chemistry - Answers :3% to 4% carbon
2% to 3% silicon
May contain signigicant nickel additions
What are the techiques for corrosion control: Design - Answers :Crevice control
No metal mixes
Corrosion allowace
Anodic protection
Cathodic protection
Welding Practice
Stagnant Areas
Hot spots
What are the techniques for corrosion control: Environment control - Answers :pH
Temperature
Velocity
Concentration
Inhibitors
Cleaning
Aeration
What is cladding and how does it help? - Answers :Bonding a surface layer of a metal or
an alloy with good corrosion resistance and anodic to the core alloy to the core alloy to
improve corrosion resistance
What is the difference between cladding and coating? - Answers :
Types of Cast irons - Answers :Alloy Cast Irons
Gray Cast Iron
Malleable Cast Iron
White Cast Iron
Ductile Cast Iron
Alloy Cast Iron:
Process - Answers :
Malleable Cast Iron:
Process - Answers :Made by converting a white iron to either a ferrite or a pearlite
matrix with the excess carbon present in the form of a small flowerike nodules called
temper
Gray Cast Iron: Properties - Answers :Good Damping Capacity
Corrosion Resistance
Increasing Tensile and Yield strength
Increasing Resistance to Wear
Increasing Modulus of Elasticity
Increasing Quality of finish for machined surfaces Decreasing ability to Dampen
vibration
, Decreasing resistance to thermal shock
Decreasing Machinability
Decreasing Castability
Ductile Cast Iron:
Process - Answers :Convert White iron to either ferrite or pearlite matrix with excess
carbon present as flowerlike nodules called temper carbon.
First stage of graphitization - Free cementite and pearlite dissolve in austenite
Second stage of graphitization - Temper carbon and ferrite/pearlite forms
White Cast Iron:
Process - Answers :Gray iron will form a white-iron structure when rapidly cooled from
the casting temperature. Nade by casting in metal or graphite molds or by using metal
inserts in sand molds.
Gray Cast Iron: Can they be machined or welded? - Answers :Machined yes but they
are prone to cracking during welding
Gray Cast Iron:
Process - Answers :
Gray Cast Iron: Chemistry - Answers :2% to 4% Carbon
1% Silicon
Gray Cast Iron: What are they used for? - Answers :General Purpose
White Cast Iron
Chemistry - Answers :2% to 4% carbon
0.5% to 2% Silicon
0.5% manganese
White Cast Iron
Can they be machined or welded? - Answers :No
White Cast iron
Properties - Answers :High hardness
High compressive strength
Excellent wear resistance
White Cast Iron
What are they used for? - Answers :Mining and Agriculture
Ductile Cast Iron
Chemistry - Answers :3% to 4% carbon
2% to 3% silicon
May contain signigicant nickel additions
