Vermicular graphite is an undesirable microstructural feature in the ductile iron; however it is the desired type of graphite in:
D Compacted graphite cast iron
The carbon equivalent value for a 3.5 wt. % C cast iron containing 1.5 wt. % Si and 0.1wt. % P.
B 4.03 %
We typically expect the strength of a cast iron to
B Decrease when the carbon equivalent increases
According to the AFS-ASTM A247 standard, the following graphite flake pattern is produced by the slow solidification of a hypereutectic grey cast iron:
E Type I
Suppose you treat liquid iron with magnesium, innoculate, then wait 10 minutes before pouring. If you produce a white cast iron microstructure instead of ductile iron, then you expect the
B Inoculating agent faded
Production of the following alloy cast iron requires addition of 20 wt. % Ni:
B Austenitic cast iron
According to ISO 5922, the following designation W 45-10 is for the following malleable cast iron:
B This is a whiteheart malleable cast iron with a minimum tensile strength of 450 MPa and % elongation of 10%
Which of the following types of cast irons is endangered by fast solidification rate?
A white cast iron
which of the following phases are said to be metastable?
E cementite, and martensite
What range of carbon defines Fe-C as cast iron?
A 2.0 - 6.67 wt%
Which of these alloys are used for service temperatures in the range between 500℃ and 1,000℃?
E Refractory alloys
The wing of an aircraft made out of a metal alloy is an example of a
B Wrought product
An automotive engine block is an example of a
A Cast product
What is the average carbon content of AISI 1080 steel?
D 0.80 wt.% C
which of the following statements best describes cast irons?
C An alloy of carbon in iron
What range of carbon percentages defines Fe-C alloy as steel?
C 0.02 - 2.0 wt.%C
What is the average carbon content of AISI 4330 steel?
A 0.30 wt.%C
Which of the following statements are not true?
1 Si enhances graphitization, and thus increases the tendency of graphite to transform to cementite
2 Cr enhances the chilling tendency in a solidifying cast iron.
3 C Grey cast iron formation is promoted by either a high carbon with the low silicon or a low carbon with high silicon
4 In general, grey cast iron formation is enhanced by slow solidification rate, high Cr content , and low Si
5 Cast irons with carbon equivalent values of 4.3 wt. % are called hypoeutectic irons.
6 Flake graphite cast irons are inoculated to reduce chilling tendency.
7 The gray iron eutectic reaction: Liquid → Austenite + graphite occurs at 1,153०c and carbon equivalent of 4.30 wt. %
8 The L → ૪ + Fe3C eutectic reaction is the metastable reaction that produces ductile cast iron
9 The excellent damping capacity of graphite-based cast iron is independent of the nature and size of the graphite in cast iron.
10 None of the above
1, 4, 5, 8, and 9
As an engineer in a malleable cast iron foundry which of the following would concern you:
Increase the molten metal temperature prior to pouring it into the casting mold.
Incoming raw material with the composition 2 wt. % Si, 0.8 wt. % Mn, and 0.4 wt. % S.
A suggestion by a crew supervisor to inoculate melts 20 minutes before pouring.
Suggestion by one of the foundrymen to cast a thin section in a sand mold.
Suggestion by an experienced shop floor worker in the foundry to use a high-Cr raw material to cast a thin section in a copper mold.
Changing to a new supplier whose raw material is cheaper but has slightly higher carbon and lower Cr (with the same Si level) than your present supplier.
Increase the molten metal temperature prior to pouring it into the casting mold. $$$$ Incoming raw material with the composition 2 wt. % Si, 0.8 wt. % Mn, and 0.4 wt. % S. $$$$ Suggestion by one of the foundrymen to cast a thin section in a sand mold. $$$$ Changing to a new supplier whose raw material is cheaper but has slightly higher carbon and lower Cr (with the same Si level) than your present supplier.
Amorphous Polymers exhibit which properties?
No melting temperature - broad softening temperature, Usually transparent, Low shrinkage, Solvent sensitive, Poor fatigue and wear resistance properties
Crystalline Polymers exhibit which properties?
sharp melting temperatures, Usually opaque, High shrinkage, Solvent resistive, Goor fatigue and wear resistance properties
Which one of the following is the correct definition of ultimate tensile strength, as derived from the results of a tensile test on a metal specimen?
C The maximum load divided by the original area of specimen
Which one of the following types of stress-strain relationship best describes the behavior of most metals at room temperature?
B Elastic and strain hardening
The shear strength of metal is usually
A Greater than its tensile strength
The stress at which the maximum force that can be withstood by either a ductile or a brittle material is called the:
A Tensile strength
B Modulus of elasticity
C Yield strength
D Breaking strength
ATensile strength
The slope of stress-strain curve, which is determined primarily by the strength of the atomic bonds within the material, is called the:
C Modulus of elasticity
What does manganese do as an alloy in steels?
D combine with sulfur to prevent brittleness and improves hardenability
Which of theses are not base physical properties of materials?
G corrosion
Which part has the greater stress:(i) a rectangular aluminum bar of 24.6 mm x 30.7 mm cross section, under a load of 7,640 kg; or (ii) a round steel bar whose cross sectional diameter is 12.8 mm under a 5,000 kg load?
B The Round steel bar
What is Damping Capacity?
The ability to absorb vibrations
An age hardening alloy is
B A heat treatable alloy
The location of the specimen taken in a metallographic study is determined by:
C The purpose of the metallographic study
What are the typical etchants used for the macroetching of steel?
D A heated 50% conc. HCl solution at 70/80 degrees C for 13-30 minutes
What are the typical etchants used for the microetching of aluminum and its alloys?
C Keller's reagent and Graff/Sargent
Which of the following metallic elements is the most abundant on the earth?
A. Aluminum
Which of the cast irons above is/are produced by heat treatment of the cast product?
