ME381 Manufacturing Exam 1
The chemical formula for polyisoprene in natural rubber is:
C5H8
What elements are traditionally alloyed with copper to form (a) bronze and (b) brass?
(a) Sn and (b) Zn
What is considered a basic metal shaping process? Welding Electroplating Heat treating Casting
Casting
As the degree of crystallinity in a given polymer increases, the polymer becomes denser and stiffer, and its melting temperature decreases: T or F
False
Which one is NOT an application for Molybdenum? Die casting molds; Filament wire for incandescent light bulbs; Jet engine parts; Heat shields
Filament wire for incandescent light bulbs
Which the alloying elements increase hot hardness in steel: Mo, Co, W, P, Cr
Mo, W, Cr
Besides high carbon content, what other alloying element is characteristic of the cast irons? Silicon, Cobalt, Cadmium, Manganese
Silicon
A branched molecular structure is stronger in the solid state and more viscous in the molten state than a linear structure for the same polymer: T or F
T
The basic difference between low density polyethylene and high density polyethylene is that the latter has a much higher degree of crystallinity: T or F
True
Degree of polymerization is which one of the following sum of the molecule weights of the mers in the molecule proportion of the monomer that has been polymerized average number of mers in the molecule chain none of the above
average number of mers in the molecule chain
From which of the following ores is aluminum derived: cementite, alumina, scheelite, bauxite, hematite
bauxite
Which of the following is not an elastomer? butyl rubber styrene-butadiene rubber polyisoprene cellulose polyurethane polybutadiene
cellulose
Which of the following polymers are normally thermoplastic? Phenolics Cellulose acetate Polyisoprene Acrylics Polychloroprene Polyesters Polyethylene Nylon Polyurethane
cellulose acetate, acrylics, polyethylene, nylon
Which of the following alloying elements are most commonly associated with stainless steel (two best answers): tungsten chromium nickel molybdenum manganese
chromium and nickel
Which of the following is the most important cast iron commercially: gray cast iron ductile cast iron white cast iron malleable iron
gray cast iron
What property is titanium NOT noted for: high electrical conductivity; high temperature strength, corrosion resistance (due to the formation of a thin but tough oxide film), high strength-to-weight ratio
high electrical conductivity
What are some of the properties aluminum is NOT noted for: high temperature strength high thermal conductivity good corrosion resistance ( due to the formation of a tough oxide film on its surface) low density
high temperature strength
What properties does Boron add as an alloying element? Reduces cutting friction and decreases hardness; Largely increases hardenability and improves surface finish; Increases weldability and reduces corrosion; Increases wear-resistance and hot-hardness ability
largely increases hardenability and improves surface finish
Which one of the following metals has the lowest density: magnesium, tin, titanium, aluminum
magnesium
Which of the following metals has the highest density: lead, gold, platinum, tungsten, silver
platinum
Which of the following plastics has the highest market share: polypropylene, polyvinylchloride, polyethylene, phenolics, polysterene
polyethylene
The following repeat unit is for a polymer that is used in the fabrication of milk jugs. H H I I --C--C-- I I H CH_3 Name the polymer.
polypropylene (PP)
The following repeat unit is for a polymer that is used in the fabrication of soda bottles. O O H H II II I I --C--(())--C--O--C--C--O-- I I H H Name the polymer.
polythylene terephthalate (polyester, PET)
Which of the following is NOT a class of superalloys: nickel-based alloys, cobalt-based alloys, iron-based alloys, potassium-based alloys
potassium-based alloys
Which metal is NOT refractory: molybdenum (Mo) selenium niobium (Nb) tungsten (W) tantalum (Ta)
selenium