Properties Flashcards
What do the digits of the SAE/AISI steel designate?
XXXX
First two indicate the material in the steel, second two digits indicate carbon content (10 = 0.1%)
1010 Steel = low carbon steel with .1% carbon content
What is 4130 steel composition?
Chrome-Moly steel with 1% Chrome and 0.3% Carbon
composition 5130 steel?
1% Chromium steel with 0.3% carbon
Define Wallner Lines
Failure analysis tool, especially in amorphous/polycrystalline materials like glass. Wallner lines are rib shaped marks which indicate crack propagation direction. the wallner line is perpendicular to the crack propagation direction.
What element will increase tensile strength of steel?
Carbon content
What type of indenter does the Brinell Hardness test use, and what is the abbreviation?
10mm sphere of steel or tungsten, BHN
What type of indenter does the Vickers Hardness test use, and what is the abbreviation?
symmetrical Diamond pyramid, VHN
What type of indenter does the Knoop microhardness test use, and what is the abbreviation?
elongated diamond pyramid, KHN
What type of indenter does the Rockwell Hardness test use (for each grade), and what is the abbreviation?
A, C, D - Diamond Cone
B, F, G - 1.6 mm steel sphere
E - 3.2 mm steel sphere
Abbreviation: R (subscript)
Define Hardness
a measure of resistance to permanent plastic deformation
What affect on material properties does grain size have?
Elastic modulus
Strength
Hardness
Ductility
Smaller grain size = higher strength, higher hardness.
DOES NOT DECREASE DUCTILITY or Elastic Modulus
What does the Hall Petch Equation describe?
That yield strength is inversely proportional to the square root of the grain size.
Smaller grains = stronger material
What factors can affect the Young’s modulus (elastic modulus) of a given material?
Trick Question. Young’s modulus is a material property and cannot be altered by processing.
How to calculate density of composite given densities of components? 80% composite 1 and 20% composite 2
Assume 100g composite, then divide 80g by density 1 and 20g/density 2. Add 2 volumes together (volume of total sample).
Then 100g / volume = density of composite
What mechanical properties does 65-45-12 Ductile Iron have?
> = 65 ksi tensile
= 45 ksi yield
12% elongation
What does Ksubscript(1c) represent?
Fracture toughness - a measure of the resistance of a material to crack extension under predominantly linear-elastic conditions (i.e. low toughness conditions when there is little to no plastic deformation occurring at the crack tip).
It is generally thought of as the lower limiting value of fracture toughness in the environment and at the speed and temperature of the test, and can be considered as a size-independent fracture parameter for brittle materials
When should one use each of the different hardness tests?
1. Rockwell
2. Brinell
3. Vickers/Knoop
- Rockwell - hardened steels with small grain size that require high PSI loading
- Brinell - cast irons and powder metals that need a much larger indenter
- Vickers/Knoop - very small parts or sections (microhardness)
What are the 2 components of a composite material? and what is their purpose?
Matrix - binds the fiber reinforcement; provides shape and surface quality
Reinforcement - provide strength to component
What are the three phases of zirconia? which transition increases toughness?
Cubic, Tetragonal, monoclinic.
Tetragonal –> monoclinic increases toughness
What is grey cast iron? what is another name for it?
what are some common properties of it?
flake graphite cast iron.
Lower strength and not ductile
good thermal conductor and damper
easy to machine
What is white iron? what are common characteristics?
Cast iron without graphite. Has Cementite (iron carbide) instead.
hard and brittle, good wear resistance
What is malleable iron?
heat treated white cast iron. iron carbide breaks down to form spherical graphite throughout.
Define Ductile Cast Iron. What is another name for it?
aka. nodular cast iron. graphite forms into tiny nodules. similar properties to malleable iron but you can make large castings with it.
Temp conversion factor F to Rankine?
F + 460 = R
What are the following AISI designations mean?
10xx
11xx
12xx
13xx
15xx
10xx - plain Carbon (1% max Mn)
11xx - resulfurized
12xx - resulfurized and rephosporized
13xx - Manganese 1.75
15xx - plain carbon (Mn 1-1.65%)
Why add manganese to steel?
Manganese removes oxygen and sulfur when iron ore is converted into iron. As an alloy it decreases the brittleness of steel and imparts strength.
In AISI Designation what is the following?
xxLxx
xxBxx
xxLxx - leaded steel (improves machinability)
xxBxx - boron steel (improved hardness)
Define Modulus of Resilience
The modulus of resilience is defined as the maximum energy that can be absorbed per unit volume without creating a permanent distortion
What is an isomorphous phase diagram? what prorperties are required for two elements to be isomorphous?
two elements with full solubility in a solid solution
requires: same crystal structure, atomic radius within 15%, same valence structure, similar electronegativity
How do you tell an intermediate compound on the phase diagram?
vertical line on phase diagram
What is hooke’s law for anisotropic material?
strain (x) = stress(x)/Mod(x) - pois(yx)stress(y)/Mod(y) - pois(zx)stress(z)/Mod(z)
What is the common use for the following etchants?
Nital
Kroll’s reagant
Picral + HCl
Keller’s etchant
Adler
Nital - carbon steel and cast iron
Kroll’s reagant - titanium
Picral + HCl - carbides, pearlite, martensite, etc. (sensitized SS)
Keller’s etchant - aluminum and titanium
Adler - 300 SS and hastelloy
What is purpose of leco combustion analyzer?
Measure carbon and sulfur content of steels
