Module 1 Relationship of NDT to Manufacturing

Objectives
 Define NDT
o Non-Destructive Testing – the use of physical methods for testing materials and products without harm to
those materials and products.
 Discontinuity – used to describe a local variation in material continuity, including geometry, holes,
cavities, cracks, structure, composition, or properties.
 Defects – a discontinuity becomes a defect when it creates the potential for the failure of the
product in its intended function.

 Define material failure and list the causes

o Failure is when the item of interest becomes unusable (Fracture/Fatigue Failure)
 Excessive loading
 Static loads (stationary or fixed)
 Dynamic loads (varying)
 Environmental
 Corrosion (loss of material, stress risers)
 Vibration (
 High elevated temperatures (Creep and Transition)
 High pressures)
 Mechanical failure (stresses above elastic limit)
 Deterioration due to age

 List the uses of NDT – Ensure reliability and to prevent premature failures of the product
o Identification of materials
o Identification of material properties and reliability
o Assure proper dimensions and geometry
o Discover initiation of possible failure locations (stress risers)
o Test during service
o Diagnostic test after failure to determine reason

 Explain how NDT is used in fracture control

o Products are designed with Safety Factors
o Fracture toughness is quantitatively expressed in terms of stress intensity factor K
o Need to establish smallest detectable flaw for a given exam technique
Module 2 Introduction to Manufacturing Technology

Objectives
 Define engineering materials and list four characteristics
o The majority of metals/alloys and some other materials (solid plastics)
 Characteristics are:
 Hardness - the measured resistance of a metal to indention, abrasion,
deformation, or machining.
 Strength – ability to resist stress or strain
 Toughness – the resistance to fracture
 Durability – the ability to endure

 Explain industrial relationships and how it relates to competition and personnel

o Cost / Compromise
o NDE used to ensure final product meets defined specifications

 Define the step involved in manufacturing processes

o Change shape
o Change properties
o Heat treatments
Module 3 Properties of Materials

Objectives

 Define 3 classes of properties

o Chemical – reaction with other materials
o Physical – density, specific heat, melting point
o Processing (mechanical)– strength and hardness
 List the loading systems applied to materials
o Physical loading (compress, pull, twist, or shear)
o Bending loads
 Define the two major types of tests
o Direct – involves use of actual product samples (many) and most are destroyed
o Indirect – requires correlation between the measured factor and the critical factors, most are non
destructive
 Define points A through F on a stress-strain diagram
o A – No Load point (between lines A and B specimen will resume original shape)
o B – The Elastic limit
o C – The Yield point
o D – End of specimens work hardening
o E – The Ultimate strength
o F – The Breaking strength
 List 6 tests that are conducted on materials to determine specific properties
o Tensile Test (can determine Resilience, ductility and toughness)
o Notched Bar Test (imparts sudden shock load)
 Charpy item held on 2 sides and struck from opposite of notch
 Izod item held on 1 side and struck on notch side
o Bend Test – applied to materials subject to deformation
 Free Bend – slightly bending a flat specimen then loading through tensile or compressive forces to
either 180° or break
 Guided Bend – specimen is bent around a fixed radius
o Hardness Testing – (Most frequently used to determine properties of a material)
 Definable properties of a hardness test are Heat Treatment, Wear Resistance, and Strength.
 Mohs Test – Scratch test using ten different minerals (talc to diamond)
 Brinell Test - uses hardened steel balls
 Rockwell Test – uses pointed penetrator
 Vickers Test – uses pyramid shaped penetrator
Module 4 The nature of materials and solid state changes in metals

Objectives

 Define 3 states of matter

o Gas – High energy level / repulsive forces dominate
o Liquid – Atoms begin to congregate and occupy a fixed volume
o Solid – Atoms continue to lose more energy

*Sublimation- change of a solid substance directly to a vapor without first passing through the liquid state.

*Negative coefficient of conductivity with increasing temperature

 List the 3 space lattices

o Basic Centered Cubic
o Face Centered Cubic
o Hexagonal Close Packed

 Explain the importance of grain size

o Coarse Grain = metal processing
o Fine Grain = Finished product
o Fine grained metals are harder and stronger than coarse grain
o
 Define the treatments that are used to improve mechanical properties of materials
o Work Hardening – may be used to increase the useful properties of the metal
 Slip deformation – which is sliding between atomic planes within the grains
 Twist deformation – occurs as a twist load applied to the grains
 Rotational Deformation – application of a rotational force to the grains
o Recrystallization – will leave a metal in a ductile state and can be a means by which grain refining can occur.
o Age Hardening - Increasing the hardness and possible strength of an alloy by a relatively low-temperature
heat treatment that causes precipitation of components or phases of the alloy from the supersaturated
solid solution. Also known as precipitation hardening
o Allotropic – Some metals undergo a lattice structure change while being heated and or cooled

 List 5 heat treatments processes that are used to control a metal's properties
o Austenitization – metal is heated to a point which carbon present will be dissolved in a solid solution with
the iron (must consider grain growth)
o Annealing - Heating metal to above its critical temperature range, then slowly cooling to remove stresses,
induce softness, remove gases, alter ductility, induce toughness, or modify electrical, magnetic or other
physical properties
o Normalizing – is similar to annealing (improves machinability, relieves stress, reduce distortion
o Speroidizing – is an expensive process
o Hardening of Steels – Heating metal to within its critical range as in annealing, followed by rapid cooling as
in quenching. Designed to produce percentages of Martensite. Metal is heated as required and rapidly
cooled and finally tempered. Relieves stress and increases ductility
Module 5 Ferrous Metals

Objectives
 Explain how steel is made from raw materials
o Most important commercial metals:
 Copper
 Lead
 Tin
 Aluminum
 Magnesium
 Iron
 Titanium
 Zinc
 Nickel
o Casting alloys lack the ductility of wrought alloys
o First ore is mined
o Then placed in blast furnace at 3000°F with oxygen which reduces iron ore, lime stone, and other
ingredients into molten pool of metal
o Heavy iron is tapped off the bottom into pigs
o Pig iron is very hard, weak and not very ductile (excess carbon)
o Pig iron with reduced iron content creates Cast Iron
o When carbon content is reduced to less than 2% Steel is formed
o
 List 4 steel making processes
o Open-hearth
o Bessemer Converter
o Electric Furnace
o Basic Oxygen (most common)
 Carbon Steel
o Most economical form of steel
o Mainly consist of iron and carbon
o Carbon can be added to increase strength but reduces ductility
o Low Carbon (.06% - .25%)
 Maximum ductility
 Readily brazed, welded, and forged.
 Sheet, rod, plate, pipe, wire
o Medium Carbon (.25% - .50%)
 Good strength, hardness, and machinability
 NOT great for welding
o High Carbon (.50% -1.6%)
 Heat treatable for desired properties
 Classified as tool and die material due to hardness
 Define the 3 stainless steels and associated characteristics
o Martensitic – contains 4-6 points of chromium
o Ferritic – contains 30% or more of chromium
o Austenitic – contains high amounts of chromium(18+%) and nickel (8+%)
 In cast state Stainless steel have very coarse grains
Module 6 Nonferrous Metals and plastics

Objectives

 Give 2 advantages of nonferrous metals compared to ferrous metals

o Improved corrosion resistance
o Better processing appearance
 List 5 nonferrous alloys
o Aluminum Alloys – mainly used for the electric industry
o Copper Alloys – 10% greater density than steel, excellent ductility, high thermal conductivity
o Nickel Alloys – Gives steel high corrosion and temperature resistance
o Magnesium Alloys– One of the lightest commercially availability metals,
o Zinc alloys – Very inexpensive, low in strength compared to weight, plating with Zinc is known as
galvanizing.
 Special group of Nonferrous metals – used in high stress , high temperature conditions, cost are very high to
produce.
o Stainless Steels
o Nickel Alloys
o Cobalt Alloys
 Define polymerization – occurs when monomers (smallest unit that identifies a molecule of plastic) joins together to
form a larger molecule in the chain – caused by heat, light, pressure, and agitation
 Define synthetic –a combination of 2 or more raw materials used as a base to form a desired plastic
Module 7 The nature of manufacturing

Objectives

 Explain the role that markets have on modern manufacturing

o
 Define the relationship between design and processing of a product
o
 Define how NDT affects the product design
Module 8 The casting process

Objectives

 Define Casting
o Flow of liquid metal and its final shape are controlled by means of the cavity which it is poured
 Explain the casting process
o A mold of the part must first be constructed
o A sprue must be added to allow molten metal to fill cold

*Eutectics tend to freeze at a single given temperature

*Noneutectics tend to freeze through a temperature range (dendrites are more common to noneutectic alloys)

 List the 3 phases of solidification

o Crystal growth begins on the outside of the liquid and is usually fine and randomly oriented
o As freezing continues, grains grow in a columnar shape toward the hot zone
o As cooling continues, grain size tends to increase
o Grain characteristics are in this way affected by cooling rates and characteristics
 Define the 3 stages of shrinkage
o Liquid contraction – results from a decrease in liquid temperature as it is poured into the mold
o Solidification contraction – metal shrinks as it cools
o Solid contraction – shrinkage after solidification that affects dimensional changes
 Define green sand
o Mixture of sand, clay and water used for making casts
 List 6 metal mold processes
o Green Sand molds
o Dry Molds
o Die Cast / Metal molds
o Floor / Pit molds
o Shell molds
o Investment Casting
o Plaster molds
o Centrifugal Casting
Module 9 The welding process

Objectives

 Define welding
o The permanent union of metallic surfaces by establishing atom to atom bonds between surfaces.
 List 4 bonding categories and give an example of each
o Fusion – involves melting of 2 metals to be joined without the use of pressure (SMAW, GMAW, TIG, MIG
o Cold bounding – Sufficient pressure with no heat in used to create required cleanliness and closeness (most
used for copper and aluminum)
o Pressure bonding – The application of heat normally accompanies pressure bonding to assure adequate
chemical activity and to disrupt the oxides into spherical shapes (may be stronger than original base
material).
o Flow bonding – Base material is not melted, a filler metal is used in the joint and heated to its melting point.
Fluxes are used to provide cleaning. The joint is defined by temperature and spacing (Brazing or Soldering).
 Define welding metallurgy
o Melting
o Alloying
o Solidification
o Casting
o Hot and cold working
o Recrystallization
o Heat treating
 List five effects welding can have on metal
o Composition effects
o Grain size
o Structural effects
o Could form Martensite
o Distortion and stresses
Module 10 Welding processes and design

Objectives

 List 2 heat sources for welding

o Electric arc
o Chemical reaction
 Explain the role of the electric arc in the welding process
o Most used today. Used to create intense heat in localized area.
 Define hoe fluxes improve the weld
o Helps protect weld form oxidation and slows cooling rates
 List 3 special welding processes
o Shielded metal arc welding (Stick or SMAW)
o Gas metal arc welding (MIG or GWAW)
o Tungsten arc welding (TIG or GTAW
o Submerged Arc welding (SAW) High production rates
 List five joint types
o Butt joint weld
o Tee joint weld
o Edge joint weld
o Lap joint weld
o Corner joint weld

*3 Types of welding discontinuities:

 Dimensional
 Structural
 Weld and base material

 List and define 6 types of weld defects

o Shrinkage cracks
o Under cut
o Lack of penetration
o Lack of fusion
o Porosity
o Spatter
o Inclusions (slag, metal oxides, non-metallic solids)
Module 11 Plastic Flow

Objectives

 Define plastic flow

o Rolling, drawing, forging tend to improve strength and ductility. Material must be ductile to achieve plastic
flow

 Explain the effects of deformation

o Work hardening – Properties of a material are permanently changed when it is stressed past the elastic
limit. Atomic structures become strained (can be reversed by reheating PWHT)
o Recrystallization – A time dependent process. Termed hot working.
 Explain the effects of temperature and loading

o Elastic failure depends on shear stresses applied at a given temperature

o Fracture failure depends on tensile stresses of the material and is relatively unaffected by temperature
o Deformation processing induces high compressional stresses and low tensile stresses

 Define how the mechanical properties are changed by hot and cold working
o Hot Working – Majority of deformation is hot. Equipment life is reduced at elevated temperatures
 Hot worked materials exbit good ductility but minimum strength
 Recrystallization is used to refine (decrease) grain size in metals. If material is held at temperature
too long grain size may increase. The only method for grain size control in nonferrous metals
o Cold Working – Done at room temperature. Lower work energy required
 The last cold work after recrystallization determines the strength properties of the material
 Improves machinability – a result of decreased ductility before finishing machine work
Module 12 Millwork, forging, and powder metallurgy

Objectives

 Define hot rolling – compresses material into flat and 2 dimensional forms at elevated temperatures
o Uses flat or shaped rollers to compress metal to desired shape and thickness
o Permits ductility recovery by recrystallization as deformation occurs
 Differentiate between hot working and cold finishing and understand the relationship between the 2 processes
o Hot Working – see above
o Cold Finishing
 Effect the properties of the materials
 Ductility is required and lowered during process
 Hardness, yield strength, and tensile strength are increased through cold finishing

 Describe the tube and pipe making process

o Tubing is usually considered seamless and piping is usually not
o Pipe can be made by a welding bell / Roll welding, spiral welding
o Tubing is usually shaped, formed, and welded in a single resistance process
o
 Define extrusion and name some examples
o Extrusion requires material to be ductile enough – Direct and indirect – high energy process
 Differentiate between open die and closed die forgings
o Open Die forging
 Die on one side hammer on the other
 Manual operation (blacksmithing)
 Lower cost process
 Hard to produce products in quantity with similar dimensions
o Closed Die forging
 Fully enclosed by die
 More expensive
 Direct competition with casting
 Define powder metallurgy and name 3 associated processes
o The art of producing powders and object shaped from various powders with the application of pressure and
heat

*Sintering – The process by which materials are bonded together through the application of heat and/or pressure.
Module 13 Pressworking of sheet metal

Objectives
 Define Shearing
o A cutting operation that applies loads perpendicular to the main axis of a part

 Describe the bending process and name a disadvantage

o Plastic flow of a material about one or more axes
 Outside of the part will be distorted

 Define Drawing
o Involves bending and stretching
 Creates multiple stresses in the part

 List 2 new processes that are used to form metal

o Explosive Forming
o Electrical Forming
Module 14 Machining fundamentals

Objectives
 Define machining and some of the advantages
o A shaping process that is machine driven and results in material removal in chip form
 Can be done with very close tolerances and good finishes
 Low set up cost for small quantities

 Describe the steps involved in the theory of chip formation

o Cutting tool applies the load and causes the failure (chips)

 List several examples of cutting tool materials

o High speed steel – an alloy that maintains hardness and strength to about 1000°f (drill bits)
o Cemented carbides – a powdered metallurgy product of tungsten, titanium, and or tantalum carbides
combined in various mixtures with cobalt or nickel. Wit stand temps up to 2000°F (cutting tips)
o Ceramics or Cermets - see above, but with almost pure aluminum oxide
o Diamonds – The hardest material know to man, but brittle and subject to failure
o Coated tool material – example : high speed steel impregnated with wear resistant materials (titanium
carbide)
 Describe a vital characteristic of a material used as a tool cutter
o Maintain strength at elevated temperatures
 List the five basic types of machine tools
o
 Define material finish and list three variables that can affect finish
o
 Define numerical control. Give some advantages and limitations
o Are automatic systems that are used to control the machining process (C and C machine)
Module 15 Miscellaneous Processes

Objectives

 Define Plastic processing and list 4 different processes

o The forming of sheets of plastic is similar to pressworking of metals
1. Compression molding – uses pressure and heat to form plastic
2. Closed Die molding – similar to charged (injection) casting
3. Casting – used for novelty items
4. Extrusions – plastic is finished as rods, tubes, filament, films

 Describe the advantages and limitations of compression molding

o Large articles are possible, No waste material, little erosion of dies
o Moldings must be simple, telescoping nature of dies must be accounted for, cleaning required

 Define reinforced plastic molding

o Plastic containing reinforcing fibers (glass/paper) and uses alternating layers of fiber and plastic to
strengthen material.
*Plastics have a better strength to weight ratio
*Plastics have a better resistance to corrosion
Module 16 Surface Finishes

Objectives
 List 3 reasons why we finish the surface on products
o Clean surface
o Smooth edges
o Polish before plating
o Corrosion protection

 Define casehardening and economic benefit as a result of this process

o Process results in hard, shell like surface
 Economic benefit is due to not wasting expensive alloys for entire product and just applying
to the needed surface
 List 2 processes used to caseharden a material
o Carburizing (added carbon and heat, grain size does increase)
o Flame hardening (Heated and water quenching)

 Define Pickling
o Places iron or steel in vat of water-diluted sulfuric acid

 List 3 ways a product can be cleaned

o Blasting
o Wire Brushing
o Buffing
 List 2 advantages of coatings
o Hides imperfections
o Protects from environment

 Describe the differences between paints, varnishes and enamels

o Paint is the application of any organic compound
o Varnish is a mixture of natural and synthetic resins in a drying oil
o Enamel is a mixture of pigment in varnish

 Distinguish between metalizing, Plating and electroplating.

Module 17 Surface Finishes

Objectives