Methods for investigating and testing materials Flashcards
How can you ensure the testing of different materials is fair?
use same size materials
make sure environmental conditions are the same
same testing equipment and technique
one person take all measuremnts
Describe a simple workshop toughness test
tough materials absorb impact, brittle materials bend or shatter
place test piece in vice
hit using hammer
Describe a simple workshop test for hardness
material is tested using a dot punch and force from a hammer
compare indents
Describe a simple workshop. malleability and ductility test
test pieces held in vice bent to an angle of 90 degrees
crack on outside = lack of ductility
crack on inside = lack of malleability
Describe a corrosion test
place equals sized material samples outside in an area exposed to the effects o weather and leave for a set length of time
visually inspect
Describe an electrical conductivity test
collect materials samples of the same dimensions and mark a set distance to place the multimeter probes
measure resistance on multimeter
higher resistance = lower conductivity
Describe a thermal conductivity test
collect material samples
measure set distance an place thermometer
light Bunsen burner under other end
record time takes for temperature to reach set point
shorter time = higher thermal conductivity
Describe the industrial tensile strength test
tens-meter machine.
piece held in clamp
one clamp fixed and other moves on worm drive gear mechanism
test piece stretched and range of data retrieved e.g. yield point, maximum load
Describe the toughness industrial test
Izod impact test
notched test piece held vertically in vice of machine
pendulum released from set position and swings to strike set piece
energy absorbed calculated from height the pendulum swabs to after hitting test piece
smallest pendulum swing - toughest as absorbs most impact
What are the names of the three industrial tests for hardness?
rockwell
brinell
vickers pyramid
What is rockwell hardness testing?
preload applied to material using diamond indenter which breaks through surface of materials
additional load then applied and held
load released and distance between preload and applied load measured
Describe the brinell test
hardened standard size steel ball forced into materials surface using pre-set load
Describe the Vickers Pyramid test
used for very hard materials
diamond square based pyramid used o indent surface of material
microscope measures indent size
What is non-destructive testing?
carried out on products rather than samples
product is not destroyed during test
used to find defects in material
What are the two standard NDT methods?
ultrasonic (sonic waves pulsed into material, different sounds indicate diff faults)
x-ray (beam passes through material and images projected on to display allowing observation
