Testing of Materials

Question 1

Tensile Testing, Method

Answer 1

• Material pulled apart by a hydraulic machine
• Test piece apart in a constantly increasing load
• Pulled till failure

Question 2

Tensile Testing, Info

Answer 2

• Data collected in Load/Extension diagram
• Destructive Test
• Load/Extension diagram converted to stress/strain

Question 3

Ht, Brinell

Answer 3

• The hydraulic machine presses indentor into material
• Spherical steel indentor
• Destructive
• Formula H=Force/Surface Area

Question 4

Ht, Vickers

Answer 4

• Hydraulic press machine
• Dimond pyramid indentor
• Destructive
• Formula = Brinell

Question 5

Ht, Rockwell’s Info

Answer 5

• Hydraulic press machine
• Diamond conical indentor
• Destructive

Question 6

Ht, Rockwell Method

Answer 6

• First press 98N minor force, then 1373N major force applied, major force removed minor force continues
• Depth from 1st press and third press measured
• Formula, (o.2-e)500

Question 7

Notch Bar Toughness

Answer 7

• Toughness of material
• Notch cut to a certain standard, for each test
• Destructive

Question 8

NBT, Izod

Answer 8

• Notched bar sits upright in clamp
• Striker hits notched side
• Where striker stops indication of toughness
• Mechanically of digitally calculated

Question 9

NBT, Charpy

Answer 9

• Bar sits horizontally supported on both sides
• Striker hits non-notched side
• Same calculation method as Izod

Question 10

X-ray Testing

Answer 10

• Non-destructive
• Identifies internal voids
• Gamma waves used, high frequency and highly penetrative
• Shown of photographic film or digitally
• Internal voids allow gamma waves to pass easily, dark area of film
• Used in welding

Question 11

Ultrasonic Testing

Answer 11

• Non-destructive
• Surface Voids
• High-frequency vibrations hit surface irregularity return at a different time to the regular surface
• Shown on cathode ray tube
• Useful in testing over 6mm thick
• Welding

Question 12

Penetrant Testing

Answer 12

• Non-destructive
• Objects coated in visible/fluorescent dye solution, on chemically clean surface.
• Developer applied , reacts causing dye to bleed out
• Fluorescent dyes, ultraviolet light, increased visibility
• Surface defects only

Question 13

Magnetic Particle Inspection

Answer 13

• Non-destructive
• Surface dusted in iron particles (liquid or dry)
• Ferromagnet held near surface, imperfections distort magnetic field, near imperfections
• Quick
• Can be used on ferromagnets

Question 14

Slump Test, Info

Answer 14

• Measures workability
• Strength increases with water:cement ration decreasing
• Strength measure after 28 days

Question 15

Slump Test, Method

Answer 15

• Concrete placed in 300mm high mould
• Mould removed and height of the concrete measured
• 0-25mm dry mix
• 175-250mm sloppy mix

Question 16

Compression Testing

Answer 16

• Destructive
• Hydraulic press gradually applied load
• Brittle materials i.e concrete fail with hour glass failure
• Ductile material deform
• Used heavily in concrete mix and timber pieces