METALLOGRAPHIC ANALYSIS

Khairol AriffinYadie AbdullahWan Muhammad FirdausNurul Nurdiyana

What is Metallography? Metallography is the study of the

physical structure and components of metals ,typically using microscope.

Procedure of Metallography Analysis

Cutting

Moulding

Grinding

Polishing

Etching

Observing

CUTTING Cut the welded specimen into 10 mm

width using the band saw.

MOUNTING/MOULDING Switched on the power supply of the heat mounting machine. Set the air pressure at 6 – 7 atm. Bring up the lower ram by pressing the ram ‘Up’ button. Applied ‘Mould Release Agent’ to the surface of lower ram. Place the specimen on the top of the lower ram. The specimen must be

clean, dry and free from dirt. The distance between the specimen and the cylinder wall must be minimum 3 mm to avoid cracks in the resin.

Bring down the lower ram by pressing the ram ‘Down’ button. Filled a suitable amount of Bakelite powder (Phenolic powder) into the

cylinder by means of the funnel. The powder level should be normally 10 – 12 mm above the specimen.

Placed the lock nut and turns clockwise for closing. Do not apply excessive force.

Bring up the lower ram. Stop the cycle. Pressed ram ‘Up’ button and open the lock nut and put your specimen. Switch off power supply.

GRINDING Placed on the 240 silica paper on the plate of

polishing machine. Switched the power supply and ‘On’ button at the

back of the machine. Set the speed at 250 – 300 rev/ min only. Adjusted the water outlet. Applied the moulded specimen faced to the

moving silica plate. Do not apply excessive force. Then, changed the 240 silica paper with 320, 400,

480, 560, 640, 720 and 800 silica papers for the next session.

POLISHING Rinse and dry the sample before transitioning from

sandpaper to diamond suspension. Start polishing using the cloth specialize for

polishing. Spray about 4-5 sprays of the suspension onto the

wheel. Firmly place the sample face down on the polishing

wheel, moving your hand in clockwise circles. Check to see that the lines are even buffed out,

and the surface appears shinier. This should take about 10 seconds.

Rinse and dry the sample.

The purpose of the polishing step is to remove the damage produced during cutting and planar grinding.

ETCHING Dripped the etcher onto the silica

paper (polishing machine). Applied the moulded specimen onto

the moving silica paper. Washed the specimen by using water. Dripped the specimen into the

ethanol for 15 seconds. Washed the specimen by using water

and wiped with dry cloth.

Metallographic etching is the process of revealing microstructural details that would otherwise not be evident on the as-polished sample.

OBSERVING Observe the specimen microstructure

under the optical microscope.

The example of specimen under the microscope

Pearlite

Cementite

The end.