Question

Problem # 1: 50 Points Write down the “Basic Steps” that are necessary to mount a metal sample with polymer powder. Write the basic steps in your own words. Do NOT copy and paste from the Power Point file.

Answer 1

Section and Cutting

We use following steps for sectioning and cutting of a small specimen from work piece :-

Ø First we define the intended sectional plane and marks it on work piece.

Ø Than we put the work piece in oppressive sort and fix it securely, selects the cutting parameters and starts first oppressive cutting.

Ø Intensive water cooling and Appropriate cutting parameters to keep the material as cool as possible.

Ø Then specimen is placed in Ultra sonic cleaner bar for a few seconds. Alcohol and ultra sonic waves help to remove loose particles from the surface.

Ø After that we use hot air, now the specimen is dry and clean for mount.

Ø Proper sectioning is required to minimize damage, which may alter the microstructure and produce false metallographic characterization.

Ø Proper cutting requires the correct selection of abrasive type, bonding, and size; as well as proper cutting speed, load and coolant.

Mounting: -

The mounting operation accomplishes three important functions: -

1. It protects the specimen edge and maintains the integrity of a materials surface features

2. Fills voids in porous materials

3. Improves handling of irregular shaped samples

Mounting Process: -

Ø To mount the specimen small plastic molds are suitable, then we put clear specimen carefully places it in the mold.

Ø The intended plane of the examination must be at the bottom .Attach the mounting ring cylinder to the base by simple pressing firmly in place.

Ø Than we pour a mixture of cold settling compound hardner and cold settling compound binder into the mold.

Ø After 25-30 min. we remove the resin from mold but the specimen surface is still uneven and slightly sticky.