Ductile Iron - Polishing

This SOP describes the process of polishing SSFDI to prevent contamination, graphite pull-out, and other polishing defects. This SOP references SME Julia Scruton and Ale Almanza polishing steps for Ductile Iron.

Polishing Steps for Solid Solution Strengthen Ferritic Ductile Iron

Grit	Force	Time	Head Rotation
120	15N	until flat	yes
180	15N	1 minute	yes
600	15N	1 minute	yes
800	15N	1 minute	no
1200	15N	1 minute	no
1μ diamond	15N	1 minute	no
0.05 Al2O3	15N	1 minute	no

Safety Concerns

• Make sure fingers and debris are clear from rotating head and base
• If etching samples, be in a fume hood and wear gloves
• Have safety glasses on at all times
• Report any problems to Dr. Dan Seguin

SSFDI Polishing Procedure

1. Gather necessary consumables:
   120 Grit Paper
   180 Grit Paper
   320 Grit Paper
   600 Grit Paper
   800 Grit Paper
   1200 Grit Paper
   Felt Pad
   Red Lub3
   0.5 Al2O3 Suspension
2. Adhere grit paper to the magnetic pad and place on the Struthers Polisher
3. Place Samples into the Struthers Polisher
4. Turn On Polisher
5. Set timer and add necessary parameters
   - Reference Table For Specific Settings Per Polishing
   - Add two drops off Red Lube, add more when the polisher head makes a clanking sound
   - To make the autopolisher head static, turn off the switch located on the back of the base of the polisher
6. After each polish, clean the samples with water and dry with the air compressor
7. Remove grit paper and dispose
   - Do NOT dispose of cloth pad for final polishing steps
8. Repeat 1-6 until polishing steps are compeleted

Etching

For further analysis of microstructure, a 3% nital etchant can be used

1. Gather necessary consumables:
   3% nital etchant
   petri dish
   cotton swab or pad
2. In a fume hood, turn on the water
3. Pour nital into petri dish
4. Dip cotton swab/pad into the etchant
5. Once the sample surface start to become cloudy, rinse the sample with running water
6. Dry sample with air compressor