View source for Ductile Iron - Polishing

[[Category: SOP]]

This SOP describes the process of polishing SSFDI to prevent contamination, graphite pull-out, and other polishing defects. This SOP references SME [https://digitalcommons.mtu.edu/etdr/748/ Julia Scruton] and [https://events.mtu.edu/event/cobalt_additions_to_improve_low-temperature_toughness_of_as-cast_thin_wall_ductile_iron Ale Almanza] polishing steps for Ductile Iron.

=Polishing Steps for Solid Solution Strengthen Ferritic Ductile Iron=

{| class="wikitable"
|-
! 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 Al<small>2</small>O<small>3</small>|| 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 [https://www.mtu.edu/materials/department/staff/seguin/ Dr. Dan Seguin]

=SSFDI Polishing Procedure=
[[File:Consumables.jpg|thumb|alt=A Consumables.|right|upright=0.35]]
[[File:Machine.jpg|thumb|alt=A Consumables.|right|upright=0.35]]
[[File:PressureSetting.jpg|thumb|alt=A Consumables.|right|upright=0.35]]
[[File:BackSwitch.jpg|thumb|alt=A Consumables.|right|upright=0.35]]
#Gather necessary consumables: <br />120 Grit Paper<br />180 Grit Paper<br />320 Grit Paper<br />600 Grit Paper<br />800 Grit Paper<br />1200 Grit Paper<br />Felt Pad<br />Red Lub3<br />0.5 Al<small>2</small>O<small>3</small> Suspension 
#Adhere grit paper to the magnetic pad and place on the Struthers Polisher
#Place Samples into the Struthers Polisher
#Turn On Polisher
#Set timer and add necessary parameters<br />- Reference Table For Specific Settings Per Polishing <br />- Add two drops off Red Lube, add more when the polisher head makes a clanking sound<br />- To make the autopolisher head static, turn off the switch located on the back of the base of the polisher
#After each polish, clean the samples with water and dry with the air compressor
#Remove grit paper and dispose<br /> - Do NOT dispose of cloth pad for final polishing steps
#Repeat 1-6 until polishing steps are compeleted

=Etching=
For further analysis of microstructure, a 3% nital etchant can be used
#Gather necessary consumables:<br />3% nital etchant<br />petri dish<br />cotton swab or pad
#In a fume hood, turn on the water
#Pour nital into petri dish
#Dip cotton swab/pad into the etchant
#Once the sample surface start to become cloudy, rinse the sample with running water
#Dry sample with air compressor