Iron Micro Structure

Welcome to your Iron Micro structure walk through...



First Step: Identify the Iron. It all starts with this little "slug"
Lets say that we are in a Laboratory and we happen upon a little piece of iron that looks like this...
How to identify?
-Normal circumstances would tell you what kind of iron it was with some sort of sample ID
EX 03222023222202 would tell us the sample was today at 1020PM and it is a ductile iron of the 2202 grade...which basically tells us the hardness range we are looking for.
However that is hardly enough...we must uncover more about this little slug.


Second Step: Hardness

If you are lucky your lab will have a camera used specifically for checking hardness.
Check for calibration...there should be a block around labeled with the correct measurement.



Intermediate Step:
POLISH that surface until it appears like a mirror and then give it an etch.







Step 4: Examine under the microscope

After a proper polish under 100X the surface should appear something like this....

The nodularity of the second photo is much better. So a good polish is key to a good sample.

Better polish...worse picture.

poor polish however nodules still present

Gray Iron

Grey Iron has a few major differences than ductile

First the chemistry
gray iron has more of the following elements
-manganese
-Sulfur (bonded with pyrite)
-Silicon
-Chrome

Grey Iron

...hmmm
Less Carbon
....and
a dash of titanium

Polished up it looks like this



In a foundry gray iron gets poured much faster than the ductile iron because it can be melted faster and it needs less additions before it gets poured into a cast



As you can clearly see there are no nodules present. The addition of magnesium right before the iron gets poured forces the iron to form into nodules. This makes the iron much stronger in tensile and hardness aspects.
Gray iron is much better for absorbing and redistributing heat...so it still has plenty of uses.

Working in my first laboratory

Quality Control on iron is generally know as Metallugy.
Metallurgy is the study of...metal! More specifically the alloys and percent ratio of elements that combined to make metal have certain electrical, thermal, or ductile properties.Depending on the part that is being made determines what sort of properties that part needs to have. Example: pieces close to the engine need to be able to absorb a lot of heat.

My first real job out of college with my degree in geology and earth science is a little more than a step above what I could easily do with my high school diploma....but at this rate any job getting paid more than 8.50$ is a step in the right direction.
Everyday I get to analyze iron samples for chemistry and make sure the samples fall within specific ranges in order to determine if the iron is "good" or "bad". Usually the iron samples fall within the range, but every so often someone makes a mistake and the lab must capture the discrepant iron.

This is the spectrometer...it uses an argon spark in order to 'excite' the electrons of particular elements and then fiber optics read and interpret the amount of energy caused by the argon.