6.16.2019

Cold Iron: The mythological material reborn!

After learning what I have about metallurgy, I am very confident I have decoded what the mythical "cold iron" was and why it was effective against the supernatural.

We know that pure iron is very good at magnetic permeability, which is the ability to control invisible magnetic fields which appear to effect the supernatural.  Also we know that the rapid cooling of iron into the form martensite or even amorphous (which is very hard) also enhances this effect of iron (like metglas)

The term cold iron likely came to be because it it feels colder than normal iron because this form conducts heat better and would feel cold to the touch.  Also it was impossible to forge because it was so hard.  The ancients likely figured the iron was inherently "cold" and couldn't be worked until it was heated up.  All iron is harder when cold but this iron would be extremely hard, order of magnitude harder. 

Where could the ancients have found this?  In meteorites that fell into the ocean.  The hot melting temperatures at reentry combined by the ultra fast cooling that takes place when it shoots through the cold water and that shock of it contacting the water would have produced an extremely hard or "cold" form of iron.  The nickel present in the meteorite would have made it easier for cold iron to form but here we are going to try to keep the iron pure so it is an even more effective magnetic field manipulator.

So to recreate this mythical material we need to do a few things.

1. Make austenite grain size as small as possible.  This not only helps martensite form initially, but also toughens the iron as well.

2. Rapid cool the iron from austenetic temperatures.  This induces martensetic formation because of the stresses induced.

3.  Compress or shock the iron during rapid cooling.  This helps give energy to form martensite.  Another way of looking at it is is creates more stresses in the material leading to more nucleation sites for the martensite.

4.  Create an electric current, perhaps pulsed, through the material.  This is known to help iron whiskers form which is even stronger and harder than martensite but will also helps martensite form.

5.  If you still can't get it to form you can add 4-30% nickel (or less) which will help the martensite to form but would reduce the cold iron's effect on magnetic fields greatly.

There can be an unlimited number of ways to achieve this but here is an example.

Process:

1. Use high purity (99.9%+) Iron powder

2.  Melt iron in suitable crucible in inert atmosphere furnace at around 1540c.

3.  Pour iron into Room Temp mold of your desired shape (lets say 4"x1"x1/8" investment casting mold)

4.  Immediatly drop that in dry ice-antifreeze (DIAF) bath.

5.  Recover iron bar and wash.  Add to austenetic temperature (930 c) inert gas furnace for 30 mins.  Immediately remove it from furnace and place metal between plates cooled to DIAF or liquid nitrogen temperature and compress to 40 tons (basically as many tons as possible).  Keep compressed for 15 minutes while actively cooling the plates if possible.  Repeat this step 3x.  This will sucessively reduce austenite grain size and leave us with hopefully high % martensite at the end.  Make sure on the last pass that the iron reaches full liquid nitrogen temperature.

7.  Compress bar at 40 tons (or as high as possible) and turn plate temperature to 150c.  Plates should be anodized if aluminum or coated with something to prevent electrical conductivity but allow thermal conductivity.  Attach pulsed or constant DC power supply with the negative wire at the tip of the future blade and the positive wire to the bottom (base) of the blade.  This will induce crystal formation starting at the tip to strengthen it. Paint all exposed surfaces of the metal and wire with high temperature paint to prevent any reaction with oxygen.  Let sit for 96 hours.  Quench in DIAF or liquid nitrogen.

8.  Grind into blade or other shape (like a cross) with a wet belt sander with ceramic grit.  Make sure temperature of the blade does not heat up while sanding, keep a bucket with ice water and dish soap nearby and after every pass dunk it in the water.  The dishsoap will help prevent rusting.

9.  Wash item well and coat with wax often

Whiskers grow from anode; current, compression, and elevated temperature induce growth
https://www.google.com/amp/s/www.researchgate.net/publication/234898891_Tin_whisker_growth_driven_by_electrical_currents/amp

Electric current helped martensite formation
https://www.tandfonline.com/doi/abs/10.1080/02670836.2017.1304619

Electropulse increased hardness and strength
https://www.google.com/url?sa=t&source=web&rct=j&url=https://oro.open.ac.uk/47196/1/stabilityofmartensite_1-s2.0-S0921509316310590-main.pdf&ved=2ahUKEwjDzs-R0e7iAhUFwVkKHXJHDwwQFjACegQIBhAB&usg=AOvVaw102ejdxcZgJMY-C13IR_PN

NASA searching for cold iron
https://www.google.com/amp/s/mashable.com/article/nasa-meteorite-pacific-ocean-exploration.amp

99.95% pure iron chunks
https://www.surepure.com/Iron-chunks-3-4-inch-and-down-99.95Percent-pure/p/6723

No comments:

Post a Comment

Thank you for your feedback! Sharing your experience and thoughts not only helps other customers but also helps me to improve what I do!