Wednesday, November 15, 2017

Phase Transition in Steel

That's an interesting addition to the iron wire demo: a glass rod to exaggerate the 'dip'.

The glass rod makes sense because it's non-conductive enough to not be too dangerous, I would think.

The graphing on the video really makes the phase transitions remarkably visible, though.

I like it.

The video's description gives a little more detail as well as the reason for the slow, overall downward slope.
A steel wire is heated up by a current and it expands. When the phase transition temperature is reached the wire takes up additional energy which cools the wire down for a short time and shortens it. 
This step can also be observed in the opposite direction when the current is switched off and the wire cools down. When the phase transition takes place the wire is heated up and it expands for a short time. 
Over three cycles the thin wire gets already worn out. Is is deformed so that the diameter, the heating power and the temperature is not equal along the wire and the phase change occurs more distributed over time.

Thursday, November 9, 2017

Heat treating tool steel -- the phase change

I'm going to trust the video's description (copied below) when it says that the flashes of light at 0:32 are visual indications of the BCC --> FCC phase change that takes place at 910 C.
Visual indication of tool steel phase change to austenite when heat treating. Small pools of iron are forced from the steel as the volumetric change takes place and small amounts of carbon are burned off.
So, my understanding from reading that, is that the BCC (ferrite) --> FCC (austenite) change squeezes some of the carbon out of the structure. That carbon then - because of the high temp and the presence of oxygen around the steel - burns off in the flashes that we see.

Can anybody tell me that I'm reading the situation correctly?

Wednesday, November 1, 2017

The Coolest Way to Open a Bottle of Wine

Yeah, that's one way to open a bottle of wine.

Shatter the glass, yeah.

It causes some secondary challenges (possible shards of glass in the wine, a messy lip of broken glass), all of which seem to have brought about solutions to those challenges.

As neat as the science is (hot glass contracts quickly and unevenly when cooled suddenly, aka thermal shock), the whole process just seems needlessly Rube Goldbergian to me.

Sunday, October 22, 2017

High-paying jobs for people who don't like stress

I'm not sure that I agree with this "24 High-Paying Jobs for People who Don't Like Stress" article.

They list material scientist as being the #1 most stress-free high paying job.

All the material scientists I know seem to always be talking about stress...and strain.

(In all seriousness, as I type this at the end of the quarter and think about all the grading I'm behind on finishing and the letters of recommendation I need to write and the National Honor Society applications I need to evaluate, I'm thinking I might've steered down a less stressful, higher paying career path if I'd known about material science back in high school.)

Saturday, July 29, 2017

ASM Summer Camps - 2017

The summer ASM teacher camp schedule is up and posted on the ASM Foundation website - link here.

The teachers camps - in case you weren't aware, and the majority of you folks visiting here are probably familiar if not intimately so - are phenomenal. Check out the testimonials and news reports from the camps here.

Sunday, July 9, 2017

Railroad Thermite Welding: Europe & Russia

Yup, dramatic music at the beginning. That'

In addition to possibly watching this with the sound off, I'd also suggest turning off the annotations because they're just annoying ads for other videos.

There's a pretty stunning, handheld blowtorch at 0:30. All those tiny flames makes me wonder just how frickin' hot the torch gets.

Most of what we get in the video - including the phenomenally bright fire at 1:55 - is pretty standard railroad, thermite welding.

The animation at 2:09, however, isn't standard. It's a great cutout view of what's happening within the thermite weld.

After that, there isn't much more than three barely  different versions of thermite welding. The first ends around 3:05. The second ends around 5:50, and the third wraps up at about 8:25.

Really, the animation at 2:09 is the only new thing to see here.

Wednesday, July 5, 2017

The History of Iron and Steel

I'll be right back. I'm going to refresh myself with the video Material Properties 101 before I watch the rest of this. Luckily, your friendly neighborhood blogger already linked to that video, too.

The video is a great exploration of...

  • the differences between wrought iron, steel, and cast iron
  • the processes in purifying iron ore - especially highlighting other videos that show primitive ways of doing this in modern times
  • blast furnaces, used to purify iron ore in modern times
  • producing steel in various ways - including via a puddling furnace
  • the Bessemer converter to produce steel

The video is, I think, too long to show in class unless your students have a better attention span - and tolerance for foreign accents - than mine do.

The video shows that it's 13:35 long, but it's really about ten minutes followed by a plea for a charity donation for the last three and a half minutes. The charity donation link is no longer accepting donations.

At 2:38 there's a hiccup in language. He says wrought iron is less than 0.8% carbon, but his graphic shows that it's less than 0.08% carbon. Wikipedia agrees with his graphic. Decimal places are hard sometimes.