Fukalyal

If I see a mill or lathe sticking out of a bin during the demloish, some "deals" might be struck on the spot. There is always a way.

Joe Perez

iTrader: (8)

You use a copper block to extrude molten steel through?

Interesting.

palmtree

iTrader: (4)

Sub'd for awesomness

This is facinating IMO

Fukalyal

It's not extrusion, that's for solid materials. The continuous caster mold is like a toaster slot with no bottom. The goal is to produce a steel slab say, 10" thick by 90" wide with whatever length. The "easy" is, you pour molten steel in the top, the copper plates (with water cooling slots on the back) cool it, you withdraw it at the same rate from the bottom as a solid = slab.

The "not so easy" is the slab isn't solid when its withdrawn from the mold bottom. It only has a skin on it 0.040 to 0.125 inch thick. Its nothing less than a steel water balloon filled with liquid steel. This has to be supported until it solidifies completely, this is the "containment" section shown in parts 6 and 7 on that Wiki page.

Every now and then the balloon pops, which means we get to fixing.

Every now and then, somebody puts steel on top of water like here

http://english.peopledaily.com.cn/90882/7736475.html

which causes a hydrogen reaction and kills people. The only error in this article is the problem was the steel going into the mold was just a few degrees above liquidus approx 2200 deg F. When a mold like this explodes, the spray of white hot steel in the air expands its volume by hundreds of times and blows the sheeting off the building with no explosive gas necessary.

RattleTrap

No wonder they don't do that here anymore. The liability would be enormous.

Fukalyal

Um... no. Lots of people still do this here. There is still real work and real work ethic and hard core industrial innovation being done in this country better, higher quality and more profitable than at any time in history. It just doesn't make news.

Joe Perez

iTrader: (8)

Bad choice of terminology on my part. I'm moderately familiar with aluminum extruding, as we use a lot of extruded parts in our consoles at PR&E (albeit, we outsource the actual extruding itself, as we're not set up for that in-house.) I've heard of continuous-casting, but never seen it in action.

But I see what you're talking about now. I'm honestly a bit surprised that even with water channels on the backside the copper plate is able to survive having molten steel poured across it, but then a lot about metallurgy surprises me.


Well 1000°C = 1,832°F, which is what you said was normal.

Fukalyal

Meh. Yes and no depending upon what hat I wear. I wear my guy walking around on the street hat then you are right. I wear my steelmakers hat and 1800 F is frozen and safe to move around.

Fukalyal

There's a bit of trickery to it. The steel is held to 30 to 60 degrees above it's liquidus (freezing) temp which means if you sneeze on it, it freezes. There is a thing called "mold flux powder" which is fed into the mold, it melts and runs down betwen the steel and the copper plates in the mold and has an insulating effect. With these tricks and the thermal conductivity of copper compared to steel (high temp steel has really bad thermal conductivity) and the water on the back of the copper plates, the copper surface gets to max 470 deg. C (problems happen at that point) and typically runs 250 to 350 degrees C.

Landrew

iTrader: (2)

We need a MT "How it works / How its made" section with pics and video. I love this kind of thing...