You lost me here.

"Killed steel" simply refers to steel that has been deoxidized. Aluminum killed steel would be the term used for steel killed with aluminum. Silicon is the other common method of killing steel. The stabbing you speak of, I have no idea where you got that but I'll give you the benefit of the doubt Generally alumminum is added to steel in the form of aluminum "cone." Al reduces FeO in this manner 2Al + 3FeO -> 3Fe + Al2O3. The resulting Aluminum oxide (Al2O3 commonly refered to as Alumina) is a ceramic with an extremely high melting point, roughly 3700 degrees fahrenheit. This is of course well above steel making temps (around 3000 degrees).

I just realized this is a fairly complicated topic and it would take a very long time to type out how all this works starting with why alumina doesn't become a large brick on top of the steel. I will stop boring everyone. Steel is definately one of those topics where I border on ultra dork status in all facets...

 

Isn't it hard to weld as well...

 

That depends who you ask.

Your average muffler shop dude that might know how to weld mild steel probably doesn't know how to weld Al. It is more difficult, but I wouldn't say hard. As with anything, you just have to know what you are doing. Welding is definately something were practice makes perfect. Welding exhaust piping is fairly trivial as far as welding goes. Just make sure you use highly skilled people when building rollcages and things like that...

 

on my 93 accord coupe, I had custom galvanized aluminum exaust from cat back, never had any issues with rust, leaks, or cracks and after 3 years , the last time I had it on the lift it still looked like it did when it was new.

 

well i dunno but my materials professor gave me that term "killed steel", he used to do research at a steel mill. maybe it was their term...

 

i dont think its one bit hard but thats me, other people say they cant see what they are doing, and others say they just poke a hole right through it...but those people arent regualar welders. and practice DOES make perfect.

 

You had an aluminized exhaust from the cat back, and it was not galvanized. The term "galvanized" means "coated with zinc (galvanum is Latin for zinc). Since zinc would oxidize and turn to dust at elevated temperatures, you would never use it on an exhaust.

BTW: All steel is killed in modern steelmaking. Rimmed steel hasn't been made in the US for about 25 years.

 

yay! i win!

 

As far as I know, you are right. My point was that not all killed steel is Al killed. Si killed is very common as well.