OK.

And let me close the door.

All right, so now we're moving on from the fundamentals

of the metallurgy to the alloying elements.

And I always apologize in advance

for the next two lectures, because they're

going to be a little bit dry, because they kind of have

to be.

But we're going to have to go through the alloying elements

so that you later understand what

we do with the various steels and various processes.

And I think you already know quite a fair bit of which

elements you are going to have in the steel anyway,

just because they're residuals from the production process.

And a lot of elements can be both.

They can be residuals from the production,

or they can be alloying elements.

Actually, all elements, even phosphorus and sulfur,

can be alloying elements.

We're going to talk about when we're going to use them,

and what the details are of the effects

of the individual elements.

OK

and before we dive into the actual individual elements

we're going to look at some ways of classifying alloying

elements.

There's a couple of ways of how we can split up

alloying elements and what they do.

And the first and probably most important ones

is to look at them at their influence at the phase

equilibria.

And there we have ferrite stabilizers,

and we have austenite stabilizers.

We have ferrite stabilizers and austenite stabilizers.

And they do essentially exactly what it sounds like.

So ferrite stabilizers stabilize the BCC phase

and austenite stabilizers stabilize the FCC phase.

They stabilize the FCC phase.

And essentially what they do is they expand or they

contract the austenite phase, more or less,

the existence of the austenite phase.

And the most important ferrite stabilizers

are chromium and silicon, but also molybdenum, vanadium,

and aluminum.

This is just a more comprehensive list,

but chromium and silicon you should probably remember.

And austenite stabilizers, the most important ones

are carbon, manganese, and nickel.

Copper, nitrogen, cobalt, zinc are also FCC stabilizers.

Occasionally we're going to make use of nitrogen explicitly