question on steel

[Ed Tipton]

I have looked for the answer to this question on the "net" and in books, but I have yet to find the definitive answer. Carbon steels are generally rated as 1020-1080 where the last two digits indicate the % of carbon. If I understand it correctly, 1020 steel consists primarily of pure iron with approximately .002% of carbon added. My question is: .002% of what? Does it relate to .002% weight, or volume, or what? Trying to think about it logically, neither weight nor volume amounts would seem to work, but I don't know where to go from there. I'm sure with all the expertise on this board, someone can provide the answer. For me, this is just one of those things that I am having trouble getting my head around. Also, in a related question, are all additives used to make steels and their various alloys calculated in the same manner? I'm leaning towards the % of weight, but I'd like to know for sure just to expand my knowledge base.
I have recently started to do some very simple blacksmithing, and to accomplish what I want to do requires a knowledge of metallurgy which far exceeds my current level of knowledge. I've read some on the subject, and talked to a few people, but it seems to be one of those things akin to the black arts. Why is it that as I get older, everything gets to be so much more complicated than it needs to be? Are there no simple answers anymore?
Thanks...Ed

[kjbllc]

i am going to guess by weight, as the volume would change with the heat?

[Seastar]

Steel

This is an excellent web page that is for blacksmiths.(knife makers)

http://www.knives.com/steel.html

I have it on my shop wall.
Bill

[ptjw7uk]

I thought 1020 steel contains 0.2% Carbon by weight and all alloys are by weight otherwise how would you make it all athe alloying constituents are added by weight or by using a high element alloy.
When I started work I worked in a copper refinery and the silver copper alloys were made by adding silver bullion to the copper melt.
All the other alloys were made using a master copper alloy which were made by someone who could control the burn off of the usually lower melting point metal (ie cadmium) only one that I remember that didnt use a master alloy was brass. The brass was melted in an induction furnace so as to limit zinc burn off.
Peter

[dan s]

It's by weight.

[rantbot]

.002 is .2%. As the boys say, by weight. The 10xx format is the AISI designation. (American Iron and Steel Institute - not the ANSI, which is something different.) There are loads of other ways to specifiy steels.

[Peter N]

.002 is .2%. As the boys say, by weight. The 10xx format is the AISI designation. (American Iron and Steel Institute - not the ANSI, which is something different.) There are loads of other ways to specifiy steels.

He actually said .002% not .002 just to be pedantic
And it is actually .2%, and I'm pretty sure it's by weight.

Peter

[Seastar]

Steel

You are all correct - it is by weight.
Here is another excellent website.

http://www.materialsengineer.com/E-steels.htm

Good information.
Bill

[Ed Tipton]

Thanks to all. I'm not sure why I've had a problem with this subject, but I guess that I was basically on the right track. Thx for the new sites, I've added them to my favorites.

[rantbot]

He actually said .002% not .002 just to be pedantic

That was my point. The original ".002%" is wrong, by a factor of 100. A fraction is converted to a percent by dividing by 100, not just by sticking on a "%."

[Ed Tipton]

Point taken, and you are correct. While 0.2% is in fact .002 of the whole, it is not correct to say .002%. I was trying to be understandable and correct, and wound up being neither. In any event, you have helped me in understanding what it is we're taking a % of. Thanks again.