[LT] Iron and Steel Armor

[Tyneras]

In Low Tech, iron and steel are used rather interchangeably. The Plate (p.108) armor section calls it iron, Armor of Quality (p.109) calls it good steel, Iron and Steel (p.20) talks about iron, wrought iron, cast iron, hardened and unhardened steel, etc.

So, what exactly is the iron/steel armor in LT made from? Is it wrought iron? Or is wrought iron what the cheap armor is made from? Or does it change with TL?

[DanHoward]

Steel basically means iron that has been alloyed with carbon - in other words everything ever historically made from iron. There is no such thing as pure iron outside of a modern smelter. It makes no difference at all whether the term "iron" or "steel" is used to describe historical stuff. Today the term "steel" is reserved for iron that has a limited range of carbon in it. Any lower or any higher and it is called iron. The only thing to worry about in GURPS is whether it is "hardened steel". If it isn't then it doesn't matter what the exact alloy is.

[Tyneras]

Alright, that works for me. It was just that phrases like

Originally Posted by Low Tech p.20

...producing pieces that balanced wrought iron’s resilience with steel’s durable hardness.

and

Originally Posted by Low Tech p.20

Cast iron could later be cooked in an oxygen-rich atmosphere to reduce its carbon content, turning it into steel.

lead me to feel like there must be some difference between wrought iron, cast iron and steel to maybe matter, but I guess not.

[whswhs]

Originally Posted by Tyneras

Alright, that works for me. It was just that phrases like

and

lead me to feel like there must be some difference between wrought iron, cast iron and steel to maybe matter, but I guess not.

The Encyclopedia Britannica claims that low iron content gives you wrought iron (relatively low strength, easily bendable) and high iron strength gives you cast iron (high strength, especially high compressive strength, but a bit brittle). In between is the optimal set of mechanical properties, and that's what "steel" means. Dan's "no iron is completely free of carbon" strikes me as a bit of a distraction; if you read solid state chemistry you can find all sorts of cases where continuously varying the percentage of a substance in an alloy or mixture takes it across boundaries of discontinuous change in properties.

Bill Stoddard

[DanHoward]

My point is that the terms "iron" and "steel" are arbitrary and have no sensible distinction. IMO it shouldn't be called steel unless it has a high enough carbon content to be hardened. Which means that cast iron should probably be called "cast steel" and some types of mild steel should really be referred to as "iron". It gets worse: what we call "wrought iron" today is actually 18-19th-century "puddled iron" and is pretty useless for weapons and armour. Medieval or smelted iron should really be called "bloomery iron" and has different mechanical properties. Every time the term "iron" or "steel" is used it just creates confusion. Same with the term "bronze". I've started just using the generic "ferrous alloys" and "copper alloys" when writing about these groups of metals.

[whswhs]

Originally Posted by DanHoward

My point is that the terms "iron" and "steel" are arbitrary and have no sensible distinction. IMO it shouldn't be called steel unless it has a high enough carbon content to be hardened. Which means that cast iron should probably be called "cast steel" and some types of mild steel should really be referred to as "iron". It gets worse: what we call "wrought iron" today is actually 18-19th-century "puddled iron" and is pretty useless for weapons and armour. Medieval or smelted iron should really be called "bloomery iron" and has different mechanical properties. Every time the term "iron" or "steel" is used it just creates confusion. Same with the term "bronze". I've started just using the generic "ferrous alloys" and "copper alloys" when writing about these groups of metals.

Isn't there a point where the ferrous alloy has been hardened past the optimum for resiliency? That was what I thought was the point of the expression "cast iron."

Bill Stoddard