Is there a scientific term for heating metal in a furnace?


Is there a scientific term for heating metal in a furnace? I couldn’t find any. I look forward to your feedback.

induction heating perhaps?

Well, heating works. In the metallurgical world I once inhabited, heating is referred to by the more specific terms for the particular process/desired result/method. If you were heating to relieve stresses you would call it stress relief (sometimes called normalizing). If you were heating to soften you would say you were tempering. The more general term for heating with a purpose would just be heat treating.
Induction heating is a specific type of heating of ferrous (iron-containing) metals. There would also be gas-fired heating, flaming, resistance heating, etc. I don’t recall using a generic term for just making metal hotter.

So if I were making crucible steel for example, would it be ‘induction heating’ of the iron and carbon?

I’m no metallurgist, but I am an electrical engineer. Induction heating isn’t just generally heating metal in a furnace, it refers to heating a metal by subjecting it to a high-frequency magnetic field. The magnetic field creates tons of small eddy currents in the object being heated, and, like any (non-super) conductor, some of that energy is transformed into waste heat. There’s no burner or anything, the heat is being created in the metal itself.

If you were using an induction furnace to make your crucible steel, by heating up the iron until it melts, then you’d be induction heating the iron (and, by conduction, the carbon). If you were using a gas furnace or a resistance furnace or whatever else, not so much.

Like Toledo Jim said, I’m pretty sure the term you’re looking for is just “heating”.

I used to do some blacksmithing. We got really good at getting the metal to a certain temperature (and could eyeball it within 100º just based on the color of the metal).

We always used the word heating.

Induction heating is a method of heating that works on ferromagnetic materials. It isn’t a term for any heating of such materials.

If you used a magnetic field to heat the crucible steel inductively, then you would be using induction heating. If the heat came from some other source, then you wouldn’t be.

Honestly, the generic scientific word for heating is heating. You may be overthinking this.

Crucible steel, like any form of steel is an alloy of carbon, iron, and other elements. The carbon is dissolved in the iron. The process requires heating the elements to some temperature, and clearly from the statements above that is just called* heating*. There is some temperature at which the carbon will dissolve in the iron so aside from simply heating there may be some term in chemistry or physics that defines that temperature and the process.

Wikipedia talks about the carburization of wrought iron or the decarburization of cast iron to make crucible steel, but that really describes specific processes with specific intents, not just the general heating of metal in a furnace. There are a bunch of different words for different techniques and reasons for heating metal, but again, they’re all for a specific reason…

I’ll go with forging metal.

The term “anneal” is used when you are heating the metal in order to alter it’s structure. It’s also used in the semi-conductor industry when the Si wafers (or other material) is heated up after impurities are deliberately introduced to alter the electrical characteristics. The heating serves to more evenly distribute the impurities and to embed them more into the crystalline structure of the wafer.

Forging is the act of hitting the metal.
However, a “Forge” is a type of metal-heating furnace.

Thanks John Mace. I’m curious to know if the term ‘annealing’ can be applied to heating metal in a blast furnace, as in the heating of iron mixed with carbon etc to alter its structure to form steel?

Annealing is specifically re-heating a “worked” metal, and then cooling slowly.

Annealing is the process of heating metal to certain temperatures and cooling at certain rates to affect the crystalline structure of the metal primarily in terms of hardness. Blast furnaces are used to reduce iron ore, not to produce steel, although a bloomery, the smaller and older cousin of the blast furnace can be used to produce some small amounts of steel with the right ore.

Steel is rather complex, the wiki on steel is a good start to understanding this complex alloy. Steel is iron with a limited amount of carbon dissolved in it to form an alloy, unlike cast iron which just a mixture of iron and carbon (and usually a lot of silicates). The amount of carbon and other elements in the alloy provide a wide range of characteristics for the metal.

The Viking Sword episode of NOVAcan give you some insight into the earliest crucible steel processes. In that show they surmise that an unusual type of furnace was used to heat the steel that reached the temperatures necessary. Crucible steel didn’t really take off until the development of coke, baked coal which burns hot enough for steel to form. Making crucible steel requires rather pure iron to start with, and there are a variety of methods for removing excess carbon and slag from smelted iron to begin the process. Most other steel making processes use oxygen to heat the iron sufficiently for steel to form and to vaporize excess carbon and slag.

The OP appears to suffer from the Random Metallurgical Terminology Syndrome and that is understandable, (as mentioned upthread, look at the differing meanings of “forge”) but would benefit greatly in a little independent study of metalworking concepts if he/she desires to carry on a conversation.

Not a scientific or technical term, but I think what the OP seeks is “a (or the) heat”. As in: “Heat #24 was in spec., but heat #25 failed because it came out 1.2% short on chromium.” “#25 was a bad heat.” “The heat you are making right now should be fine.” Some folks would refer to the above in terms of “melts”. I worked in the ferroalloy business back in the '70s, and our furnaces were of the submerged arc type, a continuous process, opposed to the batch type for steel production. We differentiated our lingo by calling the opening of a furnace and extracting the molten metal a “tap”.

A nerdier description of the temperature at which any given metal completely melts is called the liquidus point. The maximum temperature that it completely solidifies is (amazingly) called the solidus point. The range between the two, if any, is called the eutectic, whereas the metal is neither liquid or solid, but kind of, ahem… slushy.

The point is, there is not any scientific term for heating metal up, be it the primary reduction of ores for refinement, or, simply annealing an existing alloy. Irrespective of the intent or method of application of the heat, one is simply making the stuff hot enough to achieve the desired end result.

Vikings were late to the game by about 300 years. In 6th century India used to make crucible steel which went by the name wootz in the western world. It was traded by Arabs to the western world and Syria used to be the hub - with Damascus steel being very popular. In fact Damascus steel knives are very high priced even now - even though they are not made in Damascus.

Cite : Wootz steel - Wikipedia

Thank you TriPolar. Can you tell me what you would call the ‘special oven’ (furnace) Richard Furrer uses in the Nova episode to reproduce the Ulfberht sword ?

Modern Damascus steel knives are a fad, much unrelated to the original metallurgical reason for their existence. Other than a semblance to the (at the time necessary) method of rolling and hammering of alloys, most modern Damascus products have no reason for existence other than nostalgia… Like Damascus barrels on shotguns, the product (despite the sales hype) is inferior.

Though from an “old school” perspective, it’s pretty cool.:slight_smile:

If you watch the NOVA show you’ll see that they considered this but found in some Viking swords even higher quality steel. As mentioned above modern Damascus steel is not the same thing.