is it damaging to heat metals too much?

[cool4rmour]

I'm a beginner and self taught, sometimes I feel like I'm making mistakes and heating the metal again and again
does it damage the strength or durability of the piece if I do that?
I mean, does it increase the risk of cracking, shearing or maybe it affects the indentation and straightness?
need your opinion about this

 

[quenchquest]

Yeah, I used to overheat stuff all the time when I was learning. Just keep an eye on the color because too much heat can mess up the metal

 

[FireAndFury]

When I was a newbie, I would reheat stuff a bunch to get the shape right. After a while, I learned that a few reheats are okay but too many can hurt how strong it is. Now, I plan my hammering better and watch the heat so I don't mess things up.

 

[Anvilenvy]

I taught myself too! I kept reheating steel 'cause I was never sure about the temp. I figured out that doing it too much makes the steel weak. Now, I try to keep the heat even and not go overboard.

 

[Dociron]

It's difficult in the beginning to not take too many consecutive heats. Your trying to learn were to hit the metal, how hard to hit and what heat to do certain forging steps at.

That said in the beginning your going to take more heats than necessary to accomplish a certain task. Hopefully with time the number of heats you require for any project will be reduced.

There are three factors that reduce the strength of steel from multiple heats. The first is that once steel has reached the curie point ( about 1475 F for most steels ) the carbon in the steel starts to migrate into the fire, second what isn't consumed by the fire migrates into the oxide scale on the surface. Have ever noticed how hard fire scale is ? This is because of it's high carbon content. Thirdly consecutive heats expose the steel to multiple heat cycling from hot to cold.

All of these negative factors increase in severity when forging alloy steels like 1084 or 4140. This is one of the reasons why alloy steels are usually forged at lower temps on the high end of a heat.

 

[Alan]

Thanks for sharing this insight. It really helps new smiths grasp the craft more effectively, and that’s what makes this forum such a great space for learning.