Refining/Shaping Bloom Steel.

[DanielC]

This was some work done this past Friday night, using a 3# and 12# sledge. It was after working on a much larger piece of bloom iron so I was pretty tired. Didn't squish into a bar, but this video is basically some cool footage of bloom being worked to muck bar stage with a camera that can focus in on high temps. Don't be fooled by the color captured by the camera as well. This thing is at the cusp of sparking, if it isn't sparking every time I pull it out of the forge. Also since it is bloom steel, it is a little more difficult to deform than the bloom iron I am used to working with.

 

EDIT: This is also the reason I missed the NCABANA meeting at Peter Ross's shop. I hadn't swung the 12# in weeks, and between using it on a 4.5# bloom iron chunk and then this, my body was wiped at 7am the next morning.

[ThomasPowers]

I have a 20# sledge head---I use it as an anvil...

[DanielC]

Yea, right now a 12# sledge is my power hammer...

[arkie]

Not being well versed in the bloom composition, how did you go from bloom iron to bloom steel?  Added carbon how?

[ThomasPowers]

Blooms can be anything from very low carbon material all the way up to cast iron.

 

He was using a higher C bloom.

[SJS]

Ifen he is sparking every time it comes out it won't stay higher carbon;-)

[ThomasPowers]

If he's close to 2% C he may want to decrease the amount for a tougher blade.

 

The repeated folding and welding the Japanese do can take a starter of almost 2% and end up at .5%

[DanielC]

Usually we use limonite ore we mine locally. This ore tends to want to be iron regardless of furnace design. This video is from a titanium-magnetite supply we ran through the smelter. If you are familiar with japanese magnetite, it often is a titanium bearing magnetite.

This is steely, but not high carbon steel. The smelter's height of 3' is designed more for iron. Plus we tapped off a lot of slag, allowing the air supply to blast a lot of the carbon away. Tend to not care if it has any carbon in the bloom any more since after repeated folding and forge welding temps it is mostly just iron. That is the trick with bloom. It must be worked at forge welding temps. Almost always a white heat to sparky, otherwise it would crack. Similar to erought but a little more extreme since wrought is bloom iron, just folded several times.

If i want high carbon steel we hearth refine it using evanstad method. Which depending on tuyure height can yield either highly pure iron or high carbon bloom steel.

Even more recent my good friend has been carburizing in stainless tubes in a process nearly identical to making blister steel.

[DanielC]

Also i am not really aware of any bloomery process making workable steel at the 2%C range. White cast iron is a byproduct if the process ever now and the, but the japanese take this and perform orishigane to bring it down to workable carbon ranges.

[DanielC]

I take some of that back. A few friends if mine add white cast iron at those carbon ranges to their bloomery material as they are folding.

[ThomasPowers]

I might not call it "workable" at that carbon levels as much as "materials to be worked down into usable levels". Like some of the pucks with wootz, you decarb the outside to get it to hold together while working it and tucking the excess carbon into the carbides.