Which Steel creates more scale?

[Mark Barone]

I know I have asked this question before but i am looking at different variables. Do certain steels produce more scale/black after quenching? 1075 versus 1095 for example. Does forging versus stock create more of a blackened bar after quenching?

 

[IJM3567]

I think it’s more a matter of time at high temperature and amount of oxygen present at that temperature rather than steel type. So forging would have more black scale since you repeatedly heat it to high temps and expose it to oxygen. Two stock removal knives with similar surface finishes and heat treat time/temp would likely be about the same heat treat finish. Could be wrong though I’ve only worked with maybe 5 or 6 steels.

 

[tkroenlein]

I have not seen an appreciable difference between from 1075 up to 52100 in the build up of scale when forging, and the resultant finish strikes me as similar, though I've never done a side by side and tried for anything specific. This is 1075, forged of course, and brushed a few times through out forging and a final brushing prior to final quenching heat to knock off the scale and leave the forged finish. Quenched in heated canola wiped off with a rag and baked in the temper. I think the greater part of the difference in forged finish vs mill scale is the texture imparted by the texture of the scale being hammered into the steel. This is not "big" chunks of scale hammered into the steel, but the texture from the ever present scale that happens because the steel oxidizes the most when it is removed from the forge and starts cooling in O2 rich atmosphere. Mark needs a forge.

 

[Mark Barone]

. Mark needs a forge.

Yup tk I think you nailed it. I don’t plan on forging though but I want the ability to heat my steel quickly sometime, either for a hammered look, certain effects. I will never forge my blades. My shoulder is missing some anatomy from surgery during my meat cutting days, but am looking forward to hitting some hot metal for a few minutes. My kiln is great for heat treating but sloooooowwww and expensive to run. Now to look for something reasonable. Oh I gues I need some anvil too. any thoughts of what might be reasonable and still do the job I’m looking for.

 

[Kevin R. Cashen]

Iron has a very high affinity to oxygen, I have found that the less alloying, and the closer to a basic iron/carbon alloy, the greater the scaling may be. Scale is, after all, nothing but super heated rust. We really don't see much of a contrast with any modern steel. But if you ever work with ancient steels. like bloomery product or tamahagane, you will see the difference in a very clear way. That stuff scales like crazy! If you want an idea of what I am talking about, forge a bit of wrought iron, it will give you a small taste of the scaling I am referring to. we are truly blessed with our modern alloys when it comes to material loss to scaling.