Flame Hardening O1

[mikey]

OK, now I know to keep the surrounding area clear and turn off the smoke detectors.

-Ed

Also stand clear of the can of oil unless you want to permanently live without eyelashes and eyebrows! You think I jest, eh?

Leather gloves to deal with the inevitable splashes and eye protection are a must. I don't normally use a mask because there isn't much smoke and I can hold my breath long enough to get clear but safety is a really big deal when doing this stuff so please be careful - hot, splashing oil is not that much fun.

 

[Rockytime]

Thanks Mikey for the post. That is exactly how I was taught in clock repair school 40 years ago. I still use boric acid when making small single point cutters.

 

[Downunder Bob]

If you are using a MAPP gas torch, you are indeed flame hardening (as opposed to using a controlled atmosphere heat treat oven).

Thanks,
-Ed

No, not exactly, you might be using a flame as your heat source, but that is not "Flame Hardneing". Flame hardening is defined process, I don't think MAPP gas has enough free carbon in it. You need to use oxy acetylene with the flame set to give a caburising flame, or even a blacksmiths forge, this adds carbon to the steel so when quenched it hardens it. Also flame hardening is not required to harden what is already tool steel, just heat and quench. Flame hardening is used to harden steels that are low in carbon, so the process is used to add extra carbon, it will result in a surface or case hardening only, for through hardening you need an alloy designed for this.

 

[WoodBee]

, this adds carbon to the steel so when quenched it hardens it.

Bob,
I have no clue about flame hardening, but reading this thread made me wonder.
I assume using flame hardening in combination with boric acid is a bad thing because it interferes with the carbon absorption into the steel?

Thanx,
Peter

 

[WoodBee]

, this adds carbon to the steel so when quenched it hardens it.

Bob,
I have no clue about flame hardening, but reading this thread made me wonder.
I assume using flame hardening in combination with boric acid is a bad thing because it interferes with the carbon absorption into the steel?

Thanx,
Peter

 

[Downunder Bob]

Bob,
I have no clue about flame hardening, but reading this thread made me wonder.
I assume using flame hardening in combination with boric acid is a bad thing because it interferes with the carbon absorption into the steel?

Thanx,
Peter

Yes Peter, I think it would interfere with the carburising effect of the flame. I have never heard of, or seen any flame hardening process where any coating was used. That doesn't mean it can't be done

Bob,
I have no clue about flame hardening, but reading this thread made me wonder.
I assume using flame hardening in combination with boric acid is a bad thing because it interferes with the carbon absorption into the steel?

Thanx,
Peter

Quite OK peter, we all have to learn somewhere, I have the benefit of having done a 5 year apprenticeship, and although a bit rusty in some areas, I think I've remembered most of it, and spent some 50+ years in the industry.

Of necessity I was rather brief in my description on flame hardening. and I really only mentioned the process where it is used to give a thin shell or case hardening effect to low carbon steel. In the case of higher carbon and other alloying ingredients the flame hardening process can also be used but it is not essential to provide the carburising effect of a reducing flame, as you are really only using a flame as a heat source. In this case I guess you could use MAPP gas on small parts.

As in almost all things, Google is your friend, look it up. Ignore the articles that go against the main stream. I'm sure you will even find links to books that you can buy if seriously interested.

 

[EmilioG]

What about using TempilSticks? Do they work and are they better than watching for color change? More accurate?

 

[chips&more]

Ignore the articles that go against the main stream.

Boy, ain’t that the truth, can’t say that enough!!!!

 

[Bob Korves]

Ignore the articles that go against the main stream.

Consider them with careful thought. We are only parrots if we just just regurgitate the party line. Read and listen to all ideas, take them under advisement, give them discriminating scrutiny, and then test for what works best for YOU. This is not a popularity contest...

 

[Downunder Bob]

What about using TempilSticks? Do they work and are they better than watching for color change? More accurate?

I haven't used them but I imagine they would be a help, depending what accuracy and at what temperature.