case hardening with sugar-question about terms used

I was reading an article recently about case hardening using sugar rather than Kasenit or Quick Hard or the other commercial case hardening powders. The author mentioned using "half a teaspoon of Tate and Lyle". I have no idea what "Tate and Lyle" is. I'm guessing it is a very common item in the UK, probably related to sugar somehow. Can anyone enlighten me?

JD (just off the turnip truck, you're probably thinking, and you'd be right....)

You want Silver Spoon!

But yes, it's one of the two British sugar producers.

Tate and lyle sugar

He was pretty big and we got the Tate Gallery London

Tate

JD, it's just a facetious reference to plain sugar, like the stuff some folk add to their tea or coffee. Was this article in a magazine, or on the Internet? If the latter, have you a link to it?

Andy

Thanks to all for the info. Not sure about the "silver spoon" reference - I guess maybe it's the other leading brand of sugar in UK?

Anyway the article was in a print magazine, not online. The article claims sugar can be used exactly the same way as commercial case hardening powders, ie dip the hot part in it, heat to red heat, quench, repeat, etc. It did not say whether it will work with pack hardening in a closed stainless wrapper in a furnace or forge or not. I would think there would be a lot of flame and (sticky) fume off a large bit of sugar in a pack hardening scenario.

I'll mess around over the next week or so with some sugar re the case hardening (and I won't bore you all with our local brands) and advise how it went vs commercial case hardening powders. I'm sure the sugar will smell a lot better than commercial stuff and it sure is a lot cheaper.

Probably have all the neighborhood kids coming around looking for campfire roasted marshmallows....

Thanks again JD

Going off subject a bit, one time in my chequered career I worked for a blacksmith who always case hardened using oxyacetylene. Once the part was red hot he turned off the oxygen and coated the job with the acetylene smoke, which is pure carbon, he then induced it into the metal by reintroducing the oxygen. It seemed to work and as I've never heard of using sugar before, just goes to prove that there's more than one way to skin a cat besides pulling out lumps of fur.

The good old Kasenit would always bubble (just like sugar!) when you heated it after plunging the item into the powder, it was not really a powder, more granular than that, just like sugar but with black bits.

I do not think sugar would be very good in pack hardening inside a container, could be very messy.

For non UK readers, Tate & Lyle is cane sugar (the best) and Silver Spoon is beet sugar and no where as sweet as cane.

Edited By KWIL on 26/06/2012 12:00:03

I suspect the reason for suggesting the use of sugar instead of charcoal for open-air case hardening is that it will melt and stick to the steel, whereas charcoal won't. It certainly contains plenty of carbon atoms.

I've never heard the suggestion before that cane sugar is sweeter than beet. I was about to get all chemist on you and say that they are both sucrose ,and it will taste exactly the same irrespective of its source. On reflection, it is possible; sucrose is a disaccharide formed from two monosaccharides, glucose and fructose. Glucose is about half as sweet as sucrose, but fructose is twice as sweet. Thus if the sugar (sucrose) is partially hydrolysed, split into its two components, it could tast a little sweeter. So, possibly something in the processing could make a difference - and possibly cane sugar contains more than pure sucrose. Anyone know? (or care!).

David

My understanding of the process is that you are trying to diffuse carbon into the surface of the metal so packing any material which will donate carbon atoms around the metal and heating will acheive the desired result with the proviso that some substances are more effective and less messy than others. Wrapping the componant with strips of leather within a closed iron box works. Excuding oxygen is good as this prevents surface oxidation and subsequent loss of the cased layer. Acetylene sheilds the componant in the same way as the argon gas shield in wire welding and provides the carbon from the gas. The melting of casenite or indeed sugar similarly protects from atmospheric oxygen like a flux, I suspect that the casenite mix is acidic and reducing so could well mop up stray oxygen too again like a flux

Martin.

I seem to remember, maybe read in a book, that sugar was used by allied POWs to harden bits of escape gear, wire cutters etc. It is mostly carbon after all.

Hi

Sugar chemical composition is C12 H22 O11 That is when it is burned it turns Black, the water part burns off and the carbon part remains. unfortunate the bruning action melts the sugar so a lot of the original sugar remains intact. If the process is done with the aid of Sulphuric Acid to strip the water moluces and leave the carbon component in tact with the right concentartion and volume of Acid a dry foam remain. this is pure Carbon, and should be ideal for case hardening.

Eddie

Hi Eddie

The problem with this method is that you need concentrated sulphuric acid to start with, its a highly exothermic reaction and the result is a mass of carbon that is brittle and acidic as not all the acid is used up in the reaction . I think I would rather ram a hot piece of iron into a pile of sugar let it carbonise, heat and repeat until the case is deep enough then harden. The only draw back being the strong smell of caramelising sugar that might, as Jeff D suggests, have the neighbourhood kids looking for whose toasting the marshmallows .

Cheers

Martin W

Eddie,

I think the sulphuric acid idea is one of the worst I have seen on here. I can see no advantage in it, and as Martin say, some of the acid would remain, enough to make a real mess of the steel. H2SO4 is not something to muck about with if you don't know how to handle it.

If you want a good clean source of pure carbon, you could do worse than to use some graphite powder, as sold as a lubricant - very popular for lubricating locks, as it doesn't attract grit like oil does. However, the powders specifically sold for case hardening do contain extra things to make the process more efficient, so why not just use them. After all, we're not stuck in a POW camp.

David

I suspect raw cane sugar, or better still demerara would work better. I understand mollasses is an ingrediaent in some commercial formulas, and that the 'contaminants' help the process.

Neil

Francis,

Thank you; seems my first instinct was correct then!

David

I know one thing is that cane sugar makes better jam than Beet sugar! I dont know why but it does.

Regards the hardening, using any carboniferous materiel packed in with the metal to be surface hardened will work.

The quality of materiel and the length of time are the factors.

I have used leather and carbon sticks and sugar mixed into a powder and all put in a metal container(substantial) and cooked for an hour or so.

The subsequent part was better than the original ( the cylinder pawl off a pistol and had not changed shape or dimension at all)

Clive

Very interesting this thread.

i may try this later.

Andy.

Glucose is about half as sweet as sucrose, but fructose is twice as sweet

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So should we really be case hardening mild steel in mashed banana and oxygen?

I'll have to get rid of that oil drum full of sperm whale bits to make room

Edited By Ady1 on 28/06/2012 00:16:55