Chronos silver steel, water or oil quench?

[Goran HosinskyParticipant @goranhosinsky61367]

[Goran HosinskyParticipant @goranhosinsky61367]

The silver steel that Chronus sells, should I use water or oil to quench it?

Goran

Canary Islands

[mickParticipant @mick65121]

Hi.

     Dosn’t much matter who supplies it, its still quenched in cold clean  water, although it will still take on hardness if quenched in oil, but not to the same degree.     I’ve heard of old engineers who would quench in a container of oil and water.    The oil floating on top is the first quench and then the water beneath completes the job, its supposed to harden and temper in one go, although I’ve never been brave enough to try it! 

[DustyParticipant @dusty]

Goran

       The oil and water trick is good and works, but it will not harden and temper in one go. The oil which should be about 6/8mm thick is to help prevent cracking the shock of plunging small sections into cold water can cause stress cracks to appear. Usually the first you know about them is when the component falls apart. For most items I use a jar of about 500grams capacity. The glass jar allows you to drop the item to be hardened into the jar and being glass you can see it to recover it.

[Tony Pratt 1Participant @tonypratt1]

A water quench will give you maximum hardness and also maximum brittleness, an oil quench will give you a slightly less hard component but not by much. After hardening the job will always have to be tempered to suit the components application.

I have never heard of the oil/water combined quench or seen it mentioned in any of the tool steel manufacturers heat treat specifications and I imagine the benefits are a bit of a myth and more imagined than real.

 

Tony

[macmarchParticipant @macmarch]

When I was an apprentice, way back in 1900 and frozen to death, we were trained to water quench silver steel and gauge plate but oil quench tougher grades like EN24 and the like.  Perhaps someone has an ancient copy of Kemps or an old treatise on hardening circa 1950.  When I started to H & T at home there were times that cracking became apparent.  I have now changed my method of tempering and have not since had any problems that I am aware of.  After hardening and cleaning I temper in the electric oven. I find that a good half hour plus a minute per 10 thou of thickness does the trick . It is satisfying to see the required colour all over the part. It enables the grain structure to realign after the surface shock of quenching.  I have found that ‘most’ people heat to cherry red then quench when the cherry red stage should be held for some time to allow the grain to adjust all the way through before quenching and then the tempering temperature! held for the same reason.

 

Is there someone here that could give a simple explanation of the Iron/Carbon Diagram for the benefit of the newer members to the craft.

 

If you are a person that changes the own engine oil then keep some next time.  When a mild steel compenent has to used outside then heating to a dull red then dropping in the carbon rich oil won’t harden it but it will give it long lasting protection against rust. Just don’t try welding it after.

 

ray

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Water must be some days old to be sure the air are disappeared from the water to give good conduct of cooling of the part who are quenced. After the part are in the water, move the part around in the water to be sure the water are not heated by the part who are hardening.

 

In case you has a part who has a thinnest part and the thickest part, begin first with thinnest part then rest of the thicker part while you are quencing the part.

[Anonymous]

A rule of thumb I use for hardening carbon steel is to maintain the hardening temperature for an hour per inch of thickness.

 

Ideally one should quench in brine, rather than plain water, as this inhibits the formation of bubbles at the interface with the hot metal and hence improves the cooling.

 

Regards,

 

Andrew

[adyParticipant @ady]

Canary Islands?

Dunk it into a volcano on the end a rope, use water to quench.

 

Read up on hardening and tempering on the net, there are some good resources.

 

[John OlsenParticipant @johnolsen79199]

The Canary Islands are I beleive surrounded by a convenient supply of Brine.

 

regards

John

[Goran HosinskyParticipant @goranhosinsky61367]

The brine we have yes, and the volcano. Just two small problems. One is the distance as the volcano is at about 8000 feet and the brine at 0 feet, the distance in time I do not really know as the road is very curvy. Second problem is my supply of quality rope which will stand the heat …

 

Ray, at what temperature do you run the oven?

 

I have read in some publications that there are two types of silversteel, one which should be quenched in oil and one type that should be quenched in  water, that is why I asked.

 

Thanks for the clarifications!

Goran

 

 

[adyParticipant @ady]

I don’t know about temperatures, they tend use a lot of colour descriptions.

‘Straw colour’ was one I read about a lot.

 

One article I read had them only quenching with a quick dunk in brine, to harden the outer skin, then leaving the hot steel item on a cool concrete floor to temper.

I think it was a motor bike part which kept failing, that part never failed again after this approach.

 

An interesting subject.

[macmarchParticipant @macmarch]

The colour you temper to is determined by the use the tool is put to.

 

Assuming standard silver steel.  (should have “Stubbs” marked on one end.

   

                                     Oven Temp

Brass turning tools  180 C

Lathe tools                200 210 C      (and chisels)

Milling cutters           220 230 C

Scrapers                   190 200 C

Springs                      Flat out

 

By colour

Pale straw               190  200

straw                         210  220

dark straw                220 230

 

For things like cold chisels and screwdrivers  take them out of the oven and give a blast with a gas torch to get a little blue at the tip and plunge immediately.

 

I had a word with an old friend (85) and I quote,

” Quench in brine for a faster cool down. Quench in oil hardening oil but only if the silver steel is specifically an oil hardening type. The brine shoud be rock salt or other form not table salt as it has additives that can alter the material. Use a solution of about 10% salt. Don’t forget that as you have cooled down a lump of overheated steel it will have all sorts of stresses in it so the slower and longer the heating and holding at the right temp during tempering the better.”

 

HTH

 

PS If swimbo allows you can also use the chip fryer.  BUT MAKE SURE their is NO WATER on the parts.

As I was writing this I have been advised that Tubal Cain’s book WPS1 covers this subject in great depth.

 

Edited By macmarch on 05/10/2010 09:46:37

Edited By macmarch on 05/10/2010 09:49:03

[Anonymous]

I second the recommendation of Tubal Cain’s WPS1 book. It explains a complex subject in sufficient detail to allow proper hardening and tempering of carbon steels in the home workshop.

 

Regards,

 

Andrew

[jomacParticipant @jomac]

Hi, I need enlightening, (no dieting). When I was a young fellow growing up in the West Midlands before the WW2,  I often went with my old man to his cousins large blacksmiths factory, and the first thing all the men had to do, was piddle into the large cooling vat, (no women allowed), The unmistakable aroma is unforgetable, ???? asked why we had to do this, simple lad ! it’s give a better edge to the scythes and other tools, they made. Now, down in the silt of my brain cells, I recall reading that the Sarecen and Spanish sword makers did the same thing, Is there something in the urine that does this, or is it a tradition. anyway the only good thing urine does is, if it’s watered down it’s good for garden ( I dont do this) also just filtered through the kidneys it does wonders for my Lemon tree (I do this when no one is looking). Is there anyone out there who can enlighten us if there is any truth in this, hardening and tempering technique,

Keep doing and not thinking works for me.

John Holloway, (now living in Oz for the last 60 plus years)

[Anonymous]

I don’t know for sure, but the second biggest constituent of urine, after water, is urea. Urea contains nitrogen, and gives off ammonia when in contact with water. That might explain the nasty niff. Perhaps it was a early form of nitriding?

 

I don’t have a lemon tree in the garden, but I have been known to micturate on the compost heap, rather than traipse back indoors when caught short.

 

Regards,

 

Andrew

[Sub MandrelParticipant @submandrel]

I met David Bellamy,

 

He spent a long time discussing peeing on the compost with a colleague

 

Neil

[Ian S CParticipant @iansc]

In the days of gunpoweder, nitrate was extracted from urine for use in the manufacturing of gunpoweder. I read of it some time ago, not sure if it was on the web, or there was an artical in ME. Ian S C

[Sub MandrelParticipant @submandrel]

To return to the question (for once!), I use water to quench Chronos silver steel and rapeseed oil for the gauge plate and I haven’t had a duff result or a crack yet.

 

Neil

[Sam StonesParticipant @samstones42903]

Gentlemen,

I couldn’t resist `chipping’ in with a couple of comments.

I would go along with most of what has been mentioned, although I always use clean cold water for quenching silver steel and gauge plate.

Both are high carbon steels, (above the eutectic of 0.87% carbon). Lower than this amount of carbon, the more difficult to impossible it is to reach a satisfactory hardness result. That’s why mild steel has to be carburised to achieve any kind of additional hardness. For those (beginners) not in the know, this is known as case-hardening. I have used Kasenit(?) for many on my MS parts, and always got good results.

For the technically inquisitive, I recall that there’s something about the carbon atoms shifting between body-centred and face-centred, but I can’t remember which way round.

If you don’t temper after hardening these steels, you should anticipate a high level of brittleness. Curiously, the smallest bearings in the skeleton clock (referred to as jewels), are left `dead’ hard. But with an OD of 3/32″, an ID of 0.025″, and a length of 1/8″, they are not under much stress.

Now, as for cracking. What about mentioning notch-sensitivity, and the reason for radiusing inside corners?

With more than 40 years experience in the plastics industry, I can assure you that sharp corners (notches) are very much the cause of (apparent) brittle failures in plastics components. These stress-raisers are one of the reasons plastics get their bad name.

Ask a reputable toolmaker to leave sharp notches in any part of his tooling which is subsequently due for heat treatment, and he should look at you askance. Yet have a close look at any plastic component which has broken, and I could almost guarantee, you’ll find a sharp notch where the sharp (external) edge of a mould has been overlooked.

I thought the Japanese quenched their swords in ox blood?

Regards to all,

Sam

 

One hundred postings – Time to celebrate!

Edited By Sam Stones on 12/10/2010 02:21:50

Edited By Sam Stones on 12/10/2010 02:23:02

[Sub MandrelParticipant @submandrel]

> quenched their swords in ox blood?

 

 I don’t know, but I harden my cutting tools by heating them to the colour of the rising sun, and test them by cutting a peasant in half.

 

Neil

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, posted by Sam Stones, For the technically inquisitive, I recall that there’s something about the carbon atoms shifting between body-centred and face-centred, but I can’t remember which way round.

 

  Sam, I believe you are describing the allotropy of Iron.

 

I had to dig out my college notes from 1977 for this one.

 

Iron can exist in two forms, Ferrite and Austenite. On cooling, it is in its Austenite form at temperatures above the upper transformation line (695 to 920 degrees C)

As cooling continues through the transformation zone (between upper and lower lines) the Austenite changes to Ferrite. During this change Carbon is precipitated from the Austenite, because Carbon is insoluble in (Iron) Ferrite. The precipitated Carbon is in the form of Cementite which goes to form Pearlite, or in the case of steels with over 0.83% Carbon the excess cementite remains on the grain boundries.

Time is needed for these changes to take place. A slow cool will enable the changes to take place and will result in a large grain structure. A faster cool will result in a smaller grain structure.

However, if the cooling rate through the transition range is increased sufficently (i.e. quench) time will not be allowed for the changes from Austenite to Ferrite to take place. In this case there is insufficient time for the Carbon to be precipitated out of solution and this result in the Carbon atoms being forcibly locked in the Ferrite structure. This may be described as a super saturated solid solution of Carbon in Ferrite Iron.

Due to the distortion caused by the Carbon, the grains are acicular (needle like) and are very hard and brittle. The name of this structure is Martensite.

 

Regards Nick.

Edited By Nicholas Farr on 13/10/2010 00:16:09

[Sam StonesParticipant @samstones42903]

Hi Nick,

Thank you for such a succinct and eloquent explanation. I almost had tears in my eyes as I read familiar words like pearlite and cementite, etc. There was even a memory vestige from way back, as I momentarily recalled the iron-carbon phase diagram. I had to get onto the Internet to satiate a burning desire for verification.

Observing first hand, the `point of recoalescence’ in a darkened laboratory held my fascination as to how a solid could dissolve into or migrate from another solid, and how this phenomenon briefly increased the level of radiation during cooling.

I feel sure that your explanation will prove very useful to readers in bringing additional clarity to the heat treatment process, especially with regards to the rate of carbon migration, and its effect upon the hardness of high-carbon steels.

 

Good stuff!

 

Sam

[SamsarandaParticipant @samsaranda]

Reference " peeing " in the quenching tank, years ago was told the story of a metal treatment shop in a large engineering concern, a new manager was appointed and as part of flexing his muscles he decided that the metal treatment shop , particularly where heat treatment took place, had to be cleaned up as it was like a tip. He organised a blitz of the area and in the corner was a tank containing murky not very pleasant smelling liquid which he had emptied and then scrubbed clean. It soon became apparent that the components that were heat treated where significantly below the standard usually achieved, an enquiry took place and the elderly gentleman who worked in the heat treatment area said that they would not be able to attain previous hardness values because the tank that they had emptied and cleaned out had not been emptied for years and he always peed in it and this unsavoury brew was the reason for the high hardness values they used to achieve.

Dave

[Rik ShawParticipant @rikshaw]

The preferred method way back was to quench in water that had a layer of sperm whale oil floating on top.

Rik

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