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You Rang? BTW, I know George Totten very well (as well as his co-authors) - all very good. I will see them either in Shanghai this May or in Brazil in July. You are correct - the P-50 that you are using has a very light viscosity - about 50 SUS. Most of the canola products are around 500 SUS or so. Canola works well - it has a high flash, a high boiling point (which contributes to a high transition from nucleate boiling to convection. This also contributes to a fast quench with good distortion properties. However, from a commercial aspect, they are expensive, and hydrophillic - they pick up water and tend to emulsify. That makes them difficult to clean. It can leave a residue like burned on residue on the bottom of a pan. That said, it has a very nice cooling curve and is capable of high temperatures - but breaks down fairly fast....

Use of a carbon cover is common. Contact me at smackenzie@houghtonintl.com and I will see what I can do for you. Scott

Martempering or Mar-Quenching is primarily done for controlling distortion while achieving the desired hardness. Martempering can be done on either the 5160 or W1.

Bump Agree with bump, found graphic offensive though. Don

Actually it does. You get a stable vapor phase with oil. Using surface roughness you can speed it up (or you can slow it down if the roughness is too much and the bubbles "stick"). I would imagine clay would do a similar thing.

I think they have some simple boards that would work thru a firewire or USB port....

You can get a cheap I/O board from Omega and use about a 50Hz acquisition rate then graph it in Excel....it works well

http://www.shibuiswords.com/tatsuoinoue.htm I have met Dr. Inoue and have seen him give this presentation. Very fascinating.....

Different types of Martensite

Decarb is the loss of carbon from the surface from an oxidizing atmosphere. You end up with a fully ferritic structure if the carbon is completely depleted. Carburizing is the exact opposite.

So the oil doesn't heat up too much and keep you safe - figure a gallon of oil pper pound of part. Anything more than that and you will be fine. I would look at having agitation running up the length of the tube - will do wonders to keep the vapor phase down and get a nice even quench.

The clay used will not hurt the oil if it flakes off. Simple filtering will go a long way to make the oil last longer. Most of the clay will settle to the bottom - not big deal. Commercial heat treaters abuse their oil a lot more than any one of you will. For your oil, it should last a lifetime - you really have to abuse it to make it go bad.

Standard metallurgist answer - it depends. It depends on how rapidly you move the part or agitate the oil. Beyond the SA answer, I would relaistically expect most oils to fall in the .2 - .35 range. You can estimate the relative hardness from the correlations of H factor to equivalent round from the old Grossman charts (from Practical Guide for Metallurgists, by Timken - a wonderful text):

Yep - I would probably say that - especially in the absence of agitation.

I appreciate the kind words regarding Houghton. If you PM me - or email me at work (smackenzie@houghtonintl.com) I can help you find the right oil for you. There are many type - depending on the application. Scott

Brine is faster - the relative ranking can be done using Grossman H-Values: http://www.quenchtek.com/pdf_files/technic...y%20Factors.pdf It can be made faster with surfactants, etc.

Yes - salt acts as a nucleation site for bubble formation and makes the vapor phase less stable. Try a bit of surfactant in it (aka super quench) to make it faster.

Ultrasonic quenching in water has been used - it was first cited by the Russians a long time ago in some post WWII literature. I had to strain to translate it. It has also been tried for aluminum with good results. Trouble is that you use a lot of energy to get the ultrasonic energy into the part. It is easier just to use an impeller.

I am trying to remember - I think it is in one of my books on quenching of aluminum - or heat treating of steel. It may be in both - I am shameless to use in multiple sources.

Yes - vapor phase would be elongated in carbonated water....

Liquid nitrogen is a very slow quench because it goes right to vapor. creates a very long and stable vapor phase. The same would be said for alcohol - it would have a long vapor phase. Not a good idea.

Look at http://www.ferrochrome.co.za/for_sale.htm They sell Ferrochrome - it would melt easier that way. There are other suppliers too - you might be able to get a freebie if you ask nice.

I know - but it is too bad because it was a nice piece of work. I am surprised he didn't just forge some cable and look at it.

The hardness of the water can have a huge impact on the cooling rate. The softer the water, the more stable the vapor phase (and the slower the overall quench. See the attached picture comparing distilled water and hard water at various temperatures.