Metal Hardening by Chilling Process

[Samarjit Sen]

Can some one explain the process of hardening of metal by chilling the same. I understand that the metal component which is to be hardened is put in a Low Temperature chamber . This produces better hardening property and is most suitable for bearing and cutting tool manufacturing. I am interested to know more about it and in case some one can provide details, I shall be very grateful.

[Brian_UK]

This website provides some basic info, it might give you start...
http://www.americanmetaltreatinginc.com/cryo.htm

also this one...
http://www.metaltreaters.com/page4.html

[hendry]

Can some one explain the process of hardening of metal by chilling the same. I understand that the metal component which is to be hardened is put in a Low Temperature chamber . This produces better hardening property and is most suitable for bearing and cutting tool manufacturing. I am interested to know more about it and in case some one can provide details, I shall be very grateful.

this has to do with the grain size of the material's structure.

as i remember ... smaller grain size cause ductile while bigger structure produce brittleness.

adequate quenching effects give the end results we seek.

[Brian_UK]

adequate quenching effects give the end results we seek.

But quenching may not produce the effect required here.

[NH3LVR]

I do remember something years ago about Auto Racers leaving their differental gears in liquid Nitrogen to harden them. I belive they put them in at room temp, and left them for several hours

[hendry]

But quenching may not produce the effect required here.

i do hope the below explains my points.

http://en.wikipedia.org/wiki/Quenching

[Brian_UK]

i do hope the below explains my points.

http://en.wikipedia.org/wiki/Quenching

We are discussing the treatment of metal using low temperatures not simply 'cooling' hot or heated metal.

Remember that Wikipedia is written by the viewers of Wikipedia and does not always provide 100% of the answer.

[hendry]

Can some one explain the process of hardening of metal by chilling the same. I understand that the metal component which is to be hardened is put in a Low Temperature chamber . This produces better hardening property and is most suitable for bearing and cutting tool manufacturing. I am interested to know more about it and in case some one can provide details, I shall be very grateful.

sorry, samarjit. could you explain if you means subzero chilling? or, it just lower temperature than the metal piece?
that would be great if you could elaborate ...

[Samarjit Sen]

Hello,

I have been trying to find out details for hardening of metals by chilling. Over the period I had collected some datas and informations from the net. I would like to share the same with forum members so that it may be of use to some one. The link to the details are as follows. Please do download it immediately.

http://download.yousendit.com/753D5119180EC8F9

All that I have learnt is that by gradual chilling of the metal components the product becomes more hard. I have seen some plants of these types, but due to inability to control the drop of temperature, the metal components cracked and got damaged.

[hendry]

Hello,

I have been trying to find out details for hardening of metals by chilling. Over the period I had collected some datas and informations from the net. I would like to share the same with forum members so that it may be of use to some one. The link to the details are as follows. Please do download it immediately.

http://download.yousendit.com/753D5119180EC8F9

All that I have learnt is that by gradual chilling of the metal components the product becomes more hard. I have seen some plants of these types, but due to inability to control the drop of temperature, the metal components cracked and got damaged.

those days when i were with the metal foundry....

we are very careful during pouring of melting metal into the mould. sometimes we got cavity due to poor pouring sequence & mould design. we even had explosion ... good experience ...

we fabricate train boogie.

coming back ... you need plenty data on the metal esp. temperature coolign profile, its grain transformation thru out.

crack is becuase you have chilled too fast ...

i think your meaning of 'chilling' is same with my understanding.

[Samarjit Sen]

Hello Hendry,

Happy and a prosperous NewYear to you. Thank you for your mail. I was out of station and such could not reply earlier.

I shall be grateful if you could please provide me with some informations or links to metal cooling/chilling. You have stated the facts which I am looking for. It is just for knowledge that I am trying to learn about metal chilling and hardness.

With best wishes,

[hendry]

thanks.

i wasn't paying attn to my lecturers those days. only until working in foundry, i find that those are fairly precious pieces of info.

some of mcgraw-hill books are good!
i've william callister book as my main reference for materials science.

hope that helps...

anyway, i'm back ...

[grump]

Hi Samarjit i see you were born 1941,NHLVR,Brian Catching up,Hendry ?In the meantime my experience with various metals in HVAC Chillers DX R22 with constant change in temperature say cw in + 20c evap -40 cw out 10c can cause the various materials To crack or breakdown. I have also replaced a water cooled condenser, made from mild steel when the outer skin became perforated.
I have made the assumption that your interest in metal processing is as a result of difficulties encountered.
In the meantime the contributions to date amount to approx 120-150 years practical hands on experience free and for nothing.
Engineers of the world unite Grump

[Contactor]

Don't forget Copper is hardened by rapid cooling with water whereas other metals are weakened, this is why all braised Copper joints should be cooled rapidly.

[PaulZ]

Hi Contractor When copper is heated and then cooled it is annealed and not hardened. It is not necessary to cool soldered joints as heating the copper even if hard drawn will anneal it and you basically end up with soft drawn copper at the solder point. Some types of steel are hardened or toughened by heating and then cooling rapidly. Paul

[Samarjit Sen]

Sorry for not coming back on this thread. Yes Grump, we are old but think young.

My interest on Metal Hardening by Chilling was created by some Metal Hardening people. They felt it would have a better effect and so I started venturing into it. The first thing that I learnt that the bringing down the temperature has to be in steps so that complete job has an uniform temperature. This will not crack the metal.

I am still trying to find out more and as Hendry has suggested some books I shall try to procure them and study. Meanwhile your suggestions and discussions on this will help me.

[hendry]

Sorry for not coming back on this thread. Yes Grump, we are old but think young.

My interest on Metal Hardening by Chilling was created by some Metal Hardening people. They felt it would have a better effect and so I started venturing into it. The first thing that I learnt that the bringing down the temperature has to be in steps so that complete job has an uniform temperature. This will not crack the metal.

I am still trying to find out more and as Hendry has suggested some books I shall try to procure them and study. Meanwhile your suggestions and discussions on this will help me.

Hola Samarjit!
how's things?!

yeap, metals isn't cheap these days. cement too!
we order by tonnes but delivers by kilos.
delvier schedule is very uncertain.

find that you are still "struggling" with metal hardening .... do let me know if you happen to find somethings interestings.