Immersion Quench vs Spray Quench

[nsdev]

I have an question regarding the cooling of a piercing plug used in a seamless tube piercing mill.

A plug which is itself water cooled internally, is retracted after rolling each tube and quenched in a "qunech box" which currently consists of a perforated jacket distributing a large volume of water over the plug. The plug is in the region of 500 to 700 degrees Celsius on entering the jacket.

We are looking to improve the cooling of the plug as when rolling at high rates, the plug is only in the jacket for round 3 or 4 seconds. I have maintained that a slight redesign of the jacket to improve water distribution, coupled with an increase in water volume, will improve the cooling substantially, but our business unit manager now claims that a "better idea" would be to mist cool the plug.

I have significant doubts that this will work at all, and my undertanding is that strongly agitated immersion cooling is the "best" way to quench cool an object.

Any views?

 

[siretb]

Immersion of a very hot piece into water will result in a gas (steam) film that limits the heat transfer coefficient. I am not sure that increasing the water volume will change much, I think that what limits the cooling rrate is the heat transfer across this film.

As for mist cooling, I do not know. if you manage to have enough of mist/gas circulation around the plug it might help. It might not.