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Up Topic Welding Industry / Technical Discussions / chill bars
- - By Pablo van Dam Date 01-10-2008 20:30
For vessel work and welding SA 321 steel, 3/8" thick, Lincoln suggests the use of chill bars for quick cooling to avoid sensitizing. Does anyone have an idea of how these chill bars are made? Copper?, cooling with water?, how long? cross section?
Thanks for any help you can provide
Parent - By G.S.Crisi (****) Date 01-11-2008 12:49
I suggest that you visit Lincoln's website. There's a lot of information there, and there's also a section in which you can write your doubts, that they'll clear them up for you.

www.lincolnelectric.com

Giovanni S. Crisi
Sao Paulo - Brasil
Parent - - By dbigkahunna (****) Date 01-11-2008 14:53
Chill bars or back up bars should be made of the same material as the parent metal.
Parent - By 803056 (*****) Date 01-11-2008 21:51 Edited 01-11-2008 21:54
I'm going to stir up some more mud on this inquiry.

Chill bars can be separate components used to help control interpass temperature. They can also be integral with a fixture; in some cases they can be water cooled as is the case in some seamers used with SAW for welding longitudinal seams. The the case of the SAW seamer the water cooled copper chill serves as backing with a small U-groove in it to help control the melt-through and the shape of the root surface. In some fixtures copper chills are placed adjacent to the joint to control heat dissipation from the weld to adjacent areas. Some chills have gas passages to direct shielding gas toward the root surface of the weld to prevent oxidation.

I've used both copper and aluminum chills clamped to the work when welding aluminum sheet metal to enhance the cooling rate and minimize the interpass temperature.

People in the piping industry often call backing rings "chill rings". The backing rings used typically don't have sufficient mass to effectively increase the cooling rate of the root pass. They simply serve as backing to support the molten weld metal of the root pass until it has solidified. In this case, where the backing is permanent, it should be of a similar chemistry as the base metals being joined or of the higher alloy composition if dissimilar metals are being joined.

Just another opinion for you to consider.

Best regards - Al
Up Topic Welding Industry / Technical Discussions / chill bars

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