Gas lens

Date 11-30-2015 00:49

Hi all, i was reading one of the articles by Mike sammons on fabricator written on the topic "welding of austenitic stainless steel" . He says that gas lens is recommended when using GTAW for welding austenitic stainless steel. It distributes the gas evenly around tungsten electrode , weld puddle and gives cooling action.

My question is how gas lens causes cooling action? I haven't read this use of gas lens anywhere. Is laminar flow has something to do with this?

Thanx all in advance.

By 357max

Date 11-30-2015 19:41

The gas lens collet body provides a larger mass of metal which has a larger cooling surface.

By Lawrence (*****)

Date 12-01-2015 01:31

Max has the golden nugget.

I was thinking about cooling action of the puddle or base metal... Which there is not :)

But I suppose the gas lens might help cool the electrode a bit... Might give you one or two more amps before your electrode begins to degrade :)

Using a full length tungsten will do much more in the way of cooling :)

By waqasmalik (**)

Date 12-01-2015 12:48

Thanx Lawrence and max, i m sorry i didn't understand what max said. Mike sammons was explaining carbide precipitation in HAZ of austenitic ss.

By js55

Date 12-01-2015 14:58

I fail to see how a gas lense can increase cooling other than it allows greater gas flow without aspiration.
In any case, I suspect any difference in cooling IMO is one of those things theoretical people wax on about ad nauseum when in reality it makes little difference.

By 357max

Date 12-02-2015 03:27

Back a few years ago when using 150 amp Linde GTAW torches with valves; walking the cup on 6 & 8 inch pipe. When the valve was turned off at the end of the weld without giving enough time for the gas flow to cool the hose and cable. The cable hose would be so hot it would melt and burst like a balloon. To rectify the situation Linde provided replacement 200 amp cables that threaded onto the 150 amp torches and recommended the use of gas lens for additional heat dissipation.

By js55

Date 12-02-2015 17:13

Not sure what the gas lens has to do with it. I still do not se anything inherent to a gas lens that would assist cooling other than its allowing increased gas flow without aspiration.

By Lawrence (*****)

Date 12-02-2015 21:51

I'm a big fan of Mike Sammons... He taught me a great deal about aluminum GTAW and Asymmetric power supplies back in the Mid-90's when working together on several projects.

As far as gas lenses cooling a stainless weld pool to reduce carbide precipitation, I think any gas cooling effect is negligible. Would have liked to directly questioned Mike to get him to say more about it.

As a heat sink for the tungsten? Ok.. I'll buy that.