Welding Inconel 738

Date 08-05-2004 15:33

Does anyone have any advice on welding Inconel 738? We are having problems with cracking in the HAZ and the weld metal itself.We have tried welding hotter,colder,all the basic stuff.We are using a Miller Dynasty,with argon shielding gas.using AMS 5796 L-605 filler metal.I am just a lowly CWI and former pipe welder trying to help our engineering group.Also,we are using GTAW.

By Lawrence (*****)

Date 08-05-2004 20:58

Ringo,

Welcome to the forum!

My experience with L-605 has been with it used for build up of wear areas on jet engines. L-605 is often used as a hardfacing wire, cobalt (49%) and tungsten (15%) make L-605 a material that has great toughness but is not so ductile.

Our buildups were on 718 inconel and Hastelloy X, the inconel required annealing pre weld and post weld stress relief and from time to time we still had some micro cracking problems that inspired us to use micro plasma rather than GTAW in some situations (synchronized pulsed arc/wire feed), also we put quite a bit of effort into innovative heat sinking and robust restraining fixtures.

Before I left the Aerospace business we were also doing trials on on scrap components using "temper bead" techniques with some promising results. Here is some AWS data: http://www.aws.org/wj/sept03/feature.html

Others are turning to laser and finding both increased capability and productivity gains. While I have no experience with lasers here is a cool link dealing with inco 738
http://www.sulzer.com/com/NewsAndMedia/TechnicalReview/Archive/2004_1_Mattheij_e.pdf

Are you repairing turbine blades? if yes, just the tips, or are you attempting heavy sections? If your not building wear areas perphaps an alternate filler metal closer in composition to the inco 738 could be explored.

http://www.magnatech-lp.com/Articles/EPRI-Text.htm

By Ringo

Date 08-06-2004 11:49

Thanks Lawrence

By Ringo

Date 08-06-2004 11:55

I was also going to tell you that we are tring to rework 2nd and 3rd stage vane rings out of a low pressure turbine.We do have a Metbond plasma welder,but it is an automatic process we are using to build up turbine seals with the filler metal being powder.I dont know if we can incorporate this process into manual.The problem with the vane rings is that they are becoming worn from the torque of the engine,causing the rings to shift.Once again,THANKS,you've been a great help.