I agree with Lawrence regarding "TIP-TIG" GTAW...

Now, if you already have a system and are not going to shell out for a "TIP-TIG" system then you have to work with what you got... So if the latter is the case, I would suggest that you contact Specialty Metals out of West Virginia and they would be happy to help you and become you source for Inconel...

But more importantly, is the selection of the best welding process to use for your application... For instance, choosing GTAW for cladding whereby control and consistency of the dilution without much variation percentage wise is not the optimum welding process for this type of application... Please let me elaborate further...

Dilution rate resulting from a set of welding conditions (welding process, technique, joint design, etc.) can be accurately determined by chemical analysis of a deposited bead...The dilution rate can also be determined by an area comparison on a joint cross section...

The rate is calculated from measurements of the final weld-metal area and the area of original base metal included in it... Dilution rates for shielded metal-arc welding are well established... Also, welder technique has less effect on dilution rate with shielded metal-arc welding than with other welding processes...

For flat-position shielded metal-arc welding, a dilution rate of 30% is typical and may be used to calculate weld deposit composition...
A 30% dilution rate means that 70% of the complete weld bead is supplied by the electrode, and 30% is supplied by the base metals with 15% coming from each dissimilar member... For other welding processes, dilution rates are dependent upon the specific welding technique and can vary widely... Dilution rates with the gas-metal arc process usually range from as little as 10% to over 50%, depending upon the type of metal transfer and torch manipulation...

The highest dilution rates are encountered with spray transfer and the lowest with short-circuiting transfer... Large variations in dilution rate are also found with GTAW process... Dilution rates can range from about 20% to over 80% depending on the technique and the amount of filler metal added... The amount of major elements contributed by each source can be calculated as follows: [*Note: The selection of the following alloys are examples only]

Contribution of INCO-WELD A Electrode:
70% x 70% Ni = 49% Nickel.
70% x 15% Cr = 10.5% Chromium.
70% x 8% Fe = 5.6% Iron.

Dilution by MONEL alloy 400:
15% x 67% Ni = 10% Nickel Dilution.
15% x 32% Cu = 4.8% Copper Dilution.

Dilution by Type 304 stainless steel:
15% x 8% Ni = 1.2% Nickel Dilution.
15% x 18% Cr = 2.7% Chromium Dilution.
15% x 74% Fe = 11.1% Iron Dilution.

The electrode contribution added to base-metal dilution is the calculated composition of the weld deposit:
60.2% nickel (49% + 10% + 1.2%), 13.2% chromium (10.5% + 2.7%), 16.7% iron (5.6% + 11.1%), and 4.8% copper... In a multiple-pass weld, composition remains constant along each bead in a macro or bulk sense but varies with bead location... The root bead is diluted equally by the two base metals. subsequent beads may be diluted partially by a base metal and partially by previous bead or entirely by previous beads...

Dilution Limits: Once the potential chemical composition of dissimilar weldment is determined, it becomes necessary to determine whether that composition is acceptable...
This can in general be done by use of dilution limits... Also, the cracking tendency of a weld will also be influenced by its configuration, size, residual stresses, the welding process being used, etc...

The elements normally of concern in considering dilution of nickel alloy welding products are copper, chromium, and iron... All of the products can accept unlimited dilution by nickel without detriment... Dilution limits given in the following discussion apply only to solid solution weld metal and wrought base materials... The values should be considered as guidelines... Questionable cases may require that a trial joint be evaluated. When a weld metal will be diluted by more than one potentially detrimental element
(e.g., Pb, Sn, or Zn), allowance should be made for possible additive or interactive affects... (Source: a .pdf titled "Joining" from The Special Metals Company. )

http://www.specialmetals.com/documents/Joining%20%28Oct%2003%29.pdf

http://www.specialmetals.com/products/inconelalloy22.php

While INCONEL alloy 22 is widely used for its excellent resistance to aqueous corrosion, the alloy is also resistant to many process environments at elevated temperatures up to
1250°F (677°C)... Alloy 22 has been found to be especially effective for protection of boiler tubes, waterwalls, and other components in coal-fired electric power generation boilers... The alloy has given superior service in low NOx boilers as well... Alloy 22 is resistant to attack at elevated temperatures by halides (especially chlorides) and sulfur, which are often present in the grades of coal used for power generation...

INCONEL alloy 22 also offers excellent resistance to aggressive corrosion by metal chloride and sulfate salts found in power generation boilers fired by municipal solid waste... Alloy steel components are commonly overlaid with alloy 22 by welding... Weld deposits fabricated using the Ni-Cr-Mo-W alloy 22 do not exhibit the segregation tendencies shown by Ni-Cr-Mo-Nb alloy systems... This affords significant enhancements in corrosion resistance and excellent resistance to the corrosion-fatigue cracking which is commonly observed in low NOx boiler waterwall overlays applied using Ni-Cr-Mo-Nb materials... In addition, solid components are used and alloy 22 clad steel tubes are also available.

To meet stringent emission limits, fossil fuel and waste-fired power generation boilers are being redesigned to add burners to limit the formation of oxides of nitrogen (NOx)...
Improved protection of the boiler tubes and waterwalls for service in these more aggressive environments is required... INCONEL Filler Metal 625 weld overlays have long been used for protection of such boiler components, but a recent study determined that these overlays can suffer from circumferential cracking due to stress-accelerated sulfidation
of the dendrite centers of the weld overlays in as little as 18 months of service...

The study also indicated that INCONEL Filler Metal 622 overlays should offer significantly better resistance to this attack and, thus, extended service life...
This superior performance is attributed to the higher molybdenum content and the absence of niobium, which has been blamed for elemental segregation problems in alloy 625 weld overlays... As a result, INCONEL alloy 622 welding products are preferred over alloy 625 products for overlay of boiler components...

INCONEL alloy 22 is readily fabricated by standard procedures for nickel alloys... Its high ductility aids cold forming, although work hardening may require intermediate annealing... Welding can be by gas tungsten-arc, gas metal-arc, and shielded metal-arc processes... Matched composition welding products, INCONEL Welding Electrode 122 and Filler Metal
622, are available...

Overmatching composition welds may be deposited with INCO-WELD® Filler Metal 686 CPT® or INCO-WELD Welding Electrode 686CPT...
INCONEL Welding Electrode 122 and INCONEL Filler Metal 622 welding products are also used to join high nitrogen super-duplex and super-austenitic stainless steels when the use of niobium-bearing welding products may result in the undesirable formation of niobium nitride particles... Alloy 622 welding products are also used for weld overlay of boiler
tubes, waterwalls, and hardware in electric power generation boilers fired by high sulfur coal or oil and waste-to-energy incineration systems fired by municipal and industrial waste... Information on fabrication, joining and machining is available in the Special Metals publications “Fabricating,” “Joining,” (Pages 12 thru 15 & 19 thru 21) and “Machining” respectively, on the website, www.specialmetals.com

http://www.specialmetals.com/documents/Inconel%20alloy%2022.pdf

Here's their home page:    http://www.specialmetals.com/index.php

Finally, I don't know your specific application so I'm not going to recommend a specific welding process at this time, but I will say that using Hot Wire GTAW for weld overlays suggests to me that your application is to be welded on to thinner base metal - correct? I ask this because if it is not, then you're limiting your productivity with hot wire GTAW, and instead, you should consider to use either SAW (Submerged Arc Welding), a or a Hot Twin Wire PAW system instead if dilution control and LOF (Lack Of Fusion) defects are some of your major concerns... I'll end by suggesting to look over the reference information I posted above and if necessary, to get in touch with an application engineer to help you decide better as to what direction you choose to take with this application... I hope this helps.

Respectfully,
Henry

It works well in narrow grooves especially with magnetic arc oscillation.

Jeez, Henry, I  hope you're getting a check for that post. I admire especially the part I don't understand which is a fair percentage. But I can say I've played with and viewed and heard of and experienced 'trade show' automatic TIG over 25 years with no love developing ever.

In thinking about this process, the first concern I would have would be preventing oxidation of the wire in the "hot" condition before it hits the weld puddle.  The Arc Machine paper I posted offers some practical advice.  Proper control of the length of stick out and shielding gas coverage would perhaps be heavy hitters for process control.

Kent - I guess that would be me?  Not much to offer to the OP who was discussing hot wire TIG cladding.  Stoody's cored wires are not (typically) suitable for this process as they are flux cored nickel wires.  But if they are interested in switching processes, then we might have a discussion!  I feel comfortable saying we have one of the best cored nickel FCAW wires in the world :)