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You Are Here:  Home > Products > Automatic (Direct Mount) MIG Torches > Open-Arc Gasless Overlay Torch
D/F Open-Arc Water-Cooled Gasless Overlay Machine Torch - Direct Mount

D/F Open-Arc Water-Cooled Gasless Overlay Machine Torch

D/F Machine Specialties Water-Cooled Gasless Overlay Machine Barrel on a BUG-OThe Open-Arc Water-Cooled Gasless Overlay Cladding Machine Torch is recommended for mechanized cladding applications where production demands the maximum durability and quality for multi-surfacing and rebuilding applications. This hardfacing torch is designed to last for years and is ideal for single-head machines or multiple-head machines used with hardfacing applications in up to 900 degree preheat like with the Welding Alloys Multi Surfacer: custom designed automated welding equipment. They feature dual replaceable Water Out & Power Cables to add to the durability and long life of the barrel assemblies. The Open-Arc Torch/Machine Barrel is primarily for hard/cored, metal-cored, & flux-cored wire diameters 7/64" & 1/8" (2.8mm & 3.2mm). The Open-Arc Machine Barrel offers a design that accommodates both slip-in, contact tips with a collet, and CrZr (chromium zirconium) heavy duty threaded current tips with a tip adapter nut. The suggested current level would be approximately 750 amperes (depending on application). Direct mounting is accomplished by utilizing interconnections to the welding head or wire drive.

An optional D/F Torch Rack #30418 can be used on any torch with an 8" long, 1.125" diameter water-cooled nozzle. The rack slips right over the water-cooled nozzle and is secured with 4 set screws. The rack can then be dropped into a BUG-O BUG-5188 Rack Holder. The rack has a 32 pitch gear, and with the rack holder makes torch head positioning very easy. See the images below right.

Engineered solutions for impact and abrasion challenges for hard automation, high deposition, and large wire diameters that require preheat and high amperages, a D/F heavy duty water-cooled weld automation gasless torch is ideal and has been used for metal build up, hardfacing and metal spray applications, open arc mechanized cladding applications for multi-surfacing and rebuilding applications, in the forging industry for the repair or reclamation of forging dies (also utilized in rams, sow blocks, die holders and die shanks when increased hardness is required), and in the steel mill industry for steel gears, arbors, shafts and couplings. D/F is a leading provider of hardfacing torches for impact and abrasion challenges, heavy steel fabrication in a wide range of industries, ideal for single-head overlay machines or multiple-head machines used with flux cored and metal cored large diameter wires.

D/F Machine Specialties is a leading manufacturer of torches for impact and abrasion challenges used with QT PLUS® wear steel, steel screen plates, steel cutting edges, abrasion resistant steel plates, wear resistant steel plate, chrome carbide overlay plate, 500 brinell steel plate, AR 400 steel plate and AR 500 steel plate in the heavy construction and coal mining industries.

The D/F torch is famous for the fact that if it is chilled properly, the welder can grab the front of the torch with their bare hand and it will be cold to the touch seconds after welding. With the proper chiller, this can be done even after a 4 hour arc time. Make certain the cooling water supply is at least the minimum flow rate of 3 quarts per minute (for each inner body), at 40 psi (80 psi maximum) with a 5 gallon reservoir and 15,000 BTU/hr cooling capacity. D/F Machine Specialties does not manufacture or sell chillers, we only recommend them. Click here to see our recommended chillers.

MWC-G-D - Machine Barrel, Water-Cooled - Gasless - Dual Water-Cooled Power Cables


  • Greatly Reduces Maintenance and Downtime
  • Withstands Extreme Conditions - 700° Preheat, 750 Amps
  • Water-Cooled Inner Body & Nozzle
  • Increases Tip Life up to 7-to-1
  • Heavy-Duty Construction for Long-Lasting Durability
  • Torch Longevity - Years vs. Months
  • Small Frontal Area for Hard-to-Reach Locations
  • Optional #40597 Mounting Bracket with Insulated Bushing for Remote Mounting
  • Optional Torch Holding Rack for Easy Mounting

D/F Rack
Optional Torch Rack
D/F #30418
Current Capacity 750 amp Continuous Duty
Overall Length 14.50"
Diameter of Body
Recommended Cored Wire Diameter .045"-1/8" (1.2mm-3.2mm)
Weight (approx., w/out services) 3.4 lbs.
Cooling Required 1 gallon/minute

40750 Water-Cooled Machine Barrel on a BUG-5188 BUG-O Torch Rack Mount

D/F 30390D Machine Barrel
Mounted with a D/F Rack
in a BUG-O BUG-5188
Rack Mount

Description Code No.
Model MWC-G-D Overlay Machine Barrel 30390D CAD download-9x9

Model MWC-G-D Overlay Machine Barrel Complete with Utilities
3 Ft.
4 Ft.
5 Ft.
6 Ft.
7 Ft.
8 Ft.
10 Ft.
12 Ft.
15 Ft.
Add Footage Digit to Item Code Number for Length Required.
Example: Require 4 Ft. Water-In Hose Assembly - 30390D-4



Hardfacing is gaining more and more importance in the most varied fields of modern engineering. In the case of wear, corrosion and other types of surface attack, the application of hardfacing permits the economical reconditioning of many structural members. Reconditioning may comprise work pieces subjected to metal-to-metal wear. Such as rollers, crane wheels, shafts, rails or which are subjected to metal-to-mineral wear, like building machinery, conveyor screws, excavator bucket edges, etc.

The possibilities of hardfacing not only lie in the field of reconditioning, but more and also in the manufacture of new tools and components. In this manufacturing process, a non-alloyed or low- alloy steel is used as carrier material to which are imparted special properties by welding on a suitable high quality weld metal. Decisive factor in hardfacing is the knowledge of the wear conditions, that is, whether it is a frictional wear caused by metal or minerals, corrosion, cavitation, erosion or temperature. The selection of the welding consumable to be used will depend on these conditions. Besides this, it is most important to know the composition of the base metal to be surfaced, because of the measures likely to be taken, such as preheating and/or post weld treatment.

Depending on the use of the workpiece to be hardfaced, the weld metal shall meet the most varied demands. These can be cited as follows:

  1. Hardness in the as-welded condition
  2. Red hardness under thermal loads
  3. Resistance to metal-to-metal wear
  4. Abrasion resistance to frictional and grinding wear
  5. Impact strength
  6. Corrosion resistance
  7. Resistance to scaling

In some cases, more than one of these modes of load may occur simultaneously, so that the weld metal must posses the respective properties. Hence, a conscientious selection of the proper weld metal will be a must. Of course, there doesn’t exist a weld metal possessing all these properties in full measure. Nevertheless, in most cases it will be possible to find a satisfactory compromise in practice.

Hardfacing Tools
An interesting field of application in hardfacing is reconditioning of hardened tools, such as shear blades, punching dies, cutting edges, deep-drawing tools, etc. For this purpose, the so-called “step hardening weld method” has proven a success. Welding is carried out in the delayed transformation range which is situated between the perlite and bainite zones of TTT-curves of the steel in question. Thereby, the hardenability of the steel is taken into account. Generally, the temperature range in which welding shall be carried out is from 400°C to 600°C. This means, that step welding is based on the fact that in such steels the transformation of austenitic is clearly delayed within a certain temperature range.

The sequence of operations is as follows:

  1. Slow heating of the workpiece to its hardening temperature. At this temperature the structure becomes austenitic.
  2. Cooling to step temperature; that is, to the range in which the delay in austenitic transformation (according to TTT-diagram) is most pronounced.
  3. Welding the workpiece at this temperature.
  4. Cooling the workpiece to room temperature in still air or better in oil (50°C to 150°C).
  5. Tempering to the respective temperature which in the case of high-speed steels lies in the range of 550°C to 570°C.
  6. Machining the weld area.

For the solution of the many cladding and hardfacing problems, D/F offers a complete line of welding Torches & consumables for flux cored wire electrodes, solid wire electrodes, gas metal arc welding and submerged arc welding fluxes.

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D/F® is the registered trademark of D/F Machine Specialties, Inc. D/F Machine Specialties, Inc. is not affiliated with Lincoln Electric®, Miller Electric®, ESAB®, Linde®, Tweco®, Thermal Arc®, Profax®, American Torch Tip®, Superior Consumables®, Fanuc Robotics®, Thermadyne®, ABB®, Hobart®, Kuka®, Mavrix®, American Weldquip®, Bernard®, Binzel®, Dinse®, Fronius®, M.K. Products®, Tregaskiss®, Motoman®, OTC Daihen®, Panasonic®, Welding Alloys®, Pandjiris®, Bug-O Systems®, CK Worldwide®, Weldcraft®, Airco®, Tec Torch®, CM Industries®, Alcotec®, and other MIG & TIG welding manufacturers. Those manufacturers mentioned are for reference only and are the registered trademarks of their respective companies.
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