Sub Arc Flux Holding Ovens
Keep Conditioned Flux Ready for Production
Keen Flux Holding Ovens are designed to maintain rebaked or conditioned submerged arc welding flux at the proper holding temperature until it is needed in production. Available in multiple capacities, these hopper-style flux ovens help fabrication shops, shipyards, pressure vessel manufacturers, structural steel producers, and heavy equipment builders keep flux organized, accessible, and ready for continuous SAW operations. By supporting ready-to-use flux availability throughout the workday, Keen flux holding ovens help reduce handling, minimize interruptions, and keep welding production moving.
From compact point-of-use models to high-capacity hopper systems, Keen offers flux holding ovens engineered to match the production requirements of virtually any submerged arc welding operation.
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Don't compromise your submerged arc welding (SAW) process by allowing humidity to degrade subarc flux. The American-made, Keen KF-150 sub-arc welding flux storage oven is your storage solution, assuring factory-fresh dryness by providing heated storage for up to 150 lbs of submerged arc welding flux. Ruggedly-constructed and easy to use, the KF-150's innovative portable design allows users to relocate the oven among different stations, and the hopper itself can be removed easily from the stand to mount directly on the welding manipulator. Maximum temperature 550F. Top-loading design with bottom dispensing valve. External dial thermostat with adjustable range of 150F-550F. External thermometer (not shown) is now included.
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Eliminate hydrogen-Induced cracking and other adverse welding defects. The Keen KF-300 Submerged Arc Flux Storage Oven is the essential safeguard for mid-sized to large fabrication shops that demand X-ray quality welds in every pass. Specifically engineered for the rigorous requirements of pressure vessel fabrication, structural steel, and heavy equipment manufacturing, the KF-300 provides a dedicated, heated environment that keeps your granulated flux free from moisture contamination. In Submerged Arc Welding (SAW), even trace amounts of atmospheric humidity in the flux can lead to catastrophic porosity, "wormholes," and hydrogen embrittlement. The KF-300 eliminates these variables by maintaining a constant, uniform temperature, ensuring your flux remains in "factory-fresh" condition from the moment the bag is opened until it hits the weld puddle.
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Eliminate welding flux contamination and ensure high-deposition weld integrity. The Keen KF-600 Submerged Arc Flux Storage Oven is the ultimate safeguard for large-scale fabrication shops where weld failure is not an option. Designed specifically for the high-capacity needs of shipbuilding, pressure vessel manufacturing, and structural steel, the KF-600 provides a precision-controlled thermal environment that keeps your expensive granulated flux in "factory-fresh" condition. Submerged arc welding (SAW) is prized for its productivity, but its Achilles' heel is moisture. Even a trace of humidity in your flux can lead to hydrogen-induced cracking, porosity, and failed X-ray inspections. The KF-600 eliminates these risks by maintaining a constant, uniform temperature, ensuring your flux performs exactly as the manufacturer intended.
Once removed from factory packaging, granulated subarc flux immediately starts absorbing moisture from the air. This moisture can deposit hydrogen into the weld, potentially causing embrittlement and porosity. Store up to 1000 lbs of granulated subarc flux in the American-made, Keen KF-1000 flux oven. Designed for the requirements of a large subarc operation, Keen produced this high-performance, high-capacity flux oven with the sole aim of satisfying the most demanding engineers and welding professionals working in rigorous environments. Highly-engineered and packed with features such as: heavy-duty hopper design with welded construction, well-built supporting stand with welded construction, support bars at top of hopper to rest flux bags for easy loading, heavy-duty lid supports and much more. Keen’s innovative, energy-efficient design provides rapid heating of flux while reducing overall wattage and minimizing amp draw. Loaded with electrical and design safety features: digitally-adjustable, ON/OFF microprocessor-based controller with ±1 degree accuracy, manual reset high-limit fail-safe control and more.
Protect subarc welding flux from atmospheric moisture exposure with the Keen KF-900 subarc welding flux oven. Once removed from factory packaging, hygroscopic granulated subarc flux must be stored in a dry, heated environment to prevent defects in the final weld such as porosity and hydrogen embrittlement. Uniquely-designed, versatile and built to last, this rugged subarc flux storage oven features three individually heated hoppers for storing submerged arc welding flux. The hoppers are structurally connected but separate, and each is individually temperature controlled with a digital microprocessor. The Keen KF-900 provides divided storage capability for multiple types of subarc flux and can be placed centrally in a tool room or shop floor. Each hopper stores 300 lbs of flux for a total combined capacity of 900 lbs, and has a temperature range of 150°F-550°F (38°C-288°C). Made in USA.
Keeping Conditioned Flux Production-Ready
Submerged arc welding flux follows a controlled handling process from storage through production. Flux holding ovens play a critical role by maintaining conditioned flux at the proper holding temperature out of factory packaging and after rebaking. Keeping flux production-ready before it is delivered to the welding operation helps reduce unnecessary handling while supporting consistent weld quality and continuous manufacturing operations.
Receive
New submerged arc welding flux is received in its original packaging and stored until needed for production. Proper handling during storage helps protect the flux before it enters the conditioning process. Depending on the application and manufacturer recommendations, flux may be transferred directly to production or first undergo a rebaking cycle to restore its condition.
Recondition (When Required)
If flux has absorbed moisture during storage, handling, or recovery, it is reconditioned in a flux rebake oven according to the flux manufacturer's recommended temperature and holding time. Rebaking removes absorbed moisture and restores the flux to a production-ready condition before it is transferred to a holding oven.
Flux rebaking is only performed when required by the flux manufacturer or welding procedure.
Hold
Once conditioned, flux is transferred to a Keen Flux Holding Oven where it is maintained at the specified holding temperature until it is needed for welding. By keeping conditioned flux readily available throughout the workday, holding ovens help reduce unnecessary handling, minimize production interruptions, and ensure operators have immediate access to production-ready flux.
Weld
Conditioned flux is delivered from the holding oven to the flux hopper or directly to the welding operation, providing a continuous supply of production-ready flux for submerged arc welding. Maintaining proper flux condition throughout production helps support consistent arc performance, reliable weld quality, and efficient manufacturing operations.
How to Select the Right Flux Holding Oven
Selecting the right flux holding oven depends on more than capacity alone. Consider your daily flux consumption, production volume, available floor space, and whether your operation requires storage for a single flux classification or multiple flux types. The guide below provides a general starting point for selecting a flux holding oven that matches your production workflow.
| Production Need | Recommended Models | Best For |
|---|
| Point-of-Use Storage | KF-150 |
Keeping small quantities of conditioned flux close to the welding station for convenient access. |
| Daily Fabrication | KF-300 |
General fabrication shops and moderate-volume submerged arc welding operations. |
| Continuous Production | KF-600 |
Heavy fabrication, pressure vessels, pipe mills, and production environments with higher daily flux consumption. |
| Multiple Flux Classifications | KF-900 |
Facilities using several welding procedures or different submerged arc fluxes requiring centralized storage. |
| High-Volume Production | KF-1000 |
Large-scale manufacturing operations where maximum flux capacity supports continuous welding. |
Design And Build Your Own Custom Industrial And Welding Ovens
Each customer often has a specific process that requires the heat treating of parts, components or materials prior to assembly. Their parts are unique in size and shape, and a customized heat treatment oven specific to the part and application is often the only solution to streamline the process. Keen is your solution.
We design and build custom ovens for a variety of applications
Made in the USA and ruggedly constructed, Keen submerged arc flux storage and rebake ovens are available in a variety of capacities to suit the most rigorous subarc welding operations. Our flux ovens have industry-leading heat up times due to our proprietary design, and can be found in a wide variety of industries across the world.
Below is a list of industries where Keen subarc flux storage and rebake ovens are commonly used:
- Wind Turbine Tower Fabrication
- Railroad Tank Car Fabrication (Carros Tanque)
- Longitundinal Submerged Arc Welded Pipe (LSAW) Production
- Helical Submerged Arc Welded Pipe (HSAW) Production
- Double Submerged Arc Welded Pipe (DSAW) Production
- Carbon Steel Tank and Vessel Fabrication
- Boiler Fabrication
- Pressure Vessel Fabrication
- Large Bridge Joint Installation
- Thick Plate Installation in Shipbuilding
- Offshore Platform Construction and Repair
- Oil Terminal Steel Storage Tanks
- Welded Steel Municipal Water Tanks
- Power Generation Storage Tanks
- Monopile Fabrication for Wind Turbines
- Tripod Fabrication for Wind Turbines
- Jacket Fabrication for Wind Turbines
- LNG Above-Ground Tank Fabrication
- LPG Above-Ground Tank Fabrication
- Beam Fabrication
- Bridge Fabrication
- Crane Fabrication
- Offshore Construction
- Offshore Process Equipment Fabrication
- Double-Jointed Pipeline Fabrication
- Pipe Mill Subarc Welding
- Heat Exchanger Construction (Tube-to-Fin Welds)
- Truck Wheel Fabrication
- Clean Plate Subarc Welding
- Chemical Tanker Fabrication
- Hydrocracker Fabrication
- Shipbuilding (Butt and Fillet Welds)
- Beam Construction for Truck and Rail Cars
key differences between welding flux holding ovens and welding flux rebake ovens
Keen ovens are specifically designed according to the temperature range of the process, and the amount of subarc flux to be stored. The standard holding ovens are designed to accommodate a maximum temperature of 550F and the rebake ovens are designed to reach 999F. The higher temperature ovens have larger wall thicknesses to accommodate more insulation and digital programmable temperature controllers. More information is available on the individual product pages. Please select a product from the chart above and you will be taken to the product page which has digital photos of each flux oven and technical specifications.
Frequently Asked Questions
Please read the following FAQ section for more information about KEEN flux ovens, as well as individual product overviews and specifications for the various subarc flux ovens we manufacture at KEEN.
What is subarc flux and what is submerged arc welding (SAW)?
Submerged arc welding (SAW) is a common welding process that is frequently used in the structural and vessel construction industries. The process requires a tubular or consumable solid electrode that is continuously fed into the work area using fully-automatic or semi-automatic methods. As the electrode is fed into the arc and melted, a layer of granular material provides a protective cover beneath which the welding occurs. Called flux, this fusible material consists of lime, silica, manganese oxide, calcium fluoride, and other compounds. The flux forms a hardened layer after it is heated and becomes molten. In this melted state the flux becomes conductive, thus enabling it to supply a constant current between the electrode and the welding work. The remainder of the flux is recovered and reused, unless it has become contaminated.
The granular flux used in SAW serves several functions. In addition to providing a protective cover over the weld, the flux shields and cleans the molten puddle. The flux also affects the chemical composition of the weld metal, the weld bead shape, and the mechanical properties of the weld. Another function of granular flux is to act as a barrier that contains and concentrates the heat into the weld area thus enabling deeper weld penetration.
Why do I need to store subarc flux in a heated oven?
In order to answer this question, it is pertinent to describe the four types of welding fluxes that are commonly available: fused, bonded, agglomerated and pre-mixed fluxes.
Fused — this type of flux is non-hygroscopic (does not absorb moisture from the air). Any surface moisture on the particles can be removed at a low temperature oven setting of 300°F.
Bonded — this type of flux is hygroscopic (absorbs moisture from the air) and is comprised of a combination of dry ingredients that are glued together with a liquid binder, then baked at a low oven temperature.
Agglomerated — this type of flux is hygroscopic and is manufactured the same way as bonded fluxes only a ceramic binder is used instead of a liquid binder.
Pre-Mixed — this type of flux is hygroscopic and is simply a combination of two or more bonded or agglomerated fluxes.
Just as stick welding electrodes readily pick up moisture from the surrounding atmosphere, the same applies to bonded welding fluxes that are comprised mostly of dry, powdered ingredients. As described above, the purpose of flux is to clean and shield the weld area from impurities. If moisture has contaminated the flux, hydrogen is released into the metal when heat is applied. When the weld cools, it can become brittle, crack and/or develop pinholes. Moisture-contaminated flux can also accelerate corrosion to certain metals like aluminum and must be kept dry throughout the welding process.
Welding flux holding ovens and rebake ovens are an indispensable addition to any subarc welding operation to help ensure quality welds. Our flux holding ovens and rebake ovens are suitable for almost any flux heating application that is required for today’s professionals.
What are the proper storage and rebaking guidelines for subarc flux?
For specific storage and rebake temperature guidelines, we recommend contacting the welding consumable manufacturer directly. It is also important to check with local welding codes and/or ask a welding inspector to provide some information. Welding standards change frequently, and each manufacturer often provides a different recommendation regarding welding consumable storage. Check the packaging and also manufacturer websites for information. Keen offers a wide range of products to handle almost any welding consumable storage requirement.
What is the difference between subarc flux holding/storage and subarc flux rebaking/reconditioning?
Generally, there are two involved with the proper maintenance of subarc welding flux: holding (also called storing) and rebaking (also called reconditioning).
The holding process refers to the long-term* heated storage of welding flux to maintain factory-fresh dryness. Storing the flux at elevated temperatures prevents atmospheric moisture contamination of the hygroscopic granules. There are various temperature requirements according to the type of flux and also that are also set forth by welding codes. For specific holding temperature guidelines, please contact the manufacturer of your welding consumable.
The rebaking process refers to the short-term*, high temperature heating of subarc flux that has been contaminated by atmospheric moisture. The rebaking process “reconditions” the welding flux, meaning it bakes out the moisture that has been absorbed thus restoring the flux so it is suitable for reuse. For specific rebake temperature guidelines, please contact the manufacturer of your consumable.
* - In relation to our products, we consider long-term to mean 24 hours/day 7 days/week.
How can I determine the amp draw for a particular model?
Use this formula: Watts / Voltage = Amps
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