Brazing flux is selected for a particular base metal, filler metal and heating process. A product that works for one combination may be unsuitable for another, even when the joint materials appear similar. The reference table organizes selected Aufhauser flux recommendations by the base metals and fillers named by the manufacturer, along with product form, active temperature range and listed specification.

Use the table as a shortlist for identifying products to investigate. It is a product-specific selection chart, not a universal compatibility matrix. The manufacturer’s exact product label and current technical and safety data take precedence over a summary row.

Match both sides of the joint

Start by identifying the exact base-metal grade and the brazing filler alloy. Then find a flux row that names both materials or the applicable material families. Do not infer compatibility simply because a flux is described as suitable for “steel,” “stainless” or “copper alloys.” Alloying elements, surface oxides, joint clearance, atmosphere and heating method can change the requirements.

The active temperature range indicates the range in which the listed flux is intended to perform, as stated by the product chart. It is not a recommended furnace setpoint or proof that a filler will flow at that temperature. The filler’s liquidus and solidus, the joint temperature, heating rate and time at temperature still have to be considered. Keep the base metal below damaging temperatures and follow the qualified procedure for the assembly.

Distinguish product form and process

Paste, powder and liquid fluxes are not interchangeable application methods. Coverage, storage, mixing, application and residue behavior differ. Select a form that can be applied consistently to the joint and used with the chosen heating process. Some entries in the manufacturer chart are intended for soldering or welding rather than brazing; those are not included in this table. The included rows focus on selected brazing products.

Listed specifications can help with procurement and document control, but they do not replace confirmation of the current revision or the customer’s governing requirements. A specification number in a product chart should be checked against the actual supplied product and project documents. If the assembly is safety-critical, use an approved procedure and qualified personnel.

Check residue and safety requirements

Flux residue may be corrosive or difficult to remove. Determine the manufacturer’s cleaning instructions, whether the residue is water-soluble, and how the finished joint will be inspected. Verify ventilation, personal protective equipment, storage and handling requirements in the current safety data sheet. Avoid breathing flux fumes and keep flux away from incompatible materials.

Before production, confirm that the exact product supports the base metal and filler, that its activation range fits the process, and that the chosen heating and cleaning method are acceptable. A sample joint can reveal wetting, coverage and residue problems before a process is released. Record the flux product and lot, filler alloy, base-metal grades, heating conditions and cleaning method with the procedure.

When comparing candidate rows, keep the filler classification and the actual commercial filler designation together in your process notes. Broad labels such as “silver alloy” can cover products with different melting ranges and service limitations. Likewise, a powder product may need a different application method from a paste product. Ask the supplier to confirm uncertain combinations instead of treating a nearby row as an equivalent recommendation.

The manufacturer’s product information is the authority for current compatibility and handling. The table narrows the search; it does not predict joint strength or replace a brazing procedure, filler-metal data sheet or engineering review.

Review Aufhauser’s flux selection chart, the SilverFlux product information, and the current product safety data sheet for the flux under consideration.

Flux selection is only one part of process qualification. Confirm joint fit-up, filler placement, heating uniformity and post-braze inspection criteria with the applicable engineering procedure.