From the heavy duty, high-speed throughput of stick and wire welding, to the intricate, high-precision fields of brazing and soldering, high temperature fusion is the simplest and most effective way of permanently joining metals. And not surprisingly, the one attribute that all these processes have in common is their dependence on high quality rods, wires and fillers.
Not all joining and filling materials are designed to perform the same job, though. And more specifically, not all filler materials are manufactured using the same mixing and coating processes. Rods and fillers that are coated too heavily with flux or ones with flux compounds that are prone to retaining moisture can be dangerous. Experienced welders and metal fabricators know the risks, which is why they insist on working only with the best rods that money can buy.
High Performance Rods and Fillers Help Keep Welding Safe and Simple
Let’s be honest: with so many different types of welding and brazing rods and fillers on the market, it’s easy to forget just how specialised they are. The Australia/New Zealand Standards (AS/NZS) 1554 and 3992 prescribe the standards for the coding and composition of alloy fillers used in welding and brazing rods across the country, and their mixtures are precisely engineered to match a wide range of material requirements and joining factors, including:
- Exact base metal types. With a virtually limitless range of metal alloys to choose from, fabricators can buy welding wires for practically any fusion job.
- Maximum tensile strength. Both the tensile and joint strength of the alloys used in welder electrodes are optimised to resist maximum loading, corrosion and ultimately failure.
- Amperage requirements. Because thicker base metals require greater weld penetration and deeper deposition for core strength, the amperage of the welding electrode, together with its flow characteristics, are the key to welder arc stability.
- Welder current characteristics. In the same manner that some electrodes for welding are better suited for higher amperage applications, others based on the amount of metal that needs to be applied are also formulated to work better with either AC or DC current.
- Required welding position. There are five acknowledged metal joining positions, and as fabricators can’t always work from one that’s ideal, some welding and metal brazing rods perform better when working on horizontal, vertical, inclined and overhead projects more than flat ones.
These complex brazing and welding rod mixtures are used for everything from sealing HVAC systems to joining gas pipelines, and they all face the same inherent risk. Flux coating shortcomings, together with poor environmental conditions can severely compromise a rod’s reliability and ultimately the integrity of a weld joint. That’s why special attention has to be payed to the state of the flux coating, as well as how welding wires and rods are stored.
Knowing the Difference Between Flux Coating Types and Compositions
While the coding and composition of welder electrode alloys are determined by AS/NZS standards, the chemistry of their flux mixtures is largely at the discretion of the electrode’s manufacturer. Flux mixtures are responsible for everything from shielding weld pools from atmospheric contamination, to ensuring clean weld bead profiles. That’s why the formulation, mixing, and baking processes for flux coatings have to be perfect every time.
There are four primary types of flux coatings used on the widest range of welding and brazing rods:
- Rutile flux coatings. Minimum-spatter, rutile-coated welders electrodes contain titanium dioxide, and are admired for their arc stability, all round versatility and smooth bead joints.
- Cellulosic flux coatings. Cellulose-coated welding electrodes are formulated specifically for vertical welding, and are known for high penetration arcs for especially strong joints.
- Basic flux coatings. Basic flux coatings are formulated from calcium and magnesium carbonate, and produce deep penetrating arcs that are preferred for high tensile strength joints that require exceptional crack resistance.
- Acid flux coatings. Acid flux coatings typically contain a mix of iron oxides, ferrous alloys, and sand, and are used in low- and medium-carbon steel applications that require good bead qualities with minimal residue.
With such a wide range of flux coatings and coating attributes, tasked with laying the groundwork for the most reliably fused joints possible, it’s crucial that welders and metal fabricators understand the impact that their choice of wire welding consumables will have on the reliability of fused joints.
It’s also important for them to recognise the broader problems that a degraded or compromised flux coating can indicate. Coatings that are allowed to absorb moisture are rife with potential problems, which is why regardless of whether they’re purchasing welding electrodes online or in person, welders and fabricators need to be careful of their condition.
Recognising the Root Causes of Compromised Flux Coatings
Although the condition of the coatings on electrodes used for non-critical welds may not be especially important, relying on them for structural, high performance or high pressure applications can have disastrous results. Welding rods with compromised coatings are easy enough to recognise, but it’s crucial that welders and fabricators understand what a weakened flux coating can indicate, including:
- Excessive moisture absorption. Flux coatings are extremely hydroscopic, and not only can water cause flux coats to crumble and disintegrate, it can also lead to severely weakened welds.
- Improper storage habits. Rods stored in damp or humid conditions, or in poorly sealed containers are prone to levels of flux and alloy degradation that can also lead to severely weakened and porous welds.
- Metallurgical problems. Although a combination of a crumbling coating and rust or corrosion buildup on the welding wire would normally indicate moisture exposure, they can also be signs of a potentially disastrous manufacturing fault.
Make no mistake, using rods or wires with failed flux coatings, exposure to degradative conditions or signs of poor manufacturing processes can be catastrophic. Ideally, welders and fabricators should only buy welding rods and wires from manufacturers and vendors whose quality they trust.
And, when it comes to proper handling and storage after they buy welding electrodes, there are a handful of simple procedures that they need to follow to ensure that their rods and consumables continue to stay safe and serviceable until they’re ready for use.
Simple Steps That Help Keep Welding Rods Serviceable
While shopping exclusively for the highest quality welding electrodes for sale is the best way for metal fabricators to get the finest joining materials, how the materials are handled and stored weeks and months after they’ve been purchased is an essential part of maintaining that quality.
Depending on their composition and storage conditions, some welding machine wire and rods can potentially last for years without any problems. It still makes sense though, to be sure that they’re shielded from excess absorption and mishandling as much as reasonably possible. Fortunately, it only takes a few simple precautions to protect welding rod supplies from costly and dangerous degradation, and they include:
- Ensuring that all rods and wire for welding are stored in a warm, dry environment that’s designed to protect flux coatings from dampness and moisture;
- Only purchasing joining materials in quantities that are conducive with reasonable usage, and in packaging that helps protect them from the environment; and,
- Isolating and disposing of any wires, welding rods, or other joining consumables where either the electrode or the flux coating appears cracked, corroded or even melted.
Ideally, investing in a welding rod drying oven is the most effective means of combating welding rod damage and moisture absorption. With electrode capacities up to 5 kg, they’re designed to maintain optimum rod temperature and security until needed, helping keep a business’s valuable rod inventories in top form at all times.
The Final Word
At the end of the day, it’s no wonder why high temperature fusion is the method of choice for all types of metal joining. The reliability of the joint depends on the quality of the rods and wires used to make them though, and that includes the state and condition of their flux coatings.
Today’s welding, brazing and soldering rods and fillers boast the most versatile and longest lasting flux compounds ever. They’re formulated to provide the best shielding environment for the strongest possible joints, ensuring that welders and metal fabricators are consistently able to deliver their best work.
