Quality welding is about understanding the different elements that contribute to the process. Filler metals are some of the materials that are used in welding. A filler metal is can bam alloyed or not and is melted into fitting parts to act as joint. It means that a filler material must be capable of liquefying when put under extreme heat. Over time, more and more compounds have been classified as filler metals, giving welders options for various welding requirements. The specific welding applications usually determine the most appropriate choice of filler metal. For instance, the filler metal used for a high-temperature product would not be suitable for a welding joint that is exposed to low temperatures. Manufacturers sometimes alter the composition of filler metals to make them more suitable for welding, and deoxidisers are some of the compounds blended into these metals.
What are Deoxidisers
A deoxidiser mixes with the oxygen such that during welding, the oxygen is diffused as the weld metal cools. The diffused oxygen rises to the surface, and by doing so allows welding through rust. A deoxidiser ensures that even when a surface is covered with mill scale or rust, the arc quality remains consistent. A welder doesn’t have to worry that the finished product will pick up undesirable inclusions.
The Need for Deoxidisers
Why should metal fillers be combined with deoxidizing agents at all? This question is familiar with welders and welding students who may not get the need to alter metal fillers given that they comprise only a small portion of the weld. Cost and time savings are the two biggest plus sides that welders get with metal filler deoxidisers. Adding a deoxidising compound eliminates the need for certain pre-welding activities. With a deoxidised metal, filler, the welder doesn’t have to clean the metal before the process. The smooth texture of a deoxidised metal also means that grinding is not a requirement. With such process out of the way, the welding process takes less time and money. Another cost-efficiency of deoxidised filler metal is the opportunity to use base metals that don’t cost too much. When metals have to go through an additional processing step to remove contaminants like mill scale, it raises the price of the base materials. A company can direct those resources towards increasing the productivity of the process.
The other huge benefit that deoxidisers offer is the ability to weld over contaminants. Various compounds can compromise the quality of the arc welding process such as rust oil and mill scale. Contaminants are especially big challenges when welding for structural applications. Because there is no grinding pre-welding, the mill scale is not an issue. The deoxidising agent also allows for welding without the contaminants blending into the final piece.
Compounds Used as Deoxidisers
Aluminium is a common choice of deoxidiser in applications that require slag formation in self-shielded wires. When using aluminium as a deoxidising agent, it is necessary to measure the composition carefully. Aluminium can lower the low-temperature toughness of the metal when used in high concentration, causing brittleness in the weld.
Manganese is a high-quality deoxidiser that results in a reliable weld metal. Besides that, adding manganese to the filler metal will boost its strength. Welders, however, need strict safety measures when working with manganese because it requires correct fume management. Some metal and flux-cored wires are made with low manganese composition for these safety reasons.
Silicone is preferred for its high fluidity as a deoxidising compound. The compound allows the metal filler to melt and fuse completely with the joints, resulting in a smooth bead. A filler metal will be as fluid as the percentage of silicone it is blended with. Silicone is a popular deoxidiser in metal-cored wires.
Titanium and zirconium are other metals that are used as deoxidising agents. Weld wires have classifications, and these will determine the deoxidisers that can be added. The blended compound will impact how a filler metal will behave and, therefore, manufacturers have to be cautious when picking deoxidisers.
The performance of a filler metal is a critical element when welding, and deoxidisers are some of the factors that dictate it. The increased demand for quality welding as a result of the evolving technologies has made deoxidisers important parts of the process. Welders now have a broad selection of compounds that deliver varying chemical and mechanical properties.