Why Stainless Steel Welds Are So Hard to Clean
Stainless steel welds are very prone to contamination in a number of different ways. This is probably due to the fact that stainless steel welds are always engaged in heavy duty applications.
The moisture in the air can lead to corrosion in the crevices of the stainless steel welds. We know that welds should always be full penetration weld to produce the greatest possible strength. When there is a lack of penetration, crevices are formed. The crevices and the corners on the stainless steel welds are very much vulnerable to corrosion. Crevice corrosion is therefore one of the reasons why stainless steel welds are contaminated so easily. When corrosion takes place in the crevices, it becomes extremely difficult for the manufacturers to reach into the corners of the crevice and alleviate the rust or the corrosion.
At times it’s a case of the wrong design. Whether a stainless steel weld will develop corrosion crevices or not depends heavily on the design of the weld. If the weld is designed in a faulty manner, then corrosion will intensify and cleaning the rust will become a huge problem for the welders.
Embedded Free Iron
Rusting can affect stainless steel welds in more ways than one. One major reason why rust settles in on the surface of stainless steel welds is because of the embedded free iron. If this free iron is not removed from the stainless steel weld, then corrosion can take place if the surrounding environment is moist and airy enough. Even if the environment is not too conducive for corrosion, a little bit of the rust will still appear on the stainless steel weld. A number of different precautions need to be taken to ensure that stainless steel welds do not contain free iron. Usually, these precautions are not taken seriously by the welders and therefore the rusting occurs. Once the rust is present on the stainless steel weld, it becomes difficult and sometimes costly to remove it.
Key Areas of Cleaning
The key areas where the weld needs to be cleaned the joint edges and two to three inches of the adjacent surfaces. When these are not cleaned properly, they lead to cracks, porosity or lack of fusion. Once again, these are hard to reach regions of the weld and are often left neglected. Sometimes the welders clean these areas, but forget to sheathe the weld joints properly after the cleaning is done. This leads to an accumulation of contaminants. Unless welding is to be performed immediately after cleaning, the weld joints should remained covered.
Other Sources of Contamination
Most welders tend to not pay attention to the surface oxides that build up on the weld joints after thermal cutting is conducted. This oxide film is not only difficult to removed, but also very difficult to detect even by radiography.
Other sources of stainless steel weld contamination include cutting fluids, grease, oil, waxes and primers. These contain sulphur and carbon. Lead, zinc and copper are also considered as harmful stainless steel weld contaminants and can be found in tools such as hammers and backing bars. Then again, there is shop dirt, which often turns out to be an even bigger menace.
So as you can see, contamination is all around stainless steel welds. Since these contaminants affect the hard to reach areas and are each of a different nature, the cleaning process of stainless steels becomes quite painstaking.
Cougartron ProPlus and InoxFURY – Your Safe Bet for Effective Weld Cleaning and Surface Passivation
Heavily oxidized welds and contaminated stainless steel surfaces are best treated using Cougartron’s high-powered machines such as ProPlus and InoxFURY. Both are designed to effectively and, first of all, safely restore the attractive appearance of stainless steel without compromising its health and quality. Cougartron InoxFURY is generally stronger and should be used on larger stainless steel structures where you can truly explore its strength to achieve faster results.