Post-weld cleaning, especially on stainless steel, isn’t the most pleasant job in the shop so the most a welder can hope for is a quick and easy solution to help them accomplish the task in
short order and move on. The product must also be safe and environmentally friendly, of course.
The challenges surrounding post-weld cleaning of stainless steel are, to a certain degree, grounded in the material’s inherent characteristics. Stainless steel is protected from corrosion by a passive surface layer – a thin, impervious layer – that consists mainly of chromium oxide. When stainless steel is welded, the high heat generated causes the chromium to deplete, leaving more iron around the weld. The high concentration of iron on the surface and the high welding temperatures cause the iron to oxidize immediately. This results in discoloration around the weld bead and the heat-affected zone.
The “heat tint” aesthetic is typically not desirable, but more importantly, the discolored area corrodes easily. Because chromium isn’t present in high enough concentrations, it destroys the ability of the stainless steel to protect itself against corrosion. Therefore, it’s important to remove the heat tint and repair the passive surface layer, all without damaging the look of the stainless steel.
Traditional cleaning methods after welding stainless steel include mechanical abrasion, such as grinding machines and abrasives. This method is time consuming and not particularly effective as it can change or damage the surface finish. Also, further processes are required to repair the surface of the stainless steel.
Chemical pickling paste is quite effective for cleaning stainless steel, but it contains a variety of toxic acids, including hydrofluoric acid. These chemicals are dangerous and can cause serious, long-term damage to the body with exposure and are damaging to the environment. Again, a separate “passivation” step has to be performed to repair the surface.
Electrochemical cleaning is considered a much more effective method for cleaning stainless steel because it successfully removes the discoloration from the surface and restores the anti-corrosive, passive layer while not affecting the finish of the stainless. So, when it comes to post-weld cleaning, it’s a solution that welders prefer – if and when it’s brought to their attention.
A better system
The TIG Brush stainless steel electrochemical weld cleaning system is one of those solutions welders are happy to become more familiar with. It produces superior results on stainless steel surfaces quickly, safely, efficiently and cost-effectively.
The TIG Brush system uses a proprietary electrochemical process, combining low-toxicity fluids with a patented power supply and unique brush design. The conductive brush is dipped into a mild electrolytic cleaning fluid and then applied to the areas to be cleaned. The brush converts the electric current to high temperatures, especially at the end of the bristles, and then heats the fluid to an elevated temperature to activate it. This results in an accelerated chemical reaction at the surface of the stainless steel. The fluid is removed with water, and a neutralizing agent is sprayed on, if required.
The system offers several benefits, but most importantly, it cleans and passivates the stainless surface in one step so the welder doesn’t have to carry out repetitive tasks. In addition, it’s a quick and easy process to learn and perform, requiring little training. Cleaning is easy to perform anywhere because the equipment is quite portable and easy to move around.
The low-toxicity cleaning fluids are custom-designed for maximized user safety. Furthermore, the active ingredients of the fluids are not inherently dangerous to operator health; they only contain a mild phosphoric acid. Also, highly protective PPE isn’t necessary, just some gloves and an apron. If used correctly, the fluids are non-toxic to the environment.
The start of an idea
New product ideas often start with helping out a friend and end up paying off with great rewards. In 2004, electrical engineer Clive White, one of Ensitech’s founders, was approached to
help find a solution for a friend who had received a large contract to manufacture a coin chute panel for a fast-food chain. The panel needed to incorporate a coin chute, welded onto a stainless steel plate, for customers to drop in spare coins.
When the coin chute was welded to the panel, the heat from the welding caused heat tint to form. The friend tried the common methods used to remove the discoloration, but none proved effective or safe.
White started working spare nights and weekends utilizing his electronic engineering skills to try and to determine a way to remove the heat tint. Working with his friend and an aeronautical engineer, the team discovered a method that provided the perfect solution. The resulting product removed the heat tint quickly and safely without damaging the stainless steel surface finish.
With this new invention in hand, they manufactured 10 TIG Brush machines and sold them to local manufacturers for trial. In 2006, Ensitech was formed and it began to manufacture the TIG Brush stainless steel weld cleaning system. The invention was a unique fast, safe and effective solution that could change the way a company handles post-weld cleaning and passivation. Demand quickly grew from there and the company expanded internationally. In 2013, Ensitech established a U.S. presence and, more recently, expanded to a larger U.S. facility.
Today, Ensitech offers several TIG Brush models and proprietary cleaning fluids to offer maximum weld cleaning and passivating fast and efficiently. The safe and simple-to-use solution can radically improve or replace outdated and dangerous weld cleaning processes in the metal fabrication industry.
