Contaminating stainless steel with mild steel can be a costly mistake to make when shotblasting, and it is often difficult to correct and remove. In addition, getting the best surface finish can be very tricky unless you use the most appropriate cleaning chemicals and processes.
Unfortunately for one of our customers, they found themselves in this very situation on one of their prestigious projects. They were delighted to receive a commission for installing shot blasted stainless steel facades, as part of the refurbishment of an iconic building in Dublin city centre. However, during the project, they were incorrectly supplied with mild steel shot blast media, by another supplier (not our good selves!), when installing the facades. Shotblasting Stainless steel can be problematic in any case, as the sandblasting process may also result in the decrease of corrosion resistance. Using mild steel shot blast increased the risk of corrosion thanks to the presence of iron oxides. This iron oxide film (rust) is “active” and accelerates corrosion by making it easier for more iron oxide to form.
In this particular case, the humidity of the environment caused iron oxide corrosion on the stainless steel, which resulted in the stainless steel becoming contaminated. However, the contamination did not become visible until a few weeks after the facades were already installed. Our customer contacted our Technical Support Manager, Garry O’Connell for guidance as to how they could solve this unsightly issue, which was jeopardising the success of their project. Garry explained that there were two options which would properly remove the contamination.
The first option was to investigate if the panels could be mechanically cleaned in a workshop. If this was not possible, then the corroded panels would have to be replaced at huge expense.
The second and much more cost-effective option was to clean the panels on-site without creating any more dust, which could have possibly contaminated the surrounding environment. Naturally, with Garry’s help and guidance, this was the option they chose. He recommended using a process using our heavy-duty stainless steel cleaner which completely removed the contamination from the facades. This saved time and money, as there was no need to remove the facades from site. A second process of passivation was then added to the panels to give protection to the stainless steel.
The extent of the contamination on the panels is obvious on the first two photographs and you can imagine how disastrous this was for the project manager. However, the third and fourth images show the successful outcomes of the cleaning operation using our chemicals on site, which allowed the facades to be restored without having to be removed. Solving problems for our customers is why we are constantly researching new and improved methods and products to finish surfaces more cost effectively and professionally.
Our technical sales team has a broad range of experience and knowledge on surface refinishing processes, so don’t hesitate to get in touch with any questions or inquiries you may have for your own applications.