American sheet metal specialist Red Bud is pushing a new 'green' acid pickling process of hot-rolled black steel that is also said to open pickling to smaller activities, such as material distributors and service centres.
Although only recently made generally available, following extensive development, the new process, called Eco Pickled Surface (EPS), has been used to process millions of kilograms of material have been pickled with the EPS Process, claims the company, and is proven to be interchangeable with acid-pickled material for roll forming, stamping, laser, and plasma cutting, as well as punching and tube production. EPS coils have also been successfully cold reduced, annealed, and galvanised.
Additionally, the EPS Process can be changed from one job to the next to produce a rougher or smoother surface, based on the intended use of the finished product. The EPS Process can produce a designer finish on the material, which is clean and uniform, and can mitigate minor flaws such as roll marks or pitting.
Used for decades, traditional acid pickling uses strong caustic acids to remove scale and dirt from the material. While progress has been made to reduce the impact that this chemically-based process has on the environment, many issues persist, says Red Bud.
That being the case, the legal process involved to get the permits required to install an acid-pickling line can be lengthy, if not impossible. Additionally, the areas where these systems can be installed are also restricted.
To address such issues, Red Bud Industries now manufactures equipment for both sheet and coil applications that employs its environmentally friendly, patented, slurry pickling process - EPS.
The EPS Process does not use acids to strip scale and dirt from the steel, but, rather, a wet slurry and should not, says the company, be confused with shot blasting, which is a very different and less productive dry process.
EPS sees a slurry spray, which consists of an engineered angular grit, a cleaning agent, corrosion inhibitor, and water, fed into a series of impellor pumps that spray the slurry across the steel. The result is pickled steel without the environmental issues of acid-pickling. The closed loop slurry system does not discharge any effluent.
The EPS process is currently in operation in the United States and in South Korea.
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