Henkel has helped Envases Técnicos Zaragoza S.L. (Entinox), a Spanish manufacturer of stainless steel beer barrels, set up an innovative pickling and passivating line using a nitric acid-free Bonderite process. Benefits include superior HSE performance and bath life over traditional mixed acid pickling systems, as well as outstanding corrosion resistance.
The challenge in pickling solutions for stainless steel lies in removing all scale, iron contamination and welding oxides for achieving a fully passivated surface with an even, clean and aesthetic finish. In the food industry and for key products such as beer kegs, the surface must also be absolutely free from any traces of pickling agents after the process.
Bonderite C-CP 1300 is the latest generation of Henkel’s established nitric acid-free cleaning technologies that were originally developed several years ago. In contrast to common mixed acid pickling systems, which are still used in many stainless steel segments, it contains no HNO3 (nitric acid), while delivering excellent pickling and passivating results. Furthermore, its absence of citric compounds also addresses the growing concern among beer brewers about residual flavors in the barrels.
Bonderite C-CP 1300 can be used in spraying or immersion lines and is suitable for almost any stainless steel grades based on austenite, ferrite, martensite or duplex, including high-chromium AISI/SAE 4XX qualities. The system includes a starter for bath make-up, two components to maintain the acidity of the bath as well as the oxidizing and passivating capacity of the pickling solution, and an optional accelerator for use in tough to pickle materials or in applications with limited contact times.
Entinox’s kegs are normally made from 1.4307 (AISI 304L) grade stainless steel sheet, which is one of the most widely used austenitic chromium-nickel steel alloys.