Subscribe to our monthly newsletter.

Share this item

While the alloy composition has a very high influence on corrosion resistance, it plays a rather subordinate role in the fouling behavior and cleanability of vessels and systems. These system properties are massively determined by the physical properties. Here, the quality of the surface treatment plays an extremely important role, since the lattice structure in the outermost edge zone is massively disturbed during mechanical treatment.

This area, also known as the Beilby zone, has a considerable influence on the physical properties of the surface. At the end of the process, electropolishing uses an electrochemical process to remove a few atomic layers, thus removing some of the material damaged during the previous mechanical processing. Depending on the intensity and depth of the Beilby layer, influences from the previous processing and machining of the steel remain. The approach to solving this problem is to minimize energy input and microstructure damage as early as the manufacturing stage, especially during mechanical surface treatment by grinding.

This is where a processing strategy developed at Bolz Intec comes into play, in which damage to the outermost microstructure zone (Beilby layer) is minimized over a longer period of time by means of semi-automated ultra-fine grinding. This process, also known as Optimized Grind Finishing or OGF, leaves fewer lattice defects in the outermost microstructure zone and, in combination with final electropolishing, produces an optimized surface. In addition to reduced roughness, physical effects in particular lead to altered reactions on contact with a wide variety of media.

Initial experience with this surface design shows that adhesion to the surface is reduced and flow and cleaning behavior are improved. Whether and in what way these effects occur naturally depends on the type of contact material and its physical and chemical properties.
Since the usual machining process inside containers in the industry usually still consists of manual machining, the OGF process also offers the advantage of much better reproducibility of the machining process and provides advantages in quality monitoring.

The consistent optimization of the entire manufacturing route is reported. Only in this way can the high demands on surface quality be met in a sustainable manner and the equipment and containers meet the high safety requirements for multiple use, even in sensitive areas.