Features, differences and alternatives
After welding, grinding or other machining operations, a stainless steel surface is not always ready for use straight away. Heat tint, oxides, contamination or stresses can remain in the surface. That affects the appearance, but more importantly: corrosion resistance, hygiene and cleanability.
That is why terms such as stainless steel pickling, stainless steel blasting, wet blasting stainless steel and passivation are often mentioned. But they do not mean the same thing. More importantly, they do not produce the same surface.
Anyone searching for stainless steel blasting or pickling is usually not looking for a dictionary definition. They want to know which treatment is right for their part. Especially when it involves stainless steel in food, pharma, high-tech or hygienic machine building.
In this article, we first explain the difference between blasting, pickling and wet blasting. Then we take a closer look at ViwateQ® Finishing: the chemical-free stainless steel surface treatment Van Geenen uses when cleanability, hygiene, corrosion behaviour and process control matter more than simply removing heat tint.
Stainless steel pickling is a chemical surface treatment. It is often used after welding stainless steel. During welding, heat tint and oxides form on the surface. These areas are more sensitive to corrosion if they are not properly removed.
With pickling, these contaminants are removed chemically. This can be done using:
pickling paste;
a pickling bath;
spray pickling.
In practice, pickling is often combined with passivation. Pickling mainly focuses on removing heat tint, oxide scale and contamination. Passivation then helps restore or strengthen the protective chromium oxide layer on the stainless steel.
That is why terms such as pickling stainless steel, stainless steel pickling, pickling and passivation and passivating stainless steel are often used together. In many technical specifications, pickling/passivation is still a well-known post-treatment for welded stainless steel.
Stainless steel blasting is a mechanical surface treatment. A blasting medium is projected onto the stainless steel surface with force. The purpose can vary depending on the application: cleaning, roughening, matting or creating a specific surface finish.
Important to know: blasting is not automatically the same as cleaning, passivating or improving durability. The result depends heavily on:
the blasting medium used;
the process settings;
the level of contamination;
the required final surface;
the risk of contamination.
With stainless steel, extra care must be taken to avoid iron contamination and other surface contamination. An incorrect blasting process can actually create new problems, such as flash rust, an uneven surface structure or a surface that is harder to clean.
So, stainless steel blasting can be useful, but only when the process matches the final purpose of the part.
Wet blasting stainless steel is a surface treatment in which water is part of the blasting process. This creates less dust than dry blasting. The process can also produce a more even, calmer and cleaner surface.
At Van Geenen, we use ViwateQ® Finishing for this, among other processes. ViwateQ® Finishing is a specific form of wet blasting, developed for stainless steel surfaces where not only visible contamination matters, but also the functional quality of the surface.
ViwateQ® Finishing focuses on:
a smoother and more uniform surface;
better cleanability;
reduced adhesion of contamination;
a controlled surface finish;
improved corrosion behaviour;
a chemical-free treatment compared with traditional pickling.
This makes ViwateQ® particularly interesting for sectors where hygiene and process control are important. Think of food, pharma, medical technology, high-tech and hygienic machine building.
Pickling and wet blasting can both be used after processing stainless steel. Still, the process and the final result are clearly different. That difference matters, because the choice often determines how well the part can be cleaned later, how predictable the surface is and how it performs in use.
Topic | Pickling | Wet blasting / ViwateQ® Finishing |
Process | Chemical treatment | Mechanical, water-based process |
Purpose | Removing heat tint, oxides and contamination | Cleaning, evening out and functionally improving the surface |
Chemicals | Yes, traditional pickling chemicals | With ViwateQ®: no traditional pickling chemicals |
Surface appearance | Depends on the process, often technically functional | Uniform, controlled and visually calmer |
Cleanability | Can improve by removing contamination | Focused on a smoother and easier-to-clean surface |
Corrosion resistance | Supports recovery of the passive layer | Focused on reduced adhesion and lower corrosion risks |
Application | Commonly used after welding stainless steel | Interesting for food, pharma, high-tech and hygienic machine building |
So, the difference is not just chemical versus mechanical. It is mainly about what the surface needs to do in the end.
Does the part mainly need to be free from heat tint? Then pickling can be a logical choice. Does the surface also need to be easier to clean, more consistent, more hygienic and better controlled? Then ViwateQ® Finishing becomes a much stronger option.
In many applications, ViwateQ® Finishing is a strong alternative to traditional pickling. Not because pickling never works, but because pickling is mainly aimed at chemically removing oxides, heat tint and contamination.
For many modern stainless steel applications, that is not enough. The surface must also be easy to clean, retain less contamination and perform predictably in a production environment. Think of machine parts, frames, funnels, pipework, housings or components that are cleaned regularly.
ViwateQ® Finishing is interesting because the process is aimed at functionally improving the stainless steel surface:
chemical-free compared with traditional pickling;
uniform and controlled surface appearance;
better cleanability;
reduced adhesion of dirt and product residues;
suitable for hygienic applications;
interesting when corrosion resistance and process control are important.
This does not mean that ViwateQ® always replaces pickling one-to-one. The right choice depends on the base material, heat tint, contamination, application and surface requirements. But when hygiene, cleanability and reliable performance in use are important, ViwateQ® is often the treatment you end up with.
Pickling can be a logical choice when the main goal is to remove heat tint, oxide scale or chemical contamination after welding stainless steel.
You are more likely to choose stainless steel pickling when:
pickling/passivation is explicitly specified;
the main requirement is removing heat tint;
a conventional chemical post-treatment is sufficient;
the part has less demanding requirements for visual uniformity;
hygienic optimisation is not the main requirement.
In those cases, pickling is a familiar and widely used method. It is still important to consider safety, process control, residual chemicals and the required final result.
But as soon as the part is used in an environment where cleaning, hygiene and surface quality are critical, it is worth looking beyond pickling alone.
ViwateQ® Finishing becomes interesting when the stainless steel surface has to do more than simply be “clean”. For example, with parts that are cleaned frequently, come into contact with product flows or are used in environments where hygiene and corrosion resistance are important.
You are more likely to choose ViwateQ® when:
cleanability is important;
chemical pickling processes are undesirable;
staining or inconsistent pickling results are a problem;
the surface must be uniform and controlled;
contamination must adhere less easily;
the part is used in food, pharma, medical technology, high-tech or hygienic machine building;
you are not just looking for a post-treatment, but for a better functional stainless steel finish.
In these applications, we do not only look at the appearance of the stainless steel. We also look at the function of the surface. A well-chosen stainless steel surface treatment can make a real difference in cleanability, service life and reliability in use.
That is where the strength of ViwateQ® Finishing lies: it is not a cosmetic step at the end, but a deliberate choice for a more controlled stainless steel surface.
There is no standard answer. The best choice depends on the application. But the direction is often clear:
If the main goal is removing heat tint, pickling may be sufficient.
If pickling/passivation is specified, that route is often leading.
If cleanability, hygiene, corrosion behaviour and control over the surface are important, ViwateQ® Finishing is usually the more interesting choice.
We look at factors such as:
the type of stainless steel;
the welds and level of heat tint;
existing contamination or oxide scale;
the required corrosion resistance;
hygiene and cleanability requirements;
the required Ra value or surface roughness;
visual requirements;
applicable customer specifications or standards;
the final use of the part.
Van Geenen has multiple processing and finishing options under one roof. That means we do not look at one standard process, but at what the part needs. In many cases, that means: not automatically pickling, but assessing whether ViwateQ® Finishing is technically the better and cleaner choice.
Pickling removes contamination, oxides and heat tint from the stainless steel surface. Passivation focuses on restoring or strengthening the protective chromium oxide layer. In practice, pickling and passivation are often combined.
No. Pickling is a chemical treatment. Wet blasting is a mechanical, water-based surface treatment. The purpose may partly overlap, but the process and the effect on the surface are different.
Yes, depending on the application. ViwateQ® Finishing can often be a chemical-free alternative to traditional pickling. Especially when hygiene, cleanability and controlled surface quality are important. For many parts in food, pharma, high-tech and machine building, that is exactly why ViwateQ® is chosen.
After welding, heat tint, oxides and contamination can form on the surface. These can reduce the corrosion resistance of stainless steel. Pickling is used to remove this layer and make the surface suitable for use again.
That depends on the part and the application. Pickling is a familiar chemical method for removing heat tint and oxide scale. ViwateQ® is often the better choice when a chemical-free process, better cleanability, reduced dirt adhesion and a controlled surface are important.
Twijfel je tussen RVS beitsen, natstralen of ViwateQ® Finishing? Dan kijken we graag mee naar het onderdeel, de toepassing en de eisen aan het oppervlak.
Not sure whether to choose stainless steel pickling, wet blasting stainless steel or ViwateQ® Finishing? We are happy to look at the part, the application and the surface requirements with you.
If it is only about removing heat tint, pickling may be suitable. If the goal is a more cleanable, controlled and hygienic stainless steel surface, ViwateQ® Finishing is often the logical next step.
Van Geenen.
Finishing every challenge.
Not sure whether pickling is sufficient, or whether ViwateQ® Finishing is the better fit for your stainless steel part?
Send us the application, material type and surface requirements. We will take a practical look at the right treatment with you.
