CategoryPreservation
Steel preservation: temporary corrosion protection after blasting
Preservation — Konservieren in the German steel trade, where it always appears paired with blasting as Strahlen und Konservieren — is temporary corrosion protection applied to a blast-cleaned steel part: an oil, wax, lacquer or primer coat that protects it through transport, storage and intermediate processing, not a permanent multi-layer coating system. This page covers what that means in practice: the surface prep it depends on, the protection methods providers actually use, and what a provider needs from you before quoting.
What drives the price
- Part size and geometry
- Surface condition before blasting
- Protection method — oil, wax, lacquer or primer
- Coverage area
- Total volume
- Colour requirement
What to send for a quote
- Grade or material number
- Form and dimensions
- Current surface condition
- Required corrosivity category, or simply how long and where it will be stored
- Protection method preference, if you have one
- Whether you need an inspection certificate
- Delivery address and required date
Traceability and EN 10204 certificates
Standard for steel purchases: 3.1
The certificate belongs to the material, not to the treatment. Preservation does not create an EN 10204 certificate — the real question is whether traceability survives blasting and preservation, and how the piece stays marked so that it does.
Standard-defined
Source: EN 10204 defines inspection-document types.
Surface preparation: Sa 2½
ISO 8501-1:2007
Standard-defined
Surface preparation: Sa 2½
Two independent suppliers reviewed both blast to Sa 2½ before preservation — this is the surface condition preservation depends on, not a guarantee every provider follows the same grade.
Supplier-published
Temporary protection methods
- Oils, greases, hard waxes or clear lacquers
- A thin primer coat, compatible with any coating system applied later
A published example: primer preservation
| Chemistry | zinc phosphate alkyd resin welding primer | | |
|---|
| Typical thickness | 15 – 20 µm | | |
|---|
| Standard finish | reddish-brown (standard welding-primer shade) | | |
|---|
| Alternative colours | RAL 9002 (greyish-white) · RAL 9010 (pure white) | | |
|---|
Indicative figures from one published supplier example. Confirm chemistry, thickness and colour options with the provider.
Supplier-published
Choosing the right protection: ISO 12944 corrosivity categories
ISO 12944-2:2017
- C1 — very low
- C2 — low
- C3 — medium
- C4 — high
- C5 — very high
- CX — extreme
ISO 12944-2 classifies how corrosive an environment is, from C1 (very low) to C5 (very high) plus CX (extreme, offshore). Stating your category — or simply how long the part needs to stay protected and where it will sit — is what lets a provider recommend oil, wax, lacquer or a primer coat instead of guessing.
Standard-defined
Services
What does preservation actually mean for steel?
Preservation — Konservieren in the German steel trade — is temporary corrosion protection for a steel part: an oil, wax, lacquer or thin primer coat applied after blast cleaning, meant to protect the part through transport, storage and intermediate processing steps. It is not a permanent, multi-layer protective-coating system — providers who offer both treat them as separate services, and this page is about the temporary one.
What surface preparation does preservation need first?
Preservation is applied after blast cleaning, and the suppliers we reviewed blast to Sa 2½ — ISO 8501-1's "very thorough blast-cleaning" grade, where the surface must be free of visible oil, grease, dirt, mill scale, rust and old coatings before the protective layer goes on. Two independent suppliers confirmed this grade for their own preservation lines.
What protection methods are used?
Two approaches are used in practice. For short-term protection through transport or storage, providers use oils, greases, hard waxes or clear lacquers. Where the part will go straight into a customer's own coating process, a thin water-based primer is applied instead — compatible with standard coating systems, so it doesn't need stripping before the real finish goes on.
What is a typical primer preservation coat made of?
One published example: a zinc phosphate alkyd resin welding primer at 15–20 µm, in a standard reddish-brown shade, with grey-white (RAL 9002) or white (RAL 9010) available for larger quantities. That is one supplier's own product, not an industry-wide specification — confirm chemistry, thickness and colour options with your provider.
How long does the protection last?
No supplier we reviewed states how long the protection is expected to last, and we won't invent one — it depends on the method chosen, the storage conditions, and how corrosive the environment is. Tell the provider how long the part needs to stay protected and where it will sit, rather than assuming a default.
What is ISO 12944 and why does it matter for preservation?
ISO 12944-2 classifies environments by how corrosive they are, from C1 (very low, dry heated buildings) up to C5 (very high) and CX (extreme, offshore). It isn't a spec any of the suppliers we reviewed quote for their preservation service directly — it's the vocabulary that lets you describe your requirement precisely: naming a category, or just how long and where the part will be stored, is what turns a vague request for "protection" into something a provider can actually plan for.
Can I send my own material to be preserved?
Sending your own material for blasting and preservation is common practice in this trade, but whether a given provider accepts it, and on what terms for liability and traceability, varies. Ask before shipping, and if the material carries an inspection certificate, ask in the same message how the piece will stay marked through blasting and preservation.
Do I get an EN 10204 3.1 certificate?
EN 10204 defines inspection document types 2.1, 2.2, 3.1 and 3.2, with 3.1 the usual buyer default in steel procurement. But preservation doesn't create a certificate any more than sawing does — the certificate belongs to the material. What matters is whether traceability survives blasting and the protective coat, and how the piece is marked so it stays linked to its heat. Ask the provider directly.
What information do you need for a quote?
Send the grade or material number, the form and dimensions, and the current surface condition. State the corrosivity category if you know it, or simply how long and where the part will be stored — that's what lets the provider choose between oil, wax, lacquer or a primer coat. Say whether you have a protection-method preference, whether you need a certificate, and give the delivery address and date. That turns an enquiry into a firm price.
Is there a minimum order quantity?
No industry-wide minimum order quantity exists for preservation; it varies by provider, and none of the suppliers we reviewed publish one. Ask as part of your enquiry rather than assuming a single piece is either fine or impractical.
What is the lead time?
No general lead time can be stated honestly — none of the reviewed suppliers publish one, and it depends on part size, coverage area and the provider's current load. Ask for a committed date with your quote.
Is preservation the same as a protective coating system?
Preservation is a temporary measure — oil, wax, lacquer or a thin primer — meant to carry a part through transport, storage or a gap before its next processing step, and providers who also offer full coating systems keep the two separate. A protective-coating system is the permanent, multi-layer finish a part keeps for its service life. If what you need is the finished part's final surface protection, ask for a coating quote, not a preservation quote.
