Stainless  Restora‚Äčtion Ltd

Metal Finishing and Surface Engineering Technologies

SRL Technical Library

PICKLING AND PASSIVATION TROUBLESHOOTING  During, following or indeed before the cleaning operation all sorts of strange things can occur as a result of the chemicals used. Our technical library gives a variety of examples that SRL has encountered along its way. This list is by no means complete - these pages will be continually updated as we/you experience other strange phenomena.

Spatter

Identification

Brown "rust" / free iron oxide. This is a very common problem which we at SRL see quite often. The problem arises when the fabricator or operative has been careless. The cause is usually the swarf that has blown onto the surface from a plasma cutting operation (next time you see plasma cutting in use just see how far the "flame" from the cut can travel). The swarf is made of molten metal from the base material and is highly oxidised as it travels through the air. The molten metal adheres tightly to the surface and manifests itself as "rust". The deposit appears as a speckled mass that is raised and rough to the touch.

Possible Detriment

Apart from the fact that the surface will look unsightly and indeed, if a food/pharmaceutical bearing surface it will look unhygienic.This kind of problem is a serious one since the "spatter" deposit acts as a crevice and can/will give rise to crevice corrosion. This type of problem is particularly bad in Duplex materials since the spatter deposit will be high in ferrite and bear no resemblance to the parent/base material therefore susceptible to corrosion attack as well as crevice corrosion.

Solution

If the spatter deposit is only lightly adhered to the surface it can be removed with one of the stronger cleaning products listed in the product section ie Enerjex 410. If the spatter deposit is heavy then it will have to be pickled from the surface. The area can cleaned manually by brushing the paste by hand on to the offending area.

Method: Cover the entire fabrication with Enerjex 410. If the fabrication is large and the area to clean of Spatter is small then the offending area can be wiped down with Enerjex 410. Once the offending spatter is removed the area needs to be HP washed or wiped down with clean water.Note there may be some "scaring" of the surface owing to the "skin" of the steel surface having been broke.

Products  Available

Pickling Products

Cleaning Products

Technical Notes

It is important to follow the instruction given for each individual product used and the advice given in the "product application data sheets" available on line in the product section of SRL Chemical and Analytical Services Ltd.

Information given in this page may be subject to alteration without notice.

Care has been taken to ensure that the contents of this publication are accurate but SRL Site Services Ltd do not accept responsibility for errors or for information that is found to be misleading.

Suggestions for, or descriptions of, the end use or application of products or methods of working are for information only and the company accept no liability in respect thereof.

Before using products supplied or manufactured by the company the customer should be satisfied of their suitability.

If further assistance is required, we have access to extensive research facilities, we will often be willing to help.

Stainless Restoration Ltd, Adamsons Industrial Estate, Hyde SK14 1EE

Stainless Restoration Ltd offer an Electropolishing service to the stainless steel fabrication/manufacturing industry at its newly refurbished fully automated Electropolishing plant at Hyde Manchester.