how it works
Why clean welds? The cleaning of stainless steels welds is required for aesthetic but more importantly technical reasons. The aesthetic aspect is self-evident, so let’s take a closer look at the technical reasons.
Stainless steel is inherently corrosion resistant due to its fine passive, protective layer of chromium oxide. During the welding process, the intense high temperature destroys the chromium content resulting in an iron-rich zone surrounding the weld area. Characterised by blue tones and bronze/brown discolouration this oxidisation results in the surface being openly susceptible to further corrosion.
The discolouration and free-iron left after welding must be removed from the surface before the stainless steel can achieve its distinctive, unique, chromium-rich passive layer.
"STAINLESS STEELS CANNOT BE PASSIVATED UNLESS THE STEEL SURFACE IS CLEAN AND FREE FROM CONTAMINATION AND SCALE FROM WELDING OPERATIONS."
it's the answer
Historically, oxide discolouration removal and passivation have been achieved firstly by chemical methods with the application of pickling paste, a combination of either Nitric or Hydrofluoric acid which is extremely hazardous to handle, toxic and requires long exposure times whilst leaving stubborn white marks post-cleaning. Secondly by mechanical means, either blasting or grinding/brushing, although neither are toxic the latter will result in iron oxide inclusions within the surface that will prompt new corrosion, the former although leaving a uniform finish blasting methods are associated with damaging and changing the material surface, also often impractical, costly and time consuming. More importantly though the major flaw with these processes is that passivation of the stainless has not been achieved leaving fabrications requiring additional, costly re-working in often a further two or three-stage process.
Electrolytic weld cleaning is the answer to all these challenges. Our technology cleans & passivates the stainless surface in a one-step easy to use the application without the use of toxic chemicals.
Using mild NSF approved fluids, certified for use within the food & drink sector the Weldbrush and TIG-MAX range of electrolytic weld cleaners, clean and passivate with no costly additional processes.
APPROVED BY NSF
NSF international (formerly known as the national sanitation foundation) is an independent, non-profit, global organization that certifies food service equipment and ensures it is designed and constructed in a way that promotes food safety. Nsf is internationally recognized, and most food service and production equipment require NSF certification. Our complete range of fluids is supplied with full NSF approval.
Surface Finishing and passivating large areas with TIG-MAX X17000 in an effective method of cleaning large vessels, tanks, frames or pipework. Not just localized the weld seam a flawless finish can now be achieved on all stainless surfaces to remove surface rust and imperfections.