WHY STAINLESS STEEL HAS TO BE PASSIVATED AFTER WELDING?

Stainless steel is naturally corrosion-resistant, however various industrial processes can destroy the protective layer on the steel surface.

Pressure and heat as integral parts of the welding process are directly responsible for the formation of rust on stainless steel surfaces.

As the steel structure changes through melting, the free iron particles begin to accumulate on the surface where they react with oxygen and cause corrosion.

Stainless steel would not be stainless without a protective chrome layer.

The concentration of chromium particles decreases even in the heat-affected zones – not just on the surface exposed to melting.

When this occurs, the passive state of the stainless steel has to be artificially restored.

However, effective passivation is impossible without a thorough post-welding cleaning and treatment of the surface.

The protective chromium-oxide layer cannot fully re-emerge unless all contaminants are removed from the affected areas.

Electrochemical process – weld cleaning and passivation in one pass

The combination of electricity and specialized electrolytic fluids is sufficient for successful cleaning and passivation of the surface – in one step.

The electrochemical process will not only remove imperfections on the surface after welding – it will also restore the oxide layer that returns stainless steel back to its normal passive state.

Unlike grinding, this cleaning method will successfully remove all dirt and discoloration from the welds. This is especially important for successful restoration of the passive layer.

Cougartron weld cleaning machines are designed to initiate and induce the formation of the chromium oxide film on stainless steel surfaces and welds. Thus, you can be sure that rust and other contaminating factors will not reappear after they are successfully eliminated.

Read more information about passivation of stainless steel after welding by clicking the link down below.

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