Outokumpu

Preventive Measures in Project Design, Production, and Installation

All stainless steels are clean and passivated when they are delivered by the steel manufacturer. In other words, the material has a natural corrosion resistant film over its entire surface.

The following instructions should be taken into account from the moment of project design, through to the production and installation stages, particularly for building components installed outdoors, in order to maintain as much as possible of the original appearance and corrosion resistance of the stainless material.

Do not use steel brushes or steel tools made of plain carbon steel.
Do not carry out shot blasting using ordinary steel shot materials that have been used for shot blasting plain carbon steels
Do not use hydrochloric acid to remove residues of cement or mortar on steel. Instead use water to wash off the mortar before it dries. Hydrochloric acid may not be used for cleaning of stainless steels.

  • Specify the correct steel grade, taking into account the occurrence of deposits and air pollutants such as soot, sulphur dioxide, salt water or road salt in the immediate surroundings.
  • Specify the correct surface finish, a smooth surface has better staining and corrosion resistance and is easier to clean than a rougher surface.
  • Select the correct design that allows rainwater to rinse away deposits of dust and dirt from the entire surface.
  • Specify a grade of steel with a higher alloy content for parts that are inaccessible to rainwater or for parts installed in more aggressive geographical locations.
  • Remove slag, splatter and oxide from welded joints.
  • Use fasteners, such as nails, screws and bolts, made of stainless steel during installation.
  • Avoid the risk of galvanic corrosion between components of stainless steels and those of plain carbon steels in areas exposed to moisture and water (e.g. by providing electrical insulation).
  • Use clean tools that are free from residues of plain carbon steel, such as swarf and iron particles from previous work. 
  • Remove the protective plastic film when it is no longer needed, i.e. when the construction phase is completed and the local environment is free of debris and dirt particles. Some plastic films deteriorate in sunlight and can become difficult to strip.