Austenitics Stainless Steels

• Carbon low content, less than 0,1%
• Chromium included between 18% and 25% - nickel between 8% and 20%. The presence of nickel stabilizes the typical crystallin structure of high temperature
• The main families are:
  • Chromium nickel steels quality A2 (AISI 304). They contain chromium at 18% and nickel at 8%. They can be used in kitchen tools or in equipment for the food, chemical industry or for the furniture or building. It is underlined that it is not suitable for being used in acidic or where there is some chloride (for example: sea water)
  • Chromium molybdenum nickel steels quality A4 (AISI 316). They contain chromium 17% and nickel 12%. The addition of molybdenum, between 2% and 3%, increases its corrosion resistance because it enforces the passive chromium oxide film that covers stainless steels; they are defined “acid prof steels”. They resist chlorides, main enemies of stainless steel, because they can break the passive film or avoid its formation. They are suitable in sea areas.

At UBB, we have used stainless steel 304 for the production of special self-tapping screw with cylindric head ISO 7049, diameter 4,8. We have produced these screws of different lengths for an important company that produces aluminium windows.

It is important the production of stainless steel 316 self-drilling screws with hexagonal head diameter 5,5mm and length 25mm, it is preassembled with metallic washer and vulcanized EPDM gasket. The fastening is used for the construction of wood’s dryer.