めっき技術

Stainless steel materials

When the chromium content in steel exceeds 12%, the corrosion resistance improves dramatically. From this, iron-chromium alloys containing 12% or more chromium is called stainless steel. The corrosion resistance of this stainless steel originates in the ultrathin chromium oxide film (passive film) formed on the most superficial layer. From the perspective of the adhesion property of plating, how to remove this passive film is a factor.
Classification Main ingredient Metallographic structure
(crystalline structure)
Magnetism Uses
Cr-based stainless steel 13%Cr (SUS410-based) Martensite (body-centered cubic structure) Strongly magnetic All sorts of industries
14%Cr (SUS430-based) Ferrite (body-centered cubic structure) Strongly magnetic
Cr-Ni-based stainless steel 25%Cr (SUS329-based) Austenite/ferrite Magnetic
18%Cr-8%Ni (SUS304-based) Austenite (face-centered cubic structure) Non-magnetic

- Others: Austenite/ferrite-based (SUS329-based): High resistance to chlorine.
Precipitation hardened (SUS630-based): High strength.
- Note: Even if stainless steel is non-magnetic, only the superficial layer is magnetized when subjected to strong cold working.

採用事例
Stainless steel materials
Appearance of electroless nickel plating on stainless steel after adhesion test