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Ferritic Stainless Steel

Ferritic stainless steel, abbrviated as FSS, is a class of stainless steels primarily composed of iron and chromium, typically ranging from 10.5% to 30% chromium, with a very low carbon content (usually less than 0.1%).  Their distinguishing characteristic is a body-centered cubic (BCC) crystal structure, which makes them magnetic, unlike many other stainless steel types.  While they generally offer good corrosion resistance, particularly in oxidizing environments and excellent resistance to stress corrosion cracking, they are not hardenable by heat treatment.  However, they can be softened through annealing and exhibit good ductility and formability.  Due to their low or absent nickel content, ferritic stainless steels are often more cost-effective than austenitic grades and find common applications in automotive exhaust systems, kitchen appliances, and various industrial equipment where moderate corrosion resistance and magnetic properties are desired.

Ferritic Stainless Steel is Primarily Composed of the Following Elements
Iron (Fe)  -  Base metal
Chromium (Cr)  -  10.5% to 30%  Provides corrosion resistance
Carbon (C)  -  ≤ 0.08%  Very low, to maintain ductility and corrosion resistance
Silicon (Si)  -  ~1%  Improves oxidation resistance
Manganese (Mn)  -  ~1%  Deoxidizer and improves hot-working properties
Phosphorus (P)  -  ≤ 0.04%  Usually kept low to avoid brittleness
Sulfur (S)  -  ≤ 0.03%  Usually kept low unless added for machinability
Molybdenum (Mo)  -  0% to 2% (optional)  Enhances pitting resistance in chloride environments
Aluminum (Al), Titanium (Ti), or Niobium (Nb)  -  (optional)  Stabilizers for weldability and grain refinement
Ferritic stainless steels do not contain significant amounts of nickel, which differentiates them from austenitic grades.

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