Stainless Steel

• Austenitic Stainless Steel:

  • Composition: Typically contains 16-26% chromium, 6-22% nickel, and may include elements like manganese and nitrogen.
  • Characteristics: Non-magnetic and highly resistant to corrosion and oxidation. It has good ductility and weldability. It is the most widely used type of stainless steel.
  • Applications: Kitchen utensils, chemical processing equipment, and architectural structures. Examples include grades 304 and 316.

• Ferritic Stainless Steel:

  • Composition: Contains 10.5-27% chromium and very little or no nickel. May include small amounts of carbon and other elements.
  • Characteristics: Magnetic, with good corrosion resistance and high resistance to stress corrosion cracking. Less ductile than austenitic stainless steel.
  • Applications: Automotive exhaust systems, industrial equipment, and appliances. Examples include grades 430 and 446.

• Martensitic Stainless Steel:

  • Composition: Contains 12-18% chromium, with higher carbon content (up to 1.2%). Typically has lower nickel content.
  • Characteristics: Magnetic and known for high strength and hardness. It can be heat-treated to achieve varying hardness levels but has lower corrosion resistance compared to austenitic stainless steels.
  • Applications: Cutlery, surgical instruments, and industrial blades. Examples include grades 410 and 420.

• Duplex Stainless Steel:

  • Composition: Combines austenitic and ferritic stainless steels, typically containing 18-28% chromium, 3-10% nickel, and other elements like molybdenum.
  • Characteristics: Offers a balance of strength and corrosion resistance. It has higher tensile strength than austenitic grades and improved resistance to stress corrosion cracking.
  • Applications: Chemical processing, oil and gas industries, and marine environments. Examples include grades 2205 and 2507.

• Precipitation-Hardening Stainless Steel:

  • Composition: Contains chromium (15-20%), nickel (3-8%), and additional elements such as copper, aluminum, and titanium.
  • Characteristics: Can be hardened by heat treatment, offering high strength and hardness. Corrosion resistance is typically lower than austenitic grades.
  • Applications: Aerospace components, high-stress applications, and tools. Examples include grades 17-4 PH and 15-5 PH.

Property/Specification	Austenitic Stainless Steel	Ferritic Stainless Steel	Martensitic Stainless Steel	Duplex Stainless Steel	Precipitation-Hardening Stainless Steel
Carbon Content	Up to 0.08%	Up to 0.20%	Up to 1.2%	Up to 0.20%	Up to 0.15%
Chromium Content	16-26%	10.5-27%	12-18%	18-28%	15-20%
Nickel Content	6-22%	Very low or none	Low (generally less than 2%)	3-10%	3-8%
Tensile Strength	520-800 MPa	350-550 MPa	700-1,200 MPa	650-850 MPa	1,200-1,500 MPa
Yield Strength	210-310 MPa	220-380 MPa	450-1,000 MPa	450-750 MPa	900-1,200 MPa
Hardness	160-200 HB	150-250 HB	200-600 HB	250-300 HB	300-400 HB
Ductility	High (often > 40% elongation)	Medium (often 20-30% elongation)	Lower (can be <10% elongation)	Medium to High	Medium (varies by aging)
Machinability	Good	Moderate	Poor to Good (depending on heat treatment)	Good	Moderate to Good
Weldability	Excellent	Good	Fair to Poor (depending on grade)	Good	Fair to Good
Applications	Kitchen utensils, chemical processing equipment, architectural structures	Automotive exhaust systems, industrial equipment	Cutlery, surgical instruments, industrial blades	Chemical processing, oil and gas industries, marine environments	Aerospace components, high-stress applications
Heat Treatment	Annealing	Annealing	Quenching and Tempering	Solution Annealing and Aging	Aging (for hardening)
Standard Specifications	ASTM A240, ASTM A276, ISO 15510	ASTM A240, ASTM A276, ISO 5002	ASTM A276, ASTM A370, ISO 5832	ASTM A240, ASTM A276, ISO 14343	ASTM A564, ASTM A693, ISO 5832