quiz 2

• Stainless steel


  Steels that do not corrode or rust easily
• Stainless steel


  • Main alloying elements are chromium and nickel
  • Steels containing at least 10.5% chromium, less than 1.2% carbon and other alloying elements
  • An important metal for many industries
• Stainless steels


  • Generally high strength, with some examples being among the highest tensile and yield strengths of all metals
  • Corrosion resistance and mechanical properties can be further enhanced by adding other elements, such as nickel, molybdenum, titanium, niobium, manganese, etc.
• Discovery of Chromium (Cr) (Louis Vauquelin)


  1798
• Observation and discovery of resistance of chromium (Faraday, Pierre Berthier)

  Early 1800's - 1821
• Start of production of Chromium steel (Britain and Germany) (Sheffield Steelmakers, Robert Mushet)

  1840's - 1861
• American production of Chromium Steel "Weater - Resistant Alloys" (John T. Woods and John Clark) (Patent)

  1869
• Developed an aluminothermic process (Hans Goldschmidt)


  1890's
• Experiment in different composition of steel (Harry Brearly)

  1912
• He added 12.8% of Chromium and 0.24% Carbon to Iron to produce a metal named "Rustless Steel", later called "Stainless Steel" by Ernest Stuart


  1912
• Stainless steel


  Created by mixing metals like chromium, nickel, molybdenum, carbon and other elements. This blend gives it special qualities such as being better at resisting rust, stronger, and more flexible.
• Elements in stainless steel

  • Iron (Fe)
  • Chromium (Cr)
  • Nickel (Ni)
  • Copper (Cu)
  • Silicon (Si)
  • Molybdenum (Mo)
  • Manganese (Mn)
  • Nitrogen (N)
  • Carbon (C)
• Chromium


  Resistant to rust and corrosion
• Nickel


  Contributes to its strength and durability
• Carbon


  Small amounts can improve the steel's strength, but it can also decrease resistance to corrosion
• Copper


  Functions as a stabilizer of austenite and enhances resistance to specific acids, improving corrosion resistance
• Silicon


  Resistance to highly concentrated nitric and sulphuric acids
• Nitrogen


  Austenite stabiliser and it improves the strength and localised corrosion resistance
• Molybdenum


  Improve general and localised corrosion resistance properties
• Manganese


  Improves the properties of strength, toughness and hardenability
• Iron


  Stainless steel
• Benefits of stainless steel

  • Corrosion Resistance
  • Temperature Resistance
  • Strength and Durability
  • Sustainability/Recyclability
  • Formability
  • Appearance and Longevity
  • Cleanliness/Hygiene
• Applications of stainless steel

  • Kitchen
  • Hospitals
  • Food & Beverage Industry
  • Fabrication
  • Cladding
  • Jewelry
• Austenitic stainless steel


  • Most common stainless steel type (70% of production)
  • Contains minimum 16% chromium and 6% nickel
  • Other alloying elements include manganese, nitrogen, and sometimes molybdenum
  • High corrosion resistance, ductility, and toughness
  • Non-magnetic and cannot be hardened by heat treatment
• Austenitic stainless steel


  • Primary microstructure is austenite
  • High toughness and resistance to elevated temperatures
  • Rapid work-hardening with cold working
  • Suitable for low-temperature or cryogenic applications due to nickel content
• Austenitic stainless steel classification and grades

  • 300 and 200 series
  • Grade 304 ("18/8") most popular
  • Grade 316 common in food prep, medical, and marine
• Austenitic stainless steel applications and modifications

  • Used in kitchen, cutlery, food processing, automotive, aerospace, medical
  • Modifications with elements enhance specific properties
  • Some grades like 904L are super austenitics with increased molybdenum
• Austenitic stainless steel alloying elements and naming


  • Austenitic stabilizers promote austenite formation
  • Principal elements reflected in steel names (e.g., 304 as "18/8")
• Martensitic stainless steel


  • Stronger and harder with lower corrosion resistance
  • Contains 12–18% chromium, may have nickel or molybdenum
  • High carbon content sets it apart
• Martensitic stainless steel classification and grades

  • Belongs to 400 grade series
  • Contains 12% to 15% chromium and up to 1% molybdenum
  • Notable grades: 410 and 416
• Martensitic stainless steel applications and modifications

  • Used in compressor blades, turbine parts, kitchen utensils, etc.
  • Used for parts needing corrosion resistance, high strength at low temperatures, and creep resistance at high temperatures
• Martensitic stainless steel


  • Higher hardenability, can be heat treated
  • Poor weldability
  • Hardened martensitic steels can't be cold formed
  • Moderate corrosion resistance
  • Magnetic with high ductility and toughness, easier to form
• Ferritic stainless steel


  • It is composed of bulk iron
  • It has chromium ranging 10.5% to 30%
  • Low carbon content usually less than 0.10%
  • Good corrosion resistance
  • Can't be hardened by heat treatment
  • Magnetic
  • 400 series of stainless steel
  • Most common grades : 409 and 430
• Ferritic stainless steel applications

  • Waterheating appliances
  • Automotive Components
  • Fuel lines
  • Food Equipment
  • Architectural trim
  • Domestic appliances
• Duplex stainless steel


  • Feature properties of both classes
  • High Chromium and Low Nickel contents
  • Toughness
  • Corrosion Resistance
  • Readily welded
• Duplex stainless steel classification and grades

  • Grade 2205
  • Grade 2304
  • Grade 2507
• Duplex stainless steel applications

  • Heat exchangers
  • Marine applications
  • Desalination plants
  • Food pickling plants
  • Off-shore oil & gas installations
  • Chemical & petrochemical plant
• Precipitation-hardening stainless steel


  Achieved by the formation of small particles, precipitated within the material, that increase its strength and hardness by inducing lattice stress. This can commonly deliver 3–4 times the strength of basic austenitic stainless steel.
• Precipitation-hardening stainless steel applications

  • Aerospace applications
  • Turbine blades
  • Nuclear waste casks
  • Mechanical components
• Precipitation-hardening stainless steel have various modifications to tailor properties for specific applications, such as improved corrosion resistance or higher strength.