Properties of Stainless Steel - Stainless steel is an alloy of iron that is resistant to rusting and corrosion. - It contains at least 10.5% chromium and usually nickel, and may also contain other elements. - Stainless steel can be rolled into sheets, plates, bars, wire, and tubing. - It is used in various applications such as cookware, cutlery, surgical instruments, and major appliances. - Stainless steel is also used in industrial equipment, construction material, and storage tanks. - Stainless steel rusts only on the outer few layers, while deeper layers are shielded by its chromium content. - Nitrogen can improve resistance to pitting corrosion and increase mechanical strength. - Different grades of stainless steel with varying chromium and molybdenum contents are available. - Corrosion resistance can be increased by increasing chromium and nickel content, and adding molybdenum. - ISO 15510 standard lists the chemical compositions of stainless steels in various specifications. - The tensile yield strength of common stainless steel type 304 is around 30,000psi in the annealed condition. - Cold working can strengthen stainless steel to a tensile yield strength of 153,000psi in the full-hard condition. - Precipitation hardening alloys like 17-4 PH and Custom 465 can have tensile yield strengths up to 251,000psi. - Different stainless steel grades have varying strength levels to suit different applications. - Strength can be tailored through heat treatment and alloy composition. - Stainless steel has a melting point near that of ordinary steel, higher than that of aluminum or copper. - The melting point is expressed as a range, typically between 1,400 to 1,530°C (2,550 to 2,790°F). - The specific consistency of the alloy determines the melting point range. - Stainless steel melting point is affected by its composition and alloying elements. - The melting point range is important for processing and fabrication of stainless steel. - Stainless steels have lower electrical conductivity compared to copper. - Non-electrical contact resistance (ECR) arises due to the protective oxide layer on stainless steel. - Copper alloys and nickel-coated connectors have lower ECR values and are preferred for electrical applications. - Martensitic, duplex, and ferritic stainless steels are magnetic, while austenitic stainless steel is usually non-magnetic. - Austenitic stainless steel can become slightly magnetic through work hardening.

History of Stainless Steel - German chemist Hans Goldschmidt developed aluminothermic process for carbon-free chromium in the late 1890s. - Leon Guillet of France prepared alloys that would be considered stainless steel today between 1904 and 1911. - Friedrich Krupp Germaniawerft built the sailing yacht Germania with a chrome-nickel steel hull in 1908. - Philip Monnartz reported on the relationship between chromium content and corrosion resistance in 1911. - Christian Dantsizen of General Electric and Frederick Becket at Union Carbide industrialised ferritic stainless steel in the United States. - Harry Brearley discovered and industrialised a martensitic stainless steel alloy in 1912. - The discovery was announced in a 1915 newspaper article. - The alloy was marketed under the Staybrite brand by Firth Vickers. - Brearley applied for a US patent in 1915 but found that Elwood Haynes had already registered one. - Brearley and Haynes formed the American Stainless Steel Corporation in Pittsburgh, Pennsylvania. - Harry Brearley initially called his alloy rustless steel. - The alloy was sold in the US under different brand names like Allegheny metal and Nirosta steel. - The name stainless steel was given by a local cutlery manufacturer. - Ford Motor Company continued calling the alloy rustless steel in 1932. - Over 25,000 tons of stainless steel were manufactured and sold annually in the US in 1929.

Austenitic Stainless Steel - Austenitic stainless steel is the largest family of stainless steels. - They possess an austenitic microstructure achieved by alloying steel with nickel and/or manganese. - Austenitic stainless steels are not hardenable by heat treatment. - Metastable austenitic stainless steels are widely used in manufacturing cryogenic pressure vessels. - Cryogenic cold-forming improves wear resistance of austenitic stainless steel.

Ferritic Stainless Steel - Ferritic stainless steels possess a ferrite microstructure like carbon steel. - They contain between 10.5% and 27% chromium with little or no nickel. - Ferritic stainless steels cannot be hardened by heat treatment. - They are less expensive than austenitic steels and are used in automobile exhaust pipes, architectural applications, and building components. - Additions of niobium, titanium, and zirconium allow good weldability in ferritic stainless steels.

Martensitic Stainless Steel - Martensitic stainless steels have a body-centered cubic crystal structure. - They offer a wide range of properties and are used as stainless engineering steels, stainless tool steels, and creep-resistant steels. - Martensitic stainless steels are magnetic and less corrosion-resistant than ferritic and austenitic stainless steels. - They fall into four categories: Fe-Cr-C grades, Fe-Cr-Ni-C grades, precipitation hardening grades, and creep-resisting grades. - Heat treatment can improve the mechanical properties of martensitic stainless steels.

Note: The content does not provide enough information to create comprehensive groups for the subtopics: Stainless Steel Grades, Quenching Process, Tempering Process, Carbon Replacement with Nitrogen, and Time Frame.