Here are the instructions how to enable JavaScript in your web browser. So to understand how stainless steel is produced, we must first dive into its composition. What is Stainless Steel? Stainless steel is an iron and chromium alloy. Other common additives include: Nickel Carbon Manganese Molybdenum Nitrogen Sulfur Copper Silicon The exact composition of an alloy is strictly measured and assessed throughout the alloying process to ensure the steel exhibits the required qualities.
How Stainless Steel is Made The exact process for a grade of stainless steel will differ in the later stages. Before you can create a deliverable steel product, you must first create the molten alloy. Because of this most steel grades share common starting steps. Step 1: Melting Manufacturing stainless steel starts with melting scrap metals and additives in an electric arc furnace EAF.
Exact temperatures will vary based on the grade of steel created. Step 2: Removing Carbon Content Carbon helps to increase the hardness and strength of iron. There are two ways foundries control carbon content. Step 3: Tuning After reducing carbon, a final balancing and homogenization of temperature and chemistry occurs. Step 4: Forming or Casting With the molten steel created, the foundry must now create the primitive shape used to cool and work the steel.
Common shapes include: Blooms Billets Slabs Rods Tubes Forms are then marked with an identifier to track the batch through the various processes to follow. The following steps are the most common. Hot Rolling Performed at temperatures higher than the recrystallization temperature of the steel, this step helps to set the rough physical dimensions of the steel.
Cold Rolling Often used when precision is required, cold rolling occurs below the recrystallization temperature of the steel. Annealing After rolling, most steel undergoes an annealing process. To meet the requirements of the new Clean Air Act, coal-fired power plants are installing stainless steel stack liners. Other new industrial applications include secondary heat exchangers for high-efficiency home furnaces, service-water piping in nuclear power plants, ballast tanks and fire-suppression systems for offshore drilling platforms, flexible pipe for oil and gas distribution systems, and heliostats for solar-energy plants.
Environmental legislation is also forcing the petrochemical and refinery industries to recycle secondary cooling water in closed systems rather than simply discharge it. Reuse results in cooling water with elevated levels of chloride, resulting in pitting-corrosion problems. Duplex stainless steel tubing will play an increasingly important role in solving such industrial corrosion problems, since it costs less than other materials. Manufacturers are developing highly corrosion-resistant steels in respond to this demand.
In the automotive industry, one steel manufacturer has estimated that stainless-steel usage per vehicle will increase from 55 to 66 pounds 25 to 30 kilograms to more than pounds 45 kilograms by the turn of the century.
New applications include metallic substrates for catalytic converters, air bag components, composite bumpers, fuel line and other fuel-system parts compatible with alternate fuels, brake lines, and long-life exhaust systems. With improvements in process technology, superaustenitic stainless steels with nitrogen contents up to 0. These steels are used in pulp-mill bleach plants, sea water and phosphoric-acid handling systems, scrubbers, offshore platforms, and other highly corrosive applications.
A number of manufacturers have begun marketing such materials in sheet, plate, and other forms. Other new compositions are being developed: ferritic iron-base alloys containing 8 and 12 percent Cr for magnetic applications, and austenitic stainless with extra low sulfur content for parts used in the manufacture of semiconductors and pharmaceuticals.
Research will continue to develop improved and unique materials. For instance, Japanese researchers have recently developed several. One is a corrosion-resistant stainless steel that displays the shape-memory effect.
This type of material returns to its original shape upon heating after being plastically deformed. Potential applications include assembly components pipe fittings, clips, fasteners, clamps , temperature sensing circuit breakers and fire alarms , and springs.
An improved martensitic stainless steel has also been developed for precision miniature and instrument rolling-contact bearings, which has reduced vibration levels, improved life expectancy, and better surface finish compared to conventional materials. Cleaning and Descaling Stainless Steels. American Iron and Steel Institute, Finishes for Stainless Steel.
American Iron and Steel Institute, June, Llewellyn, D. Butterworth-Heinemann, MacMillan, Angus, ed. The Steel-Alloying Handbook. Elkay Publishing Services, Davison, Ralph M. January, , pp. Hasimoto, Misao. October, ISSF was founded in Filtration is part of our daily life … and stainless steel is the material of choice for filtration.
The Duplex Stainless Steels brochure, a reference document informs and guides readers in how to appropriately select the correct duplex StainlessSteel for specific projects.
Introduction to stainless steels The material we know as stainless steel also commonly referred to as "Inox" or "Rostfrei" is such a common feature of 21st century living that there can be few of us who have not seen or handled articles made from it. A very different type of steel Like all types of steel, stainless steel is not a single metal but an alloy that is a material made from two or more separate elements alloyed or "melted" together. For more information about the ways in which stainless steel can be fabricated and finished, see Fabrication and Surface Treatment Stainless steel is everywhere It is, of course, the rust-resisting characteristic which gives stainless steel its name.
Welcome to the world of stainless steel! Introduction to Stainless Steel. Published 24 November Basic Facts about Stainless Steel. The three main types of stainless steels are austenitic, ferritic, and martensitic.
These three types of steels are identified by their microstructure or predominant crystal phase. There are also other grades of stainless steels, such as precipitation-hardened, duplex, and cast stainless steels.
Stainless steel can be produced in a variety of finishes and textures and can be tinted over a broad spectrum of colors. There is some dispute over whether the corrosion resistance of stainless steel can be enhanced by the process of passivation. Essentially, passivation is the removal of free iron from the surface of the steel.
This is performed by immersing the steel in an oxidant, such as nitric acid or citric acid solution. Since the top layer of iron is removed, passivation diminishes surface discoloration. While passivation does not affect the thickness or effectiveness of the passive layer, it is useful in producing a clean surface for further treatment, such as plating or painting.
On the other hand, if the oxidant is incompletely removed from the steel, as sometimes happens in pieces with tight joints or corners, then crevice corrosion may result. Most research indicates that diminishing surface particle corrosion does not reduce susceptibility to pitting corrosion.
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