How Is Stainless Steel Made? Raw Materials Stainless steel is an iron alloy with added elements such as chromium, nickel, silicon, manganese, nitrogen and carbon.
When you see a steel structure pop up like a takeout box, don’t be fooled, as constructing superior metal buildings is no easy feat!From the ground to the skyscrapers, the element of steel has a long journey before it can live up to the high standards of quality expected at our.In this post, we’ll outline each step of how steel is made and it’s life cycle before it reaches our client’s construction projects.How Is Steel Made From Iron Ore?Good question! Fun fact: The earliest steel and iron found in weapons dates all the way back to 1800 B.C. (Spoerl, A Brief History of Iron and Steel Production)What is the Life Cycle of Steel?Steel starts out in the ground as iron ore, and in its most useful state, ends up as one of the in your neighborhood, or in the superstructure of your local grocery market.So what happens in between iron ore and construction?Step 1: Extraction of SteelFirst, rocks and minerals in the ground which contain iron ore must be extracted in an economical fashion. The actual iron in rocks generally occurs in the form of either hematite, limonite, siderite, magnetite, or goethite.The iron ore will be used to make pig iron, which constitutes one of the main materials used in the manufacture of steel.After extraction from a mining site, the iron ore is shipped to an iron-making plant.Step 2: Remove Impurities in the SteelThe next step is smelting, a two-step process to create a base metal from the raw iron ore by removing all unwanted materials. Fun fact: Once a furnace is started up for operation, it is often kept running continuously for several years, and is not shut down until maintenance is required or demand for steel diminishes. Fun fact: Nearly 70% of all steel in America is recycled each year, and this represents a total greater than plastic, glass, aluminum, and paper combined. ( American Iron and Steel Institute)Sustainable Suppliers For High Quality ProductsWe are proud to have developed such great working relationship with reputable and sustainable suppliers such as.
Nucor’s steel mills are among the most modern and efficient in the United States.Recycled steel scrap and other metallics are melted in electric arc furnaces and poured into continuous casting systems. Highly sophisticated rolling mills convert the billets, blooms, and slabs into rebar, angles, rounds, channels, beams and other products.Nucor has become an innovative leader in the industry, constructing the world’s first “micro-mill,” which transforms molten metal directly into steel sheet in just one remarkable step. The company also installed the industry’s first vacuum degasser for thin-slab casting, which allows for the production of grades of steel beyond anyone’s expectations. Fun fact: Roughly 75% of all major appliances today are made from steel. ( American Iron and Steel Institute)Only the finest metal are used to create our superior steel buildings, and that’s why clients have come to rely on Pascal Steel for all their steel structure needs. Our suppliers use innovative techniques to create steel in the most effective way possible, and we use recycled materials and innovative practices that reduce the impact on the environment, as well as reducing the time necessary for preparing materials used in steel construction. Learn More About Hight Quality Steel DesignsOne of the most popular uses of steel today is in the construction of long-lasting commercial buildings.Pascal Steel is a premier manufacturer of metal buildings and steel structures in California.
We have provided buildings to consumers, commercial companies, and government projects for six decades.View our for more examples of Pascal Steel’s craftsmanship with sustainable steel. With questions about how our building are constructed or would like to bring your structure to life.
Stainless steel is an iron-containing alloy—a substance made up oftwo or more chemical elements—used in a wide range of applications.It has excellent resistance to stain or rust due to its chromium content,usually from 12 to 20 percent of the alloy. There are more than 57stainless steels recognized as standard alloys, in addition to manyproprietary alloys produced by different stainless steel producers. To make stainless steel, the raw materials—iron ore, chromium,silicon, nickel, etc.—are melted together in an electricfurnace. This step usually involves 8 to 12 hours of intense heat.Next, the mixture is cast into one of several shapes, includingblooms, billets, and slabs.and then it is cast into solid form.
After various forming steps, thesteel is heat treated and then cleaned and polished to give it the desiredfinish. Next, it is packaged and sent to manufacturers, who weld and jointhe steel to produce the desired shapes.Melting and casting.1 The raw materials are first melted together in an electric furnace.This step usually requires 8 to 12 hours of intense heat. When themelting is finished, the molten steel is cast into semi-finished forms.These include blooms (rectangular shapes), billets (round or squareshapes 1.5 inches or 3.8 centimeters in thickness), slabs, rods, andtube rounds.Forming.2 Next, the semi-finished steel goes through forming operations,beginning with hot rolling, in which the steel is heated and passedthrough huge rolls. Blooms and billets are formed into bar and wire,while slabs are formed into plate, strip, and sheet. Bars are availablein all grades and come in rounds, squares, octagons, or hexagons 0.25inch (.63 centimeter) in size. Wire is usually available up to 0.5 inch(1.27 centimeters) in diameter or size.
Plate is more than 0.1875 inch(.47 centimeter) thick and over 10 inches (25.4 centimeters) wide. Stripis less than 0.185 inch (.47 centimeter) thick and less than 24 inches(61 centimeters) wide. Sheet is less than 0.1875 (.47 centimeter) thickand more than 24 (61 centimeters) wide.Heat treatment.3 After the stainless steel is formed, most types must go through anannealing step. Annealing is a heat treatment in which the steel isheated and cooled under controlled conditions to relieve internalstresses and soften the metal. Some steels are heat treated for higherstrength. However, such a heat treatment—also known asage hardening—requires careful control, for even small changes from therecommended temperature, time, or cooling rate can seriously affect theproperties.
Lower aging temperatures produce high strength with lowfracture toughness, while higher-temperature aging produces a lowerstrength, tougher material.Though the heating rate to reach the aging temperature (900 to 1000degrees Fahrenheitor 482 to 537 degrees Celsius) does not effect the properties, thecooling rate does. A post-aging quenching (rapid cooling) treatmentcan increase the toughness without a significant loss in strength. Onesuch process involves water quenching the material in a 35-degreeFahrenheit (1.6-degree Celsius) ice-water bath for a minimum of twohours.The type of heat treatment depends on the type of steel; in otherwords, whether it is austenitic, ferritic, or martensitic. Austeniticsteels are heated to above 1900 degrees Fahrenheit (1037 degreesCelsius) for a time depending on the thickness. Water quenching isused for thick sections, whereas air cooling or air blasting is usedfor thin sections.
If cooled too slowly, carbide precipitation canoccur. This buildup can be eliminated by thermal stabilization. Inthis method, the steel is held for several hours at 1500 to 1600degrees Fahrenheit (815 to 871 degrees Celsius). Cleaning partsurfaces of contaminants before heat treatment is sometimes alsonecessary to achieve proper heat treatment.Descaling.4 Annealing causes a scale or build-up to form on the steel. The scalecan be removed using several processes.
One of the most common methods,pickling, uses a nitric-hydrofluoric acid bath to descale the steel. Inanother method, electrocleaning, an electric current is applied to thesurface using a cathode and phosphoric acid, and the scale is removed.The annealing and descaling steps occur at different stages depending onthe type of steel being worked. Bar and wire, for instance, go throughfurther forming steps (more hot rolling, forging, or extruding) afterthe initial hot rolling before being annealed and descaled. Sheet andstrip, on the other hand, go through an initial annealing and descalingstep immediately after hot rolling. After cold rolling (passing throughrolls at a relatively low temperature), which produces a furtherreduction in thickness, sheet and strip are annealed and descaled again.A final cold rolling step then prepares the steel for final processing.Cutting.5 Cutting operations are usually necessary to obtain the desired blankshape or size to trim the part to final size. Mechanical cutting isaccomplished by a variety of methods, including straight shearing usingguillotine knives, circle shearing using circular knives horizontallyand vertically positioned, sawing using high speed steel blades,blanking, and nibbling.
Blanking uses metal punches and dies to punchout the shape by shearing. Nibbling is a process of cutting by blankingout a series of overlapping holes and is ideally suited for irregularshapes.Stainless steel can also be cut using flame cutting, which involves aflame-fired torch using oxygen and propane in conjunction with ironpowder. This method is clean and fast. Another cutting method is knownasplasma jet cutting,in which an ionized gas column in conjunction with an electric arcthrough a small orifice makes the cut. The gas produces extremely hightemperatures to melt the metal.Finishing.6 Surface finish is an important specification for stainless steelproducts and is critical in applications where appearance is alsoimportant. Certain surface finishes also make stainless steel easier toclean, which is obviously important for sanitary applications.
A smoothsurface as obtained by polishing also provides better corrosionresistance. On the other hand, rough finishes are often required forlubrication applications, as well as to facilitate further manufacturingsteps.Surface finishes are the result of processes used in fabricating thevarious forms or are the result of further processing. There are avariety of methods used for finishing. A dull finish is produced byhot rolling, annealing, and descaling. A bright finish is obtained byfirst hot rolling and then cold rolling on polished rolls. A highlyreflective finish is produced by cold rolling in combination withannealing in a controlled atmosphere furnace, by grinding withabrasives, or by buffing a finely ground surface. A mirror finish isproduced by polishing with progressively finer abrasives, followed byextensive buffing.
For grinding or polishing,grinding wheelsor abrasive belts are normally used. Buffing uses cloth wheels incombination with cutting compounds containing very fine abrasiveparticles in bar or stick forms. Other finishing methods includetumbling, which forces. The initial steel shapes—blooms, billets, slabs,etc.—are hot rolled into bar, wire, sheet, strip, andplate. Depending on the form, the steel then undergoes furtherrolling steps (both hot and cold rolling), heat treatment(annealing), descaling Ito remove buildup), and polishing toproduce the finished stainless steel.
How Is Steel Made From Iron Ore
The steel is then sent theend user.movement of a tumbling material against surfaces of parts, dryetching (sandblasting), wet etching using acid solutions, and surfacedulling. The latter uses sandblasting, wire brushing, or picklingtechniques.Manufacturing at the fabricator orend user.7 After the stainless steel in its various forms are packed and shippedto the fabricator or end user, a variety of other processes are needed.Further shaping is accomplished using a variety of methods, such as rollforming, press forming, forging, press drawing, and extrusion.Additional heat treating (annealing), machining, and cleaning processesare also often required.There are a variety of methods for joining stainless steel, withwelding being the most common. Fusion and resistance welding are thetwo basic methods generally used with many variations for both. Infusion welding, heat is provided by an electric arc struck between anelectrode and the metal to be welded. In resistance welding, bondingis the result of heat and pressure. Heat is produced by the resistanceto the flow of electric current through the parts to be welded, andpressure is applied by the electrodes. Afterparts are welded together, they must be cleaned around the joinedarea.Quality ControlIn addition to in-process control during manufacture and fabrication,stainless steels must meet specifications developed by the AmericanSociety for Testing and Materials (ASTM) with regard to mechanicalproperties such as toughness and corrosion resistance.
Metallography cansometimes be correlated to corrosion tests to help monitor quality.The FutureUse of stainless and super stainless steels is expanding in a variety ofmarkets. To meet the requirements of the new Clean Air Act, coal-firedpower plants are installing stainless steel stack liners. Other newindustrial applications include secondary heat exchangers forhigh-efficiency home furnaces, service-water piping in nuclear powerplants, ballast tanks and fire-suppression systems for offshore drillingplatforms, flexible pipe for oil and gas distribution systems, andheliostats for solar-energy plants.Environmental legislation is also forcing the petrochemical and refineryindustries to recycle secondary cooling water in closed systems ratherthan simply discharge it. Reuse results in cooling water with elevatedlevels of chloride, resulting in pitting-corrosion problems. Duplexstainless steel tubing will play an increasingly important role in solvingsuch industrial corrosion problems, since it costs less than othermaterials. Manufacturers are developing highly corrosion-resistant steelsin respond to this demand.In the automotive industry, one steel manufacturer has estimated thatstainless-steel usage per vehicle will increase from 55 to 66 pounds (25to 30 kilograms) to more than 100 pounds (45 kilograms) by the turn of thecentury.
New applications include metallic substrates for catalyticconverters,components, composite bumpers, fuel line and other fuel-system partscompatible with alternate fuels, brake lines, and long-life exhaustsystems.With improvements in process technology, superaustenitic stainless steels(with nitrogen contents up to 0.5 percent) are being developed. Thesesteels are used in pulp-mill bleach plants, sea water and phosphoric-acidhandling systems, scrubbers, offshore platforms, and other highlycorrosive applications. A number of manufacturers have begun marketingsuch materials in sheet, plate, and other forms. Other new compositionsare being developed: ferritic iron-base alloys containing 8 and 12 percentCr for magnetic applications, and austenitic stainless with extra lowsulfur content for parts used in the manufacture of semiconductors andpharmaceuticals.Research will continue to develop improved and unique materials. Forinstance, Japanese researchers have recently developed several.
One is acorrosion-resistant stainless steel that displays the shape-memory effect.This type of material returns to its original shape upon heating afterbeing plastically deformed. Potential applications include assemblycomponents (pipe fittings, clips, fasteners, clamps), temperature sensing(circuit breakers and fire alarms), and springs. An improved martensiticstainless steel has also been developed for precision miniature andinstrument rolling-contact bearings, which has reduced vibration levels,improved life expectancy, and better surface finish compared toconventional materials. Where To Learn MoreBooksCleaning and Descaling Stainless Steels.American Iron and Steel Institute, 1982.Finishes for Stainless Steel.American Iron and Steel Institute, June, 1983.Llewellyn, D. T.Steels: Metallurgy & Applications.Butterworth-Heinemann, 1992.MacMillan, Angus, ed.The Steel-Alloying Handbook.Elkay Publishing Services, 1993.Stainless Steel & Heat Resisting Steels.Iron & Steel Society, Inc., 1990.PeriodicalsDavison, Ralph M. 'Practical Guide to UsingDuplex StainlessSteels.'
Materials Performance.January, 1990, pp. 57-62.Hasimoto, Misao. 'Combined Deposition Processes Create NewComposites.' Research & Development.October, 1989.Tuthill, Arthur and Richard Avery. 'Specifying Stainless SteelSurface Treatments.' Advanced Materials & Processes.December, 1992, pp.