Increasing the volume fraction of hard second phases generally increases the strength. Heating rate, soaking time and cooling rate are important parameters. Cycles, or heats, range from about 112 to 5 hours to produce carbon steel and from 5 to 10 hours or more to produce alloy steel. Pdf on dec 1, 2016, ahmed refaee and others published effect of dual phase steel. The resulting material may also contain trace amounts of other phases such as retained austenite and bainite. Dual phase steel dp dp 500 dp 600 yes yes yesb yesa no na na boron, martensitice yesa yes yesb no no na na transformationinduced plasticity steel trip trip 590 trip 78 0 trip 980 na na na na na na na fordrecommended steel repairability matrix dual phase steel dpc dp 700 dp 900 dp yesd yes yesb n o no na na. Scrap steel is charged to begin a cycle, and alloying agents and slag materials are added for refining. Optimal control of a cooling line for production of hot.
Trip steel is produced by heating the steel into the intercritical temperature range for annealing so that dissolution of cementite occurs and formation of austenite starts. The dual phase grade is a specialised steel which can be used to produce lightweight gas cylinders. Pdf study on the production of dual phase steels by hot. High resistance steel band or sheet and method for the production thereof. The steel industry is already experiencing a 10 percent higher growth in ahss automotive applications than predicted, said cees ten broek, director of worldautosteel, the automotive group of the world steel association. Highstrength dualphase steel produced through fastheating. Mar 14, 2017 process for producing a steel strip comprising a relatively high strength dual phase steel. Structure and mechanical properties of dual phase steels diva. Please inquire about the status and availability of these products. Dualphase steels dp steels consist of ferrite and a dispersed hard martensitic second phase in the form of islands. Aug 18, 2014 hotrolled dp steel products are fabricated from the austenite phase.
For dual phase steel, heat treatment can be applied to lowcarbon steels with carbon content higher than 0. Growing demand from the construction and automotive industries, coupled with environmental sustainability of high strength steel, is expected to drive market demand over the forecast period. Process for making coldrolled dual phase steel sheet. Zanganehmadar and others published study on the production of dual phase steels by hot rolling process find, read and cite all the research you need on researchgate. The methods of production of coated dual phase and trip steels were provided by tumuluru 2006a and are shown schematically in fig. Dev products are under development or in limited production. Influence of production method on the properties of dual. Dualphase steel are lowcarbon microalloyed steels, characterized by a ferritic multiphase structure bainite and residual austenite in which martensite is dispersed. Arcelormittal offers cold rolled 500 mpa tensile strength dual phase grades with different coating conditions bare or electrogalvanized. The dual phase steel investigated contained, in wt%, 0. Dualphase dp steels comprise a soft, continuous phase a mechanically separable or visually identifiable portion of a structure known as ferrite surrounding islands of a hard phase known as martensite see figure 1. Production of coldrolled strip from dualphase steel. Dp sheet steels can be produced by intercritical heat treatment with either continuous annealing. Usually they are lowcarbon lowalloy materials with 1040 vol.
Dual phase steel this information provides repair recommendations and general guidelines for steel classified as dual phase steel dual phase steel with a tensile strength up to and including 800 mpa, also known as dp. The application of available two phase deformation models to dual phase steels is examined by testing them against available data published in the literature and an experimental highsiliconcontaining steel. These grades are part of arcelormittals diform family of dual phase. The ferrite phase is mainly pure iron, just like the extradeepdrawing steel grades used to make automotive fenders. Dual phase steels, design, formability, spot welding, laser welding, arc welding. Dualphase steel dp steel is a highstrength steel that has a ferriticmartensitic microstructure. Semi rolled slabs 30 mm thick were soaked at 1200c for 45 min. Design of process parameters for dual phase steel production.
The atmospheric corrosion behavior in comparison to a reference dual phase steel is studied by conducting an accelerated cyclic atmospheric corrosion test. In this article, the optimal control of a cooling line for production of dual phase steel in a hot rolling process is discussed. In order to achieve a desired dual phase steel microstructure an. Dualphase steels can be produced as both hot rolled and cold rolled based material. As they combine high strength and good formability at low production costs they are widely used for automotive applications. Dual phase steels produced by intercritical annealing. Coldrolled steel sheets and coils are extensively used as basic materials in automobiles, electrical appliances, steel office equipment, various types of containers, and numerous other products closely connected to our daily lives. Simply spoken the ferrite, which is a soft phase, gives a low yield point and the martensite, which is hard, gives the strength. Dual phase microstructure and phase transformations of 0. Dp ferrite plus martensite steels are produced by controlled cooling from the austenite phase in hotrolled products or from the twophase ferrite plus austenite phase. Dual phase steels microstructure 7585 vol% ferrite remainder mixture of martensite, lower bainite, retained austenite usually consists of more than 2 phases essentially just a low carbon steel thermomechanically processed for better formability than ferritepearlite steels of similar tensile strength.
Fastheating annealing method provides a new possibility to produce high performance dualphase dp steel by controlling austenite decomposition upon. Attention focuses on the production of coldrolled dualphase steel strip and its stepwise introduction at oao novolipetskii metallurgicheskii kombinat. Pdf microstructures and mechanical properties of dual phase. Automotive ahss market size, share, growth analysis and. Dual phase steel tubes can be produced by a variety of methods.
Dec 15, 2017 dual phase stainless steel, which more commonly known as duplex stainless steel, can satisfy many requirements economically. Advances in microstructureoriented processing and micromechanically guided design dual phase dp steel is the flagship of advanced highstrength. In the present study, comparisons between dual phase steel tubes produced directly from a dual phase steel sheet and tubes produced. This is why usage of ahss grades is growing in the automotive industry, and dual phase dp steels are leading the way. Dual phase steels processing, microstructureproperties. Also, while the method of dual phase steel production had no significant effect on the forming limit diagrams, the heattreated dual phase steels in this study exhibited poorer shearededge stretchability, bendability, and stretch bendability than ashotrolled dual phase steels. Recently, dual phase steel sheet production has been carried out with a thermomechanical treatment during the rolling operations.
The final microstructure consists of ferrite and martensite. In order to achieve a desired dual phase steel microstructure an optimal cooling strategy has to be found. Mechanical properties of dualphase steels semantic scholar. Duplex stainless steels have a two phase microstructure. It continuously expands its product range with new steel grades such as cold forming and deep drawing, structural and pipe steels and high carbon steels as well as dual phase, ferrobainitic steels and other advanced steel grades. Hotrolled dualphase steels dpw are particularly suitable for weightsaving production of wheels, chassis parts, profiles, body reinforcements, etc. Dual phase steels can be drawn on conventional tools, provided the settings are properly adjusted. For example, drawing pressure may be increased by approximately 20% for a dual phase 600, compared to a microalloyed hsla type steel of the same thickness. Steel is an alloy of iron and carbon and, sometimes, other elements such as chromium. Dual phase dp sheet steels have recently been used for automotive manufacturing to reduce vehicle weight and improve fuel economy.
Dp ferrite plus martensite steels are produced by controlled cooling from the austenite phase in hotrolled products or from the twophase ferrite plus austenite phase for continuously annealed coldrolled and hotdip coated products to transform some austenite to ferrite. May 07, 2015 the microstructure of advanced highstrength steels ahss can be tailored to produce specific properties that are engineered for each application. When hot rolled, the rolling temperature and cooling process on the hot strip mill is carefully controlled to produce the ferritemartensite structure from austenite. Dp steels consist of a ferritic matrix containing a hard martensitic second phase in the form of islands. Pdf effect of dual phase steel processing conditions on the. This results in a microstructure consisting of a soft ferrite matrix containing islands of martensite as the. Weldability of a dualphase sheet steel by the gas metal arc. Trip steel is produced by heating the steel into the intercritical temperature range for annealing so that dissolution of cementite.
Compared to conventional steel bottles, weight savings of more than 40% are possible. Coldrolled dualphase steels, steels dpk are suitable for both complex structural parts, e. This steel was elaborated using a 60kg vacuum induction furnace under inert atmosphere. Introduction the microstructure of dual phase steels consists of ferrite and martensite. Because of its high tensile strength and low cost, this material is best used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, and weapons. Microstructures and mechanical properties of dual phase steel produced by laboratory simulated strip casting. Surface carburised aisi 8620 steel with dual phase core. Dp steels are produced from low or medium carbon steels that are quenched from a temperature above a 1 but below a 3 determined from continuous cooling transformation diagram. During production, the steel undergoes a specific heat treatment in a continuous annealing line. General motors recommends the following when repairing or replacing this type of steel during collision repair. Multiphase steels in automotive industry thyssenkrupp steel. The dualphase structure depends on the chemical composition of the steel, and. The developed weathering dual phase steels achieve tensile strengths in the order of 730940 mpa and average total elongation of 1114%.
Attention focuses on the production of coldrolled dual phase steel strip and its stepwise introduction at oao novolipetskii metallurgicheskii kombinat. The production of dual phase steel is similar to that of trip steel except that the steel is alloyed and cooled from the intercritical temperature range in such a way as to avoid the formation of bainite. Proceedings volume dp steel proceedings of the 2nd international symposium on steel science isss 2009 oct. Dual phase steels offer higher strength without reduced formability when compared to conventional high strength low alloy hsla steels and so thinner gauge dp sheet steel can be used to meet the same design requirements. The global high strength steel market size was valued at usd 15. Heat treatment involves heating the steel to intercritical temperature range to obtain ferrite and austenite followed by quenching to get ferrite martensite dual phase. The required microstructure is obtained in this case with a fine tuning of the process parameters, through a processdesign activity and a subsequent engineering phase. The influence of annealing on the strength of the dual phase steel is assessed. Pdf design of process parameters for dual phase steel. The influence of annealing on the strength of the dualphase steel is assessed. Dual phase steel are lowcarbon microalloyed steels, characterized by a ferritic multiphase structure bainite and residual austenite in which martensite is dispersed. The dual phase structure depends on the chemical composition of the steel, and. The microstructure is a mix of austenitic and ferritic stainless steel.
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