Automated Determination and On-Line Correction of Emissivity Coefficient in Controlled Cooling of Drop Forgings

Skubisz, P.; Micek, Piotr; Sińczak, J.; Tumidajewicz, M.

doi:10.4028/www.scientific.net/ssp.177.76

Cited by 10 publications

(6 citation statements)

References 17 publications

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“…In forging tests, conducted on a hydraulic press of capacity 5 MN at working speed 20 mm/s, which for flat billet resulted in strain rate corresponding to its average level observed during soft blows of hammer forging of the part concerned, forged specimens of square cross-section 30×30 mm were deformed with true strain 0,48. After hot deformation the specimens were subject to controlled cooling with accelerated air with and without mist, varying increased cooling rate, realized in a laboratory controlled cooling simulator, an extended version the forced-air based cooling conveyor [15,16]. On the basis of thermocouple measurements cooling curves were plotted.…”

Section: Methodsmentioning

confidence: 99%

Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

Skubisz¹,

Żak²,

Burdek³

et al. 2015

Archives of Metallurgy and Materials

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Effect of plastic processing and controlled cooling on microstructure and mechanical properties of experimental steel grades with microalloyed with Ti, V and/or Nb, varying in the content of Mo is presented as an offer for mining industry for replacement traditionally heat-treatable hardenability grades. The goal of the work is producing microstructure condition, which after controlled hot forging and direct heat treatment, involving quenching and self-tempering, are meant to provide good combination of mechanical properties, such as TYS 800 MPa, UTS 1050 MPa, elongation to fracture at least A5 15% and/or impact strength at room temperature KCV 60 J/cm 2 . Hardenability assessment and dilatometric examination allowed formulation of direct heat treatment guidelines, taking into consideration fields of temperature and strain in a typical hot forging process, estimated numerically, with the use of plastometric tests results, as well as the use of unique cooling cycles after forging.On the basis of numerical analysis of thermomechanical parameters and temperature progression, hot forging and direct cooling conditions were selected to achieve assumed structural components, morphology and dispersion of both grain and precipitates. For established heat transfer model and experimentally plotted cooling curves numerical analysis of direct cooling, enabled by definition of characteristic points of austenite transformation and CCT diagrams was conducted. The modeling aided with dilatometric characterization enabled prediction of transformation products distribution. The formulated conclusions were verified in the experimental sampling of forging, evaluating the applicability of designed combinations of chemical composition and cooling cycle for selected forged part for mining industry.Keywords: microalloyed steel, thermomechanical processing, direct cooling, hammer forging, grain control Przedstawiono badania wpływu warunków odkształcania na gorąco i kontrolowanego chłodzenia na efektywność umocnienia eksperymentalnych stali z mikrododatkami Nb, Ti oraz V o zmiennej zawartości Mo. Pierwszym etapem pracy było zaprojektowanie składów chemicznych stali mikrostopowych, które po kontrolowanym kuciu na gorąco oraz obróbce cieplnej, polegającej na zahartowaniu i samoodpuszczeniu odkuwki bezpośrednio po kuciu, pozwolą na uzyskanie właściwości mechanicznych, tj.: granicy plastyczności 800 MPa, wytrzymałości na rozciąganie 1050 MPa, wydłużeniu A 5 15% i udarności w temperaturze otoczenia KCV 60 J/cm 2 . W oparciu o wyniki badań hartowności i analizę dylatometryczną opracowano wytyczne bezpośredniej obróbki cieplnej, uwzględniając obliczenia równowagi faz i wpływ temperatury na udział wydzieleń w wybranych wytopach oraz wyznaczone numerycznie pola temperatur dla typowego procesu kucia na gorąco, oparte o próby plastometryczne na symulatorze Gleeble 3800, oraz kontrolowane chłodzenie po kuciu.W oparciu numeryczną analizę parametrów termo-mechanicznych i zmian temperatury odkuwki modelowej dobrano warunki procesu kształtowania oraz sch...

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Section: Methodsmentioning

confidence: 99%

Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

Skubisz¹,

Żak²,

Burdek³

et al. 2015

Archives of Metallurgy and Materials

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“…Thermal analysis was based on the determined functions of heat transfer coefficient for given settings of the cooling line (presented in Section 3.2 ). For natural air cooling (transfer and the end of the process) constant value 30 W/m 2 ·K, water temperature 25 °C and temperature-dependent emissivity function based on [ 44 ] were assumed. As in the experiment where a one-sided or symmetrical air inlet could be alternatively used, both symmetrical and asymmetrical cooling conditions were taken into consideration.…”

Section: Models and Assumptionsmentioning

confidence: 99%

Determination of Heat Transfer Coefficient for Air-Atomized Water Spray Cooling and Its Application in Modeling of Thermomechanical Controlled Processing of Die Forgings

2022

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The paper presents the method and results of determination of heat transfer coefficient for air-atomized water spray cooling with consideration of infrastructural factors of industrial cooling conveyor, such as effect of accelerated air. The established values of heat transfer coefficient were implemented into a numerical model of cooling line, with special definition of sprayers and the movement of the part subjected to quenching. After quantitative validation on selected samples, the obtained coefficients were used for the solution of the technological problem by means of localized cooling rate enhancement, which forms a case study confirming reliability of the established water spray heat transfer functions and suitability of the determined models for design of thermomechanical controlled processing of complex-geometry parts.

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“…Having validated the temperature calculations, using pyrometer measurement with on-line correction of emissivity (Skubisz et al, 2011), temperature, effective strain and effective strain rate, were taken from the simulation to carry out mathematical modeling of microstructure development for all of the investigated forging chains. These are: I) impressiondie forging with preforming in cogging operation followed by blocker and finisher impression forging, realized altogether in 11-14 hammer blows, see figure 3 (Skubisz et al, 2015); II) assumption of bend axis, which resulted in preforming in bending operation (figure 4), and III) multiple forging impression forging with use of cogging to reduce flash (figure 5).…”

Section: Geometry and Materials Characteristicsmentioning

confidence: 99%

Effect of forging sequence on evolution of parameters controlling microstructure in multistage drop forging process

Skubisz¹,

Lisiecki²,

Majta³

et al. 2019

cmms

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The study presents the comparative analysis of competitive techniques of forging and analysis of the effect of the forging sequences on microstructure development. Starting with industrial practice of hammer-forged elongate geometry, two competitive processes were numerically analysed in term of forging economy and quality. Numerical modeling of temperature, strain and strain rate fields let theoretical prediction of the microstructure development in multi-stage drop forging process consisting of progressive sequence of multiple blows in preforming and die-impression forging operations. The aim of the modeling was prediction of the parameters of austenite in as-forged condition, which in thermomechanical controlled processing form the restored austenite condition prior to direct cooling. Dynamic recrystallization kinetics was analyzed with use of Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, taking advantage of numerically calculated of temperature, strain and strain-rate in selected location in the volume of the part. The obtained results show the possibility of look-ahead microstructure prediction and form the basis for comprehensive selection of the forging process parameters aimed at producing required microstructure and its uniformity in the bulk in multi-stage hammer-forging process.

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Automated Determination and On-Line Correction of Emissivity Coefficient in Controlled Cooling of Drop Forgings

Cited by 10 publications

References 17 publications

Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

Design of Controlled Processing Conditions for Drop Forgings Made of Microalloy Steel Grades for Mining Industry

Determination of Heat Transfer Coefficient for Air-Atomized Water Spray Cooling and Its Application in Modeling of Thermomechanical Controlled Processing of Die Forgings

Effect of forging sequence on evolution of parameters controlling microstructure in multistage drop forging process

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