Investigation of thermomechanical behavior of a work roll and of roll life in hot strip rolling

Sun, C. G.; Hwang, Soonkyu; Yun, Chan-Su; Chung, Julianne

doi:10.1007/s11661-998-0117-y

Cited by 56 publications

(65 citation statements)

References 28 publications

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“…The detailed finite element formulation may be seen in the references. 9,10) The flow stress s of the strip within two phases of austenite and martensite may be represented by the mixed rule 4,5) : Where C g1 -C g5 , and C aЈ1 -C aЈ5 , taken from the references, 4,5) were described in Table 2.…”

Section: Fe Model For Analysis Of Rigid-viscoplastic Deformationmentioning

confidence: 99%

“…Among them, finite element (FE) model was especially successful with regard to revealing the most detailed aspects of the metal flow characteristics and thermal behaviors in rolling process. [6][7][8][9][10] However, the related works were mostly limited to examining the mechanical/thermo-mechanical behaviors of low carbon steel or Al occurring at a single mill stand. In the sense of thermo-mechanical/metallurgical behavior of austenite stainless steel, recently, Ding et al 11) well applied the finite volume method to simulate the forging process by considering the aforementioned strain induced martensite transformation, however, very few studies have been undertaken on the application in the cold rolling process.…”

Section: Introductionmentioning

confidence: 99%

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Finite Element Modeling of Thermo-mechanical and Metallurgical Behavior of Type 304 Stainless Steel in Cold Strip Rolling

Sun

Lee

et al. 2003

ISIJ International

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A finite element-based, integrated process model is presented for the coupled analysis of the thermo-mechanical and metallurgical behavior of type 304 stainless steel occurring in the entire tandem mill during cold strip rolling. The validity of the proposed model is examined through comparison with measurements. The model's capability of revealing the effect of diverse process parameters is demonstrated through a series of process simulation.KEY WORDS: Type 304 stainless steel; finite element method; thermo-mechanical behavior; metallurgical behavior; cold strip rolling. model 5) was adopted for the prediction of the evolution of the martensite during cold rolling.Under constant temperature, strain rate and stress state, volume fraction of martensite may be described as: Where the kinetic parameter a 0 and b, strong function of temperatures, were determined from the experimental observation, which were shown in Figs. 1(a) and 1(b), respectively. n, ė y , and M, taken from the references, 4,5) are described in Table 1. The predicted fraction of martensite evolution was in good agreement with the measurements, as shown in Fig. 2..Considering that the aforementioned martensite is mainly generated under the condition of the deformation in the rolling process, the fraction of martensite evolution can be determined based on the strain and temperature fields, as follows:........... (3) Where, d f m /de may be determined from Eq. (1). FE Model for Analysis of Rigid-viscoplastic DeformationA steady-state, rigid-viscoplastic deformation behavior of the strip was adopted in the present investigation. The detailed finite element formulation may be seen in the references. 9,10) The flow stress s of the strip within two phases of austenite and martensite may be represented by the mixed rule 4,5) : Where C g1 -C g5 , and C aЈ1 -C aЈ5 , taken from the references, 4,5) were described in Table 2.Assume that the strain rate may be decomposed into the Vol. 43 (2003) .(9)Parameters R and Dh, taken from the references, 4,5) may be found in Table 1. With respect to the high process speed in the tandem cold rolling process, ė trans and ė v may be neglected when comparing to ė p , which was verified from the comparison of mean values among these three components by FEM analysis. We found that plastic strain rate ė p (ϭ32.8 (1/s)) was extremely much larger than the summation of the other two components ė trans and ė v (ϭ1.04 (1/s)). FE Model for Analysis of Heat Transfer in the Strip and in the RollThe governing equation for steady state heat transfer in the strip as well as that in the roll is given by (10) where r is the density; u i represent the components of the velocity vector and Q represents the heat dissipated by plastic deformation. Note that Qϭse¯in the strip and Qϭ0 in the roll, when the roll deformation is purely elastic. Q l represents the latent heat discharged during phase transformation according to the references, 4 Where, f˙m, the rate of the fraction of martesite, was determined by finite difference method.In t...

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Section: Fe Model For Analysis Of Rigid-viscoplastic Deformationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finite Element Modeling of Thermo-mechanical and Metallurgical Behavior of Type 304 Stainless Steel in Cold Strip Rolling

Sun

Lee

et al. 2003

ISIJ International

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“…Details regarding Model A, Model B, and Model C may be found in the reference. 7) Interaction among the thermal and mechanical behavior of the strip and the thermal behavior of the work roll may be summarized as follows: the heat transfer and plastic deformation occurring in the strip affect each other, since the flow stress is temperature-dependent while plastic deformation generates heat; and the thermal behavior of the strip is coupled to that of the work roll due to roll-strip contact. In the present investigation, the interaction was taken into account by adopting an iterative solution scheme, as shown in Fig.…”

Section: Integrated Fe Model For the Analysis Of The Rollstrip Systemmentioning

confidence: 99%

“…As a result, most of the modeling efforts were concentrated either on revealing the metal flow characteristics only [1][2][3][4] or on revealing the two dimensional thermomechanical behaviors of the roll-strip system at a single mill stand. [5][6][7] Recently, some researchers were focused on the three dimensional aspect of the problem, but the related works [8][9][10][11] were mostly limited to examining the thermomechanical behaviors occurring at a single mill stand.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Three Dimensional Strip Temperatures through the Entire Finishing Mill in Hot Strip Rolling by Finite Element Method.

2002

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A finite element-based approach is presented for the prediction of the thermal behavior of the strip occurring in the finishing mill during hot strip rolling. The approach, which is fully coupled and three dimensional, is described in detail. The validity of the proposed approach is examined through comparison with measurements. Then the capability of the approach to predict the detailed aspects of the thermal behavior is demonstrated through an application to revealing the effect of an edge heater.KEY WORDS: hot strip rolling; finite element method; thermal behavior; three-dimensional; edge heater.

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“…It is demonstrated during the last two decades that the thermo-mechanical behavior can be made far more accurately predicted on the basis of the finite element (FE) process models [1][2][3][4][5][6][7][8][9][10][11][12] than on the basis of the elementary models which inherently involve many simplifying assumptions. However, a precision process model, such as a FE process model, tends to require a large central processing unit (CPU) time, rendering itself inadequate for on-line calculation.…”

Section: Introductionmentioning

confidence: 99%

Dimensional Analysis of Hot Strip Rolling for On-line Prediction of Thermo-mechanical Behavior of Roll-Strip System

et al. 2005

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General, dimensionless expressions are derived for the parameters describing the thermo-mechanical behavior of the roll-strip system, on the basis of the boundary value problem associated with hot strip rolling. Then, it is shown that, by conducting process simulation with an integrated finite element process model, the dimensionless expressions may be transformed into various on-line models which may be applied to precision process set-up and control. The validity of the proposed approach is examined through comparison with predictions from finite element process simulation.KEY WORDS: finite element method; thermo-mechanical behavior; effective strain; non-dimensional analysis; hot strip rolling. (7) where DTϭT 2 ϪT 1 . Note that V 2 and T 2 may be precisely predicted from the FE process model described previously. It is to be noted that FЈ and PЈ represent the theoretical minimum (or very close to the theoretical minimum) of roll force and roll power, respectively, in the context of the assumed distribution of strip temperatures in the bite zone. Dimensionless Expressions for the Process ParametersLet us consider a 2-D boundary value problem for the analysis of the rigid-plastic deformation of the strip, with the process geometry given in (18) where K, C 1 , C 2 , are constants that possess the same unit as s , T, and ē , respectively. Note that C 1 and C 2 are introduced since s is governed by non-dimensional T and ē , and therefore, their values may be chosen arbitrarily. In the present investigation, C 1 ϭ1°C and C 2 ϭ1 rad/s are assumed.Let us define the average values of the flow stress for the hypothetical mode of rolling, as follows: Selecting xϭCs 0j , where C is a prescribed constant, it follows from Eqs. (17) and (24) that˜˜,˜, Vol. 45 (2005) where N S represents ē, ė /w, s/w, as well as V ĩ /Rw. Now, let us consider the boundary value problem for the analysis of heat transfer in the strip, with the process geometry given in Fig. 2. • energy balance equation: (39) where Ñ s represents all the basic non-dimensional fields, which are, ē, ē˜/w, s, s 0j , and T/T 1 .It may be deduced from Eq. (39) that any, reasonably selected, dimensionless parameters that describe the thermomechanical behavior of the strip should, in general, be influenced by eight independent dimensionless parameters appearing in the right hand side of Eq. (39). Note that all of them represent design variables (variables to be prescribed by an engineer), except b˜3, since q s is unknown.For the work roll, the boundary value problem associated with the steady-state thermal behavior of the roll may be given, with the definition sketch shown in (42) Assuming a uniform roll cooling system (water is uniformly sprayed on the entire roll surface, except the roll-strip interface), it may be deduced from the boundary value problem that (43), which involves nine variables, may be reduced to a dimensionless form with five independent dimensionless variables, since four independent units (temperature, force, length, and time) are identified ...

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Investigation of thermomechanical behavior of a work roll and of roll life in hot strip rolling

Cited by 56 publications

References 28 publications

Finite Element Modeling of Thermo-mechanical and Metallurgical Behavior of Type 304 Stainless Steel in Cold Strip Rolling

Finite Element Modeling of Thermo-mechanical and Metallurgical Behavior of Type 304 Stainless Steel in Cold Strip Rolling

Prediction of Three Dimensional Strip Temperatures through the Entire Finishing Mill in Hot Strip Rolling by Finite Element Method.

Dimensional Analysis of Hot Strip Rolling for On-line Prediction of Thermo-mechanical Behavior of Roll-Strip System

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