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Abstract: Considering roll elastic flattening, new equations were proposed to calculate the average strain s and average strain rate ... in the hot strip rolling process. By comparing the proposed equations with currently used equations, it was observed that the strain rate of thick strip and strain are not sensitive to roll elastic flattening. However, for thin strip, a noticeable calculated difference in the strain rate occurred when roll elastic flattening was considered.
Key words: hot strip rolling; roll elastic flattening ; strain ; strain rate
doi: 10.3969/j.issn.1674-3458.2015.02.002
1 Introduction
In the hot-rolling process, the strain s and strain rate s are the key parameters needed to calculate the metal deformation resistance and rolling force and directly affect strain hardening and recrystallization. These parameters can also affect the rolled texture,final property,and workability of some metals. Therefore, precise calculation of s and e is very important for the hot-rolling process.
In the hot strip rolling deformation zone,¿r and £ are variable. Their average values are usually used in the correlation calculation. Currently, there are several frequently used equations for calculating £ and ¿F,as listed belowL1'2] :
where, f is the length of the rolling deformation zone, H is the entry thickness of the strip, and hx is the thickness of the strip in the rolling deformation zone. Eq. ( 1 ) is the accurate equation for calculating e . The result of the integration in Eq. ( 1 ) is equal to the rolled area AS/primary area S, as shown in Fig. 1 :
where,v, is the exit velocity of the strip and Ah is the rolling reduction. Eq. (2) is the accurate equation for calculating s. Eqs. (3) and(4) are the approximate equations for calculating e...