Abstract
This paper presents a study of the effect of varying the roll gap of oval pass in round-oval-round pass sequence on the interfacial slip of workpiece, entrance and exit velocities, stresses and roll load that the workpiece experiences during rolling, by applying analytical method, finite element simulation and verification through hot bar rolling tests. The results have shown that the roll gap variation of oval pass affects the interfacial slip of workpiece along the groove contact and the specific roll pressure. The optimum conditions in terms of minimum interfacial slip and minimum specific roll pressure, which might influence the maximum groove life, is obtained when the subsequent round pass is completely filled.
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Abbreviations
- a r :
-
Torque arm ratio
- A e :
-
Profile cross sectional area
- A s :
-
Projected area of roll contact
- 2b :
-
Profile central width
- b s :
-
Width of contact at exit
- c :
-
Slip coefficient
- e :
-
Centroid height of half exit sectional area
- 2g :
-
Oval pass roll gap
- 2h :
-
Profile central height
- h s :
-
Height of contact at exit
- L :
-
Length of roll contact
- m :
-
Friction factor
- q :
-
Stress coefficient
- p :
-
Surface pressure
- p s :
-
Specific roll pressure
- P :
-
Roll load
- r g :
-
Groove radius
- r n :
-
Neutral roll radius
- r s :
-
Profile side radius
- 2r c :
-
Rolls center distance
- 2r i :
-
Roll inner diameter
- 2r o :
-
Roll outer diameter
- s i :
-
Slip at roll inner diameter
- T :
-
Rolling torque
- v e :
-
Workpiece exit velocity
- \(\bar \varepsilon \) :
-
effective strain
- v i :
-
Workpiece velocity at inner roll radius
- v o :
-
Workpiece entry velocity
- \(\dot \bar \varepsilon \) :
-
Effective strain rate
- \(\bar \sigma \) :
-
Flow stress
- ω:
-
Roll angular velocity
- μ:
-
Coefficient of friction
- σ θ :
-
Tangential stress
- τ:
-
Shear traction
References
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Bayoumi, L.S., Lee, Y. & Kim, H.J. Effect of roll gap change of oval pass on interfacial slip of workpiece and roll pressure in round-oval-round pass rolling sequence. KSME International Journal 16, 492–500 (2002). https://doi.org/10.1007/BF03185079
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DOI: https://doi.org/10.1007/BF03185079