Meliegy, Maha; Bitar, Taher; Tabakova, Bozhana; El-Meliegy, Maha; El-Bitar, Taher; Мелиеги, Маха; Ел-Мелиеги, Маха; Битар, Тахер; Ел-Битар, Тахер; Табакова, Божана; Лолов, Н. рец.
Numerical model detecting the effect of inter-pass time on grain size for Nb-microalloyed stell.
Числен модел за установяване на влиянието на времето между отделните преходи върху размера на зърното на микролегирани с ниобий стомани
2005
PROCEEDINGS OF THE TECHNICAL UNIVERSITY - SOFIA, 55, 2005 - Anniversary “Sixty Years Technical University - Sofia”, pp. 305-316
TU - Sofia
0374-432Х [issn]
Article
eng
стомани, микролегирани - производство - математическо моделиране; steel, microalloyed - conducting - mathematical modeling
An analysis was conducted on pass by pass to evaluate the austenite grain size
during hot strip rolling of Nb microalloyed steel. This is achieved by using the available mill log data and the previously developed equations relating the rolling parameters to the grain size. The model calculates the total strain. Recrystallization and precipitation times are computed for the corresponding conditions of strain, temperature, initial grain size, strain rate and chemical composition. The inter-pass time is compared with the recrystallization time to detect the partial recrystallization occurred due to either short inter-pass time or precipitation starting. The strain, strain rate and Zener-Hollomon parameter is used in the model to detect weather static or dynamic recrystallization is initiated. The data of industrial X52 API steel trial with160 ton is used to verify the results
of the numerical model. The heat is processed by the compact slab process. Grain size of strips is compared with that detected by model. The grain size results of the model compare well with actual measured grain size. However cooling after rolling has a pronounced effect on the measured grain size. The model calculates the effect of decreasing the inter-pass time on raising the transition temperature from completely dynamic recrystallization to partially recrystallization which would have a good impact on the grain size.
Reviewer prof. N. Lolov. - Incl. graphics and ill. - References, pp. 315-316