Effects of process parameters on fragment and refinement of millimeter- grade coarse grains for 316LN steel during hot cogging
The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement...
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Published in | Journal of iron and steel research, international Vol. 24; no. 5; pp. 529 - 535 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Singapore
Elsevier Ltd
01.05.2017
Springer Singapore |
Subjects | |
Online Access | Get full text |
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Summary: | The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement of millimeter-grade coarse grains (MCGs) during hot cogging. The experimental results in- dicate that the stress of MCG specimens is much larger than that of fine grain (FG) ones at 1150 ℃, while the stress difference between MCG and FG samples became smaller at 1200 ℃. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 ℃, strain rate of 0.01 s-1 , and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of ex- periments and simulations comprehensively demonstrate that the MCG results in the increase of de- formation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 ℃ so that the plastic deformation energy decreases remarkably with the increase of temperature from 1 150 to 1200 ℃. |
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Bibliography: | 316LN steel;Hot deformation;Coarse grain;Microstrueture evolution;Numerical simulation 11-3678/TF The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement of millimeter-grade coarse grains (MCGs) during hot cogging. The experimental results in- dicate that the stress of MCG specimens is much larger than that of fine grain (FG) ones at 1150 ℃, while the stress difference between MCG and FG samples became smaller at 1200 ℃. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 ℃, strain rate of 0.01 s-1 , and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of ex- periments and simulations comprehensively demonstrate that the MCG results in the increase of de- formation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 ℃ so that the plastic deformation energy decreases remarkably with the increase of temperature from 1 150 to 1200 ℃. |
ISSN: | 1006-706X 2210-3988 |
DOI: | 10.1016/S1006-706X(17)30080-8 |