| Autor: |
Amuda, M. O. H., Akinlabi, E. T., Mridha, S. |
| Předmět: |
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| Zdroj: |
Usak University Journal of Material Science; Dec2015, Vol. 4 Issue 2, p13-27, 15p |
| Abstrakt: |
A major challenge limiting the widespread application of ferritic stainless steel is the loss of ductility in the fusion welded grade owing to grain coarsening in and around the weld section. It is identified that refined grain structure in welds can guarantee improved ductility in such welds. This is facilitated by ensuring low net heat input and faster heat dissipation in the welds; and this may be achieved by controlling the proportion of the arc heat input that is actually delivered to the workpiece or enhancing the solidification process by artificially agitating the weld pool. Addition of elemental powder ex-situ and the weld cryogenic cooling offer means for controlling net heat input and generating faster rate of cooling from the grain coarsening temperature. In the present work, grain refinement was attempted in medium chromium ferritic stainless steel weld via ex-situ elemental powder addition and cryogenic cooling. It emerged that grain refinement averaged 40% with cryogenic cooling, 35% and 55% with aluminum and titanium powders, respectively. The refinement from cryogenic cooling is due to the steep thermal gradient provided by the cooling liquid while ex-situ elemental powders provide sites for heterogeneous nucleation of equiaxed grains leading to higher micro hardness value which is indicative of greater resistance to flow stress and a measure of strength. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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