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Vol.48, No.1, 39 ~ 49, 2010
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| Title |
| Effects of Tempering Temperature and Heat-Treatment Path on the Microstructural and Mechanical Properties of ASTM Gr.92 Steel |
| 김연근 Yeon Keun Kim , 한창희 Chang Hee Han , 백종혁 Jong Hyuk Baek , 김성호 Sung Ho Kim , 이찬복 Chan Bock Lee , 홍순익 Sun Ig Hong |
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| Abstract |
| In order to investigate the effects of tempering temperature and heat-treatment path on the microstructural and mechanical properties of ASTM Gr.92 steels, foul samples with different tempering temperatures and heat-treatment paths were prepared. Three experimental steels showed tempered martensitic microstructures. but the sample tempered at 8l0℃ was presumed to retain partially untempered martensitic microstructures due to a lower α+γ phase regime. M23C6. V(C,N), and Nb(C.N) precipitates were observed in all samples. In addition, Cr2N was observed to be precipitated finely and uniformly by isothermal heat-treatment. The lath width and precipitate size increased with an increase of the tempering temperature. In particular, the lath width and precipitate size in the isothermal heat-treated samples were much smaller than those of the tempered-only specimens. Because of a fine and uniform precipitate, a reduction of lath width would enhance precipitation hardening, and it was shown that mechanical propertiesincluding the hardness and tensile properties of the steels were improved by isothermal heat-treatment. |
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| Key Words |
| sodium-cooled, fast reactor, SFR, fuel cladding, ferritic/matensitic steel, heat-treatment, microstructures, tensile properties |
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