| Title |
Effect of Cooling Rate on the Microstructure and Mechanical Properties of Fe-Mn-Al-C Light-Weight Steels |
| Authors |
박준영(Jun Young Park); 박성준(Seong-jun Park); 이재현(Jae-hyun Lee); 문준오(Joonoh Moon); 이태호(Tae-ho Lee); 정경재(Kyeong Jae Jeong); 한흥남(Heung Nam Han); 신종호(Jong-ho Shin) |
| DOI |
https://doi.org/10.3365/KJMM.2017.55.12.825 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
light-weight steel; microstructure; cooling rate; κ-carbide; β-Mn |
| Abstract |
The effects of cooling after solution heat treatment on the microstructure and mechanical properties of light-weight steels were investigated using Fe-30Mn-xAl-0.9C alloys containing 9.0-12.8 wt% Al. Lab-scale specimens (thickness: 10 mm) of the alloys were cooled by different cooling rates from -337 to -0.053 ℃/s using water, air, and furnace cooling. As the cooling rate decreased, hardness of the alloys increased due to precipitation of κ-carbides. However, reduction of the cooling rate induced the growth of intergranular κ-carbides. This resulted in the decrease of impact absorbed energy of the alloys at room temperature, and exhibited intergranular brittle fracture behavior. The 12.8 wt% Al alloy cooled at the slowest cooling rate in particular showed the formation of β-Mn. To estimate the cooling rates of large-scale slabs of light-weight steels, finite element simulations were conducted. The cooling rates at the center of the slab under air and water cooling (free convection) were calculated to be -0.049 and -0.15 ℃/s, respectively. The results indicated that water cooling could prevent the excessive formation of κ-carbides/β-Mn during fabrication of large-scale slabs of alloys containing an Al content lower than 10.5 wt%.(Received September 1, 2017; Accepted September 20, 2017) |