The toughening mechanisms of microstructural variation and Ni addition in direct-cooled microalloyed ferrite-pearlite steels
The toughening mechanisms of microstructural variation and Ni addition in direct-cooled microalloyed ferrite-pearlite steels
复制标题
直冷微合金化铁素体-珠光体钢显微组织变化和Ni添加的增韧机制
DOI：
10.1016/j.msea.2018.10.001
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发表时间：
2018-12
期刊：
影响因子：
6.4
通讯作者：
Ya Zheng Liu
中科院分区：
文献类型：
--
作者：
Meng Wu;Fan Zhao;Ju Long Che;Bo Jiang;Chao Lei Zhang;Ya Zheng Liu
用U型缺口Charpy试验研究了两种直接冷却微合金化铁素体-珠光体钢的组织变化和添加Ni的增韧机理。结果表明，当原始奥氏体晶粒度从10 µm增大到37 µm时，低镍钢的冲击韧性从110 J急剧下降到20 J，当原始奥氏体晶粒度从37 µm增大到90 µm时，冲击韧性基本保持不变，当原始奥氏体晶粒度小于37 µm时，解理断裂明显延缓，塑性断裂面积显著增大，塑性变形能力显著提高。当原始奥氏体晶粒粗大时，解理断裂所消耗的能量符合Griffith方程，与韧性断裂所消耗的能量相比，解理断裂所消耗的能量较小，冲击韧性较低。铁素体含量和珠光体片层间距对冲击韧性的累积影响不明显，因为随着冷却速度的提高，两者的影响是相互矛盾的。当奥氏体晶粒度超过约37 µm时，高镍钢的冲击韧性比低镍钢稳定提高约20 J，高镍钢的位错迁移率增加，延性断口面积增大，冲击韧性提高。微合金化铁素体-珠光体钢通过优化锻造和冷却工艺，很难将原奥氏体晶粒度细化到37 µm以下。但少量的Ni加入量有利于提高冲击韧性，且不会显著增加成本。
The toughening mechanisms of microstructural variation and Ni addition were investigated in two direct-cooled microalloyed ferrite-pearlite steels by using the U-notched Charpy tests. Results show that the impact toughness of the low Ni steel decreases dramatically from 110 J to 20 J when the prior austenite grain size increases from 10 µm to 37 µm, and then stays unchanged as the prior austenite grain size continues increasing from 37 µm to 90 µm. When the prior austenite grains are finer than 37 µm, the cleavage fracture is much postponed and the area of ductile fracture is much enlarged by the significantly improved ability to perform plastic deformation. When the prior austenite grains are coarse, the energy absorbed by cleavage, which is the main mode of fracture, conforms to the Griffith type equation and is much less compared to that consumed by ductile fracture, leading to the low impact toughness. The cumulative effect of ferrite content and pearlite interlamellar spacing on impact toughness is not obvious, because their influences are contradictory as the cooling rate is raised. There is a steady enhancement of about 20 J in impact toughness of the high Ni steel compared to the low Ni steel, when the austenite grain size exceeds about 37 µm. The area of ductile fracture is enlarged by the increased dislocation mobility in high Ni steel, resulting in the improvement of impact toughness. It is difficult to refine the prior austenite grain size to less than 37 µm of microalloyed ferrite-pearlite steels through optimizing forging and cooling process. However, small amount of Ni addition is beneficial to the impact toughness and does not increase the cost significantly.
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DOI：
10.1179/msc.1967.1.1.56
发表时间：
1967-01
期刊：
Metal Science Journal
影响因子：
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作者：
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通讯作者：
E. Smith;J. Barnby
DOI：
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发表时间：
2003-10
影响因子：
6.4
作者：
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通讯作者：
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DOI：
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发表时间：
1976-01-01
期刊：
METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
影响因子：
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作者：
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通讯作者：
BERNSTEIN, IM
DOI：
10.1016/j.msea.2007.08.079
发表时间：
2008-07
影响因子：
6.4
作者：
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通讯作者：
B. Strnadel;P. Haušild
DOI：
10.1016/j.jmatprotec.2005.10.028
发表时间：
2006-03-30
影响因子：
6.3
作者：
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通讯作者：
Liu, C