High strength low-carbon alloyed steel with good ductility by combining the retained austenite and nano-sized precipitates
High strength low-carbon alloyed steel with good ductility by combining the retained austenite and nano-sized precipitates
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DOI：
10.1016/j.msea.2013.06.022
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发表时间：
2013-12
期刊：
影响因子：
6.4
通讯作者：
Wenhao Zhou;Hui Guo;Z. Xie;Xuemin Wang;C. Shang
中科院分区：
文献类型：
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作者：
Wenhao Zhou;Hui Guo;Z. Xie;Xuemin Wang;C. Shang
开发了一种用于厚板的含铜铌微合金化贝氏体钢，具有高屈服强度（>700 MPa）、良好的延伸率（>35%）和低温韧性。采用相间退火加回火（L-T）热处理，将逆相变与回火阶段的析出相结合。退火过程中合金元素的富集导致Ac1温度下降，使得随后的回火过程中同时发生逆相变和析出。 Mn和Ni的二次富集使得反转奥氏体足够稳定，可以在室温下保留。 L-T 工艺引入约 29% 的残余奥氏体，通过 TRIP 效应实现了超过 10% 的优异延伸率。退火和冷却阶段Nb(C,N)和(Nb,Mo)C析出物的形成抑制了位错的恢复，而更多小于10 nm的Nb析出物和尺寸为20 nm的Cu析出物对基体起到显着的强化作用。残余奥氏体和纳米双相析出相的共同作用显着提高了屈服强度、塑性和韧性。
A Cu-bearing Nb-microalloyed bainitic steel with high yield strength (>700 MPa), good elongation (>35%) and low temperature toughness was developed for heavy plates. An intercritical annealing plus tempering (L–T) heat treatment was applied for combining reversed transformation with the precipitation during the tempering stage. The enrichment of alloying elements during the annealing process leads to the drop ofAc1temperature, which makes the reversed transformation and precipitation occur simultaneously in the subsequent tempering process. The secondary enrichment of Mn and Ni makes the reversed austenite stable enough to be retained at room temperature. About 29% retained austenite introduced by the L–T process contributes to excellent elongation more than 10% by the TRIP effect. The formation of Nb(C,N) and (Nb, Mo)C precipitates during the annealing and cooling stages inhibits the recovery of dislocations, while more Nb precipitates smaller than 10 nm and Cu precipitates with sizes of 20 nm play significant strengthening role on the matrix. The combination effects of retained austenite and nano-sized dual-precipitate increased yield strength, ductility and toughness remarkably.