【作者】 蒋波； 董正强； 周乐育； 张朝磊； 刘雅政；

【Author】 Jiang Bo;Dong Zhengqiang;Zhou Leyu;Zhang Chaolei;Liu Yazheng;School of Materials Science and Engineering, University of Science and Technology Beijing;

【机构】 北京科技大学材料科学与工程学院；

【摘要】 本文利用冲击实验、硬度测试实验、FESEM扫描电镜以及TEM透射电镜,研究了回火温度和合金元素Ni对新开发的盾构机轴承套圈用钢调质后组织和性能的影响。研究结果表明,淬火温度不变,回火温度从500℃升高到650℃,冲击韧性逐渐升高,断口由准解理形貌向韧窝形貌过渡,回火硬度逐渐降低,回火温度为650℃时,冲击韧性最高为107.2J,回火硬度最低为272.3HB。回火过程中,随着回火温度的升高,回火索氏体中碳化物逐渐由马氏体板条界和马氏体束边界的连续条状碳化物加马氏体内针状碳化物,向短棒状碳化物过渡;同时板条马氏体逐渐发生回复和再结晶,转变为等轴状α相。低温回火条件下,组织中的连续的条状碳化物对材料的冲击韧性十分不利。新开发的实验钢,由于C元素和Ni元素的加入,在一定程度上抑制了回火过程中铁素体的回复与再结晶,对冲击韧性不利,但Ni元素的加入大大促进了碳化物的弥散细小分布,有利于冲击韧性的提高。更多还原

【Abstract】 The effect of tempering temperature and alloying element Ni on the microstructures and properties of the newly designed quenched and tempered steel for bearing ring for Tunneling Boring Machine was analyzed by using toughness test, Brinell hardness test, field emission scanning electron microscope(FESEM) and transmission electron microscope(TEM). Results show that the toughness increases, the hardness decreases and the fracture surface changes from quasi-cleavage to dimple with the tempering temperature from 500 to 650 oC. When the tempering temperature is 650 oC, the toughness and the hardness are 107.2 J and 272.3 HB, respectively. Accompanying with the increase of tempering temperature, the carbides in the tempered microstructure gradually changes from the continuous banded carbide distributed along the boundary of martensite lath and block and the acicular carbide in the martensite lath to the short-rod like carbide. At the same time, the recovery and recrystallization of martensite lath occur and thus the equiaxed ferrite is formed. The continuous banded carbide is detrimental to the toughness of steel when the tempering temperature is relatively low. To some content, the recovery and recrystallization of martensite are suppressed by addition of C and Ni in the newly developed steel, which is disadvantageous to the toughness. However, the addition of Ni can largely promote the dispersedly distribution of carbide and improve the toughness.更多还原