Li Bo, Luo Ming, Yang Zhanbing, Yang Feifei, Liu Huasong, Tang Haiyan, Zhang Zhonghua, Zhang Jiaquan
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Tube & Pipe Department, Baosteel Research Institute, Baoshan Iron & Steel Co., Ltd., Shanghai 201900, China.
Materials (Basel). 2019 Oct 11;12(20):3310. doi: 10.3390/ma12203310.
C110 oil well casing tubes should have high strength and corrosion resistance which is commonly used for deep wells operation containing corrosive media. In this paper, the microstructure evolution of a kind of semi-macro segregation originated banded structure in casing tubes is studied under different heat treatments. It is shown that the characteristics of the banded structure will change significantly in subsequent hot working and heat treatment processes. For the hot-rolled ones, the banded structure is composed of pearlite plus bainite. After quenching, it evolves into martensite band with high concentration solute elements. Finally, the banded structure will change into a carbide banding under the following tempering process. The temperature and cooling rate of the tempering practice show an obvious effect on the final band structure. To improve anti-SSC (sulfide stress corrosion cracking) performance, the favorable QT (quenching and tempering) practice for C110 steel should be a higher tempering temperature and a quicker cooling rate, from which the banded structure defects can be decreased together with an obvious improvement of the tube wall hardness uniformity.
C110油井套管应具有高强度和耐腐蚀性，常用于含有腐蚀性介质的深井作业。本文研究了套管中一种半宏观偏析起源的带状组织在不同热处理条件下的微观组织演变。结果表明，带状组织的特征在随后的热加工和热处理过程中会发生显著变化。对于热轧管材，带状组织由珠光体加贝氏体组成。淬火后，它演变成溶质元素浓度高的马氏体带。最后，在随后的回火过程中，带状组织将转变为碳化物带状组织。回火工艺的温度和冷却速度对最终的带状组织有明显影响。为提高抗硫化物应力腐蚀开裂（SSC）性能，C110钢合适的调质（淬火和回火）工艺应为较高的回火温度和较快的冷却速度，由此可减少带状组织缺陷，同时显著提高管壁硬度均匀性。
