Journal of Northeastern University Natural Science ›› 2020, Vol. 41 ›› Issue (4): 499-504.DOI: 10.12068/j.issn.1005-3026.2020.04.008

• Materials & Metallurgy • Previous Articles     Next Articles

Effect of Aging Temperatures on Microstructure and Mechanical Properties of 890MPa Grade Copper-Bearing Steel

KAN Li-ye, YE Qi-bin, WANG Yi-min, WANG Zhao-dong   

  1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China.
  • Received:2019-05-25 Revised:2019-05-25 Online:2020-04-15 Published:2020-04-17
  • Contact: YE Qi-bin
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Abstract: According to nano-precipitates strengthening mechanism, an ultra-high strength steel for marine engineering(NEU890) was designed with yield strength of 890MPa. Under the same solid solution conditions, the effects of aging temperature on microstructure, tensile property at room temperature and Charpy impact at -40℃ were studied. The distribution of nano-sized precipitates was analyzed by transmission electron microscopy and the strengthening contribution was estimated. The results showed that the yield strength of the solid solution sample is 852MPa, and the aging yield strength at 500℃ can reach the peak value of 1026MPa, which is achieved by a typical aging precipitation strengthening. The brittle aging temperature range of NEU890 steel is 300~500℃. When the aging temperature is 550~600℃, the yield strength becomes 994~910MPa and the impact energy at -40℃ is 108~166J, which can meet the tensile and impact requirements of EQ91 steel.

Key words: aging temperature, nano-precipitates strengthening, ultra-high strength steel for marine engineering, EQ91, 890MPa grade

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