时效温度对890MPa级含铜钢组织与性能的影响

根据纳米析出强化机制，设计了一种屈服强度为890MPa的超高强海洋工程用钢——NEU890钢.在相同固溶条件下，研究了时效温度对NEU890钢显微组织、室温拉伸性能、-40℃ Charpy冲击功的影响.用透射电子显微镜分析纳米级析出相分布，并计算出其强度贡献值.结果表明，固溶态试样屈服强度为852MPa，500℃时效屈服强度达到峰值1026MPa，呈现典型时效析出强化特征.NEU890钢的脆性时效温度区间为300~500℃.当时效温度为550~600℃时，NEU890钢的屈服强度为994~910MPa，-40℃冲击功为108~166J，可满足EQ91钢拉伸和冲击性能指标要求.

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

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.