Abstract: With regard to the whole production process of N08120 nickel-based thick plate， the precipitation law of material in each process was analyzed by using metallographic microscope， scanning electron microscope and Thermo-Calc software. The results indicate that the main precipitation type in N08120 nickel base alloy thick plate is Z phase， accompanied by dispersed MX precipitation phase， which are distributed in strips along the rolling direction. Besides， σ phase， M₂₃C₆ precipitation and transition state from MX to Z phase are also found in ingots and forging billets during production. The analysis reveals that during the mould casting process， the internal heat dissipation of the ingot is slow， which is beneficial to the transformation of NbN to Z phase， and the ingot surface is found to have σ phase precipitation during the die cooling process when it stays at medium and low temperature for a long time. The forging billet and rolling plate are air-cooled after deformation， the main precipitation phase types are Z phase and MX phase. After solution treatment， the species and distribution of precipitated phases in plate have not changed obviously， indicating that Z phase and MX phase have rapid precipitation rate and high thermal stability.

Key words: N08120 Nickel-based Alloy, Hot-rolled Thick Plate, Z Phase, Precipitation Law

摘要： 针对N08120镍基合金厚板的生产全流程，利用金相显微镜、扫描电镜和Thermo-Calc软件，分析了各工序材料内部析出规律，结果表明：N08120镍基合金厚板中的主要析出类型为Z相，且伴有弥散的MX型析出相，二者沿轧制方向呈条带状分布。除此之外，在生产过程中，钢锭和锻坯中还分别发现有σ相和M₂₃C₆的析出，以及MX向Z相的过渡态。分析可知，模铸过程钢锭内部散热慢，有利于NbN向Z相的转变，钢锭表面在模冷过程中长期在中低温停留，发现有σ相析出。而锻坯和钢板变形后均为空冷，主要析出相类型为Z相和MX相。在固溶热处理后，钢板内析出相种类和分布未发生明显变化，表明Z相和MX相析出速率快，热稳定性高。

关键词: N08120镍基合金, 热轧厚板, Z相, 析出规律