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采用Thermo-Calc热力学软件,对转K2弹簧钢在400～1600℃存在的平衡析出相及Nb、V在奥氏体相中的固溶规律进行了计算,探讨了各合金元素含量对析出相析出规律的影响,并利用碳萃取复型与透射电镜(TEM)分析了Nb含量对析出相的影响.结果表明:转K2弹簧钢中平衡析出相主要为MX、M7C3、M3C2和AlN;Nb能显著提高MX相的稳定性.TEM分析表明,析出相尺寸变化范围为几纳米到100纳米以上,形态多呈近似球形或圆片状;随Nb含量增加,从低温铁素体中析出的细小颗粒所占比例显著增大,未溶解碳氮化物比例也有所增大,总体而言析出相平均颗粒尺寸得到细化;大颗粒析出相为富Nb的碳化物,而小颗粒为富V的碳化物,这与热力学计算结果相一致.
With Thermo-Calc thermodynamic software, the equilibrium precipitation phases of Nb spring steel at 400-1600 ℃ and the solution rules of Nb and V in the austenite phase were calculated. The effects of the content of alloying elements on the precipitation of precipitation phase The effects of Nb content on the precipitated phases were analyzed by carbon extraction and transmission electron microscopy (TEM). The results show that the equilibrium precipitates are mainly MX, M7C3, M3C2 and AlN, Improve the stability of the MX phase.The TEM analysis shows that the size of precipitation phase range from a few nanometers to 100 nanometers or more, the shape of almost spherical or disc-shaped; with increasing Nb content, precipitated from the low-temperature ferrite small particles The proportion of undissolved carbonitrides also increased, and the average particle size of precipitated phase was refined in general. The precipitates of large particles were Nb-rich carbides, while the small particles were V-rich carbides. This is consistent with the thermodynamic calculations.