Abstract: Test alloy Ni30Cr20 (/% : 0.035 〜0.045C, 0.28 ~0. 30Si, 0. 73 〜0. 75Mn, 0. 005 ~0. 007P, 0. 001 ~ 0. 002S, 19.40~ 19. 93Cr, 29. 75 ~30.35Ni, 0. 30 〜0. 36A1, 0. 03 〜0. 88Ti, 0.005 7 ~0,0205N) is melted by 150kg vacuum induction furnace to cast ingot with size (mm) 120 x230 x500. The calculation on thermodynamics conditions of TiN precipitation in alloy Ni30Cr20 during solidification process is carried out and the amount, size and distribution of TiN in ingot of the alloy are analyzed by optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Test results show that part titanium nitride has been precipitated in liquid alloy including single TiN and TiN containing of MgO・Al₂O₃, MgO and TiO₂ etc. nucleus. The amount of titanium nitride decreases and their size increases gradually from edge to center of ingot. Calculation results show that it is available to the amount and size of precipitated TiN by controlling the titanium-nitrogen product less than 3. 70 x 10^-4, while to decrease nitrogen content in alloy is a efficient measure to decrease the amount of precipitation and size of titanium nitride.

摘要： 试验用Ni30Cr20合金(/%:0.035～0.045C、0.28～0.30Si、0.73～0.75Mn、0.005～0.007P、0.001～0.002S、19.40～19.93Cr、29.75～30.35Ni、0.30～0.36Al、0.03～0.88 Ti、0.005 7～0.020 5N)由150 kg真空感应炉熔炼,铸锭尺寸(mm)120×230×500。对Ni30Cr20合金凝固过程中TiN析出的热力学条件进行了计算,并利用金相显微镜、扫描电子显微镜和能谱仪分析了该合金铸锭试样中TiN的数量、尺寸和分布。结果表明,部分氮化钛在液相合金中已有析出,包括含芯和不含芯两种类型的TiN,其中含芯TiN的核心主要是MgO·Al₂O₃、MgO和TiO₂等。在铸锭试样中,TiN的数量从边部到中心逐渐减少,尺寸却逐渐增大。计算结果表明,控制合金的氮钛积低于3.70×10^-4,有利于控制TiN的析出数量和尺寸,而降低合金中的氮含量是降低氮化钛析出数量和尺寸的有效措施。

关键词: Ni30Cr20合金, 热力学, TiN, 析出, 氮钛积