倾斜板长度及角度对9Cr18半固态坯料组织的影响

为了考察倾斜板参数对9Cr18半固态坯料组织的影响, 进而为其触变成形提供微观组织基础, 采用自制的波浪形倾斜板制备9Cr18半固态坯料, 取样分析了坯料心部的金相组织.结果表明:随倾斜板长度从350 mm增加到840 mm, 初生晶粒的等效直径从53.4μm减小到44.9μm, 而形状因子从0.82略微提高到0.84;长度增大到595mm后, 初生晶粒的形貌变化不明显.在倾斜板倾斜角度为35°~55°的范围内, 随倾斜板角度增加, 由于搅拌时间不足, 初生晶粒的等效直径从50.5μm增大到70.8μm, 而形状因子变小, 从0.83下降到0.75.脱模淬火坯料比空冷坯料有更细小圆整的初生晶粒.

Effects of Lengths and Tilt Angles of Sloping Plate on Microstructure of 9Cr18 Semi-solid Billets

To investigate the effect of parameters of sloping plate on the microstructure of semi-solid9Cr18,so as to lay the foundation of its thixoforming,a self-designed sloping plate is used to make 9Cr18semi-solid billets,and specimens for microstructural characterisation are cut from the core section of the billets. Results show that as the length of the sloping plate increases from 350 mm to 840 mm,equivalent diameter of the primary grains is reduced from 53. 4 μm to 44. 9 μm,and the shape factor slightly increases from 0. 82 to 0. 84. However,after the length reaches 595 mm,its increase has little effect on the morphology of the primary grains. As the tilt angle increases in the range of 35 °-55 °,the equivalent diameter of primary grains increases from 50. 5 μm to 70. 8 μm,and the shape factor decreases from 0. 83 to 0. 75 because of lack of stirring time. Besides,the grains in released-quenched billets are finer than those in air-cooled billets.