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为改善难变形GH141合金的热塑性,本文通过La、Ca、Mg微量元素的加入,在10kg真空感应炉浇铸成φ20×140mm试棒,用落锤顶锻方法按裂纹形成的倾向性对所有试验炉号锻态样的热塑性进行了评价,并对宏观和微观组织做了观察。La、Ca、Mg的作用如下: 1.有明显改善铸态结晶组织作用,其柱晶减弱,枝晶变细。 2.具有细化碳化物和变态作用。添加过量后,呈点状聚群夹杂物增多,热塑性降低。 3.添加适量的单La、Ca、Mg或Ca和Mg同时复合加入,对扩大热加工温度范围有良好的作用。与未加的合金相比:加入0.01%Ca及其相应残留量为O.02%Ca时,效果最好,约提高170℃;加入0.005%Ca+0.007%Mg及其相应残留量为0.002%Ca+0.003%Mg,或加入0.03%Mg及其相应残留量为0.01%Mg时,约提高100℃;加入0.025%La及其相应残留量为0.0084%La时,提高50℃。
In order to improve the thermoplasticity of difficult-to-shape GH141 alloy, this article through the addition of La, Ca, Mg trace elements cast into φ20 × 140mm test bar in a 10kg vacuum induction furnace, by drop hammer forging method according to the tendency of the formation of cracks on all test furnace No. as for the thermoplastic state were evaluated, and macroscopic and microscopic observations made. The role of La, Ca, Mg are as follows: 1. There is a clear improvement in the role of as-cast crystal structure, the columnar crystal weakened, dendritic thinning. 2. With refined carbide and metamorphosis. After adding an excessive amount of inclusions in the dot-like clusters increased, the thermoplastic decreased. 3. Add appropriate amount of single La, Ca, Mg or Ca and Mg at the same time compounding, to expand the thermal processing temperature range has a good effect. Compared with the unalloyed alloy, adding 0.01% Ca and the corresponding residual amount of O.02% Ca, the best effect is about 170 ℃; adding 0.005% Ca + 0.007% Mg and the corresponding residual amount is 0.002% Ca +0.003% Mg, or 0.03% Mg and the corresponding residual amount of 0.01% Mg is increased by about 100 ° C; when 0.025% La and its corresponding residual amount is 0.0084% La, the temperature is increased by 50 ° C.