厚大铸件热裂纹预测方法研究

应用凝固过程中凝固层内应力表达式及热裂纹萌生部位的判别准则,提出了依据凝固进程数值模拟的结果预测厚大铸件热裂纹的方法。对生产条件的φ８００铸钢车轮及ＥＭＣ铝合金大板坯热裂纹进行了预测,并用常规的热塑性方法对计算结果及剖面低倍组织形貌进行了评价。

Research on a method of crack prediction in thick and large casting

Based on the thermal stress formula and thermal crack initiation criterion, a numerical simulation method of solidification is proposed to predict the hot crack position. Cast steel wheels whose diameters are 800 mm are employed to predict the locations of cracks through thermal elastic|plastic analyses and low magnifying structure observations conventionally. The results show that numerical prediction of cracks coincides with the measurement results. The cracks initiate at the two|thirds thickness of the solidified layer from the out side of castings and they do not necessarily follow where the defects such as shrinkage hole and porosity occur, and so does EMC slab. It is also found that the surface temperature control is an effective factor to avoid the crack formation.