| With the development of economy, the requirements of product with compact structure and excellent performance become more than before. Grain refinement of metal is a very important path of improving the quality of products. Presently, many kinds of grain refined methods have been used to material processing. Aiming at the solutions of the problems in the casting of 4137H steel and tin phosphorus bronze, this paper applied two kinds of fields, rare earth (RE) purification and alternating electromangnetic field to better the solidification structures of the two alloys and analyzed the effect of these two methods on the solidification structures.SEM, Microscope, Image-analysis were used to analyze the influence of different RE quantity on cleanness, undercooling, microstructure and mechanical properties of 4137H was studied. The result showed that: RE inclusion growed up on the Ca, Al high-melting oxide. The quantity of inclusion was reduced and undercooling was increased when appropriate amount of mixed RE was added. When the quantity of RE added was 1% ,the undercooling obtained a maximum value of 26K, strength of rigidity and hardness increased by 14% and 32% respectively.SEM, Microscope, Electron probe were used to analyze the influence of alternating electromagnetic field on horizon continuous casting of tin phosphorus bronze QSn6.5-0.1 band. Without electromagnetic field, the crystal grain was coarse and columnar crystal was the most; with electromagnetic field, the grain was refined and equiaxed crystal was the most. The segregation of Sn obviously decreased with the application of electromagnetic field Imposing 18 A electric current to the casting blank, the tensile strength decreased and extensibility increased, which facilitated to the plastic working and reduce of surface cracks. It is hopeful to decrease casting temperature by 20-30℃and prolong the operating life of the graphite jig from 168 hours to 336 hours with the application of electromagnetic field.
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