Effect of coupling between melt shape and temperature field on electromagnetic shaping

À´Ô´ÆÚ¿¯£ºÖйúÓÐÉ«½ðÊôѧ±¨(Ó¢ÎÄ°æ)2001ÄêµÚ1ÆÚ

ÂÛÎÄ×÷ÕߣºÉò¾ü ÅáÐÂ·ç ºî½¨Æ½ À¹ú ¸µºãÖ¾

ÎÄÕÂÒ³Â룺40 - 44

Key words£ºelectromagnetic shaping; temperature field; melt shape; coupling

Abstract: Based on the analyses of electromagnetic pressure on melt and heat induced in melt, the ratio of heat to pressure Q₀/p_m was defined. It was given that the relationship between Q₀/p_m and thickness a , electromagnetic parameter ¦Ì¦Ã of melt and electric current frequency f under electromagnetic confinement and shaping process. If the value of Q₀/p_m is big, any adjustment on melt shape will easily cause a variation of temperature in melt. In this situation, there appears a more sensitive interaction between shape and temperature field and a more narrow adjustment range for this process. Experiments on some thin plate samples with a crossª²section of 6 mm¡Á18 mm have been done in two kinds of induction coils respectively. The results show that as the coil with a trumpet inside wall is used and the positions of melt top and S/L interface are properly selected, the melt periphery is nearly vertical and the temperature gradient ahead of S/L interface is high. On this condition, a more stable and wider coupling between shape and temperature field has been continuously maintained and samples with smooth surface and unidirectional crystals have been successfully obtained.