基于MeltFlow-VAR对Ti551合金铸锭进行空间坐标变换的熔炼模拟研究OA

Vacuum arc remelting(VAR)is the key technology for the preparation of titanium alloy in-gots.However,traditional processes struggle to precisely control the coupling effect of multi-physical fields,which easily leads to compositional segregation of ingots.In this paper,melting simulation re-search was carried out on Ti551 alloy with a target composition of Ti-5.3Al-1.5Mo-1.0V-1.0Sn-1.0Zr-1.0Cr-0.1O-0.15Fe.The MeltFlow-VAR software was adopted to simulate the solidification segregation of Ti551 titanium alloy,and four melting cases with spatial coordinate transformation were designed for Ti551 alloy ingots.By simulating the melting processes of primary and secondary ingots,the distribu-tion characteristics of alloying elements such as Al,Mo and V under different cases were analyzed.The results show that obvious elemental segregation exists in the primary Ti551 ingot.Al,Mo and O exhibit negative segregation,while V,Sn,Zr and other elements present positive segregation,and the segrega-tion is mainly concentrated in the riser of the ingot head and the ingot tail.Among the four cases,the cutting and welding cases have the optimal effect on improving the compositional uniformity in the middle of the ingot.Case 2 enables the elemental content in the middle region to be closer to the stand-ard values,and case 4 effectively weakens the element concentration fluctuation of large-size long in-gots.The traditional head-to-tail inversion method cannot fundamentally eliminate segregation defects,whereas the restructured melting based on spatial coordinate transformation can break the original se-gregation distribution pattern.In addition,Mo features a high melting point and high density with prom-inent negative segregation during VAR processing.The reconstruction methods including cutting and welding can regulate the transport and redistribution mechanism of Mo in the molten pool,which effect-ively optimizes the compositional uniformity in the middle of ingots.This study provides a technical reference for the segregation control of high-melting-point elements and the improvement of finished product rate of titanium alloy ingots.