Effect of the Melting Process on the Composition Uniformity and β Fleck Segregation of the TC6 Alloy
Author of the article: LI Xinlin, ZHANG Tianyou, XING Xuewei, HAN Chengxiang, ZHANG Yingming, GUO Jinming
Author's Workplace:Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China
Key Words:TC6; compositional uniformity; vacuum consumable arc melting; β fleck
Abstract:
TC6 alloys have excellent comprehensive properties, such as medium strength, good toughness and good thermal
strength, and have been widely used in aerospace engines and other fields. To prepare a TC6 alloy ingot with a uniform
composition and no β fleck, a 3 t grade TC6 alloy ingot (Ti-6.3Al-2.5Mo-1.65Cr-0.5Fe-0.3Si) was prepared via vacuum
consumable arc melting using a small particle titanium sponge, intermediate alloy and elemental metal as raw materials.
The effects of different melting times, arc stabilizing currents and raw materials on the composition uniformity and
microstructure of alloy ingots were studied. The results show that when the binary intermediate alloy is used as the raw
material and the arc stabilizing current is 15 A/30 s, the whole chemical composition of the ingot is uniform, the Cr content
ranges from 1.53 wt.% to 1.56 wt.%, and no β fleck exists in the structure of the ingot. When the arc stabilizing current is
9 A/30 s, the composition of the ingot fluctuates greatly, and the Cr element ranges from 1.55 wt.% to 1.66 wt.%. There
are β flecks rich in Cr and Fe and poor in Mo in the ingot. A TC6 ingot with a uniform composition and no β fleck should
be prepared via a reasonable melting process during actual production.