Abstract
Tube forming technologies based on internal forming pressures, such as hydroforming or hot tube gas forming, are state of the art to manufacture complex closed profile geometries. However, materials with excellent specific strengths and chemical properties, such as titanium alloys, are often challenging to shape due to their limited formability. In this study, the titanium alloy Ti-3Al-2.5V was processed by superplastic hot tube gas forming to manufacture a helically shaped flex tube. The forming process was investigated in terms of process simulation, forming tool technology and process window for the manufacturing of good parts. Within a simulation study, a strain rate optimized forming pressure–time curve was defined. With the newly developed tool design, forming temperatures up to 900 °C and internal forming pressures up to 7 MPa were tested. A process window to manufacture good parts without necking or wrinkling has been successfully identified. The experiment data showed good agreement with the numerical simulations. The detailed study of the process contributes to an in-depth understanding of the superplastic forming of Ti-3Al-2.5V during hot tube gas forming. Furthermore, the study shows the high potential of superplastic hot tube gas forming of titanium alloys for the manufacturing of helical flex tubes and bellows.
Highlights
Titanium and its alloys have become a popular construction material in recent decades due to their high specific strength, excellent corrosion behavior and good mechanical properties [1].The extraordinary property profile of this material makes it interesting for applications in the fields of aerospace, medical technology, chemical process engineering or marine and offshore technology [2]
This publication presents a concept to combine conventional hot forming tube gas describes the forming tubes or hollowofprofiles a forming pressure insidedescribes the profile forming processes with of theheated superplastic forming titaniumwith alloys
Thisimportant is very important the microstructure and the mechanical properties of very because because the microstructure and the mechanical properties of titanium titanium alloys are significantly influenced by temperature and the degree of deformation alloys are significantly influenced by temperature and the degree of deformation [32]
Summary
Titanium and its alloys have become a popular construction material in recent decades due to their high specific strength, excellent corrosion behavior and good mechanical properties [1]. Asa described by Lee et al.and [4], forming process For this purpose, tubes or hollow profiles bulged in hydroforming process conventional flexible tubes and bellows are manufactured by a multi-stage forming process. Tubes or hollow profiles bulged in hydroforming process conventional flexible tubes and bellows are manufactured by a multi-stage forming process For this the resulting convolutions are folded in a subsequent compression process [4]. A helical flex tube or Titanium alloys arehelical difficult to form duecan to improve their microstructure This publication presents a concept to combine conventional hot forming tube gas describes the forming tubes or hollowofprofiles a forming pressure insidedescribes the profile forming processes with of theheated superplastic forming titaniumwith alloys.
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