Springback Analysis for Warm Bending of Titanium Tube Based on Coupled Thermal-Mechanical Simulation

Titanium bent tubular parts attract extensive applications, thus meeting the ever-growing demands for light weight, high reliability, and long service life, etc. To improve bending limit and forming quality, local-heat-assisted bending has been developed. However, significant springback seriously reduces the dimensional accuracy of the bent tubular parts even under elevated forming temperatures, and coupled thermal-mechanical working conditions make springback behavior more complex and difficult to control in warm bending of titanium tubular materials. In this paper, using warm bending of thin-walled commercial pure titanium tube as a case, a coupled thermal-mechanical finite element model of through-process heating-bending-unloading is constructed and verified, for predicting the springback behavior in warm bending. Based on the model, the time-dependent evolutions of springback angle and residual stress distribution during thermal-mechanical unloading are studied. In addition, the influences of forming temperature and bending angle on springback angle, thickness variation, and cross-section flattening of bent tubes are clarified. This research provides a fundamental understanding of the thermal-mechanical-affected springback behavior upon local-heat-assisted bending for improving the forming accuracy of titanium bent tubular parts and structures.

Failure analysis of a commercially pure titanium tube in an air conditioner condenser

Purpose The purpose of this paper is to determine the failure reasons and failure mechanism of the commercially pure titanium air conditioning condenser. Design/methodology/approach In this paper, chemical analysis, metallographic observation, visual examination and scanning electron microscope examination, corrosion products analysis and working conditions analysis were adopted for determining the reasons for the failure of the condenser. Findings The results indicated that TA2 titanium pipe perforation failure is caused by the synergistic effect of crevice corrosion and deposit corrosion. The corrosion processes can be divided into three steps. Originality/value This research is an originality study on the failure case of a commercially pure titanium air conditioning condenser. This study makes up for the shortage of titanium alloy failure cases and also gives the result of the failure reason and failure mechanism for titanium, which has an engineering significance.

Welding procedure research of titanium heat exchangers

In order to manufacture Gr.1 titanium heat exchangers, the welding property and weld structure of titanium tube-to-tubesheet are analyzed. The procedure of Pulse GTAW is used and the visual inspection, dimensional inspection, chemical composition, mechanical properties and metallographic structures are tested and analyzed. The results show that the weld joint can get ideal structure and good chemical composition, mechanical properties and corrosion resistance. The successful welding qualification has accumulated valuable experience for manufacture of titanium heat exchangers.

Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>

Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>

Simulation of Ti-Twin S - Shape Vibration Based Mass Flow Sensor

This paper contains in modelling of twin S-shape coriolis mass flow sensor in Titanium tube and then performing the simulation to determine the optimum phase-shift. To measure the mass flow rate coriolis mass flow sensor is placed inside the tube. The phase shift appears due to the twist in the structure as a result of interactions between the vibration and fluid flow. The phase shift calculated at different sensor positions is helpful in calibrating the accurate mass flow rate and to the optimal sensor position. The coriolis mass flow sensor is modelled in CATIA V5 and simulation is performed in ANSYS 16.2. tube material is titanium and working fluid is water.