Influence of the Combined Radial Shear Rolling and Rotary Forging on the Deformation Mode of the Small-Diameter Rod Billet Made of Titanium Alloys

Based on the analysis of trends in the development of aviation and rocketry and ground transportation, the prospect of use of high-alloy steels, and titanium-based alloys with high strength, heat-and corrosion-resistant properties is established. It is shown, that high strength and elasticity of mentioned alloy groups adversely affect the dynamics of cutting process and the resistance of the cutting tool. Processing of small diameter holes is especially difficult due to the small longitudinal stability of the instrument, chip evacuation problems, grooves sticking to the surface almost zero cutting speed near the core. The results from the analysis of works of domestic and foreign scientists have shown that the message sent to the drill by ultrasonic vibrations of the small amplitude reduces axial force and cutting moment due to reduced friction caused by local thermal effects and relief of dislocation motion. At the same time, it is stated that the stable results of the effectiveness of ultrasound were not received in relation to the small diameter end tools until recently because of additional dynamic loads reducing the longitudinal stability and therefore it is impossible to report the instrument optimal oscillation amplitude to facilitate cutting. The working hypothesis of increase of efficiency of the ultrasonic drilling of small diameter holes proposes to consider correlation frequency supplied to the ultrasonic instrument, structural parameters and physical and mechanical properties of the material and to drive oscillations in the plane of the main cutting edges which would significantly reduce the magnitude of the oscillation amplitude. Experimental studies on ultrasound indentation, micro cutting and drilling titanium alloys have confirmed this hypothesis. It was established that at the moment the drill receives a message with the oscillation frequency of 30 kHz when machining titanium alloys, the axial cutting forces decrease by 70 – 80 % and the tool life increases by 2.2 times.

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Advancements in Cone-type Rotary Piercing Technology

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2832683 ◽

1999 ◽

Vol 121 (3) ◽

pp. 313-320 ◽

Cited By ~ 2

Author(s):

Chihiro Hayashi ◽

Masayoshi Akiyama ◽

Tomio Yamakawa

Keyword(s):

Small Diameter ◽

Expansion Ratio ◽

Seamless Tube ◽

Hot Workability ◽

Piercing Mill ◽

Rotary Forging ◽

Core Technology ◽

Cone Type ◽

High Feed ◽

Tube Plant

A cone-type piercing mill was developed by the authors for materials with poor hot workability. This piercing mill is called “the super piercer” in Europe. It has a pair of cone-type main rolls supported at both ends with their roll axes inclined and crossed so as to enable piercing at high feed and cross angles. In order to ensure the best performance of the rotary piercing, disc rolls are adopted instead of plate guide shoes. The super piercer was put into practice at the small-diameter seamless tube plant operated in 1983. The recent progress in our research and development on the super piercer has resulted in the concept of “the new super piercer,” which allows expansion piercing. Namely, the development of the skewing technology for disc roll axes and its application to the cone-type piercing technology has realized remarkable increase in the expansion ratio. The new super piercer was adopted as the core technology of the new medium-diameter seamless tube plant operated in 1997. In this paper, studied in detail were the influences of the expansion ratio, feed and cross angles on the rotary forging effects, redundant shear deformations and power consumption.

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Nonlinear dynamics and stages of damage of Ti6Al4V and Ti45Nb titanium alloys in very high cycle fatigue

PNRPU Mechanics Bulletin ◽

10.15593/perm.mech/2020.2.12 ◽

2020 ◽

pp. 145-153

Author(s):

M. V Bannikov ◽

V. A Oborin ◽

D. A Bilalov ◽

O. B Naimark

Keyword(s):

Titanium Alloys ◽

High Cycle Fatigue ◽

Three Dimensional ◽

Fatigue Properties ◽

Experimental Program ◽

Cycle Fatigue ◽

Very High Cycle Fatigue ◽

Number Of Cycles ◽

Radial Shear Rolling ◽

Very High

The paper presents an experimental methodology aimed at evaluating a very-high cycle resource for aviation titanium alloys Vt-6 (Ti6Al4V) and Ti45Nb for medical applications with different microstructures (large-crystal and submicrocrystalline ones). The submicrocrystalline (SMC) state was obtained by an intensive plastic deformation realized in two ways: the three-dimensional forging for Ti45Nb and radial-shear rolling for Ti6Al4V. The experimental program tests high-cycle and very-high-cycle loading (number of cycles 107-109) realized using the in situ determination method of the accumulation of the irreversible fatigue damage by analyzing nonlinear forms of feedback in a closed system ultrasonic fatigue setup. This makes it possible to establish the connection of the microscopic fatigue mechanisms with the model views and consider the stages of the damage development based on the nonlinear kinetics of the defect accumulation under cyclic loading in high- and gigacycle fatigue modes. We established various relations between changes in the amplitude of the second harmonic of vibrations of the free end of the samples with different internal structures, which are associated with the mechanisms of stress relaxation and damage accumulation. The grain size reduction in Ti45Nb alloy by the three-dimensional forging improved the fatigue properties by 1.3-1.5 times, whereas for VT-6 alloy, the radial-shear rolling method could not increase the fatigue properties in the very high cycle fatigue range, which may be caused by the presence of large residual internal stresses. Based on the scale parameters obtained earlier from the fracture surface morphology and the relations established in this work, the kinetic equations for the origin and growth of fatigue cracks in the gigacycle loading range will be constructed. This equation, based on the empirical power parameters related to the structure of the material, will allow us to determine the number of cycles for the origin of an internal crack and its growth to the surface.

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Advanced Technology for Preparing Bar from Medical Grade Ti-Zr-Nb Superelastic Alloy Based on Combination of Radial-Shear Rolling and Rotary Forging

Metallurgist ◽

10.1007/s11015-019-00793-z ◽

2019 ◽

Vol 63 (1-2) ◽

pp. 51-61 ◽

Cited By ~ 8

Author(s):

V. A. Sheremet’ev ◽

A. A. Kudryashova ◽

Xuan Ta Dinh ◽

S. P. Galkin ◽

S. D. Prokoshkin ◽

...

Keyword(s):

Advanced Technology ◽

Rotary Forging ◽

Radial Shear Rolling ◽

Medical Grade

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Small Diameter Drilling Of Titanium Alloys on CNC Turning Machine

Technological Engineering ◽

10.2478/teen-2014-0010 ◽

2014 ◽

Vol 11 (2) ◽

pp. 5-8

Author(s):

Andrej Czan ◽

Anton Martikan ◽

Jozef Pustay ◽

Viktor Kuzdak ◽

Jozef Mrazik

Keyword(s):

Corrosion Resistance ◽

Titanium Alloy ◽

Titanium Alloys ◽

Automotive Industry ◽

Small Diameter ◽

Basic Research ◽

Cnc Turning ◽

Pvd Coating ◽

Drill Bits ◽

Drilling Conditions

Abstract The article deals with drilling of titanium alloys, which are becoming more widely used in aerospace and automotive industry as well as in other sectors for its specific properties such as hardness, corrosion resistance, biocompatibility, etc. The aim of this article is basic research with focus on drilling conditions of titanium alloy using HSS drill bits with diameter ø2,3 mm with PVD coating and without coating on CNC turning machine Polygim Diamond 12 series. This research can support problem solutions in small diameter drilling.

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Efficiency Estimation of Energy Introduction of a Ultrasound Field Into the Zone of Drilling of Complex Packages From Composite Materials and Titanium

MATEC Web of Conferences ◽

10.1051/matecconf/201929704003 ◽

2019 ◽

Vol 297 ◽

pp. 04003

Author(s):

Evgeniy Kiselev ◽

Kirill Savelev ◽

Oleg Krupennikov

Keyword(s):

Composite Materials ◽

Titanium Alloys ◽

Rational Design ◽

Industrial Robot ◽

Small Diameter ◽

Ultrasonic Vibrations ◽

Ultrasonic Oscillations ◽

Ultrasonic Drilling ◽

Ultrasound Field ◽

Efficiency Estimation

The possibility of improving the quality of holes in complex packages made of composite materials and titanium alloys in the drilling operation by using the energy of ultrasonic vibrations introduced into the treatment zone is considered. The construction of complex packages and the problems arising from their processing with an axial tool are described. The rational design of the experimental setup for testing the technology of ultrasonic drilling of small-diameter holes was chosen. The unit is based on the KUKA KR 16 R2100 robotic complex. In addition to the industrial robot, it contains a spindle attached to the robot; Ultrasonic head, dynamometer and table, on which the package made of composite materials and titanium alloys is fixed. Ultrasonic oscillations with a frequency of 22 kHz can be transmitted, depending on the execution of the installation, either to the spindle or to the table with a complex package. The device allows carrying out experiments with the imposition of unmodulated, amplitude-modulated or frequency-modulated ultrasonic vibrations on the drill or on the object table with a package of composite materials.

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Comparison of Technological Methods for Small Diameter Hole Perforation in Titanium Alloys

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.19.16995 ◽

2018 ◽

Vol 7 (3.19) ◽

pp. 105 ◽

Cited By ~ 1

Author(s):

Mikhail V. Grachev ◽

. .

Keyword(s):

Titanium Alloy ◽

Titanium Alloys ◽

Thin Sheet ◽

Small Diameter ◽

Huge Number ◽

Optimal Method ◽

Processing Mode ◽

Diameter Hole ◽

Method Selection ◽

Technological Methods

There is a huge number of methods for hole obtaining. In view of the fact that an increasing number of parts demand an increased accuracy and roughness in the obtained holes, especially concerning thin sheet parts, there is the need of research in this field. The main goal of the work is to establish the most optimal method for small-diameter hole obtaining in titanium alloys. The sheet of titanium alloy OT4-1 is studied with the thickness of 0.5 mm. At the same time, rigid tolerances are established both for the holes themselves and for their location. Drilling, laser treatment and electroerosion ("super drilling") were chosen as the drilling methods. Other methods were not considered due to the possibility of aperture rupture between holes and other profile distortions for the part and the holes. The most optimal modes of hole obtaining were selected. The productivity, the quality and the accuracy of the holes were evaluated. They studied in detail the technologies for the obtaining of holes with the purpose of processing mode setting. The main recommendations were presented for an optimal method selection concerning the obtaining of small diameter holes in thin-sheet titanium alloys.

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