Titan №4 2014

 

THE INFLUENCE OF THE COMPLEX TREATMENT TECHNOLOGIES ON THE SURFACE STRUCTURAL CONDITION AND SERVICE PROPERTIES OF THE MEDICAL IMPLANTS MADE OF THE VT6 TITANIUM ALLOY

 

A. Ilyin, V. Fedirko, A. Mamonov, S. Sarychev, Ju. Chernyshova

 

The influence of the complex treatment technologies, such as thermo-hydrogen treatment, vacuum-plasma nitration, thermodiffusion nitration and nitride coating application, on the structure and volume or surface properties of the samples made of the VT6 alloy was investigated. The data of surface phase composition, depth of the nitrogen diffusion layer, surface micro-hardness and microgeometry, corrosion behavior in the 0,9% NaCl-water solution, strength and fatigue properties of samples, as well as the results of  medical implants’ parts wear resistance was submitted.

 

Keywords: titanium alloy, thermo-hydrogen treatment, nitration, nitride coating, micro-hardness, corrosion behavior, wear-resistance, fatigue strength.

 

RESEARCH ON STRUCTURE AND PHASE COMPOSITION OF PILOT HIGH-TEMPERATURE Ti2AlNb-BASE ALLOY IN AS-DEFORMED CONDITION

 

E. Alexeev, N. Nochovnaya, P. Panin

 

Structure and phase composition of a pilot high-temperature titanium ortho-alloy Ti-13Al-40Nb-5(Zr+V+Mo+W)-0.5(Si+C), [wt.%], have been studied after isothermal deformation. Temperature intervals of the following phase areas sequence have been determined: (О + bA2), (О + bВ2 + a2), (bВ2 + a2), βВ2. Both upsetting forces increase and deformability decrease have been found to occur as a result of phase transformations upon deformation temperatures below 1000°С and prolonged duration: in these conditions decomposition of b-phase takes place together with the ordered O- and a2-phases precipitation.

 

Keywords: high-temperature titanium ortho-alloy, isothermal deformation, phase transformations, phase constituents, ordered phases, microstructure.

 

STUDY OF HYDROGEN INFLUENCE ON PHASE AND STRUCTURAL TRANSFORMATIONS IN VT23 TITANIUM ALLOY

 

S. Skvortsova, N. Mamontova, V. Zasypkin, A. Shalin, N. Ruchina

 

The regularities of hydrogen influence on structure formation and phase composition in VT23 (α+b)-titanium alloy of martensite class have been studied in this work. It was stated that the introduction of 0.6% H in VT23 titanium alloy resulted in lowering of β/α +β-transition temperature by 190°С. It was shown that the introduction in the alloy of more than 0.4% H resulted in lowering of the critical cooling rate by 1K/sec; the introduction of more than 0.7% H at the temperature of more than 800°С allowed to obtain a one-phase b-condition after cooling down to room temperature. Formation of the ordered a2-phase microvolumes inside the primary aI-phase was revealed during hydrogen saturation in the temperature range of 600–750°С. The ‘phase composition – hydrogen concentration – temperature of hydrogen saturation’ diagram has been plotted; the diagram shows the influence of hydrogen content to the phase composition of alloy to room temperature.

 

Keywords: titanium alloy, hydrogen, phase transformations, structure, thermohydrogen processing.

 

STUDY SERVICE FAILURES FAN BLADE AIRCRAFT GAS TURBINE ENGINES OF A TITANIUM ALLOY

 

M. Orlov, Y. Puchkov, S. Naprienko, A. Lavrov

 

Operational failure fan blade of titanium alloy VT3- 1 was investigated by scanning electron microscopy. Fragile mechanism of delayed fracture developing according to the crystallographic planes of the structural components of the alloy was installed. Fragile mechanism of delayed fracture identical operational failure was reproduced by simulation of two-phase titanium alloys sample loading conditions corrosion attack in aqueous salt solution.

It was established that the tendency to delayed fracture of titanium alloys is correlated with the characteristics of the corrosion resistance.

 

Keywords: two-phase titanium alloys, fan blade, fasteners, delayed fracture, stress corrosion cracking, scanning electron microscopy, fractography.

 

INFLUENCE OF HIGH-TEMPERATURE GASOSTATIC TREATMENT ON STRUCTURE AND MECHANICAL PROPERTIES OF CAST PREPARATIONS FROM TITANIC ALLOYS

 

N. Molchanova, M. Iksanov, M. Saubanov

 

Influence of high-temperature gasostatic treatment on mechanical properties, completeness of removal of the revealed defects and a microstructure is considered. At carrying out of researches temperature ТHGT=950 … 1050°С and soaking time τ varied. Optimum mode ВГО for alloy Ti-5Al-2V is chosen.

 

Keywords: high-temperature gasostatic treatment, casting titanic alloys, mechanical properties, microstructure, surface layer.

 

 

Semi-products manufacturing technologies

 

FAST FOURIER TRANSFORM AND KALMAN FILTER FOR MEASURING ELECTRODE GAP IN VACUUM ARC REMELTING

 

A. Tashkinov, A. Konyashin, P. Altman

 

In the process of vacuum arc remelting (VAR) of refractory metals electrode gap control is performed by the parameters of arc voltage drop or drip closures frequency. Since the chemical composition, fused electrode size and vacuum chamber furnaces for each melting are different, there are difficulties in the development of mathematical models to estimate the electrode gap in real time.

In this regard, the author proposes to use Fast Fourier transform (FFT) and Kalman filter as means of estimating the electrode gap.

 

Keywords: refractory metals, vacuum arc remelting, electrode gap, Kalman filter.

 

OXIDATION, GAZONCITY TITANIUM ALLOYS AT HIGH-TEMPERATURE HEATING

 

E. Razuvaev, D. Kapitanenko

 

The mechanisms of oxidation and diffusion of gas saturation of the surface layer of titanium alloys at high temperature heating in air atmosphere in the low temperature range, used in technological operations of thermomechanical processing in the production of hot-deformed semi-finished products.

It shows the influence of chemical composition and structural-phase state of alloys on the oxidation intensity and depth of gas saturation at temperatures above and below polymorphic transformation alloys.

Presents quantitative dependence of the depth of the gas-saturated layer on temperature and time mode of heating of a number of industrial alloys.

Recommendations on the use of protective coatings to reduce allowance for final processing, the removal of which provides achievement of high quality products.

 

Keywords: titanium alloys, oxidation, the depth of the gas-saturated layer, heating, diffusion, structure, phase composition, protective coating.

 

 

Semi-products treatment technologies

 

INFLUENCE OF HEAT TREATMENT ON STRUCTURE-PHASE COMPOSITION AND MECHANICAL PROPERTIES OF TITANIUM ALLOY ON BASIS OF ORTO-PHASE

 

E. Alexeev, N. Nochovnaya, S. Skvortsova, I. Grushin, Е. Agarkova

 

The investigation results of heating temperature and cooling rate influence on phase composition and structure of experimental high resistance titanium orto-alloy VTI 4 were presented. The quenching from temperature of b/В2- и (b/В2+a2)- fields can result the samples cracking in consequence of big thermal strains. It was established for increasing of samples plasticity made of alloy VTI 4 it is necessary that the temperature of first stage of heat treatment should be in (b/В2+a2)-field and cooling up to room temperature was slowly (with furnace), the second stage of heat treatment (aging) should be in (О+b/В2+a2)-field at temperature 800°C during 7 hours.

 

Keywords: high resistance titanium orto-alloy, thermal treatment, structure, phase composition, strength, plasticity.

 

Titanium market

 

CLASSIFICATION OF OPERATING COSTS OF TITANIUM ENTERPRISE

 

A. Alexakhin, L. Kostigova, A. Zolkina, N. Lomonosova

 

Benefits management is main task of titanium enterprise within the frames of operating controlling.  Whereas the price is determined by the market, benefits management is reduce to operating management of operating costs. At present time costs are calculated by standard calculation items of prime cost. Key failings of such a system are inefficiency of data acquisition and low clarity of data. Original calculation of prime cost calculation of titanium enterprise products was considered. Cost items of that calculation were divided by degree of regulation.

 

Keywords: management accounting, financial accounting, costs, prime cost calculation, controlling.

 

 

Events and anniversaries

 

To the 50-year anniversary Vladimir Lugovskoy