International Scientific-Technical and Production Journal
March
2009
# 3
English translation of the monthly «Avtomaticheskaya Svarka» (Automatic Welding) journal published in Russian since 1948
Founders: E.O. Paton Electric Welding Institute of the NAS of Ukraine
International Association «Welding»
Editor-in-Chief B.E.Paton
Editorial board:
Yu.S.Borisov V.F.Khorunov
A.Ya.Ishchenko I.V.Krivtsun
B.V.Khitrovskaya L.M.Lobanov
V.I.Kirian A.A.Mazur
S.I.Kuchuk-Yatsenko
Yu.N.Lankin I.K.Pokhodnya
V.N.Lipodaev V.D.Poznyakov
V.I.Makhnenko K.A.Yushchenko
O.K.Nazarenko A.T.Zelnichenko
I.A.Ryabtsev
Publisher: International Association «Welding»
CONTENTS
SCIENTIFIC AND TECHNICAL
Maksymova S.V. Formation of brazed joints on titanium
aluminide ...................................................................................... 2
Skulsky V.Yu. Thermokinetic peculiarities of formation of
cold cracks in welded joints on hardening heat-resistant
steels ........................................................................................... 8
International editorial council:
N.P.Alyoshin (Russia)
U.Diltey (Germany)
Guan Qiao (China)
D. von Hofe (Germany)
V.I.Lysak (Russia)
N.I.Nikiforov (Russia)
B.E.Paton (Ukraine)
Ya.Pilarczyk (Poland)
P.Seyffarth (Germany)
G.A.Turichin (Russia)
Zhang Yanmin (China)
A.S.Zubchenko (Russia)
Promotion group:
V.N.Lipodaev, V.I.Lokteva
A.T.Zelnichenko (exec. director)
Translators:
A.A.Fomin, O.S.Kurochko,
I.N.Kutianova, T.K.Vasilenko
PE «Melnik A.M.»
Editor
N.A.Dmitrieva
Electron galley:
I.S.Batasheva, T.Yu.Snegiryova
Address:
E.O. Paton Electric Welding Institute,
International Association «Welding»,
11, Bozhenko str., 03680, Kyiv, Ukraine
Tel.: (38044) 287 67 57
Fax: (38044) 528 04 86
E-mail: journal@paton.kiev.ua
http://www.nas.gov.ua/pwj
State Registration Certificate
KV 4790 of 09.01.2001
Subscriptions:
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Back issues available.
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This publication and each of the articles
contained herein are protected by copyright.
Permission to reproduce material contained in
this journal must be obtained in writing from
the Publisher.
Copies of individual articles may be obtained
from the Publisher.
© PWI, International Association «Welding», 2009
Kuchuk-Yatsenko V.S., Shvets V.I., Sakhatsky A.G. and
Nakonechny A.A. Features of resistance welding of
titanium aluminides using nanolayered aluminium-titanium
foils ............................................................................................. 11
Shonin V.A., Mashin V.S., Murashov A.P., Zelenin V.I.,
Demianov I.A., Pashulya M.P. and Teplyuk V.M. Role of
protective coating of aluminium alloy welded joints in
fatigue resistance ........................................................................ 15
INDUSTRIAL
Titarenko V.I., Tkachenko O.V., Matiko D.Yu., Pilipko V.I.,
Mudraninets I.F. and Mudraninets I.I. Experience in
designing and manufacture of welding-and-surfacing
instalations .................................................................................. 18
Shatan A.F., Andrianov A.A., Sidorets V.N. and
Zhernosekov A.M. Efficiency of stabilisation of the
alternating-current arc in covered-electrode welding ..................... 21
Shalomeev V.A., Tsivirko E.I., Petrik I.A. and Lukinov V.V.
Welding repair of surface defects in Ml-10 alloy castings
by using scandium-containing material ......................................... 23
Litvinov A.P. Development of inert-gas welding (Review) ............... 28
BRIEF INFORMATION
Onatskaya N.A. and Demidenko L.Yu.
Electrohydraulic-pulsed treatment for strengthening the
surfaces of 110G13MLS steel frogs .............................................. 32
Thesis for a scientific degree ........................................................ 34
News ........................................................................................... 35
Developed at PWI ........................................................................ 36
Стр.1
FORMATION OF BRAZED JOINTS
ON TITANIUM ALUMINIDE
S.V. MAKSYMOVA
E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
Studied were the features of formation of brazed joints on titanium aluminide, produced by radiation heating in vacuum
using brazing filler metals based on the Ti--Zr system and alloyed with other elements. It is noted that utilisation of
copper and nickel containing filler metals does not allow producing a homogeneous structure of metal of the brazed
seams. Alloying the Ti--Zr system with iron, manganese and other elements provides structure and properties of the
brazed seams close to those of the base material.
Keywords: vacuum brazing, titanium aluminide, brazing
filler metal, adhesion-active alloys, structure, eutectic, chemical
heterogeneity
Compositions based on the Ti--Al system are typical
representatives of a new generation of high-strength
and heat-resistant intermetallic alloys [1]. They hold
promise for application in aircraft engineering to
manufacture a number of parts of the hot section of
gas turbine engines [2]. In their heat-resistant characteristics
at 700--750 °C, they can compete with highnickel
alloys owing to their low specific weight [3].
This can provide a 30 % decrease in weight of a gas
turbine engine.
Extensive research has been conducted in the last
decades to study properties of heat-resistant titanium
alloys on the intermetallic base and develop technological
processes for production of permanent joints.
Traditional welding methods (heating with a high
heat input, application of pressure) are unacceptable
in many cases.
The preferable method for joining intermetallic
alloys is brazing. However, it involves a number of
difficulties. On the one hand, the brazing process allows
avoidance of high residual stresses in the joints,
melting of the base metal and formation of cracks, as
well as maintaining of mechanical properties of the
base metal without violation of its structural state.
On the other hand, production of brazed joints on
γ-TiAl and selection of composition for brazing filler
metals are limited to narrow ranges of contents of
alloying elements, within which mechanical properties
and performance of the base metal do not deteriorate.
In this case, the rate of diffusion of many components
of filler metals may be substantially slowed down
because of formation of intermetallic phases with aluminium.
In addition, intermetallic alloys differ in composition,
and each alloy requires an individual approach
to selection of filler metals and brazing temperature.
Reportedly
[4, 5], components of the Ti--Al system
differ much in their electronic structure of atoms and
form a range of alloys, such as Ti3Al, TiAl and TiAl3.
Mechanical properties of alloys based on the Ti--Al
© S.V. MAKSYMOVA, 2009
2
system depend upon their aluminium content. Hypostoichiometric
alloys Ti--(46--49)Al (further on ---at.%),
rather than single-phase γ-TiAl alloys, have
maximal ductility. They belong to the two-phase
(α2 + γ)-region, and the α2-phase is represented by
intermetallic Ti3Al [4]. Alloys with the α2-phase content
of 10--15 vol.% are characterised by the maximal
level of ductility [6]. Alloys with a fully lamellar
coarse-grained structure (α2 lamellae in the γ-matrix)
have maximal creep resistance at increased and low
temperatures.
The key drawback of the Ti--Al system based alloys
under consideration, having an ordered lattice of the
L10 type, is their low ductility (δ = 0.2--0.5 %) at
room temperature, which is caused by specific displacement
of dislocations in a face-centred tetragonal
lattice. Yield stress grows with increase in temperature
to about 800 °C.
So far only the first steps have been made in the
field of the technology for joining intermetallic alloys
by brazing. Criteria for selection of this joining
method or the other have not been developed as yet.
In this connection, we can speak only about individual
studies. Moreover, these studies do not always answer
the main goal, which consists in providing high performance
of the joints under service conditions.
Vacuum brazing [7] of intermetallic titanium alloy
Ti--37.5 % Al, whose structure is represented by the
lamellar γ(TiAl)- and α2(Ti3Al)-phases, is performed
by using the 15 µm thick aluminium foil, and by applying
a compressive force and holding at a temperature
of 700 or 900 °C, this favouring the diffusion
processes and formation of intermetallics TiAl2 (or
TiAl3) in the brazed seam metal. Long-time heat treatment
of the brazed joints at 1300 °C with holding for
3.84 ks failed to provide formation of the lamellar
γ/α2-phase and strength of the brazed joints at a level
of the base metal. Tensile strength σt at a temperature
of 20 °C was approximately 220 MPa [7]. A drawback
of this technological process is that it is labour- and
time consuming. In addition, application of the compressive
force is determined by design features of a
specific brazed part. Hence, it cannot be considered
a versatile method for production of permanent joints.
3/2009
Стр.2