International Scientific-Technical and Production Journal
December
2009
# 12
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
Makhnenko V.I., Poznyakov V.D., Velikoivanenko E.A.,
Makhnenko O.V., Rozynka G.F. and Pivtorak N.I. Risk of cold
cracking in welding of structural high-strength steels ............................ 2
Gorban V.F., Kharchenko G.K., Falchenko Yu.V. and
Petrushinets L.V. Investigation of joints of titanium aluminide
with titanium alloy VT8 produced by diffusion welding ........................... 7
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:
$324, 12 issues per year,
postage and packaging included.
Back issues available.
All rights reserved.
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
Sabokar V.K., Akhonin S.V., Petrichenko I.K. and Yasinsky A.V.
Pressure welding of titanium aluminide to other titanium alloys ............ 10
INDUSTRIAL
Welding and Cutting 2009. Essen, Germany, 14--19
September 2009 ................................................................................. 13
Shelyagin V.D., Khaskin V.Yu., Mashin V.S., Pashulya M.P.,
Bernatsky A.V. and Siora A.V. Features of laser-MIG welding
of high-strength aluminium alloys ........................................................ 21
Zelenin V.I., Kavunenko P.M., Tisenkov V.V., Teplyuk V.M.,
Poleshchuk M.A., Lebed V.D., Lipisy V.I., Bondarev S.V.,
Gavrilov S.A., Olgard N.T. and Cheburov S.A. Application of
plasma-arc metallisation for restoration of wheel pairs ......................... 28
Tsaryuk A.K., Ivanenko V.D., Volkov V.V., Mazur S.I.,
Trojnyak A.A., Vavilov A.V., Kantor A.G. and Volichenko N.P.
Repair welding of turbine case parts from heat-resistant steels
without subsequent heat treatment ..................................................... 32
BRIEF INFORMATION
Lankin Yu.N. and Sushy L.F. Electrical conductivity of slag
pool in electroslag welding with wire electrode .................................... 37
News .................................................................................................. 39
NEWS
International Conference «Improvement of Turbine Plants
Using Methods of Mathematic and Physic Modelling» .......................... 40
Seminar on welding technologies «Full Readiness to Excelent
Welding of Steel» ................................................................................ 41
International exhibition «Weldex/Rossvarka-2009» ................................ 44
International Scientific and Technical Conference «Problems
of Welding, Related Processes and Technologies» ............................... 46
International Conference «High Mat Tech» ........................................... 48
Index of articles for TPWJ’2009, Nos. 1--12 ......................................... 49
List of authors ..................................................................................... 53
Стр.1
RISK OF COLD CRACKING IN WELDING
OF STRUCTURAL HIGH-STRENGTH STEELS
V.I. MAKHNENKO, V.D. POZNYAKOV, E.A. VELIKOIVANENKO, O.V. MAKHNENKO,
G.F. ROZYNKA and N.I. PIVTORAK
E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
Mathematical model of the risk of cold cracking in welding of structural high-strength steels is considered. The model
is based on distributed data on the state of microstructure, content of diffusible hydrogen and stressed state in elementary
volumes within the welded joint zone. It is shown that the model makes it possible to more precisely evaluate the local
conditions of cold cracking on the basis of the above parameters.
Keywords: arc welding, low-alloy high-strength steels,
brittle fracture, cold cracks, diffusible hydrogen, microstructure,
stressed state, probability model
It is a known fact that the presence of quench structures,
diffusible hydrogen and tensile stresses [1] are
conditions that induce cold (hydrogen) cracks in welding
of structural steels. As to the quantitative characteristics
of the specified conditions, at present it is
possible just to approximately evaluate critical values
of the corresponding characteristics, allowing for locality
of cold cracking processes, presence of a significant
gradient of changes of these characteristics in a
zone of welding heating, their strong mutual effect
and other factors, by limiting their extreme demonstrations
with almost no account for their mutual effects.
Meanwhile, development of the methods (experimental
and calculation) for determination of distributed
parameters of the above characteristics in
welding of different joints on structural steels, as well
as the trends to optimization of the techniques to prevent
cold cracks require development of more precise
criteria of the risk of their formation.
It can be shown that many recent approaches [1]
based on such integral characteristics as carbon
equivalent in the HAZ [1], content of hydrogen in
filler metal, degree of restraint and thicknesses being
welded, used as the quantitative conditions for microstructure,
diffusible hydrogen and effective stresses
are of a very general character. They are far from
providing an ambiguous determination of the quantitative
characteristics of the conditions causing cold
cracking at certain parameters of welding heating. It
has been proved in recent decades, due to the development
of the «Sysweld» and other types of computer
systems, which help to obtain the calculation information
on the distributed characteristics in the weld
and HAZ metals regarding the cold cracking conditions,
that zones of potential cold cracks do not always
have the most extreme combinations of volumes of
quench microstructures, content of diffusible hydrogen
and level of tensile stresses. Often the zones with
a maximum volume of martensite and content of diffusible
hydrogen are within the compressive zones, or
2
the zones with high tensile stresses have a purely bainitic
microstructure and low level of diffusible hydrogen,
i.e. they are not potential centers of cold cracks.
In other words, the proper, physically substantiated
criteria that quantitatively connect, on the level of
the distributed parameters, the necessary conditions
for cold cracking to occur in welding heating of structural
steels under consideration, are required.
An approach for development of such criteria,
based on the following factors, is given below:
• probability assessment of the risk of cold cracking
is performed in a specified area of a welded joint
(certain region of the fusion zone or HAZ);
• initiation and propagation of cold cracks take
place by the brittle fracture mechanism, i.e. determined
by correspondent normal stresses σjj(x, y, z)
at a point with coordinates x, y, z, acting in an area
with normal j and corresponding characteristic of resistance
of a material, Aj(x, y, z), to brittle fracture
formation.
Àj is a function of microstructural state and content
of diffusion hydrogen for a given steel.
The probability of brittle fracture in specific volume
V, in compliance with the Weibull theory, is determined
by dependence
Pj(V) = 1 -- exp
--∫
V
σjj -- Aj
Bj
η
dV/V0
As a rule, η = 4.0, and Aj and B
__
__
,
(σjj > Aj). (1)
In (1), integration is carried out only with respect
to elementary volumes dV, where σjj > Aj, and Aj, η
and BjV0
j = BjV0
1/η are determined
experimentally.
The values of B
j depend on the size of the volume
V along the section with normal j (Figure 1). If
stresses σjj and material resistance Aj in length lj of
this volume change but slightly, then a change of
dV = ljdF can be made in integral of expression (1),
where F is the cross-section area of volume V.
Accordingly, the following will be obtained instead
of (1):
© V.I. MAKHNENKO, V.D. POZNYAKOV, E.A. VELIKOIVANENKO, O.V. MAKHNENKO, G.F. ROZYNKA and N.I. PIVTORAK, 2009
12/2009
1/η are the Weibull distribution parameters.
Стр.2