Copies of individual articles may be obtained
from the Publisher.
© PWI, International Association «Welding», 2009
Publisher: International Association «Welding»
SCIENTIFIC AND TECHNICAL
Makhnenko V.I., Shekera V.M., Velikoivanenko E.A.,
Olejnik O.I., Rozynka G.F. and Pivtorak N.I. Analysis of
conditions causing initiation and propagation of corrosion
cracks in zones of circumferential joints on main gas
pipelines ....................................................................................... 2
Nesterenkov V.M., Protosej N.E. and Arkhangelsky Yu. <...> S. Peculiarities of utilization of
hydrogen-oxygen flame in flame treatment of materials ................ 17
INDUSTRIAL
Bach Fr.-W., Beniyash A., Lau K. and Konya R.
Nonvacuum electron beam welding of structural steels ................. 22
Kah P., Martikainen J., Jernstrom P. and Uusitalo J.
Influence of joint geometry and fit-up gaps on quality of
corner joints in new modified short arc GMAW .............................. 27
Barvinko A.Yu. <...> Evaluation of residual life of welded joints
on tank vertical wall after 20--25 years of service ........................... 34
Malinov L.S., Malinov V.L., Orlov L.N. and Golyakevich A.A.
New flux-cored wire ensuring the effect of strain
hardening of the deposited metal in operation .............................. 38
BRIEF INFORMATION
Shapovalov E.V. and Kolyada V.A. Seam-tracking system
in anticorrosion coating units ........................................................ 41
NEWS
Exhibition «Metals of Siberia: Metallurgy,
Machine-Building, Metal-Working, Welding» in Novosibirsk ........... 43
Developed at PWI ............................................................ 33, 40, 44
ANALYSIS OF CONDITIONS CAUSING INITIATION AND
PROPAGATION OF CORROSION CRACKS IN ZONES OF
CIRCUMFERENTIAL JOINTS ON MAIN GAS PIPELINES
V.I.MAKHNENKO, V.M. SHEKERA, E.A. VELIKOIVANENKO, O.I. OLEJNIK, G.F. ROZYNKA and N.I. PIVTORAK
E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
The paper deals with conditions causing formation of corrosion cracks within the zones of circumferential field and
longitudinal factory welded joints on main gas pipelines. <...> K e y w o r d s : welded main gas pipelines, circumferential
welded joints, initiation and propagation of corrosion cracks,
crack resistance diagram, nominal stresses, stress concentration,
stress intensity factors
The most dangerous defects in welded main gas pipelines are corrosion cracks, which are <...>
The_Paton_Welding_Journal_№5_2009.pdf
International Scientific-Technical and Production Journal
May
2009
# 5
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., Shekera V.M., Velikoivanenko E.A.,
Olejnik O.I., Rozynka G.F. and Pivtorak N.I. Analysis of
conditions causing initiation and propagation of corrosion
cracks in zones of circumferential joints on main gas
pipelines ....................................................................................... 2
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
Nesterenkov V.M., Protosej N.E. and Arkhangelsky Yu.A.
Technological features of electron beam welding of drill
bits ............................................................................................... 8
Nikonova E.S., Korab N.G. and Kondratenko V.Yu.
Stress-strain state of welded joints on polymer pipes
produced by butt welding at an angle ........................................... 15
Korzh V.N. and Popil Yu.S. Peculiarities of utilization of
hydrogen-oxygen flame in flame treatment of materials ................ 17
INDUSTRIAL
Bach Fr.-W., Beniyash A., Lau K. and Konya R.
Nonvacuum electron beam welding of structural steels ................. 22
Kah P., Martikainen J., Jernstrom P. and Uusitalo J.
Influence of joint geometry and fit-up gaps on quality of
corner joints in new modified short arc GMAW .............................. 27
Barvinko A.Yu. Evaluation of residual life of welded joints
on tank vertical wall after 20--25 years of service ........................... 34
Malinov L.S., Malinov V.L., Orlov L.N. and Golyakevich A.A.
New flux-cored wire ensuring the effect of strain
hardening of the deposited metal in operation .............................. 38
BRIEF INFORMATION
Shapovalov E.V. and Kolyada V.A. Seam-tracking system
in anticorrosion coating units ........................................................ 41
NEWS
Exhibition «Metals of Siberia: Metallurgy,
Machine-Building, Metal-Working, Welding» in Novosibirsk ........... 43
Developed at PWI ............................................................ 33, 40, 44
Стр.1
ANALYSIS OF CONDITIONS CAUSING INITIATION AND
PROPAGATION OF CORROSION CRACKS IN ZONES OF
CIRCUMFERENTIAL JOINTS ON MAIN GAS PIPELINES
V.I.MAKHNENKO, V.M. SHEKERA, E.A. VELIKOIVANENKO, O.I. OLEJNIK, G.F. ROZYNKA and N.I. PIVTORAK
E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
The paper deals with conditions causing formation of corrosion cracks within the zones of circumferential field and
longitudinal factory welded joints on main gas pipelines. Described is the case study of force conditions and resistance
of material to initiation and propagation of stress corrosion cracks up to a spontaneous fracture.
Keywords: welded main gas pipelines, circumferential
welded joints, initiation and propagation of corrosion cracks,
crack resistance diagram, nominal stresses, stress concentration,
stress intensity factors
The most dangerous defects in welded main gas pipelines
are corrosion cracks, which are relatively difficult
to detect by using the in-pipe diagnostic method.
Initiation and propagation of such defects up to critical
sizes, when a spontaneous fracture takes place, are
determined by a number of factors:
• fracture of corrosion-preventing insulation on the
pipeline surface and, hence, formation of contact with
the environment (soil);
• time of dwelling of the pipe wall, ∆tc, under
stress corrosion conditions;
• degree of aggressiveness of the environment (humidity
of soil, its chemical composition, etc.);
• level of tensile stresses in the pipeline wall, and
presence of stress concentration zones;
• ability of the pipeline wall material to resist
initiation and growth of corrosion cracks.
The presence of the above factors is a precondition
for initiation and propagation of corrosion cracks.
However, each of them is not sufficient for formation
of the given type of defects.
As a rule, the time of reliable operation of a protective
coating on a pipeline is markedly shorter than
the specified and actual life time of the pipeline itself.
Here the probability of fracture (separation) of the
coating depends upon its type, deposition and service
conditions. The zone of field welded joints may be
very vulnerable, depending upon the coating deposition
conditions.
Time ∆tc of dwelling of the pipeline wall with a
fractured coating in the stress corrosion conditions is
hard to estimate by deterministic calculations. Estimation
of this value greatly depends upon the periodicity
of monitoring of the state of insulation (or
re-insulation) on the pipeline, duration of shutdowns
of the pipeline, changes in aggressiveness of the environment,
etc. A sufficiently conservative estimate
of ∆tc made by the reliable methods of monitoring of
the state of the insulation coating is an interval be2
tween
regular inspections (about 2--5 years), providing
that they are combined in time with the in-pipe
diagnostics of the state of the pipeline wall. It is very
important that during time ∆tc the corrosion cracks,
allowing for their initiation and growth (coalescence),
do not reach their critical sizes, at which the spontaneous
fracture takes place.
The degree of aggressiveness of the environment
for main gas pipelines is determined primarily by properties
of those soils wherein the pipelines are laid down
(the issue of corrosion damages on the internal surfaces,
which is characteristic of oil pipelines [1], is
not considered in this study). In this case, of high
importance is the degree of humidity of the soil caused
by periodic or continuous inflow of moisture.
As shown by the results of investigations conducted
by the E.O. Paton Electric Welding Institute, in the
case of periodic moistening of the soil, when it dries
out, a film of corrosion products appears on the crack
surface. Fracture of this film after an intensive moisture
inflow takes some time, this having a marked
effect on average values of the rate of crack growth
through thickness of the wall at constant stresses induced
by a force load. Constant and rather high humidity
of the aggressive environment is characteristic
of main pipelines laid down in marshland, on the bottom
of lakes, rivers and seas. When they are laid down
into the firm soil, a high humidity associated with
atmospheric precipitates is of a periodic character.
Considering the above circumstances, experimental
studies of the kinetics of growth of corrosion cracks
under laboratory conditions at a constant high humidity
(water solutions of extracts of corresponding soils
[2]) yield conservative data, which at the given stage
of investigation of the problem are fully acceptable
to predict remaining safe service life of pipelines.
The level of nominal tensile stresses in the pipe
wall is determined by an internal pressure of gas in a
pipe, as well as by bending deformations associated
most often with subsidence of the soil under the pipe
and bending moments due to the dead weight of the
pipe and backfilling material. Local geometric peculiarities
(e.g. zones of welded joints) causing the con©
V.I. MAKHNENKO, V.M. SHEKERA, E.A. VELIKOIVANENKO, O.I. OLEJNIK, G.F. ROZYNKA and N.I. PIVTORAK, 2009
5/2009
Стр.2