Contents of the Paton
Welding
Journal
no.9-10, 2000
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International Conference "Welded Structures"
Kyiv, Ukraine, 10-12 October 2000
Papers of Plenary Sessions
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PATON B.E.
MODERN TRENDS TOWARD INCREASE IN STRENGTH AND LIFE OF
WELDED STRUCTURES
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2 |
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The set of topical problems associated with fabrication of
high-efficiency welded structures, increase in their strength and
reliability and extension of their life is presented. The
importance of improvement of scientific approaches to design of
welded joints is shown. Consideration is given to issues related
to evaluation of performance of main and process pipelines and
effect of plastic deformation on fracture toughness of pipe
steels. Results of investigations aimed at development of methods
for improvement of fatigue resistance of welded joints and
fatigue crack arresting are presented. The demand for a wider
application of high-strength steels is noted. Capabilities of the
acoustic emission and optical holography methods in terms of
using them for diagnostics of welded structures are considered.
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ALYOSHIN N.P. and GORNAYA S.P.
NEW APPROACH TO THE TECHNOLOGY OF
ULTRASONIC TESTING OF COARSE-GRAINED MATERIALS
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8
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The paper describes the solution of the problem of construction
of an acousto-solidification model of coarse-grained materials,
allowing for the features of structure formation, geometrical and
energy factors of ultrasonic waves attenuation. Analytical
dependencies were derived, a program was prepared and some
results of calculation of the passage and scattering of all types
of US waves are given. A conclusion is made on the need to take
into account the actual geometry and energy of the US beam for a
correct interpretation of the results of UT of the objects from
materials of the above type.
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GARF E.F. and NETREBSKY M.A.
ASSESSMENT OF THE STRENGTH AND
RESIDUAL LIFE OF PIPELINES WITH EROSION-CORROSION DAMAGE
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13
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The urgency of the considered problem for nuclear and thermal
power generation industry, is noted. It is shown that the codes
now in force permit the pipeline wall thinning by 15 % of the
design thickness, which, in a number of cases leads to a
significant lowering of the structure reliability and can cause
fracture. Introduction of a restriction not only on the wall
thinning values, but also on the main dimensions of the thinning
zone, is substantiated.
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HEROLD H. and WOYWODE N.
ELIMINATION OF CRACKS IN STEEL
STRUCTURES USING DESIGN-TECHNOLOGICAL MEASURES
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19
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Numerous open and closed cracks were detected in thick-walled
welded elements of span structures of a metallurgical workshop
made from increased-strength steel plates 11-45 mm thick. Cracks
were registered also in welds between shafts and drum bases of a
belt conveyer. Explanations of formation of this type of defects
are given. Design-technological measures are suggested for
elimination of such cracks.
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GORYNIN I.V., ILJIN A.V., LEONOV V.P. and MALYSHEVSKY V.A.
DESIGN-TECHNOLOGICAL STRENGTH OF WELDED JOINTS OF OFF-SHORE
STRUCTURES
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26
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Problems of assurance of reliability of off-shore engineering
structures, which cover a wide range of spheres, are considered.
Optimum results are obtained at a constant allowance for a real
technology during the process of the structure fabrication.
Approaches are described for the selection of materials, a system
of safety factors, design of connections and recommendations for
additional technological procedures, justification of
requirements to the quality of welded joints, improvement of
methods of assessment of a brittle strength and a cyclic life.
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DVORETSKY V.I.
EVALUATION OF RESIDUAL LIFE OF LOAD-CARRYING
WELDED STRUCTURES AND EXTENSION OF THEIR SERVICE LIFE
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34
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It is shown that service life of welded structures can be
extended using safety factors allowed for in design of these
structures and based on differences in their actual operating
time and assigned life time. The method is suggested to reveal
the above safety factors in order to estimate residual life of
the structures on the basis of main design parameters affecting
it.
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ZUBCHENKO A.S., VASILCHENKO G.S. and DRAGUNOV Yu.G.
APPLICATION
OF LEAK-BEFORE-BREAK CONCEPT FOR PROVISION OF THE SAFETY OF
WWER-1000 TYPE REACTORS
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39
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A program of R&D on substantiation of applicability of
leak-before-break concept to nuclear reactor piping has been
outlined and fulfilled. J-R curves measured on full-scale samples
cut out of a welded pipe with the working cross-section of 70 by
250 mm with through-thickness and semi-elliptical cracks in the
circumferential weld metal were compared with similar curves
derived on ST-1T compact samples. It is found that the parameters
of plastic fracture toughness measured on ST-1T samples are
characterised by a higher level of reliability compared to those
of full-scale samples.
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ZUBCHENKO A.S., KHARINA I.L., RUNOV A.E. and MAKHANEV V.O.
CORROSION-MECHANICAL STRENGTH OF WELDED PIPING OF AUSTENITIC
STEELS OF RBMK REACTORS
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45
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Corrosion-mechanical strength of welded piping of nuclear
reactors equipment of 08Kh18N10T austenitic steel is considered.
Numerous circular and axial crack-like defects were detected,
which initiate and propagate by the mechanism of intercrystalline
stress corrosion cracking. It is found that the main factors
which determine the incubation period and intensity of welded
joint damage are the level and nature of distribution of residual
welding and service stresses, presence of the zones of
plastically deformed metal and composition of the medium which is
in contact with the inner surface of the piping.
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KRASOVSKY A.Ya. and ORYNYAK I.V.
ASSESSMENT OF RESIDUAL LIFE OF
WELDS IN PIPINGS OF THE FIRST LOOP OF NUCLEAR POWER STATIONS
DAMAGED BY INTERCRYSTALLINE CORROSION
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54
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Considered are the methodological principles of comprehensive
estimation of strength and residual life of spatial piping
systems containing cracks. The method suggested consists of such
components as global stressed-strained state of a piping allowing
for all affecting force factors, allowance for residual welding
stresses, calculation of stress intensity factors, prediction of
stable forms of development of fatigue cracks and
intercrystalline corrosion, estimation of actual residual life of
a piping containing defects and prediction of conditions causing
leak to fracture.
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KRIVOSHEEV P.I.
PROBLEMS REGARDING WELDED STRUCTURES OF THE
"SHELTER" OBJECT AT THE CHORNOBYL NUCLEAR POWER STATION
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62
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Problems with structures in the "Shelter" object at the Chornobyl
Nuclear Power Station (ChNPS) are outlined. The most important
measures intended for implementation of the strategy of
stabilization of the "Shelter" object are indicated. They are
based on building of the new and reinforcement of existing metal
structures by making an extensive use of welding. The experience
gained will be applied for further work aimed at long-term
stabilization of the "Shelter" object.
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KNYSH V.V.
DETERMINATION OF CYCLIC LIFE OF STRUCTURE ELEMENTS IN
ARRESTING FATIGUE CRACKS
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69
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Method of calculated determination of a cyclic life of structure
elements with propagating fatigue cracks at their arresting by an
artificially-induced field of residual compressive stresses ahead
of tips of these cracks has been developed on the basis of
approaches of fracture mechanics.
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LOBANOV L.M., PIVTORAK V.A. and KUVSHINSKY N.G.
DIAGNOSTICS OF
STRUCTURES OF METALLIC AND COMPOSITE MATERIALS USING HOLOGRAPHY,
ELECTRON SPECKLE-INTERFEROMETRY AND SHEAROGRAPHY
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72
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Results of application of methods of holographic interferometry,
electron speckle-interferometry and shearography for
nondestructive quality control and determination of residual
stresses in elements and members of the welded and
adhesion-bonded structures made of metallic and nonmetallic
materials are presented. To make diagnostics of structures, the
compact holographic schemes and devices have been designed and
manufactured with the help of which the local fields of
displacements and deformations in the zones of defects and
relaxation of residual stresses are recorded. Examples of
diagnostics of aircraft and machine-building structures using the
holographic interferometry, electron speckle-interferometry and
shearography are given.
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MAKHNENKO V.I. and MAKHNENKO O.V.
DEVELOPMENT OF CALCULATION
PROCEDURES FOR ASSESSMENT OF ALLOWABLE DEFECTS IN WELDED JOINTS
OF CRITICAL STRUCTURES
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79
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Algorithms of assessment of allowable defects in welded joints of
the critical structures are considered on the basis of a
well-known concept "fitness-for-purpose", developed by the
International Institute of Welding and advanced approaches of
fracture mechanics of bodies with cracks. A significant role of
residual welding stresses, geometric peculiarities of welded
joints, mechanical heterogeneity, caused by the effect of a
welding thermal cycle and appropriate impurities in weld metal,
is outlined.
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PANASYUK V.V. and ANDREYKIV O.Ye.
NEW APPROACHES TO ASSESSING THE
WELDED JOINTS LIFE
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87
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The calculation model for solving the problems of welded joint
life has been formulated. In the proposed model a welded joint is
considered as a heterogeneous (by the physical and mechanical
properties) deformed solid with a defect like faulty fusion-crack
that propagates under cyclic loading of a body. The equations for
estimating the fatigue crack growth rate were obtained on the
basis of the balance of heterogeneous joint material fatigue
fracture energy and reversive elastoplastic deformation of the
process zone in the vicinity of the defect tip. The fatigue crack
propagation direction with respect to initial defect plane was
established from the condition that this direction provides the
maximum crack rate. The proposed model was applied for assessing
residual life of the butt and T-joints and a good correlation
between the calculational and experimental data was found.
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PATON B.E. and NEDOSEKA A.Ya.
NEW APPROACH TO EVALUATION OF THE
CONDITION OF WELDED STRUCTURES
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92
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New approaches to evaluation of the condition of welded
structures in service are considered. Shown is the need to apply
the technology of structure diagnostic based on 100 % control of
materials and structures which makes it necessary to implement a
package of measures including use of special diagnostic systems
and equipment, procedures of their application and standards
which regulate this work.
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PATON B.E. and TROITSKY V.A.
DEVELOPMENT OF NON-DESTRUCTIVE
TESTING OF CRITICAL METAL STRUCTURES
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95
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The paper presents some recent developments in the field of
non-destructive testing, promising directions of NDT as a basis
for technical diagnostics of metal structures which have been in
service for a long time, new technological capabilities in
computerisation of the NDT process. The role of Ukrainian Society
of NDT and Technical Diagnostics is shown.
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PERELMUTER A.V.
WEAR AND RELIABILITY OF STEEL STRUCTURES
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102
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General principles of wear of steel structures are considered.
Possible decisions which may be made after assessment of
technical state of structures are indicated. Data on the accident
rate of basic load-carrying structures are given. It is noted
that in the majority of cases the accident rate is not related to
the safety factor. In-service monitoring of the technical state
of an object is considered to be very important. The necessity of
developing regulatory and methodological documents for
specification, assessment and maintenance of a certain level of
safety of load-carrying structures is substantiated.
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RAGUNOVICH S.P., TSYGANOV V.A. and SHELEG V.K.
ELECTRIC-ARC
WELDING UNDER FORCED CONDITIONS
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102
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Described is the approach to investigation of relationship
between volt-ampere dynamic characteristics of a heat source and
peculiarities of formation of the weld pool which determine the
quality of welding. The concept of computer diagnostics and
monitoring of the arc welding process, based on the finite number
of statistical moments of the arc power, is presented. The
quantitative indication of the welded joint quality is suggested.
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CERJAK H. and LETOFSKY E.
STRUCTURE AND PROPERTIES OF E911 STEEL
WELDED JOINTS
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112
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Weldability and creep rupture strength of a new low-carbon
chromium steel of the ferritic class at elevated temperatures
were investigated. Compared to the known P91 steel, the new steel
is further alloyed with tungsten. Investigations demonstrated
that E911 steel is not inferior to P91 steel in weldability,
while the creep rupture values of E911 steel welded joint are
higher than those of P91 welded joint.
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SMIRNOV V.V. and TSUKUROV O.A.
PROBLEMS OF CERTIFICATION OF
WELDING FABRICATION IN MACHINE-BUILDING BRANCHES OF RUSSIA
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117
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The state-of-the-art in certification of welding fabrication in
the machine-building industry branches of Russia is analyzed and
evaluated. The ways of an integrated solution of problems
existing in the field of certification are suggested.
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STEKLOV O.I.
MECHANICAL-CORROSION STRENGTH OF WELDED STRUCTURES
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125
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State-of-the-art of the metal stock of welded structures under
the conditions of their corrosion and ageing is considered.
Specifics of a mechanical-corrosion strength of welded joints and
approaches to the calculation of strength at stress corrosion are
shown.
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FROLOV K.V. and MAKHUTOV N.A.
STRENGTH AND LIFE OF WELDED JOINTS
IN NUCLEAR POWER REACTOR STRUCTURES
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132
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Features of design, technological solutions, welding defects and
their influence on generation of the stressed-strained states in
load-carrying structures of water-water power reactors are
considered. Given are the results of experimental and design
analysis of the fields of stresses which induce various limit
states during the regular and emergency operation of NPP.
Interaction of the academic, research, design, technological
organisations and branch research institutes in solving the
problems of strength and life of welded joints, is shown.
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FUJITA Yu. and YURIOKA N.
RECENT DEVELOPMENTS OF STEEL AND
WELDING MATERIALS CAPABLE OF IMPROVING STRUCTURAL INTEGRITY
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139
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A number of problems associated with the creation of
high-reliability engineering structures is considered. They
include the peculiarities of application of structural materials
of the new generation which is characterized by a high strength,
corrosion resistance, high-temperature and heat resistance. The
ways of development of materials for their welding are defined.
It is shown that a simultaneous development of steels and welding
consumables is a very important link in the process of
improvement of reliability of welded joints from the point of
view of resistance to tough and brittle fracture, fatigue,
corrosion and/or creep.
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FUJITA Yu., MANABE Yu., ZENITANI S. and URAKAWA S.
DEVELOPMENT OF
TWO WIRES TIG WELDING WITH ELECTROMAGNETICALLY CONTROLLED MOLTEN
POOL PROCESS
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145
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In horizontal position, welding bead has an inclination to become
hanging bead by gravity, and this problem makes horizontal
welding difficult for high-deposition rate welding. To solve this
problem, authors proposed a new concept of welding process,
so-called electromagnetically controlled molten pool (ECMP)
welding process. In this process the molten metal flow and bead
shape are controlled by using upward electromagnetic force.
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VON HOFE D. and MIDDELDORF K.
INNOVATIONS IN JOINING TECHNOLOGY -
PROCESSES AND PRODUCTS FOR THE FUTURE
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149
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Promising areas of development of different materials (steels,
light metals and alloys, metal foams, composites, polymers) are
considered. It is noted that in the future welding and related
technologies will be the preferred methods, because of their high
productivity, high degree of automation and simulation.
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CZWORNOG B.
EFFECT OF SHIELDING GAS COMPOSITION ON
CHARACTERISTICS OF HIGH-EFFICIENCY CONSUMABLE-ELECTRODE
SHIELDED-GAS WELDING (MAG
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157
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The results of investigation of high-efficiency processes of
welding in Ar-He-CO2 and Ar-CO2 mixtures at 450 A currents are
given. The sizes of a cross-section of deposited beads, including
the depth of penetration are evaluated. The chemical composition
was determined, metallographic examinations, and also the tensile
tests, impact bend and fracture toughness tests of metal
deposited in shielding gas mixtures at 300, 350 and 400 A
currents were performed. There were no significant differences in
properties of the metal deposited in various mixtures. Good
characteristics of properties of the deposited metal and welded
joints obtained at currents up to 430 A using all compositions of
shielding gas mixtures were confirmed.
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CHERNYAEV K.V. and VASIN E.S.
ENSURING OF SAFE OPERATION AND
EXTENSION OF SERVICE LIFE OF MAIN PIPELINES
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161
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The Joint-Stock Company Transneft developed and put into
operation the system for ensuring safe operation and extension of
service life of main pipelines. The system is based on integrated
four-level diagnostic monitoring using in-pipe high-resolution
diagnostic gears, allowing all types of defects which are the
main causes of accidents to be revealed. Repair of pipelines is
planned on the basis of estimation of an extent of danger of
defects revealed. The composite-coupling technology is employed
for selective repair of pipelines without any interruption of
pumping. The system makes it possible to fundamentally decrease
the rate of accidents at main oil pipelines and provides
substantial cost effectiveness.
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SHAN JIGUO, WU AIPING, ZHANG DI and REN JIALIE
HEAT TREATMENT AND CLADDING USING A LIGHT BEAM HEATING
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164
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The problems of heat treatment and cladding using a method of a
light beam heating to improve the serviceability of components
under the complex conditions of loading are considered. It was
established that the use of a light beam source is an alternative
to a laser source. It is shown that the light beam cladding of a
composite powder of Ni-Cr-B-Si-WC system on steel 45 contributes
to the increase in microhardness of coating almost by 2 times.
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ADVERTISING
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