Contents of
the P
aton
W
elding
Journal
no.7, 2000
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Page
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PATON B.E., SEMENOV S.E., RYBAKOV A.A., VASILENKO S.K. and
VASILYUK V.M.
Ageing and procedure of evaluation of the state of
metal of the main pipelines in service
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2
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Basic concepts of ageing of metal of the line pipelines in use
for a long time are formulated proceeding from up-to-date
knowledge and available experimental data. The principles of
classification of the state of the pipeline materials, allowing
for the service effects, are suggested.
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POKHODNYA I.K., SHVACHKO V.I. and PORTNOV O.M.
Mathematical
modelling of absorption of gases by metal during welding
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21
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Results of mathematical modelling of absorption of hydrogen and
nitrogen by iron during welding are presented. The kinetic model
of interaction of the low-temperature plasma with metal, based on
the combined solution of equations of mass traasfer in gas and
metal, has been developed. Comparison of calculation results and
experimental data shows that the model developed adequately
describes absorption of two-atomic gases by metal. The process of
absorption of gases by the molten metal pool from the
low-temperatire plasma has been calculated. The above model
allowed the effect of the plasma temperature on the concentration
of gas dtMolWfii in metal to be estimated.
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EFIMENKO N.G. and KALIN N.A.
Thermodynamic analysis of redox
carbon-involving processes occurred during fusion welding
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17
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The article suggests an approach to thennodynamic calculation of
chemical reactions proceediDg in three phases, i. e. metal, slag
and gas, at the same temperature. Series of the probable
proceeding of reactions of oxidation of elements and reactions of
carbon reduction of elements from oxides have been arraagwl for
characteristic temperatures of the melting zone in arc welding.
It is shown that temperature of beginning of carbon reduction of
oxides in the metal phase, except CeO2, and FeO, is lower than
that in the slag phase which allows the deoxidation process to
occur at lower temperatures and provides the possibility of using
carbon in a bound state as a deoxidizer in welding consumables,
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KROSHINA G.M., VASILIEV V.G. and NOVIKOVA D.P.
Peculiarities of
phase and structural transformations occurring in gray cast irons
with a differing phosphorus content during thermal-deformation
welding cycle
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21
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Phase and structural transformations in commercial cast iron
SCh20 with a phosphorus content of 0.10 and 0.28 % during welding
have been investigated. The effect of the thermal-deformation
welding cycle on deformability of cast irons has been studied.
Continuous cooling transformation diagrams for austeoite have
been plotted. It is shown that an increased phosphorus content of
gray cast iron favours development of an intermediate
transformation of austenite in the HAZ metal. Peculiarities of
behaviour of phosphide eutectic during the thermal-deformation
welding cycle have been investigated.
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NAZARCHUK A.T.
Improvement of process of consumable electrode
welding with an intermittent arc
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28
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Some basic schematics are analyzed of stabilization of arc
excitation and running in metal-electrode arc welding with weld
formation in portions, in particular using a low-amperage arc.
Shown is the rationality of making up the welding circuit of
several independently controlled loops which provide the
conductance of the arc gap, main arc running, control of the
capacitor discharge in the arc gap by means of capacitive or
inductive contours connected directly into the welding circuit.
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BERNATSKY A.V.
Influence of anisotropy of the rolled stock
mechanical properties on initiation and development of tough and
lamellar-tough fractures
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31
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Brief description of expert estimations of service failures
related to the structural texture, is given. The rationality of
introduction of new terminology is presented in order to define
the main kinds of lamellar fracture, namely lamellar-tough,
lamellar-brittle, lamellar-fatigue and lamellar-hydrogen. A
quantitative estimate of the influence of the percentage of
sulphur in the base metal on the process of initiation and
development of tough and lamellar-tough fractures, is given.
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KIRILYUK G.A. and LEVCHENKO O.G.
Hygienic evaluation of process
of arc metallizing with flux-cored wire of Fe-B-Cr-Ni
alloying system
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38
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Quantitative characteristics of aerosols evolution in flux-cored
wire arc metallizing of alloyed alloys are determined and
recommendations are given on protection of workers and
environment.
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PWI TECHNOLOGIES
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40
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ADVERTISING
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51
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