The Totals of Application of the Metal Magnetic Memory Method to Industry in
Russia and Other Countries
Dr., Professor A. A. Dubov
The metal magnetic memory method (MMM) is the
non-destructive testing method based on the analysis of self-magnetic leakage
fields (SMLF) distribution on components’ surface, and is intended for
determination of stress concentration zones, imperfections, heterogeneity of
metal structure and welded joints.
Based on the established correlation of dislocation processes with the
magnetic phenomena physics in products’ metals the concept "metal magnetic
memory" was introduced and a new diagnostic method was developed. The uniqueness
of the metal magnetic memory is that it is based using of the self-leakage
magnetic field (SLMF). Occurrence of SLMF is caused by formation of domain
boundaries at accumulation of high-density dislocations (dislocation walls).
Obtaining of such an information source like self-leakage magnetic field is not
possible in any conditions with artificial magnetization. Such information is
formed and can be obtained only in a weak external field like the Earth’s
magnetic field in loaded structures, when the strain energy exceeds the external
magnetic field energy by order. It was demonstrated in practical works that MMM
can be applied both at equipment operation and after working unloading, during
the repairs. Magnetic texture, formed under the action of working loads,
becomes, so to say, "frozen" after unloading by virtue of the "magnetic
dislocation hysteresis". Thus, there is a unique opportunity to perform
assessment of equipment’s stress-strained state and detect zones of metal
maximum damaging by reading this information using specialized instruments.
Interest of experts of Russia and other countries from various industries to
essentially new magnetic method of non-destructive testing (NDT) grows steadily.
Application of the MMM method and corresponding inspection devices to industry,
as a rule, is carried out on a voluntary basis that is vivid confirmation of the
Interest to the method is caused by unsolved problems, which arise in
practice at quality control of engineering products, at reliability control and
at equipment life estimation.
Let’s denote the basic from them.
Till now on the majority of manufacturing plants in Russia and other
countries there are no 100% quality control of production on heterogeneity of
metal structure. Due to this reason the spread of mechanical properties on new
products reaches 20% and more, that considerably reduces their lifetime.
Welding exists more than 100 years, and NDT methods, which allow in
practice to carry out express quality control of welded joints in the united
complex system of the factors "structural-mechanical inhomogeneity – defects
of a weld – structural and technological stress concentrator", till now are
not present. Now non-destructive test is commonly applied with detection of
inadmissible defects (at that, the scientifically-grounded norms for the sizes
of permissible defects in welded joints from the point of view of fracture
mechanics, as a rule, are not present). The most important – distribution of
the residual welding stresses determining welded joint reliability till now is
Existing problems of a lifetime estimation of the aging equipment with
usage of conventional methods and control devices are not solved because of
their unfitness for early diagnostics of fatigue damages.
It is possible to speak confidently, that if we have the old equipment, which
we cannot 100% inspect on metal structural damaging and detect imminent damages;
in this case we work on sudden failure.
Thus, in spite of the fact that non-destructive testing exists in Russia and
other countries already more than 100 years, many problems of products quality
control and diagnostics are still unsolved. Therefore demand of the MMM method
directed on the solution of specified NDT problems, is caused by daily practice
and a life of the enterprises.
The method of metal magnetic memory under the physical substance represents
not only essentially new NDT magnetic method, the method is a new trend in
engineering diagnostics as it unites potentials of non-destructive testing,
fracture mechanics and materials science.
The following guidance documents based on the method of metal magnetic memory
are developed and applied nowadays in power engineering, petrochemical, gas
production and other industries in Russia:
GD 10-577-03. Standard instruction for metal control and lifetime
prolongation of boilers, turbines and pipelines main units at thermal power
GD 34.17.446-97. Technical guideline for engineering diagnostics of heating
surface pipes of steam and hot-water boilers.
GD 34.17.437-95. Technical guideline for engineering diagnostics of welded
joints on pipelines and vessels (temporary document).
GD 51-1-98. The technique for on-line computer diagnostics of local gas
pipeline segments using the metal magnetic memory.
GD 03-380-00. The instruction for inspection of ball vessels and gasholders
for pressurized liquefied gases storage.
GD 03-410-01. The instruction for complex engineering examination of
isothermal vessels for liquefied gases.
GD 12-411-01. The instruction for diagnostics of gas pipelines underground
GD 102-008-2002. The instruction for diagnostics of pipelines technical
condition by non-contact method.
GD 153-39.4-053-00. The technique for gates condition diagnostics during
operation before and after overhaul using NDT methods.
GD 08.00-29.13.00-KTN-012-1-05. The regulations for procedure of
engineering examination and lifetime prolongation of oil pipelines
GD 16.01-60.00-KTN-085-1-05. The technique for diagnostics and
certification of the ODS technological oil pipelines.
MR-10-72-04. Methodical recommendations for technical condition assessment
and residual life estimation in order to determine the possibility to prolong
elevators safe operation life.
The techniques and methodical guidelines developed by Energodiagnostika Co.
Ltd and agreed with State Engineering Supervision of Russia (Rostechnadzor):
Technical guideline for engineering diagnostics of pipelines.
Technical guideline for engineering diagnostics of vessels and
The technique for assessment of steam boiler drums condition.
The technique for assessment of boiler and steampipe bends condition.
Technical guideline for magnetic inspection of elevators metallic
Technical guideline for engineering diagnostics of electrical rotary pump
systems (ERPS) end parts.
The techniques and methodical guidelines developed by Energodiagnostika Co.
The technique for assessment of steam turbine rotors condition.
The technique for assessment of steam turbine blades condition.
The technique for control of turbine rotors flushing holes.
The technique for assessment of individual parts condition in turbine
equipment (studs, bearing inserts, etc.).
The technique for assessment of turbine bodies, cylinders, lock and control
The technique for assessment of generator sleeve tubes condition.
The technique for assessment of compressor system blades and rotors
The technique for control of babbit abutment density on sliding bearing
The technique for detecting mechanical stress concentration zones in gear
The technique for control of crane pivots, buckets, hooks and hook
Technical guideline for engineering diagnostics of compressor-boring pipes
Technical guideline for in-pipe diagnostics of heat exchangers.
The technique for control of production trees at oil and gas fields.
Technical guideline for non-invasive magnetometric inspection of gas and
oil pipelines using TSC-type devices.
Technical guideline for inspection of large-diameter pipelines
(?530-1420mm) using specialized scanning devices and the MMM method.
Technical guideline for inspection of rolling-mill working and back-up
Technical guideline for ?2,0 and ?2,6 steel wire inspection.
Technical guideline for inspection of locomotive power components (frog,
shaft, spline joints).
The technique for control of stress distribution in tightened bolted
The methodical guidelines for engineering diagnostics of high-voltage line
derrick guys fastening units.
The technique for detection of mechanical stress concentration zones in
products and equipment.
Energodiagnostika Co. Ltd has developed and produces on a full-scale basis
the following specialized inspection instruments and the appropriate program
Tester of Stress Concentration Magnetometric TSCM-2FM and advanced
Electromagnetic Indicator of Cracks EMIC-1M, EMIC-2M.
Testers of Stress Concentration with scanners on the basis of
microprocessor: TSC-1M-4, TSC-2M-8, TSC-3M-12 and TSC-4M-16.
Tester of Stress Concentration on the basis of Notebook TSC-5M with
The"MMM-System" software for computer processing of MMM-inspection results
The "MMM-Lifetime" software.
The instruments are certificated in Gosstandard of Russia and are included in
the State List of Measuring Instruments. Certificates RU.C.37.003.A No.9192 and
In 2002 the standard of the Russian Welding Society ST RWS 004-03
"Non-destructive testing. Welded joints of equipment and constructions. Method
of metal magnetic memory" was approved.
Three Russian standards are published:
GOST R 52005-2003. Non-destructive testing. Metal magnetic memory method.
GOST R 52081-2003. Non-destructive testing. Metal magnetic memory method.
Terms and definitions.
GOST R 52330-2005. Non-destructive testing. Stressed-strained state test on
industrial objects and transport. General requirements.
Since 1998 the Russian and International Center for experts training and
certification by the method of metal magnetic memory with issuing of Level I and
II Certificates operates in Moscow. The branches of the center operate in Warsaw
and Beijing. As of 2008, more than 1300 experts in Russia, more than 250 experts
in China and 70 experts in Poland passed training.
The first, second, third and fourth International Conference "Equipment and
structures diagnostics using the method of metal magnetic memory" was held in
Moscow in February, 1999, in February, 2001, in February, 2003 and in February,
2007. The conference proceedings were considered at meetings of the
International Institute of Welding (Lisbon, July 22, 1999, Ljubljana, July 11,
2001, Osaka, July 11, 2004). The totals of the conference are reflected in the
IIW documents No.XI-714/99, No.V-1196-01 and No.V-1252-03.
During the period from 1994 till 2008 42 IIW documents with positive
resolutions on the metal magnetic memory method were issued.
The International Standard ISO 24497-1:2007(E), 24497-2:2007(E),
24497-3:2007(E) on the metal magnetic memory method is approved in 2007 as a
result of positive voting among 18 IIW member countries and more than 10 ISO
The metal magnetic memory method and appropriate testing instruments are used
at more than 1000 Russian enterprises. Besides Russia, the method was
implemented at a number of enterprises of 25 countries: Argentina, Angola,
Australia, Bulgaria, Byelorussia, Canada, China, Finland, Germany, India, Iraq,
Iran, Israel, Kazakhstan, Latvia, Lithuania, Macedonia, Moldova, Mongolia,
Montenegro, Poland, Serbia, South Korea, Ukraine, USA.