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 method efficiency.

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 not examined.
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 and company standards 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 stations.
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.
Guide for safety. The instruction for diagnostics of buried steel gas pipelines.
GD 102-008-2002. The instruction for diagnostics of pipelines technical condition by non-contact method.
P1-01.05 M-0183. Methodical Guidelines of the company. Technical requirements for incoming inspection, repair of electrical submersible pump units (PJSC Rosneft).
P1-01.05 M-0012 UL-099. LLC RN-YUGANSKNEFTEGAZ Methodical Guidelines. Requirements for electrical submersible equipment incoming control, quality of repair, inspection and supply package.
Technique for diagnostics of wellhead, production tree and pressure valves that have worked out their standard service life (PJSC Lukoil).
GD 19.100.00-KTN-036-13. The regulations for technical diagnostics and examination of manufacturing machinery. The procedures for technical diagnostics of manufacturing machinery. Part 2. Procedures.
GD 23.040.00-KTN-186-15. Main pipeline transport of oil and petroleum products. Technical diagnostics and hydro-testing of the technological pipelines. Procedure
GD SEC "Expertlift" 05-001-2002. Passenger, bed and freight elevators. Non-destructive testing. Methodical Guidelines for the magnetic testing of elevator metal structures.
GD 05-112-2005. Hoisting cranes. Non-destructive testing. Technical guideline for magnetic inspection (metal magnetic memory method) of metallic structures of lifting machines.
STO Gazprom GD 1.10-098-2004. The procedure for technical diagnostics of pipelines and process equipment manifolds at gas-distributing stations of gas-main pipelines.
GD 05-112-2005. Hoisting cranes. Non-destructive testing. Technical guideline for magnetic inspection (metal magnetic memory method) of metallic structures of lifting machines.
STO Gazprom 2-1.9-089-2006. Prediction of technical condition for potential service life extension of thermal power equipment.
STO Gazprom 2-2.3-085-2006. Technique for conducting basic diagnostic examination of underground gas storage buried process pipelines.
STO Gazprom 2-2.3-095-2007. Methodical Guidelines for diagnostic examination of main gas pipelines linear section.
STO Gazprom 2-2.3-112-2007. Guidelines for operability assessment of main gas pipeline sections with corrosion defects.
STO Gazprom 2-2.3-173-2007. Instructions for comprehensive examination and diagnostics of main gas pipelines susceptible to stress corrosion cracking.
STO Gazprom 2-2.3-184-2007. Technique for calculation and substantiation of main gas pipelines safety factors and stability at operation and maintenance stage.
STO Gazprom 2-3.5-252-2008. Technique for extending the safe operation period of main gas pipelines.
STO Gazprom 2-2.3-253-2009. Technique for gas pipelines' technical condition and integrity assessment.
STO Gazprom 2-2.3-327-2009. Assessment of compressor stations process pipelines' stress-strain state.
STO Gazprom 2-2.3-328-2009. Assessment of compressor stations process pipelines' technical condition and safe operation period.
STO Gazprom 2-4.1-406-2009. The technique for residual lifetime assessment of main gas pipelines shut-off and control valves.
STO Gazprom 9.4-052-2016. Corrosion protection. Arrangement of PJSC Gazprom facilities corrosion inspections. Basic requirements.
SA-03-008-08. Welded vertical steel tanks for oil and oil products. Technical Diagnostics and Safety Analysis.
STO MOG 9.4-002-2011. Technique for technical diagnostics of shut-off devices at the Moscow region SUE "Mosoblgaz" facilities.

Techniques and methodical guidelines developed by Energodiagnostika Co. Ltd and agreed with the Federal Service for Environmental, Technological, and Nuclear Supervision (Rostekhnadzor):

Methodical guideline for technical diagnostics of pipelines.
Methodical guideline for technical diagnostics of vessels and apparatuses.
The technique for assessment of steam boiler drums state.
The technique for assessment of boiler and steampipe bends state.
Methodical guideline for technical diagnostics of electrical submersible pumping systems (EPS) end parts.

Techniques and methodical guidelines developed by Energodiagnostika Co. Ltd:

The technique for assessment of steam turbine rotors state.
The technique for assessment of steam turbine blades state.
The technique for control of turbine rotors flushing holes.
The technique for assessment of individual parts condition in turbine equipment (studs, bearing inserts).
The technique for assessment of turbine bodies, cylinders, lock and control valves state.
The technique for assessment of generator sleeve tubes state.
The technique for assessment of compressor system blades and rotors state.
The technique for control of babbit abutment density on sliding bearing inserts.
The technique for detecting mechanical stress concentration zones in gear wheels.
The technique for control of crane pivots, buckets, hooks and hook hangers.
Technical guideline for engineering diagnostics of compressor-boring pipes and couplings.
Technical guideline for in-pipe diagnostics of heat exchangers.
The technique for control of production trees at oil and gas fields.
Methodical guideline for non-contact magnetometric inspection of gas and oil pipelines.
The technique for assessment of technical state of operating heat pipes using the non-contact magnetometric method (agreed with OJSC "MTC").
Instruction for inspection of heat pipes in manifolds without isolation removal (agreed with OJSC "MTC").
The technique for inspection of circular welded joints on gas and oil main pipelines by the MMM (agreed with OJSC "Gazprom").
Methodical guideline for inspection of large-diameter pipelines (530-1420 mm).
Methodical guideline for inspection of rolling-mill working and back-up rolls.
Methodical guideline for 2.0 and 2.6 mm steel wire inspection.
Methodical guideline for inspection of locomotive power components (frog, shaft, spline joints).
Methodical guideline for technical diagnostics of high-voltage line derrick guys fastening units.
Methodical guideline for expert inspection and lifetime assessment of excavator metal designs (rotary excavators, open-mine excavators, draglines) using NDT methods.

The following specialized instruments and software have been developed and mass-produced:

Electromagnetic Indicator of Cracks EMIC-1M, EMIC-2M, EMIC-Ex.
Testers of Stress Concentration TSC-2M-8, TSC-3M-12, TSC-4M-16, TSC-5M-32, TSC-6M-8, TSC-7M-16, TSC-8M-4, TSC-9M-12, MEC-TSC.
"MMM-System" software for computer processing of MMM-inspection results and "MMM-Lifetime" software.

The instruments are certificated at the Federal Agency for Technical Regulation and Metrology. Certificates RU.C.27.002.A No.35003 and RU.C.34.003.A No.42683.

The standards are published:

ISO 24497-1:2007(E) Non-destructive testing - Metal magnetic memory - Part 1: Vocabulary.
ISO 24497-2:2007(E) Non-destructive testing - Metal magnetic memory - Part 2: General requirements.
ISO 24497-3:2007(E) Non-destructive testing - Metal magnetic memory - Part 3: Inspection of welded joints.
GOST R 52330-2005. Non-destructive testing. Evaluation of deformations in industrial and vehicle structures. General requirements.
GOST R 53006-2008. Estimation of potential dangerous objects lifetime on the basis of express methods. General requirements.
GOST R 55044-2012. Technical diagnostics. Selection of test items for the calibration of equipment for measuring the stress-strain state of structural materials. General requirements.
GOST R 56663-2015. Non-destructive testing. Quality control of technical products by residual magnetization formed during their manufacture. General requirements.

Since 1996 the Russian and International Centre for experts training and certification in the metal magnetic memory method with issuing of Level I, II and III Certificates operates in Moscow. The branches of the centre operate in Prague, Warsaw and Beijing. As of 2019, more than 2600 experts in Russia, more than 500 experts in China, 85 experts in Poland and more than 230 experts in other counties passed training.

Seven International Conferences "Diagnostics of equipment and structures using the metal magnetic memory" were held in Moscow in 1999, 2001, 2003, 2007, 2009, 2011, 2013 and in 2015. 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.

From 1994 till 2017 50 IIW documents with positive resolutions on the metal magnetic memory method were issued.

The International Standards ISO 24497-1:2007(E), 24497-2:2007(E), 24497-3:2007(E) on the metal magnetic memory method were approved in 2007 as a result of positive voting among 18 IIW member countries and more than 10 ISO Committee countries.

The metal magnetic memory method and appropriate testing instruments are used at more than 1000 Russian enterprises. Besides Russia, the method is widespread in 44 countries: Angola, Argentina, Australia, Azerbaijan, Bahrain, Belarus, Bosnia and Herzegovina, Brazil, Bulgaria, Canada, China, Colombia, Croatia, Czech Republic, Finland, Germany, Hungary, India, Iran, Iraq, Israel, Italy, Japan, Kazakhstan, Korea, Latvia, Lithuania, Macedonia, Malaysia, Moldova, Mongolia, Montenegro, the Netherlands, Oman, Poland, Romania, Serbia, South Africa, Switzerland, Tajikistan, Turkmenistan, Ukraine, United Arab Emirates, the USA.