GOST R58599-2019


Technical Diagnostics


General Requirements

Fragment translated into English by CM Diagnostics


1 DEVELOPED by a Limited Liability Company "Technical Centre "Welding and Control in Construction" (TC "SKS" Ltd.), a Limited Liability Company "Magnetometric diagnostics" (Magnetometric diagnostics Ltd.), a Limited Liability Company "Advisory Engineering Centre "KRAN" (Advisory Engineering Centre "KRAN", Ltd.)

2 INTRODUCED by Technical Committee for Standardization TC 132 "Technical Diagnostics. Evaluation and Strength Tests"

3 APPROVED AND BROUGHT INTO FORCE by the Order of the Federal Agency on Technical Regulating and Metrology of 15 October 2019  No 991-st.         


Table of contents 

1 Scope 

2 Regulatory references 

3 Terms and definitions

4 Designations and abbreviations 

5 General provisions

6 Safety requirements

7 Requirements for instruments

8 Preparation and conduct of measurements

9 Measurement results processing

10 Arrangement rules for measurement results

Annex A (reference) Mechanical and magnetic properties of hot-rolled products made of carbon and low-alloy steel

Annex B (recommended) The test record sheet of coercive force        


Over the last years, diagnostics of metalwork using the coercive force measurement method (hereinafter "MCM" – a magnetic coercimetric method) has been gaining the widespread application as one of the most promising methods for ensuring trouble-free operation of important technical facilities in a number of industries such as metallurgy (GOST 30415), mechanical engineering, nuclear power engineering, construction, etc.  The application of MCM is especially effective where steel structural members are subject to permanently acting static or cyclic loads: construction metal structures [1], hoisting-and-transport facilities [2], pressure vessels, pipelines, railway rolling stock, etc.

The MCM advantage is in obtaining of more detailed information on technical condition of the facilities compared to standard non-destructive testing methods. There are numerous examples of its effective application upon the inspection of metal structures of any purpose[1].

This Standard was elaborated aiming at provision of the methodological basis for the creation of engineering practices of diagnosis and control of the technical condition of an abundance of important technical facilities by criterion of the level of accumulated service-induced fatigue microdamage to the metal.


[1] Arefief Yu.V., Shalygo A.A. Application experience of coercimetry upon the inspection of construction metalwork. In the World of Non-Destructive Testing, 2016, vol.19, No.1, p.44-48.


Effective date – 2020-01-01

1 Scope

This Standard covers the magnetic diagnostics method of steelwork made of ferromagnetic carbon and low-alloy structural steel according to GOST 380, GOST 19281, GOST 27772, including construction metal structures made of steel according to GOST 27772, based on measurement  results of coercive force, and is intended for control of physical and mechanical properties of structural metal influencing on an actual value of the remaining lifetime.  Diagnostics of the structures with the method of coercive force measurement does not apply to detection of metal defects such as films, laps, delamination, cavities, inclusions, cracks, unwelded spots, etc. and which presence or absence is established by the standard methods of non-destructive testing: ultrasonic, X-ray, eddy current, magnetic particle, capillary, etc.

Coercive force diagnostics of the structures is used in estimating of metal state as an aggregate measure of damage (expired service life) accumulation in a result of the impact of operational factors.  The MCM allows to detect structural members in which metal degradation reached a value corresponding to metal transition into elastoplastic state or a critical level of depletion of ducility margin and transition to the stage of metal failure.

The method regulated by the Standard is used for:

- routine inspection of metalworks as well as metal structures to be reconstructed, aiming at the clarification of initial design parameters;

- on metalwork exposed to unforeseen loads during the operation;

- newly mounted, complex metal structures in design models of which all the factors affecting the bearing capacity of members cannot be considered; 

- monitoring of the structure state as a whole or its individual parts, including the assessment of life characteristics;

- carrying out the expert examination of industrial safety of hazardous production facilities to clarify the location of the zones of stress concentration and increased operational damage of metal with an assessment of the level of such damage;

- carrying out experiments on full-scale models, samples in order to clarify design models, to obtain the dependences of a coercive force value on the metal fatigue failure level under various stress states.

2 Regulatory references

This Standard uses the regulatory references to the following standards:

GOST 7.32–2001 System of standards on information, librarianship and publishing. The research report. Structure and rules of presentation

GOST 12.1.004–91 Occupational safety standards system. Fire safety. General requirements

GOST 12.1.038–82 Occupational safety standards system. Electric safety. Maximum permissible values of touch voltages and currents

GOST 12.2.003–91 Occupational safety standards system. Industrial equipment. General safety requirements

GOST 12.3.002–2014 Occupational safety standards system. Industrial processes. General safety requirements

GOST 27.002–2015 Dependability in technics. Terms and definitions

GOST 380–2005 Common quality carbon steel. Grades

GOST 427–75 Measuring metal rules. Specifications

GOST 1497–84 Metals. Methods of tension test

GOST 2789–73 Surface roughness. Parameters and characteristics
GOST 15467–79 Product quality control. Basic concepts. Terms and definitions
GOST 19281–2014 High strength rolled steel. General specifications

GOST 20911–89 Technical diagnostics. Terms and definitions

GOST 27772–2015 Rolled products for structural steel constructions. General specifications

GOST 28840–90 Machines for tension, compression and bending testing of materials. General technical requirements

GOST 30415–96 Steel. Non-destructive testing of mechanical properties and microstructure of steel products by magnetic method

GOST R 8.563–2009 State system for ensuring the uniformity of measurements. Procedures of measurements

GOST R 12.1.019–2009 Occupational safety standards system. Electrical safety. General requirements and nomenclature of kinds of protection

GOST R 55612–2013 Magnetic non-destructive inspection. Terms and definitions

3 Terms and definitions

The terms in conformity with GOST R 55612, GOST 27.002 are used in the Standard herein, as well as the following terms:

3.1 emergency state: The category of technical state of a structure characterized by damages and deformations which are evidence of end-of-life.

3.2 degradation of mechanical properties of steel: The process of changing induced by operational factors of controlled mechanical characteristics (stress-strain characteristics) of steel compared to similar characteristics specified  by design-and-engineering and regulatory documents.

3.3 a defect (flaw): Each individual product non-conformance to the set requirements. [GOST 15467, number 38]

3.4 a calibration sample: A specimen from steel of certain grade (composition) undergone pre-set heat treatment, with a certain value of coercive force, intended for calibration and setting of a coercimeter.

3.5 coercive force: Magnetic field strength required for complete demagnetization of pre-magnetized to saturation ferromagnetic.

3.6 a coercimeter: A device designed for the measurement of a coercive force value of metal.

3.7 magnetometric  diagnostics: Control over technical state of metalwork made of ferromagnetic materials based on the measurement of magnetic parameters of metal.

3.8 run: Duration or scope of works of a facility.

N o t e – The run could be expressed as a continuous quantity (operating time in hours, the length of run in kilometres, etc.), so a discrete quantity (a number of working cycles, startups, etc.). [GOST 27.002, subparagraph 3.3.1]

3.9 limited state of operability: The category of technical state of a structure upon which there are defects resulting in loss of mechanical characteristics, but there is no a risk of sudden failure and functioning of a structure, if its state, service time and operating conditions are controlled.

3.10 remaining lifetime: The total run of a facility from the moment of its technical state control till the moment of reaching a limit state.[GOST 27.002, subparagraph 3.3.5]

N o t e – The limit state of a structure in this Standard means a state conforming to prefracture of its "weakest link" (see 3.13): the appearance of main cracks, depletion of ductility margin  and so on depending on the type of structure loading.

3.11 relative remaining lifetime: Percentage ratio of remaining life of a structure to its life.

3.12  life: The total run of a facility from the beginning of its operation or renewal after repair till the moment of reaching a limit state.   [GOST 27.002, subparagraph 3.3.4]

3.13 "weakest link": A load-bearing (design) member of metalwork which demonstrated a maximum value of coercive force at technical testing with the MCM, and which value is used for computation of remaining lifetime of a structure as a whole.

3.14 technical diagnostics: Field of knowledge covering the theory, methods and means of determination of technical state of the facilities.[GOST 20911, number 3]

3.15 technical testing testing: Determination of a facility technical state. [GOST 20911, number 4]

3.16 technical state of a facility: A state which is characterized in the given time, upon certain ambient conditions, by the parameters values set by regulatory and technical documents for a facility. [GOST 20911, number 2]

3.17 structural reinforcement: A package of measures providing enhancement (recovery) of load-carrying capacity and performance characteristics of individual elements and a structure as a whole that are in a critical or limited operable condition.

4 Designations and abbreviations

4.1 The following designations are used in the Standard herein:

Hc      – coercive force, A/cm;

Hmax– a maximum value of coercive force in metal of the controlled metalwork member, A/cm;

Hп     – coercive force of metal on an as received state, A/cm;

H     – coercive force of metal in the state of prefracture (conform to tensile strength brake during the bench test), A/cm;

Hт     – coercive force of metal on an as received state, A/cm;

Hl      – a value of coercive force measured along load application, A/cm;

Ht      – a value of coercive force measured along load application, A/cm;

σ       – mechanical stress, MPa;

ε        – relative deformation, %;

σT      – yield strength, MPa;

σB      – tensile strength, MPa;

T       – operation time (run) of a structure at the moment of testing with the MCM;

P       – operational life of a structure;

Prem  – remaining operational lifetime of a structure;

P'rem  – relative remaining operational lifetime of a structure, %.

4.2 The following abbreviations are used in the Standard herein:

CS – calibration sample;

MCM – magnetic coercimetric method;

MI – measuring instruments;

SSS – strain-stress state.

5 General provisions

5.1 The MCM is based on physical correlation on the level of operational damage of metal structure of the monitored construction and a value of its coercive force Hc change within the operational range of all the possible values: from as received state Hп to the state of corresponding prefracture H. Each steel grade has its specific variation range of coercive force.

5.2 A value Hп for each steel grade depends on the following main factors:

- thermomechanical processing of rolled product and its type (sheet, shaped and round pipes, shape steel-rolled stock, etc.);

- metal thickness;

- chemical composition of steel grade depending on the content of alloying constituents within the variation range regulated by normative documents;

- a grain size and structural inhomogeneity degree.

5.3 Among the factors listed, process operations for getting rolled stock have the highest influence of a value of coercive force Hп. For the given steel grade, the values Hc of hot-rolled, heat-treated and cold-rolled mill products may differ in 4 folds.

5.4. The thickness of the monitored products, in particular, within the range of 1-5 mm, influences on readings of the coercimeter with attached transducers.  Therefore, prior to inspection of the relevant structures, it is required to perform bench tests and plot calibration curves of MI readings on mechanical characteristics of rolled steel of the set thickness for the given steel gage and grade to enhance accuracy check.

5.5 A minimum value of coercive force corresponds to metal at minimum residual stresses after annealing.  A maximum value of coercive force Hf is determined for each steel at the prefracture stage by changing a Hc value in the process of bench destructive tension tests, according to GOST 1497, of standard samples at static loading with the use of machines for mechanical material tests in accordance with GOST 28840.

5.6 Coercive force Hп of metal on an as received state is always higher than of annealed metal. Moreover, a Hп value of cold-rolled or thermomechanical strengthened metal can be several folds higher compared to annealed metal of the same steel grade.  These differences are constant, systematic, not chaotic, and not accidental.

5.7 The values Hc from as received state to the state which corresponds to the start of destruction are increased (from Hп to Hf in the process of maintenance in 3-4 folds.  Such variation range Hc allows, to a high degree of accuracy, to determine the moments of construction maintenance which correspond to its metal transition from elastic strain to plastic deformation, as well as the occurrence of prefracture state.

5.8 Knowing a steel grade, values Hп, Hf, a measured current value Hc, and time period T, during which the construction worked until it reached a value Hc, it will be possible to forecast  its remaining lifetime.

N o t e – The more check measurements of the current value Hc are taken at specific time intervals (usually 1-3 years), the higher certainty of forecast of remaining lifetime is.

5.9 For assessment of metal damage on the base of value Hc, the coercimeters with a measurement module and the add-on transducers of coercive force as well as calibration samples (2 or 3 pcs.) for the coercimeter setting are used.

5.10 The coercimeter with transducers used for monitoring of the metal state is subject to certification and metrological calibration test in conformity with the legislation in force.

5.11 The method recommended by this Standard may serve as a basis for the elaboration of measuring techniques according to GOST R 8.563.

6  Safety requirements

6.1 The operators with the skills to operate equipment of magnetometric diagnostics, who are able to use the national and industry regulatory and technical documents on magnetic testing methods, trained to work with the applied MI and certified for knowledge of safety rules in the relevant industry, are allowed to perform measurement using the MCM method.

6.2 When taking measurements, the operator must be guided by GOST 12.2.003, ГОСТ 12.3.002 and technical safety rules when operating electrical installations of consumers according to GOST R 12.1.019 and GOST 12.1.038.

6.3 Measurements are made in accordance with the safety requirements specified in the operating manuals for the equipment included to the set of the MI used.

6.4 When taking indoor measurements, all the rooms and premises must comply with the requirements of [3] and [4].

6.5 When organizing work on the use of the MCM, fire safety requirements in accordance with GOST 12.1.004 must be observed.

7 Requirements for measuring instruments

7.1 Coercimeters should have the property of resistance to gaps which means a possibility of Hc measurement with a permissible error upon changes of nonmagnetic gap (incl. air-gap clearance) between the pole clamps of the transducers and the surface of the flat calibration sample within the limits specified by technical documents for the coercimeter.

7.2 Coercimeters should ensure measurement of coercive force in the range of 1 to 40 A/cm with a relative error of not more than 5 %.

7.3 Coercimeters designed for technical testing should have the characteristics such as portability and low weight (up to 3 kg), convenience of operation in the field as well as at high-rise structures and self-contained supply for operation at Category 1-4 hazardous production facilities [5].

7.4 Coercimeters with add-on transducers  that ensure stable results with accuracy guaranteed by instrument manufacturers can be used for the structural steel members with the thickness of up to 30 mm.

 N o t e – The function of testing  depth setting can be realized using a set of transducers with the fixed testing depth and also specialized universal transducers with program-controlled characteristics.

7.5 Each variety of the measuring transducer in the set of MI should have at least two calibration samples.  One is used for the lower part of the working range Hc, another – for the upper part of the range.

7.6 For the lower measuring range value, the internal value Hc of calibration sample should exceed it at least by 2 A/cm.

7.7 For the upper measuring range value, the internal value Hc of calibration sample should be lower not more than by 5 A/cm.

7.8 It is not allowed to use calibration samples of the transducer with a higher testing depth to calibrate a device with transducer having a lower testing depth.

7.9 Electric storage battery capacity of the coercimeter should be enough for continuous operation for 8 hours at least.

8  Preparation and conduct of measurements

8.1 As a rule, preliminary preparation of the surface of the monitored object is not required.  It is allowed to take measurements Hc from the not prepared surface, with the presence of protective covering, dust and dirt of thickness up to 3 – 4 mm.

8.2 To take measurements from the cylindrical surface, it is necessary to use transducers with the appropriate radii of curvature of the useful area, if a measurement error exceeds the admissible one due to curvature.

8.3 Measurement preparation is about the check of the battery charge level of the MI and its setting by calibration samples from the set.

8.4 Measurements Hc on the surface of the  tested metal are performed in two orthogonally related directions: along and across the expected direction of load application by fixing the obtained values H and Ht, respectively. The measurements of the extended objects of testing are taken along and across the direction of their extension.

N o t e s

1 In the elastic stress zone, Ht  demonstrates the highest sensitivity to tensile loads and H  is affected by compression stresses to a greater degree.

2 Hc behaviour does not depend on a sign of metal stress: Hc is increased as with the growth of compression stress, so with the growth of elastic stress.

8.5 When performing measurements on the structural members with complex loading configuration, it is required to choose a higher value among two values H  and Ht.

8.6 A structural member, on which Hc measurements are taken, is lined using a ruler or tape measure with the sections at intervals 0.5 – 1.0 m.  A measurement interval depends on the structure complexity, thickness of members and obtained measurement results, as well as on the stress concentration zone. With the set largest dimension d of the least stress concentration zone (and, consequently, of metal fatigue degradation zone), the biggest measurement interval of the coercive force, which allows for mandatory detection of that zone, should have a value of S≤d/2.  When marking, the walls of rectangular (square) pipes or forming lines of the round pipe length should be denoted with numbers to definitely bridge coordinates of each measuring point of the metal coercive force to the local coordinate system of the monitored object in general or its any part.

8.7 Measurements are taken in series to the marking-out.  When detecting the zone where the evident growth of Hc is observed, a measurement interval is reduced gradually to define the limits of that zone with the required precision (an interval here can be reduced to 1 cm).

8.8 To obtain a full picture of spatial distribution of operational damage, it is recommended to take measurements of Hc on all the surfaces of shape steel-rolled stock, roll-formed sections, round and rectangular (square) pipes. As to I-beam sections and channels, such measurements should be made on the bottom and upper shelves and the wall (at wall height of more than 300 mm, it is recommended to take measurements in two zones, close to the upper and bottom shelves).  As to rectangular pipes – on all  walls of the pipe, as to round pipes – along 4 forming lines (along the pipe length) evenly distributed around the circumference of the pipe across-section.  

9 Measurement results processing

9.1 The MCM is used for assessment of damage of metal and its closeness to the prefracture state in the structures of wide scope of application.  General regulatory base (GOST, SP) is used in each industry as well as the elaborated normative documents (RD, NP, STO, MR, MU, TU, etc.) for specific industry, therefore this Section provides the general approach to processing of measurement results Hc. The interpretation of results is done by the Performer considering the requirements of industry-specific regulatory documents.

9.2 Measurements Hc in the structural steel members are taken following the specially elaborated program of technical testing of a monitored object. The program of technical testing is developed in advance.   When making a program, the most loaded bearing structural members are determined based on computed data, as well as conditions and regimes of maintenance according to structural specifics of a monitored object. At the same time  a steel grade and as-received condition, thickness of calculated members, possible temperature effects on metal and the time of the construction operation (run) T are also established. 9.3 For most widespread low-carbon and low-alloy steel, information of the values Hп (mainly, hot-rolled metal), Hт  and Hf is given in Annex A.

9.4 If there are no data available of steel grade and as-received condition (e.g., for foreign steel grades, thermo-strengthened or high-resistance steel, and special-purpose steel), it will be required to perform a chemical analysis and mechanical tests with a record of loading diagrams σ-ε and parallel measured current values Hc, based on which the values Hп , Hт  and Hf  are obtained.

N o t e – The value Hf conforms to tension equal to σB on diagram σ-ε, where σ – relative load, ε – percentage of elongation, Нт – coercive force under load on the sample equal to yield strength σт.

9.5 After data processing for all calculated structural members, the "weakest link", i.e. the zone with maximum values of coercive force Hmax is determined. This zone, the "weakest link" with maximum values of coercive force Hmax corresponds  to maximum accumulated fatigue degradation combined with stresses which caused such degradation.  Subsequently, remaining lifetime Prem  is calculated for that "link" and estimate the possibility of the further construction operation.

N o t e s

1 Computation of Prem  "for the weakest link" is done on the basis of the value Hmax measured on it.

2 Those members which based on the project data have multiple strength margin can get into the category of the "weakest link" members due to inaccuracy during assembly, procedural violations of making and installation, and errors in the design diagram.  This is not a measurement error, but the method advantage which integrally considers the influence of all the factors in manufacturing chain and construction maintenance.

3 It should be taken into account that operation conditions (one- or multiaxial loading) and the rate of stress rise during the bench test and in the real structure are not comparable, so the values  and  obtained in a result of the bench uniaxial plane stress tests are the starting point for an operator making measurements which tell that he is dealing with metal being close to the zone of transition from elastic to elastic-plastic state or close to the zone of prefracture.  In such points of construction, it will be required to take repeated refinement measurements Hc in six months – year for the members being close to the transition line to elastic-plastic state, or in a week – month for the members being close to the prefracture line.

9.6 Computation of Prem  is performed with consideration of the requirements set in the industry-specific regulatory documents and loading conditions: cyclic or static.  Upon the values Prem, below the admissible as specified in the relevant regulatory documents, the technical state of the structural member is evaluated as "emergency". In this instance, it will be necessary to strengthen such member, to replace it, or, if said measures are economically inexpedient – to withdraw a structure from service.

9.7 It will be possible to compute the term for a structure transition to non-serviceable condition (which, for example, may correspond to the formation of plastic hinge, loss of stability or depletion of ductility reserve and formation of cleavage cracks), if the information of operation (run) time and actual conditions of structural loading is available.

9.8 The evaluation of remaining lifetime Prem, measured in the time units (years) at the run for the current control moment T is performed as followed on the assumption of linear dependence of the value Нсcurrent on operation time Т.

The coercive force of metal of the "weakest link" in the beginning of working life was equal to the values Нп.  This corresponds to as-received state, which is found in Table given in Annex A, or measured on any unstrained member of the monitored structure. The coercive force, from the moment of commissioning Т, increased to Нс(Т) and received an increment of ΔНс = Нс(Т) – Нп.  This increase was taken place with the rate of V = ΔHc/T.  Remaining lifetime in the units of coercive force makes up ΔНсrem = Нf – Нс(Т).  This resource in the time units (years) is equal to Prem = ΔНсrem/V.

Note. Such forecasting of the remaining lifetime most fully takes into account the current state of the metal, the deterioration of its mechanical properties during the service life.  Due to the deterioration of the strength properties of metal and especially its ability to resist fracture (deterioration of the crack resistance), a metal having a current value of the coercive force Нс(Т) ≥ (Нп + Hf)/2  is capable of collapsing exponentially, immediately upon temporary, jump-like operational overloads.  Moreover, no classical calculation of the strength does not "see" such a threat and allows the maintenance of such metal without limitations.  It should be also noted that there are no in-service defects in such metal.  However, the level of its fatigue microdamage, which is visible only coercimetricaly, no longer provides its initial calculated operational reliability.

9.9 Should loading conditions or static overloads of metalwork be changed, it will be necessary to again measure Нс and calculate the values Prem  and Prem.

10  Arrangement rules for measurement results

10.1 Measurements results are recorded in the log which format is given in Annex B.

10.2 If measurements of Нс are the part of scientific and research work, measurement results will be presented in the format in conformity with the requirements of GOST 7.32.

Annex A


Mechanical and magnetic properties of hot-rolled products made of carbon and low-alloy steel

! Steel Grades are defined according GOST. If there are known steel grades of ASTM (USA), AISI/SAE (USA), DIN (Germany) classifications which could have similar mechanical and magnetic properties they are stated below with parenthesis () in blue

Steel Grade

Mechanical properties

Magnetic properties,

Hc A/cm



  d, %








(A 414 Grade A,








A 570 Grade 36)


























(A 516-55 A 516-60 A 516-65 A 561 Gr70)

































(Germany St52-3)








 N o t e – Mechanical and magnetic properties of cold-rolled and heat-treated mill products differ substantially from the relevant properties of hot-rolled steel, therefore when inspecting constructions made of such steel, it is required to perform bench tests to determine the appropriate values of Нт  and Hf.

Annex B


The test record sheet of coercive force


(Organization name)

1 Facility name and address:                                                                     

2 Measuring instruments:

  • coercimeter ................., serial № ............  date of next calibration ..................... ;
  • metal ruler 150÷400 mm acc. to GOST 427;
  • tape measure 5 or 10 m.

3 Measurements taken by:                                                                                              

                                                                  (Full name)

Item No.

Member name

Arrangement in axes

Steel grade

 Нс, A/cm








Member 1





Bottom shelf






Upper shelf






Wall, upper part






Wall, bottom part






Member 2






Wall (zone) 1






Wall (zone) 2






Wall (zone) 3






Wall (zone) 4






Member 3







Shelf 1







Shelf 2





N o t e s

1. 1 – Table for I-beam sections and channels; 2 – Table for rectangular, square and round pipes; 3 – Table for angle section.

2. When taking measurements of Z- or U-shaped moulded sections, Table for member 1 needs to be used. When taking measurements of coupled angles, Table for member 3 is added with two lines "Shelf 3" and "Shelf 4".

3. Tabular format for registration of coercive force measurements on tanks, shaped engineering products etc. is developed by the organization which performs work.