WO2006022568A1

WO2006022568A1 - Method for determining a product initial and residual defectiveness, a defect detection probability and a product quality according to certainty and probability components of a residual defectiveness

Info

Publication number: WO2006022568A1
Application number: PCT/RU2004/000317
Authority: WO
Inventors: Alexandr Fedorovich Getmann; Nikolay Andreevich Mahutov; Alexander Alexeevich Tutunov; Vladimir Nikolaevich Lovchev; Dmitry Fedorovich Gucev; Yuri Grigorievich Dragunov; Yuri Alexandrovich Kurakov; Alexander Stepanovich Zubchenko; Mikhail Vladimirovich Grigoriev; Inna Vasilievna Kaliberda; Anatoly Vladimirovich Prosvirin; Yuri Viktorovich Konev; Gennady Samoylovich Vasilchenko; Vlada Alexandrovna Getman; Boris Ivanovich Lukasevich
Original assignee: Zao 'koordinacionny Centr Po Nadeznosty, Bezopasnosty I Resursu Oborudovania I Truboprovodam Atomnyh Stancy'
Priority date: 2004-08-13
Filing date: 2004-08-13
Publication date: 2006-03-02

Abstract

The invention relates to non-distructive testing of discontinuity, nonuniformity and other material defects of a product or a product group and can be used for evaluating the fidelity of non-destructive means and methods, proficiency of non-distructive test operators and for carrying out the product test during the operation and/or production thereof. In a first variant, the inventive method consists in producing and testing a test-sample, in determining the test fidelity in the form of a defect detection probability based on defects detected during the test-sample testing and a number of defects imitated during the production of the test-sample, in testing the product by the same method which is used for the test-sample, in determining the initial defectiveness taking into account the defect detection probability, in repairing the revealed defects and in determining a residual defectiveness. In another embodiment of the method for a specific item or a group m of the same type products, the inventive method consists in determining defects critical sizes χ cr in the operation mode, the maximum limit sizes of the defects in the operation mode [χ]o.d. and the maximum limit sizes of the defects in production [χ]prd, in determining an initial defectiveness Nin and the defect detection probability Pddp, in repairing defects and in determining a residual defectiveness Nres as a difference between Nin and N det, wherein the Nres is determined in three defect ranges, i.e. defects significant in terms of safety, defects significant in terms of reliability, defects significant in terms of product quality. In a third variant, the inventive method consists in determining the defect detection probability Pddp, the initial defectiveness Nin = f(χ), the residual (after testing and repairing revealed defects) Nres = φ(χ) as a difference between Nin and N det, in dividing the residual defectiveness into a certain component χ≤χ∂ and a probability component χ>χ∂, wherein χ is a defect characteristical size and χ∂ is defect sizes on the boundary between the certain and probability components.

Description

A method for determining the initial and residual defects of a product, the probability of detecting defects and product quality from the reliable and probable parts of residual defects

Technical field

The invention relates to the field of non-destructive testing (hereinafter referred to as HK) of discontinuities, inhomogeneities and other defects in the material of a product or a group of products (parts, structural elements, etc.) including ultrasonic, eddy current, radiographic and other HK methods. The invention can be used in assessing the quality, reliability and safety of a product based on HK results, evaluating the suitability of HK tools and methods, the adequacy of the qualifications of HK operators, and organizing product control during operation and / or manufacture.

State of the art

In accordance with existing practice in modern technology, HK responsible products are carried out after manufacture, before operation and during operation. It is assumed that as a result of HK, all defects that are available for detection by this control method are detected. All discontinuities, inhomogeneities, and the like anomalies of the metal, if they exceed the permissible sizes, are classified as defects and are eliminated by repair. It is believed that after HK and repair of the detected defects there are no other defects in the product (see, for example, “Equipment and pipelines of nuclear power plants. Welded joints and surfacing. Control rules)), PHAEG-7-010-89, Gosatomnadzor of Russia, Energoatomizdat , 1991). The same practice has developed in other countries. Thus, it is believed that initially (before HK) in the product there were those defects that were revealed during the inspection, and after checking and repairing the detected defects, there were no defects in the product. However, when assessing both the initial defectiveness of the product and the residual defectiveness (i.e., the defectiveness remaining in the product after it inspection and repair of detected defects) do not take into account the real detectability of defects inherent in the used inspection methods and HK operators with a certain classification level. It is known (for example, Gurvich AK “Reliability of flaw detection control as the reliability of the complex“ Flaw detector - operator - medium ”, Flaw detection, 1992, N ° 3, p. 5-13), that in almost all cases of HK there is a significant probability skipping defect large sizes exceeding permissible sizes. In practice, it turns out that almost always after HK and repair of detected defects in the product, defects still remain. It is these defects that ultimately determine the reliability and performance of the product.

Known methods for determining the defectiveness of the product, which determine the initial defectiveness of the product, however, there is no evidence that the detected defects are defects in the product. As a rule, defects still remain in the product.

Thus, the known methods do not provide complete identification of defects and does not allow the assessment of defects missed during inspection, which negatively affects the reliability and performance of the product.

A known method for determining the defectiveness of the product, in which the initial defectiveness of the product is determined, and the parameters measured during the control are selected from the condition of ensuring the maximum possible reliability of control by reducing the likelihood of making an erroneous decision (USSR Author's Certificate N ° 1406888, 1995)

However, this method does not completely eliminate the residual defect and does not allow its assessment, which negatively affects the reliability and performance of the product.

There is also a method of determining the defectiveness of the product (GOCT14782-86), which produce a standard sample with a small-sized object obtained by drilling or milling, according to which the sensitivity is determined, which determines the reliability of this control method (and control means). It is believed that the higher the sensitivity, the higher the reliability of HK, but the quantitative characteristics of this relationship in the specified method has not been established, i.e. the method does not allow to evaluate the real defect both before and after repair of the identified defects. The disadvantage is that the standard samples are not tied to real designs, to the sizes and types of defects that affect the quality, reliability and safety of operation of the product, while the method does not give an idea of the true reliability of HK.

SUMMARY OF THE INVENTION

The technical result to which this invention is directed is that it allows one to evaluate the actual defectiveness of the product both before the inspection and after the inspection and repair of the detected defects, and to establish the boundary between the sizes of defects that reliably exist in the product (their probability existence is equal to 1), and the size of the defects that may or may not be in the product (the probability of their existence is less than 1).

The technical result also consists in the fact that due to the knowledge of the initial (before inspection) and residual (after inspection and repair of identified defects) defects in the product, the accuracy of the assessment of the real state of the product increases, it becomes possible to operate it reliably and safely, and it is possible to more accurately judge the acceptability or other HK methods, product manufacturing process quality. In addition, it becomes possible to evaluate the reliability of HK conducted on one or a group of similar products, taking into account all the real features of the product design, manufacturing technology, monitoring conditions, qualifications and integrity of HK operators, control, as well as other factors that influence the results of control.

The problem is solved in that in the method for determining the defectiveness of the product, including the manufacture of a test sample designed to determine the characteristics of non-destructive testing of discontinuities in the material of the product, control of this test sample by the method of non-destructive testing, which is used to judge the reliability of the control, and control products that are produced by the same method as the control of the test sample, the test sample is made in the form of the product or its most critical part from the same material and for that the same technology as the product, with defects located at random with different characteristic sizes χ, the reliability of the control is defined as the probability of detecting defects P _water (χ):

* water (%) lioob mo \%) '™ hall mo \ k) i where N _{obn m0} is the number of defects detected during the control of the test sample,

N _Hall is the number of defects inherent in the manufacture of the sample; when testing the product, the control results are presented in the form of a histogram in the coordinates (χ, N _o in _{n U30} ), where N _o in _{n uzo} is the number of defects of a given size detected during the control of the product; the curve is determined initial defectiveness N _ucx :

N _ucx (χ) = N _obd (χ) IP _water (χ), repair the detected defects and determine the residual defectiveness N _ocm as the difference between N _ucx and N _{obn uzd} , and the test sample contains three groups of defects: defects whose dimensions lie in the range from the dimensions of defects admissible during operation to the dimensions critical for the product in operation; defects, the sizes of which lie in the range from the sizes allowed during the manufacture of the product to the sizes of defects allowed during operation; defects, sizes of them lie in the range from the sizes minimally available for detecting defects to the sizes of defects acceptable during manufacture, the first two types of defects mimic defects of an operational nature, and the third type mimic technological defects, residual defects

^N b, _f i _{c Жп} ^{in the} field of defects important to safety, is determined as the number of defects in the product whose dimensions are equal to or greater than the critical dimensions χ ^ in the product's operating mode: у / L _ fуu (γЛγγ '

^JV ostfiezop J ost \ L J ^U L »

Xcr residual defectiveness N £ _mLe in the region of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [ _{xx. E.} maximum permissible in the operation of the product:

;

residual imperfection N ^ _{m mg} in the region of defects that determine the quality of workmanship, in the form of the number of defects whose dimensions exceed the sizes [y} _{uzg of discontinuities} allowed in the manufacture:

where χ _before - the maximum possible characteristic size of the defect,

As a rule, the linear size of the defect, or a combination of the linear dimensions of the defect, or the area of the defect, or the volume of the defect, is chosen as the characteristic size χ of the defect. As a rule, the obtained initial defectiveness curve is approximated by an equation of the type N _ucx = A exp (-пχ), шιиN _ucx = A _χ χ ^'n ", or N _ucx = A _a a ^' "", or N _UCI = 4 _, Д "Vc) ^{" v} , or N _ucx = A _F F - ^H ', where a, c are the linear dimensions of the defect, F is the area of the defect, n, A are the coefficients selected from the condition that the analytical curve is as close as possible to the experimental data.

The problem is also solved by the fact that in a method for determining product defectiveness, including non-destructive testing of a product and repairing detected defects, for a specific product or group m of the same type of product, critical dimensions X _{cr of} defects in operation mode, allowable dimensions for operation [ χ] d and _e permissible defects in manufacturing dimensions [χ] _uzg defects, inspection results are represented as a histogram in the coordinates (N _obn, χ), where N _obn - the number of defects detected in the control, χ - characterized eristichesky defect size approximating equation histogram ₀₆₁₁ N (Z) = Lχ ^~ '{1 - (1 - ή) exp [-α (^ - Z _0)] - η), or Nob »(Z) = A exp (- and j) {1 - (1 - η) exp [-lQr - χ _o )] - η} _> where A, n, a, η are constants that determine from the condition that the equation N _obn (χ) is as close as possible to the control results, represented as a histogram,

Xo is the minimum defect size available for detection, the initial defect N _{ucx is determined} by the formula:

N _ucx = Aχ ^~ ", or N _ucx = Aexp (-пχ), and the probability of detecting a defect P _water by the formula: pe"> = ^{ι ~} С ¹ - V) exp [- “ClГ - Zo)] - V, determine residual defectiveness N _ocm as the difference between N _ucx and N _obn , while N _ocm is determined in three ranges: residual defectiveness ^N b _pf i _ezp ^{in the} field of defects important to safety, is determined as the number of defects in the product, the dimensions of which are equal to or greater than the critical dimensions χ ^ in the operating mode of the product:

5

residual defectiveness N ₀ ^ ₁₀₀ in the area of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [χ] _ό.e , the maximum allowable in operation of the product:

residual imperfection N ^ _{11 113} , in the region of defects determining the workmanship, in the form of the number of defects whose dimensions exceed the dimensions [χ \ _{uzg of the discontinuities} allowed in the manufacture:

where χ _front - the maximum possible characteristic size of the defect, t - the number of similar products.

As a rule, the linear size of the defect, or a combination of the linear dimensions of the defect, or the area of the defect, or the volume of the defect, is chosen as the characteristic size χ of the defect.

In particular, the minimum defect size Xo available for detection is determined when setting up the flaw detector used to inspect the product, or as the minimum defect size that was detected during inspection.

In particular, the constant η is taken equal to 0. The problem is also solved by the fact that in the method of determining the quality of the product, including determining the defectiveness of the product by non-destructive testing, determine the critical dimensions χ ^ of defects in the operating mode, the allowable dimensions in operation [ _x. defects and permissible in the manufacture of dimensions [χ] ^ defects, inspection results are represented as a histogram in the coordinates (N _Obn, X), where N _of n - number of detected when monitoring the defects, χ - characteristic defect size is determined the probability of detecting the defect P _vod , determine the initial defectiveness N _ucx = Дχ), determine the residual defectiveness N _ocm = φ (χ) as the difference between N _ucx and N _obn , and N _{ocm is} determined in three ranges: residual defectiveness N ^ _1161130n in the area of defects important for safety , determined as the number of defects in the product, Dimensions are equal to or greater than a critical size in the χ ^ operation mode items:

n-sLt.besop 5

residual defectiveness N∑ _{m d :)} in the region of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [χ] _< b _. maximum permissible in the operation of the product:

residual imperfection N ^ _{m uзг} in the region of defects determining the quality of manufacture, in the form of the number of defects whose dimensions exceed the dimensions [χ] _{uзг of the discontinuities} allowed in the manufacture:

Ni er = - \ ^N ocЛz) dχ where χrep. is the maximum possible characteristic size of the defect, t is the number of products of the same type, the residual defect is divided into the reliable part χ <χ ^, and the probabilistic part χ> fø, where χ is the characteristic size of the defect, fø is the size of the defects at the boundary between the reliable and probabilistic parts, determined from: χ max

where i _max - the maximum possible defect sizes in this product; fø value is compared with

[χ] d. _e . and [y] uzg _> and, based on the results of comparison, make a conclusion about the quality of the product and the possibility of its operation.

In one embodiment, the histogram (N _Obn , χ) is approximated by the equation

KM) = Aχ- "{\ - (l - η) e χp [-a (χ - χ o)] - η}, where A, n, a, η - constants which are determined from the condition of maximum approximation equation N _obn (χ) to the control results presented in the form of a histogram,

Xo is the minimum defect size that can be detected, the initial defect N _ucx is determined by the formula: T ¹ V 'out = A "-Ly ^' " and the probability of detection of a defect is -P _βOό By the formula: Co., = 1 "0" P) exp [ -or (^ - Z ₀ )] ^~ η. In the particular case, the semi-axis of the ellipse, which schematize the defect, is taken as the characteristic size, and the ratio a / c is taken constant for all a, determined from the condition of the maximum rate of development of the defect under operational conditions.

tø _mfd determined for a particular product or group of products of similar m, wherein m in controlling all of one type of control results are summed and are in the form of a histogram.

At the same time, the minimum defect size χ _{0 that} is available for detection is determined when setting up the flaw detector used to control the product, or as the minimum defect size that was detected during inspection.

To simplify the calculations, the constant η is taken equal to 0.

In another embodiment, a test sample is manufactured to determine the characteristics of non-destructive testing of discontinuities in the product material, this test sample is controlled by the non-destructive testing method, and the product is controlled using the same method as the test sample, and the test the sample is made in the form of the product or its most critical part from the same material and according to the same technology as the product, with defects located at random with different characteristic p χ, determine the probability of detecting defects P _water (γ):

* water (50 • * 'update CXJ' * * hall mo \ fjt where N _{obn m0} - the number of defects detected during the control of the test sample,

N _{zcuι mo} - the number of defects incorporated in the manufacture of the sample, the initial defect is defined as:

N _ucx = N _{0bn uzd} / P _w0d (χ) the histogram (N _ucx , χ) is approximated by the equation N _ucx = f (χ) or

N _ucx = f (a, c), where a, c are the linear dimensions of the defects, and when determining the residual defectiveness N _ocm use the expression

N _ocm = N _UCX - [1-P _water (%)] or N _ocm = N _UCX - N _obn ; and the boundary value & separating the reliable and probabilistic parts of the residual defect is determined from the equation χ max

≠

At the same time, the test sample contains three groups of defects: defects whose sizes lie in the range from the sizes of defects admissible during operation to sizes critical for the product in operation; defects, the sizes of which lie in the range from the sizes allowed during the manufacture of the product to the sizes of defects allowed during operation; defects, the sizes of which lie in the range from the sizes minimally available for detecting defects, to the sizes of defects acceptable in the manufacture while the first two types of defects mimic defects of an operational nature, and the third type - technological ones, residual defects N ^ _{m without} defects in the region of defects that are important for safety, determined in the form of the number of defects in the product, the dimensions of which are equal to or greater than the critical dimensions%, _p in the operation mode of the product:

residual defectiveness N∑ _{cd s} in the region of defects important for reliability is determined in the form of the number of defects whose dimensions exceed the dimensions of the defects [χ _b . _e ., the maximum allowable in operation of the product: N т £ ∑п * _{д 3э} == frосЛzW,

Xo J residual defectiveness N ^ _{m uзг} in the region of defects that determine the quality of workmanship, in the form of the number of defects whose dimensions exceed the dimensions X ₁₁₃₂ allowable for manufacturing discontinuities:

N ГlLL, u, r - = r- JN _ocm (χ) dχ,

Xw where χ _prev. - maximum possible characteristic defect size

In a particular case, the histogram (N _ucx , χ) is approximated by an equation of the type N _ucx = A _χ exp (-n _z χ), or N _UCJC = An _n exp (-i _β α), or N _ucx = A _ac exp [-and _{C C} (α7c)], or N _ucx = A _F eχp (-and F), or

N UC _* = AX ^' ""> ^{OR N} ∞ = A _* "^'"'' ^{OR N} " _* = ^A aL ^a2 l ^C Y"^" - ^' " ^{OR N} ua = ^^, where a, c are linear dimensions defect, F - defect area, n, A - coefficients selected from the condition of maximum approximation of the analytical curve to the experimental data

Brief Description of the Drawings

Figure 1 schematically depicts a defect in the pipeline, figure 2 shows the distribution of defects of critical dimensions, allowable dimensions and allowable discontinuities in the manufacturing process (the corresponding manufacturing standards are shown in table NTD PHAEG-7 010-89), Fig. 3 is a characteristic of the reliability of HK in the form of a dependence of the probability of detection of defects .P ₀₀ ^ on its size (in this case, width a), in FIG. 4 is a histogram of defects detected in the product; FIG. 5 - initial defectiveness of the product, in FIG. 6 - residual defectiveness of the product, in FIG. 7 shows the results product control in example 2, in FIG. 8 - initial defective functions

N _ucx (%), residual imperfection N _ocm (χ), and the probabilities of detecting defects P _water (χ), determined by the results of the HK product. In FIG. 9 shows the probabilistic part of the residual defect.

Variants of the method

The method is used for a specific product or group of similar products, the workmanship, the reliability and safety of which must be ensured using the well-known HK method when monitoring by an operator of known skill. When implementing the method of determining the initial and residual defectiveness of the product and the probability of detection, as well as determining the quality of the product by the reliable and probable parts of the residual defectiveness of defects, the methods of fracture mechanics determine the critical sizes of defects in the operating mode for this product χ ^, the maximum allowable defects in operation [χ \ _{d e,} permissible in the manufacture of defect size [χ] ^ (standards product defects), defined by the applicable regulations and / or specifications for the production of _(χ the Features -terrorism defect size, for example, a linear defect size is selected, or a combination of linear dimensions of the defect or defect area, or volume of the defect). It should be noted that defects that determine quality are defects whose sizes are in the range from the minimum dimensions available for detecting defects (search) to the sizes of defects acceptable during manufacture and above; defects determining reliability are those defects whose sizes are in the range from defective during manufacture to acceptable during operation and higher; defects defining safety - from acceptable during operation to critical sizes and above. In some embodiments, the method involves the use of a test sample, in this case, the determination of the size of the defects is carried out before the manufacture of the test sample. Taking into account the real operational loads and conditions, the defects (discontinuities) are determined for the product (for example, pipeline, Fig. L) using the methods of fracture mechanics (taking into account safety factors):

The distribution of defects of critical dimensions (curve 3), allowable sizes in use (curve 2), as well as allowable sizes of discontinuities in the manufacture (curve 1) are shown in FIG.

When implementing a method for determining the initial and residual defects of a product using a test sample, it is manufactured according to the shape of the product and on a scale of about 1: 1 to the product or its most critical part. The most critical part of the product is that part of the product in which the most likely occurrence of defects (welds, places of maximum operational influences, etc.) or the destruction of which is dangerous. The test sample is made of the same material and using the same technology as the product. Three types of artificial defects are laid in test samples:

-defects, the sizes of which lie in the range from the sizes of defects admissible during operation to the dimensions critical for the product in the operating mode of defects,

-defects, the sizes of which lie in the range from the dimensions acceptable during the manufacture of defects to the dimensions of defects permitted during operation,

-defects, the sizes of which lie in the range from the minimum sizes available for detecting defects to the sizes of defects acceptable during manufacturing (it is also acceptable for the upper boundary of the interval to exceed the dimensions of defects acceptable during manufacturing).

In this case, the first two types of defects (discontinuities) should imitate defects of an operational nature, and the third type - of technological defects. Operational defects - defects that can develop from technological defects or originate and develop under the action of operational loads (fatigue cracks, stress corrosion cracking cracks, etc.), technological defects are defects whose occurrence is associated with the features of manufacturing or installation technology (lack of fusion, non-fusion, pores, etc.). n. In this case, it is possible to lay a different combination of types of defects (one, any two, three), if necessary, it is also possible to produce a different number of samples, in each of which one type of effects or their various combination.

All embedded defects must be hidden from HK operators, i.e. be internal (subsurface) or, if the defect is superficial, be located in a place inaccessible to visual detection (or have dimensions that cannot be visually fixed).

It should also be noted that defects are randomly placed in the sample, for example, using random number tables.

The minimum allowable distance between defects is determined on the basis of the condition for the existence of single defects (if single defects are laid) or less for group cracks (the conditions of mutual influence are known, for example, Guidelines MP 108.7-86, M., TSNIITMASH, 1986).

The number of defects of each type should be sufficient for statistical processing of the results, for example, at least 9 pieces. (With less results are less reliable).

Any defect can be conservatively modeled by a crack, and any crack can be described by an ellipse with semi-axes: short a and long c.

There are various options for bookmarking defects in the test sample: Defects in the form of ellipses are laid in the test sample, and the ratio of the axes of the ellipse is taken on the basis of the condition for the maximum growth rate of the defect in the operational stress field;

Defects in the form of ellipses are laid in the test sample, while the ratio of the axes of the ellipse is arbitrary, and the area of the plane defect or the projection area of the volume defect on the plane of the probable development of the defect is taken as characterizing the size of the defect;

Defects in the form of ellipses are placed in the test sample, while the number of defects and the ratio of the axes of the ellipse are selected using mathematical methods for planning the experiment, based on the condition of minimizing the number of defects to be laid (K. Daniel, Using statistics in an industrial experiment, because of Mir M. 1979);

If the defects to be inserted into the test sample do not have the shape of an ellipse, then they are schematized by ellipses.

After the manufacture of the test sample, it is controlled using the same means and methods of control and by operators of the same qualifications, which will then be used to control the product, the results of the monitoring are compared with real defects embedded in the test sample.

For each characteristic size of the defect, reliability is determined as a function of the probability of detection of defects P _water (χ):

P water (%) = N _{total bύlN} hall mo (%), where N _{total m0} is the number of defects detected during the control of the test sample, N _Hall is the number of defects incorporated in the manufacture of the sample,

Based on the results of the control, a probability curve for detecting defects for a given part is constructed using this HK method depending on the characteristic size of the defects. Defect probability curve from the dimensions of the defects "α" and "c" (any defect in the material can be conservatively described by an ellipse with axes a and c), it is possible to approximate the equation that most closely describes the experimental results of control, for example, p _w

- c ₀ )] - ε, or

P _md = l - (l - ε) oxp - a _nk (a - a ₀ ) ^ - ε, or P _mx) = 1 - (l - *) exp [- « _ж (* - χ _й )] - f

Where QL _NK - confidence coefficient HK, characterizes the increase in the detection of defects depending on its size; ε is a constant characterizing the ultimate detectability of the control by this method for an arbitrarily large defect size; if the dimensions of the part are small, then this value can be neglected by introducing an appropriate adjustment of the value; χ χ is the characteristic size of the defect, for example, its area; χ ₀ is the minimum characteristic size of the defect; ao _> c _o - minimum defect sizes available for detecting HK.

Then, the product is inspected, and the inspection results are presented in the form of a histogram in the coordinates “characteristic x size of the defect χ - the number of detected defects of this size TV ₀ ^ _uzd ”.

The initial defectiveness N _ucx is defined as the ratio of N _o in _{n ISC} / P _in

the resulting histogram is approximated by an equation of the type N _ucx = A exp (- χ), or N _ucx = A _χ χ ^~ " ^z , or N _ucx = A _a a ^'p -, or their analogues of the type N _ucx = A _ac {a ² lcГ -, or N _ucx = A _F F-τ, where a, c are the linear dimensions of the defect, F is the area of the defect, n, A - coefficients selected from the condition of maximum approximation of the analytical curve to the experimental data.

The residual defects is obtained as the difference between N and N _ucx _{obn of} railway Thus N _{obn of} d can be taken directly from the results of control, and from the analytical expression N _ucx ^• P _vo d (χ); in the latter case, the residual imperfection N _ocm can be represented as the equation N _ocm = N _ucx (\ - P _water ).

The residual N ^ _mfiepp in the field of defects important to safety is determined as the number of defects in the product whose dimensions are equal to or greater than the critical dimensions χ _{* p} in the operating mode of the product:

Xpred

"ostβesop ~ J ^ OSNXXWWX

residual imperfection N∑ _{m d} in the area of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [χ] _< _{5 of the} maximum permissible product operation:

residual defectiveness N £ _mtUЗ! , in the field of defects that determine the quality of manufacture, in the form of the number of defects whose dimensions exceed the dimensions [χ \ _{uzg of the discontinuities} allowed in the manufacture:

where χ _before - the maximum possible characteristic size of the defect.

In other embodiments of the method for determining the probability of detection of defects, the initial and residual defects of the product using Using the results of non-destructive testing, as well as determining the quality of the product by the reliable and probable parts of the residual defect, the non-destructive testing of the product (HK) is carried out by the selected method (ultrasonic, eddy current, radiographic and other HK methods) and technical control equipment by operators of certain qualifications.

The results of the control are presented in the form of a histogram in the coordinates "characteristic x size of the defect χ - the number of detected defects of this size N _{UN UJ ()} ". The horizontal axis χ must include the critical size of the defect, even if as a result of the inspection all the detected defects did not reach critical sizes.

In the case of control of several products of the same type, all control results are summarized and presented in the form of a single histogram. The more products were monitored, the more reliable the final result.

The structure of the analytical expression that can describe the HK results presented on the histogram is as follows:

N _obn (χ) = N _ucx (χ) P _water (χ) where N _Obn is the number of defects detected during inspection per unit of characteristic size. If the semimajor axis of the ellipse with which the defect is schematized is selected as the characteristic size, then the dimension N ₀₀ - ,, - mm ^"1 ;

N _ucx is the function of the initial (up to HK) defectiveness with the same dimension as N _o6н ;

P _water is the probability of detecting a defect of a given size χ.

The _{form of the} functions N _ucx and P _water is determined based on the condition of the greatest simplicity of expression, the minimum number of constants and the correspondence of the physically determined dependence of N _ucx and P _water on χ. In a first approximation, the following equations can be used: N _ucx = Aχ-, pвoo = 1 - 0 - 7) ^GX P [ ^~ a (Z - Xo)] ^~ 1,

N ₀₆₁₁ (Z) = Аχ- ¹ {1 - (1 - η) exp [-a (χ - χ _o )] - η], where A, n, a, η, χ ₀ are constants.

Determine the numerical values of the constants, where A, n, a, η from the condition of maximum approximation of the equation N _obn (χ) to the results of HK, presented in the form of a histogram.

Moreover, χ ₀ - the minimum defect size that is available for detection - is determined when setting up the flaw detector used to control the product, or as the minimum defect size that was detected during the inspection; As a first approximation, η can be taken equal to 0. As a result, three unknowns remain, which greatly simplifies the task of determining them.

The constants A, n, and a can be determined either by solving a system of three equations with respect to A, n, and a, which are obtained if we take three points on the histogram, or they are determined using the least squares method.

Residual imperfection N _ocm is defined as the difference between N _ucx and N _oob : N _0C m (X) = N _ucx (χ) - N _obn (χ).

In this case, the number of remaining defects in the product is determined, as in the method using test samples, in three ranges: residual defectiveness N ^ _{1n hp} in the area of defects important for safety, is determined as the number of defects in the product whose dimensions are equal or more critical dimensions χ ^ in product operation mode:

;

residual imperfection N ^ _{m d e} in the region of defects important for reliability is determined as the number of defects whose sizes exceed defect sizes

maximum permissible in the operation of the product:

_I Хпрύ T ^ - _ т Xd residual defectiveness N ^ _{m uз} , in the region of defects that determine the quality of workmanship, in the form of the number of defects whose dimensions exceed the dimensions [χ] _{yzg of the discontinuities} allowed in the manufacture:

where χ _pre - maximum possible characteristic size of the defect in the structure with the given geometry (e.g., in the direction of the pressure vessel wall thickness defect size limit equal wall thickness), that - the number of the same products.

Based on the results, they make assessments and make decisions:

- in terms of N ^ _{m kp} - about the possibility of complete or partial destruction of the product in operation,

- in magnitude N £ _md . - on the reliability and scope of product repair during operation,

- in terms of N ^ _{m <uзr} - about the quality of control,

- according to the function P _water (χ) - about the reliability of the HK product and the qualification level of the HK operators, according to the function N _ucx (χ) - about the quality of the product before HK and repair (and therefore, about the quality of manufacture if HK was performed at the factory, or the degree of damage to the product, if the cause of the formation of defects was the operational impact). When determining the product quality by the reliable and probabilistic parts of the residual defect after plotting the histogram in coordinates ((the characteristic defect size χ is the number of detected defects of a given size N _{obd wd} y> determine the probability of defect P _water , the initial defect N _ucx = flχ) and residual defectiveness φ (χ) as the difference between N _ucx and N _obn

These dependencies can be determined by various methods.

In one embodiment, the HK results are presented as analytical expressions.

The structure of the equation that can describe the HK results presented in the histogram is as follows:

K _bn (χ) = N _ucx (χ) P _water (χ) where N _obn is the number of defects detected during inspection per unit of characteristic size. If the semimajor axis of the ellipse with which the defect is schematized is selected as the characteristic size, then the dimension is N _OH - mm ^"1 ;

N _ucx is the function of the initial (up to HK) defectiveness with the same dimension as N _obn ;

P _water is the probability of detecting a defect of a given size χ.

The _{form of the} functions N _ucx and P _water is determined based on the condition of the greatest simplicity of expression, the minimum number of constants and the correspondence of the physically determined dependence of N _ucx and P _water on χ. In a first approximation, the following equations can be used:

rp, _ύ = 1 - (1 - 7) exp [-α (^ - X ₀ )] - η, N ₀₆₁₁ (Z) = Aχ ^~ "{1 - (1 - η) cxp [-a (χ - χ ₀ )] - η), where A, n, a, η, χо are constants. The numerical values of the constants A, n, a, η are determined from the condition that the equation N _obn (χ) is as close as possible to the HK results presented in the form of a histogram.

The constants A, n, and can be determined either by solving a system of three equations with respect to A, n, and α, which are obtained if we take three points on the histogram, or they are determined using the least squares method.

The residual imperfection N _ocm is defined as the difference between N _ucx and JV ₀ ^ /. N _ocm (χ) = N _ucx (χ) - N _obn (χ). (17)

The number of remaining defects in the product is determined in three ranges as described above: residual defectiveness N ^ _{1n cr} in the area of defects important for safety, residual defectiveness N ₁ ^ ₁₀₃ in the region of defects important for reliability, residual defectiveness N∑ _{m uзr} in the field of defects that determine the quality of workmanship.

When building a histogram, the horizontal axis χ must include the critical size of the defect, even if, as a result of the control, all detected defects did not reach critical sizes.

In the case of control of several products of the same type, all control results are summarized and presented in the form of a single histogram. The more products were monitored, the more reliable the final result. According to another option, to determine the dependences P _water (probability of detecting a defect), N _ucx = Дχ) (initial defectiveness) and N _ocm = φ (χ) (residual defectiveness), a test sample is prepared by the method described above.

* water (%) - * * update mo '%)' - * * hall mo (%)> where N _{0бH mo} is the number of defects detected during the control of the test sample,

N ₃ _(U i _that - the number of inherent in the manufacture of sample defects, the results of control building curve probability detectable ™ defects to the part data by HK depending on the characteristic size of defects curve of the probability of detecting defects on the defect size "a" and "c". (any defect in the material can be conservatively described by an ellipse with semiaxes a and c) can be approximated by the equation that most closely describes the experimental results of control, for example

P _<a , _o = 1 ~ 0 - *) exp [- a _nk {a - a ₀

- c ₀ )] - ε, or

P _« * = 1 - 0 - ^) exp - a _m (a - α ₀ ) ^ - ε, or

p _sПд = 1 - (l - e) exp [- a _нк (χ - χ _o )] - ε Where a _NK - confidence coefficient HK, characterizes the increase in detected ™ defects depending on its size; ε is a constant characterizing the ultimate detectability of the control by this method for an arbitrarily large defect size; if the dimensions of the part are small, then this value can be neglected by introducing an appropriate adjustment of a _H k _. χ is the characteristic size of the defect, for example, its area; χ ₀ is the minimum characteristic size of the defect; a ₀ , C ₀ - minimum defect sizes available for detecting HK.

Next, the product is inspected, and the inspection results are presented in the form of a histogram in the coordinates “characteristic x size of the defect χ - the number of detected defects of this size N _{U JJ} ”.

The initial defectiveness N _ucx is defined as the ratio of N _{obn w} ^ P _water

(X); the resulting histogram is approximated by an equation of the type N _{^ x} = A _x & φ (-n _χ χ), or N _ucx = A _χ χ ^{~ n} *, or N _ucx = A ₀ U " ¹ ", or

N _u = KXa ¹ Ic) ^, or N _ucr = A _F F- ^* ',

2 or N _ucx = A _a a - "- p (c), or N _ucx = A ₀ ^" -t ^ exp (C - C)

'2D \ c)

where a, c are the linear dimensions of the defect, P _c is the distribution function of c, for example, the normal distribution law,

F is the defect area, n, A, D, and c are the coefficients selected from the condition that the analytical curve is as close as possible to the experimental data, with c being the average value of c, and D the variance.

As the characteristic size, we can take the semi-minor axis a of the ellipse, which schematize the defect, while the a / c ratio is taken constant for all a, based on the condition for the maximum growth rate of the defect under operating conditions; wherein

N _ref ⁼ = ((e), for example, in the case of a uniform field of voltage

dependences a / s -2 and the normal law for a distribution with with an average value of c = 2a and a dispersion of D = a / 2, we obtain

N _ucx

= Aa ^~ "

~ 2af / 0.5a ² ] dc = Aa ^~ "oh aljπ

Residual defectiveness is obtained as the difference between N _ucx and N _{obn U30} . At the same time, N _{obn is} determined from the analytical expression N _ucx ^• P _water (χ), i.e. residual imperfection N _ocm can be represented as the equation

L ost ^ ref V ^ * water) - The residual N∑ _mβezop in the field of defects important for safety is determined as the number of defects in the product whose dimensions are equal to or greater than the critical dimensions χ ^ in the operating mode of the product:

Xpreό

- * * ostjesop ⁼ J ™ ost \ Z) "Z 5

residual imperfection iV∑, ,, _od in the area of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects fø _.э. maximum permissible in the operation of the product:

>

Xd e

residual imperfection N ^ _{m uзг} in the region of defects determining the workmanship, in the form of the number of defects whose dimensions exceed the dimensions J _j132 allowable for the manufacture of discontinuities:

Hil

where χ _pre _d. - the maximum possible characteristic size of the defect.

Further, residual defects are divided into a reliable part χ <X _a , in which defects with dimensions χ <χ _d exist reliably, and the probabilistic part χ> χ д, in which defects with sizes χ> χ, may or may not exist. The boundary between the reliable and probabilistic parts of the residual

Fektnosti is determined from the condition:

where X _m ax ~ the maximum possible defect sizes in a given ¬

divisions.

The value of fø is compared with χ ^, [χ] _{d e.} and [χ] _shh , and, based on the results of comparison, draw conclusions about the quality, reliability and safety of the product.

Embodiments of the methods are illustrated by the following examples.

Example 1

Product: main circulation pipeline of a power reactor installation.

Product specifications: steel type 22K with yield strength = 320MPa, clad on the inside of the pipeline with austenitic stainless steel; welds are located both across the axis of the pipeline and along the axis; wall thickness for the base metal of the pipeline - S = 34mm; the inner diameter of the pipeline is D = 800mm.

Product operating conditions: operating temperature - 280 ⁰ C; working pressure -80kr / cm ² ; the assigned service life is 30 years.

_^ The latent discontinuities, admissible in operation, defects and critical defects, admissible at the manufacturing stage (quality standards), are shown in Fig. 2, respectively, by curves 1,2, 3.

Make the test sample containing planar defects technological nature poor fusion type weld cracking and hot i ^'J _t -. The reliability of the HK is determined using the method (ultrasonic, eddy current, radiographic and other HK methods), a technical tool and an HK operator of a certain qualification, which will also be used to control the product. The results of determining P _water from a are presented in FIG.

Conduct HK products using the same means and method, and operators of the same qualifications as in the control of the test sample (when determining the reliability of HK. The results of the control are presented in the form of a histogram in figure 4.

Using the numerical values of N _{obb W} d from the histogram (Fig. 4) and P _water from the graph (Fig. 3), the initial defect N _{ucx is determined} . The results of determining N _{ucx are} presented in the form of a graph in FIG. 5 in coordinates N _ucx — the characteristic size of the defect (in this case, the width of the defect a, the defect is schematically shown in FIG. L).

The residual imperfection graph N _ocm is presented in the same coordinates as for N _ucx , in FIG. 6. To obtain N _ocm , for each fixed value, a subtraction from the number N _{ucx of the} number of detected defects was subtracted.

The number of defects remaining in the product after HK and repair of the detected defects was determined, and it was obtained that: the total number of defects whose dimensions are equal to or exceed the critical dimensions of the defects in operation was:

^ L, = 0, l «l; the total number of defects, the sizes of which are equal to or exceed the allowable sizes of defects in operation, amounted to:

the total number of defects that are unacceptable during the manufacturing process according to the norms of discontinuities for manufacturing was:

.

Based on the results obtained, the following conclusion can be made: the manufacturing technology of the product and / or HK technology need to be improved, because in the case of transferring the product into operation, as a result of the operational HK, up to 23 defects of unacceptable dimensions will be detected, which will lead to additional repair of the product under operating conditions (which is a more expensive measure than factory repair), and in case of missing defects according to the results of operational control, an accident may occur with partial or complete destruction of the product (in this case, the pressure pipeline).

Thus, if you are guided by the regulatory documents PHAEG-7-010-89, the product after manufacturing, HK and repair of the identified defects can be allowed to operate. However, the determination of the characteristics of the initial (before HK) and residual (after HK and repair of detected defects) defects indicates a low level of reliability of the product and the need for its improvement.

Example 2

It is necessary to ensure the quality of two pipelines with an inner diameter of D = 800 mm and a wall thickness of S = 34 mm made of pearlite steel. The critical dimensions of the defects in the transverse welds are shown in figure 2 (curve 1). Permissible defects in operation were determined using the equations of fracture mechanics and safety factors (curve 2 in FIG. 2). The operational defect rates are shown in FIG. 2 curve 3.

As a result of HK, 47 discontinuities were discovered by the regular method and means before the start of operation (after installation).

All identified discontinuities (defects) are presented in the form of a histogram in Fig.7. In this case, the defect width in the direction of the wall thickness, or rather, the semi-minor axis of the ellipse, with which all the identified defects were schematized, was chosen as the characteristic size of the defect.

At a ratio of s / c ~ 0.5, the critical size of the defect corresponds to

1.15mm (FIG. 2).

Despite the fact that the maximum size of the detected defect was a _max = 13 mm, the abscissa axis contains a critical size of α = 15 mm.

The equation describing the number of detected defects N _Ob , depending on the size of a:

N _obn = Aa ^{~ n} [l-exp [-a (aa ₀ )].

According to the control results, the minimum detected defect had αø = 0.6 mm.

To determine the constants A, n, and solve a system of three equations with respect to these constants:

The first equation is obtained for the point with coordinates (α = lmm, N _obn -20) of FIG. 7:

20 = A-G "[l-exp [-a (l-0.6)]];

The 2nd equation is obtained for the point with coordinates (α = 5mm, N _obn -4) in FIG. 7:

4 = A-5 - "[l-exp [-a (5-0.6 Ш

The 3rd equation is obtained for a point with coordinates (α = 13mm, N _obn = 0.66) in FIG. 7:

0.66 = ^ 13 ^" " [l-ejψ [-α (13-0.6)]].

For the 3rd equation, N _obn = 0.66 was obtained as averaging the number of detected defects in the range from 1 1 to 13 mm, which was 2/3, where 2 is the number of detected defects, 3 is the number of intervals.

Finally, the system of equations has the form:

20 = Ail-exp (- 0.4 a)]

L = A-5- ^p [l-exp (-4,4a)] 0.66 = ALU ⁿ [\ -exp (-l2M)}

The solution of the system of equations for A, n, and yielded the following results:

A = 1000mm, n = 2.56, α = 0.05 mm ^"1

Substituting the constants A, n, and in the corresponding equations, we obtain: the equation of the initial defectiveness:

N _ucx = l000cG ² ^'56 ; defect detection probability equation:

P _water = l-exp [-0.05 (a-0.6)]; residual defectiveness equation

N _ocm (χ) = N _ucx (χ) - N _obn (χ).

These equations are represented graphically in FIG. 8.

Next, they solve the equation

\ Aa ^~ "exp [-α (α - a _o )] da = 1

with respect to a ^. Moreover, a _max = S, where S is the thickness of the pipeline wall. The results of the solution are presented in Fig.6 in the form of a curve 2. The value a _# = 14 mm determined in this way. For given operating conditions, the most rapid increase in area

defect will be provided at a / c _^ = 0.5. The critical size of the defect at

this will have a value of a _kp = 15.5 mm, which is close to the value of a _d = 14 mm. Considering that in operation, a defect with a _d = 14 mm can quickly grow to a critical value of 15.4 mm, the operation of the product should be prohibited, despite the fact that all identified defects are repaired and after repair the product meets the quality requirements of the current HT D, for example , PHAEG-7-010-89.

Industrial applicability Knowing the size of the defects that reliably exist in the product (after checking and repairing the detected defects) will allow you to more accurately assess the actual condition of the product, the possibility of reliable and safe operation, the acceptability of certain HK methods, the quality of the manufacturing technology of the product, and also, if necessary, take reasonable measures to improve the quality and reliability of the product to an acceptable level. The ability to assess the reliability of HK conducted on one or a group of similar products, taking into account all the real features of the product design, manufacturing technology, conditions for the control, qualifications and integrity of the HK operators who performed the control, as well as other factors affecting the results of the control, contributes to reliable and safe operation of the product.

Claims

Claim

1. The method of determining the defectiveness of the product, including the manufacture of a test sample designed to determine the characteristics of non-destructive testing of discontinuities in the material of the product, control of this test sample by the method of non-destructive testing, which is used to judge the reliability of the control, and control of the product the same method as the control of the test sample, characterized in that the test sample is made in the form of an article or its most critical part from the same material and using the same technology as and a product with randomly located defects with different characteristic dimensions χ, control accuracy is defined as the probability of detecting defects _vod P (χ):

P water ώ = N _{obn mo} (y) IN _{hall mo} (χ), where N _about _n is the number of defects detected during the control of the test sample,

N _{3a, then} - the number of defects incorporated in the manufacture of the sample; during product inspection, the control results are presented in the form of a histogram in the coordinates (χ, N _{obd ad} where N _o _{n UЗ d is the} number of defects of a given size detected during product inspection, the initial defectiveness curve is determined N _ucx :

N _ucx (l) = N _{obn U30} (χ) IP _water (χ), repair the identified defects and determine the residual defect N _ocm as the difference between N _ucx and N _o in _{n from} d-, and the test sample contains three groups of defects: defects, the sizes of which lie in the range from the sizes of defects admissible during operation, to sizes critical for the product in operation; defects, the sizes of which lie in the range from the sizes allowed during the manufacture of the product to the sizes of defects allowed during operation; defects whose sizes lie in the range from the sizes minimally available for detection defects to the size of defects admissible in the manufacture, while the first two types of defects imitate defects of an operational nature, and the third type imitate technological defects, and residual defects

^N lL _f i _szp ^{in the} field of defects important for safety is determined as the number of defects in the product whose dimensions are equal to or greater than the critical dimensions χ ^ _p in the operating mode of the product:

X pre

N ostfiesop ~ J "

^ * ost '

X _cr residual defect N ^ _{111 d e} in the region of defects important for reliability, is determined as the number of defects whose dimensions exceed the dimensions of the defects

maximum permissible in operation of the product:

Th r2. e, _^ = l ^N ocLz) dχ;

residual imperfection N £ _{m uзr} in the region of defects that determine the quality of manufacture, in the form of the number of defects whose dimensions exceed the dimensions [χ] _{uzg of the discontinuities} allowed in the manufacture:

TV ^y υ ∑tтjизг = J Г / V OST У СЛr / W "/ rС 1,

where χ _before - the maximum possible characteristic size of the defect,

2. The method according to claim 1, characterized in that the linear size of the defect, or a combination of the linear dimensions of the defect, or the area of the defect, or the volume of the defect, is selected as the characteristic size χ of the defect.

3. The method according to p. 1 or 2, characterized in that the obtained initial defectiveness curve is approximated by an equation of the type N _ucx = А exp (-пχ), ШШ N _UCI = A _x Z ^' "", OR N _uu = A _a a- ^I ', or N _ua = A _ac (a ² / cУ ""', or N _UCJC = A _F F ^' "', where a, c are the linear dimensions of the defect, F is the area of the defect, n, A are the coefficients selected from the condition of maximum approximation of the analytical curve to the experimental data.

4. A method for determining product defectiveness, including non-destructive testing of the product and repair of detected defects, characterized in that for a particular product or group m of the same type of product, critical sizes χ ^ of defects are determined in the operating mode, dimensions [χ] _< b, permissible in operation _. of defects and the dimensions [χ] _{south of} defects allowed in the manufacture, the control results are presented in the form of a histogram in coordinates (N _obn , X), where N _obn is the number of defects detected during the inspection, χ is the characteristic defect size, approximate the histogram by the equation

N ₀₆₁₁ (X) = Az "{1 - (1 - η) exp [-a (χ - χ ₀ )] - η}, or N _os Ax) = ^ exp (-u ^) {l - (1 - η) exp [-l (χ - χ ₀ )] - η), where A, n, a, η are constants that determine from the condition that the equation N _obn (x) is as close as possible to the control results presented in the form of a histogram, χо - the minimum defect size available for detection, determine the initial defect N _ucx according to the formula:

N _{UC *} = Aχ- ^p , or N _ucx = Aexp (-пχ), and the probability of detecting a defect P _water according to the formula:

Code = 1 - (1 - Ф ^ex Pl-a (Z ^~ Z ₀ )] ^~ 7, the residual defectiveness N _{ocm is determined} as the difference between N _ucx and N _obn , while N _ocm is determined in three ranges: residual defectiveness ^N t _{m, 5esoP} ^{in the} field of defects important to safety, is determined as the number of defects in the product whose dimensions are equal to or greater than the critical dimensions χ ^ in the operation mode of the product:

residual defectiveness N ^ _{1n d e} in the region of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [χ _b . _e ., the maximum allowable in operation of the product:

residual imperfection ∑r _> в in the region of defects that determine the quality of manufacture, in the form of the number of defects whose dimensions exceed the dimensions [y] _{uzg of the discontinuities} allowed in the manufacture:

Xpred

Ntmmzg = - m pa •> WaxAxWX,

where χ _before - the maximum possible characteristic size of the defect, t - the number of similar products.

5. The method according to claim 4, characterized in that the linear size of the defect, or a combination of the linear dimensions of the defect, or the area of the defect, or the volume of the defect, is selected as the characteristic size χ of the defect.

6. The method according to any one of claims 4 to 5, characterized in that the minimum defect size χ ₀ that is available for detection is determined when setting up the flaw detector used to control the product, or as the minimum defect size that was detected during inspection.

7. The method according to any one of claims 4 to 6, characterized in that the constant η is taken equal to 0.

8. The method of determining the quality of the product, including the determination of the defectiveness of the product by non-destructive testing, characterized in that they determine the critical dimensions χ ^, defects in the operating mode, permissible sizes [χ] _< b _. defects and the dimensions [χ] _ad defects allowed in the manufacture, the control results are presented in the form of a histogram in the coordinates (N _o in _n , χ), where N ₀ ^ _n is the number of defects detected during the control, χ is the characteristic size of the defect, determine the probability of detection defect P _water , the initial defect N _ucx = Дχ) is determined, the residual defectiveness N _ocm = φ (χ) is determined as the difference between N _ucx and N _O Q _H , and N _ocm is determined in three ranges: residual defect N ^ _{m without} defects in the defect region important for safety, defined as the number of defects in the product ii, the dimensions of which are equal to or greater than the critical dimensions%, _p in the operation mode of the product:

N stop security ~ \ N _ocm \ X) dχ j t

residual imperfection N ^ _{q x} in the region of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [ _xx. maximum permissible in the operation of the product:

V residual defectiveness N ^ _{m y:} in the region of defects determining the quality of workmanship, in the form of the number of defects whose dimensions exceed the dimensions [χ] ^ of the discontinuities allowed in the manufacture:

where χ _pre _d. - the maximum possible characteristic size of the defect, t - the number of similar products, residual defectiveness is divided into the reliable part χ <fø, and the probabilistic part χ> fø, where χ is the characteristic size of the defect, fø is the size of the defects on the border between the reliable and probabilistic parts, determined from: χ max

where i _max - the maximum possible defect sizes in this product; the value of fø is compared with χ ^, [χ] _{d e.} and [χ] _røг , and based on the results of comparison, make a conclusion about the quality of the product and the possibility of its operation.

9. The method according to claim 8, characterized in that the linear size of the defect, or a combination of the linear dimensions of the defect, or the area of the defect, or the volume of the defect, is selected as the characteristic size χ of the defect.

10. The method according to claims 8 or 9, characterized in that the histogram (N _obll , χ) is approximated by the equation

Nb (z) = Ax - {1 - (1 - η) exp [- "α - *„)] "))> where A, n, a, η are constants that determine from the condition of maximum approximation of the equation N _0bn ( χ) to the control results presented in the form of a histogram, χо - the defect size minimally available for detection, the initial defect N _ucx is determined by the formula: N = Aγ ^~ " and the probability of detecting the defect P _0O dP0 formula: pvy> = ^{ι ^~} 0- ^~ ¹ T) exp [- «(* - Zo)] - 1 -

11. The method according to p. 9 or 10, characterized in that the characteristic axis is the semi-axis a of the ellipse, which schematize the defect, and the ratio a / c is assumed to be constant for all a, determined from the condition of the maximum rate of development of the defect in operating conditions.

12. The method according to any one of claims 8 to 11, characterized in that γ ^ _p , [χ _{b .e.} , [%] _uzg is determined for a particular product or group of m of the same type of products, and when monitoring m of the same type of products, all the control results are summarized and presented in the form of a single histogram.

13. The method according to any one of claims 10 to 12, characterized in that the minimum defect size χ ₀ that is available for detection is determined when setting up the flaw detector used to control the product, or as the minimum defect size that was detected during the inspection.

14. The method according to any one of claims 10 to 13, characterized in that the constant η is taken equal to 0.

15. The method according to claims 8 or 9, characterized in that a test sample is made for determining the characteristics of non-destructive testing of discontinuities in the product material, this test sample is tested by the non-destructive testing method, and the product is inspected the same method as the control of the test sample, while the test sample is made in the form of the product or its most critical part from the same material and according to the same technology as the product, with randomly located defects with different bubbled characteristic dimensions χ, determine the probability of detecting defects _vod P (χ):

P water (%) = N _{obn m} o (g) IN ₃ cs mo (χ), where N _{ob mo} - the number of defects detected during the control of the test sample,

N _{hall m0} - the number of defects incorporated in the manufacture of the sample, the initial defect is defined as:

^ ucx ~ - <* out of σ ^L waters (%) the histogram (N _ucx , χ) is approximated by the equation N _ucx = f (χ) or N _ucx = f (a, c), where a, c are the linear sizes of the defects, and when determining the residual defectiveness N _ocm use the expression

N _ocm = N _UCX - [1-P _water (χ)] or N _ocm = N _UCX - N _obn ; and the boundary value fø separating the reliable and probabilistic parts of the residual defect is determined from the equation χ max

16. The method according to p. 15, characterized in that the test sample contains three groups of defects: defects, the sizes of which lie in the range from the sizes of defects acceptable during operation, to sizes critical for the product in operation; defects, the sizes of which lie in the range from the sizes allowed during the manufacture of the product to the sizes of defects allowed during operation; defects, the sizes of which lie in the range from the sizes minimally available for detecting defects, to the sizes of defects acceptable in the manufacture while the first two types of defects mimic defects of an operational nature, and the third type - technological, residual defects

^N t _mβcc , _m ^{in the} field of defects important for safety, is determined as the number of defects in the product, the dimensions of which are equal to or greater than the critical dimensions χ _{* p} in the operation mode of the product:

Xpreό

N оιтfi sudden ^~ J ^ ost YZ / ^ X residual defectiveness N∑ _{m d e} in the field of defects important for reliability is determined as the number of defects whose dimensions exceed the dimensions of the defects [χ] _< b _.5 maximum permissible products in operation:

\

Xd s residual defectiveness N £ _mwg in the region of defects that determine the quality of manufacture, in the form of the number of defects whose dimensions exceed the dimensions χ ^ of the discontinuities allowed in the manufacture:

where χ _before - maximum possible characteristic defect size

17. The method according to claims 15 or 16, characterized in that the histogram {N _UC χ _> ld is approximated by an equation of the type N _ucx = A _x exp (-п _χ χ), or # _"* = А exp (-and _β fl), or N _ucx = A _ac exp [and _{a> c} (α ² / c)], or N _ULX = A _F exp (-nF), or N _u = A _g X ^{~ Пχ} , or N _ucx = A _a a- ^And -, or N _ucx = A _a , (a ² / s) ^' "- ^* , or N _ucx = A _F F ^, where a, c are the linear dimensions of the defect, F is the area of the defect, n, A - coefficients selected from the condition of maximum approximation of the analytical curve to the experimental data