GOST 14782-86

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  ГОСТ 14782-86

GOST 14782−86 non-destructive Control. Welded connections. Ultrasonic methods

GOST 14782−86

Group B09

INTERSTATE STANDARD

Nondestructive testing

WELDED CONNECTIONS

Ultrasonic methods

Nondestructive testing. Welded joints. Ultrasonic methods

ISS 25.160.40
AXTU 0072

Date of introduction 1988−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Railways of the USSR

2. APPROVED AND put INTO EFFECT by DECISION of the USSR State Committee for standards from December 17, 1986 N 3926

3. INSTEAD 14782−76 GOST, GOST 22368−77

4. In the standard account of the requirements of ST CMEA 2857−81 and Recommendations of the CMEA RS 5246−75

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. REPRINTING. May 2005

1. This standard establishes methods of ultrasonic testing of butt, corner, lap and t-joints made of arc, electroslag, gas, vasopressive, electron beam, and butt welding in the welded structures of metals and alloys to detect cracks, lack of penetration, pores, non-metallic and metallic inclusions.

The standard does not specify the methods of ultrasonic inspection of welding.

The need for ultrasonic testing, the volume control and the sizes of unacceptable defects are established in the standards or technical specifications for products.

Explanation of terms used in this standard is given in Annex 1.

1. CONTROLS

1.1. When control should be used:

pulsed ultrasonic flaw detector (hereinafter detector) is not below the second group of transducers of the piezoelectric;

standard samples for setting of the flaw detector;

auxiliary AIDS and devices to meet the scan parameters and measurements of characteristics of the detected defects.

Test instruments and standard samples used for inspection shall be certified and verified in the prescribed manner.

Allowed to use a flaw detector with electromagnetic acoustic transducers.

1.2. To control, use flaw detectors, equipped with direct and oblique transducers with the attenuator to determine the position coordinates of the reflecting surface.

The value of the step attenuator should be no more than 1 dB.

Allowed to use the flaw detector with the attenuator, the value of the degree of weakening which is 2 dB, the flaw detector without attenuator with automatic measurement of the amplitude of the signal.

1.3. Piezoelectric transducers for a frequency of more than 0.16 MHz — according to GOST 26266.

Allowed the use of non-standardized converters according to GOST 8.326*.
________________
* On the territory of the Russian Federation are PR 50.2.009−94**.

** In the territory of the Russian Federation the document is not valid. Apply the Procedure of testing standard specimens or means of measurement for the purposes of type approval, Administrative regulations on granting by Federal Agency on technical regulation and Metrology of the state service for the type approval of reference materials or type of measuring instruments, Requirements to the signs of type approval for standard samples or type of measuring instruments and their application, here and hereafter. — Note the manufacturer’s database.

1.3.1. Piezoelectric transducers are selected based on:

the shape and size of the electroacoustic transducer;

the material of the prism and the speed of propagation of longitudinal ultrasonic waves at a temperature of (20±5)°C;

the middle passage of ultrasound in the prism.

1.3.2. The frequency of ultrasonic vibrations emitted by the slanted transducers should not vary from the nominal value by more than 10% in the range of St of 1.25 MHz, more than 20% in the range up to 1.25 MHz.

1.3.3. The position of the label corresponding to the exit point of the beam should not differ from the actual by more than ±1 mm.

1.3.4. The working surface of the Converter at the control of welded joints of products of cylindrical or other curved forms shall conform to the requirements of technical documentation, control, duly approved.

1.4. Standard samples of CO-1 (Fig.1)-2 (Fig.2) and 3 (damn.4) should be used for measurement and verification of key instrument parameters and control the echo-pulse method, and a combined circuit of the piezoelectric transducer with a flat working surface at the frequency of 1.25 MHz or more, provided that the width of the transducer does not exceed 20 mm. In the remaining cases to test the basic parameters of the instrument and control must use standard samples of the industry (enterprise).

Damn.1

1 — hole to determine the conditional sensitivity; 2 — wall; 3 — base; 4 — gasket, protecting the holes from dirt 1; 5 — holes for determining resolution capability; 6 — grooves to define resolution; 7 — groove to determine the error of the depth gauge;  — the time, measured to whole numbers of microseconds

Notes:

1. Limit deviations of linear dimensions of the sample — not below-14th class according to GOST 25346.

2. Limit deviations of the diameter of the holes in the standard sample should be not less than 14-th class according to GOST 25346.

1.4.1. Standard sample so-1 (see the devil.1) used to determine the conditional sensitivity, inspection resolution and error of the depth gauge of the instrument.

Sample so-1 should be made of organic glass marks the tosp according to GOST 17622. The speed of propagation of longitudinal ultrasonic waves at a frequency of (2,5±0,2) MHz at a temperature of (20±5) °C shall be equal to (2670±133) m/s Measured with an accuracy not worse than 0.5% of the speed value must be specified in the passport on the sample.

The amplitude of the third pulse at the bottom of the thickness of the specimen at a frequency of (2,5±0,2) MHz and a temperature of (20±5) °C shall not vary by more than ±2 dB of the amplitude of the bottom of the third pulse in the respective initial sample, the certified bodies of the state metrological service. The attenuation coefficient of longitudinal ultrasonic waves in the initial sample should be between 0,026 0,034 mm to.

Allowed to use samples of organic glass by the devil.1, in which the amplitude of the third sediment pulse on the thickness of the sample is different from the amplitude of the corresponding pulse in the original sample by more than ±2 dB. At the same time, and in the absence of the original sample to the certified sample must be accompanied by a certificate of a schedule or Appendix 2 table of amendments, taking into account the variation of attenuation coefficient and temperature effect.

1.4.2. Standard sample so-2 (see the devil.2) used to determine the conditional sensitivity, dead zone, the error of the gauge of an angle of input beam, the width of the main lobe of the radiation pattern, pulse conversion factor at the control joints of carbon and low alloy steels, as well as to determine the limit of sensitivity.

1 — hole to determine the angle of the input beam, the width of the main lobe of the directivity diagram, the conditional and marginal sensitivity; 2 — the hole to check the dead zone; 3 — Converter; 4 — the block of steel grade 20, or grade steel 3

Damn.2

Sample CO-2 must be made of steel grade 20 to GOST 1050 or steel grade 3 GOST 14637. The speed of propagation of longitudinal waves in the sample at a temperature of (20±5) °C shall be equal to (5900±59) m/s Measured with an accuracy not worse than 0.5% of the speed value must be specified in the passport on the sample.

In the control compounds of metals differing in acoustic characteristics of carbon and low alloy steels, to determine the refracted angle, the width of the main lobe of the radiation pattern, dead zones and sensitivity limit should apply the standard sample WITH-2A (Fig.3).

1 — hole to determine the angle of the input beam, the width of the main lobe of the directivity diagram, the conditional and marginal sensitivity; 2 — the hole to check the dead zone; 3 — Converter; 4 — block of the monitored metal; 5 — scale; 6 — screw

Damn.3

Material requirements sample, the hole number 2 and the distance determining the center of the holes 2 in the sample WITH 2A, must be specified in the technical documentation for the control.

Scale of values of angle of beam of standard samples of co-2 and-2A graduate in accordance with the equation

,

where is the depth of the location of the center of the hole 1.

The zero of the scale must coincide with the axis passing through the center hole with a diameter of (6+0,3) mm perpendicular to the working surface of the sample, with an accuracy of ±0.1 mm.

1.4.3. The time of propagation of ultrasonic oscillations in forward and reverse directions specified on standard samples of CO-1 and co-2 must be (20±1) µs.

1.4.4. The standard sample WITH-3 (see the devil.4) should be used to determine the exit point 0 of the ultrasonic beam, arrows Converter.

Damn.4

Allowed to apply the standard sample WITH-3 to determine the time of propagation of ultrasonic oscillations in the prism Converter application 3.

The standard sample WITH-3 made of steel grade 20 to GOST 1050 or steel grade 3 GOST 14637. The speed of propagation of longitudinal waves in the sample at a temperature of (20±5) °C shall be (5900±59) m/s Measured with an accuracy not worse than 0.5% of the speed value must be specified in the passport on the sample.

On the side, and the working surfaces of the sample should be engraved risks, passing through the center of the semicircle and the axis of the work surface. In both directions from the scratches on the lateral surface of the applied scale. The zero of the scale must coincide with the centre of the specimen with an accuracy of ±0.1 mm.

In the control joints of metal, the speed of propagation of transverse waves which is less than the velocity of transverse wave of steel grade 20 and, when using a transducer with an angle of incidence of the wave close to the second critical angle in steel grade 20, to determine the exit point and the arrows of the Converter to apply a standard sample of enterprises WITH a-3A, made of metal controlled by the devil.4.

Requirements of the sample WITH metal-3A must be specified in the technical documentation for the control, duly approved.

1.5. Allowed to determine the conditional sensitivity, error of gauge location of the exit point and angle of insertion, the width of the main lobe of the radiation pattern to apply the sample WITH 2P GOST 18576* the composition of samples of co-2 and co-2P with the introduction of additional holes with a diameter of 6 mm.
________________
* From 1 January 2002 put into effect GOST 18576−96 (here and below).

1.6. The flaw detector for machine control must be provided to, for the systematic verification of the parameters determining the efficiency of equipment. The list of parameters and their validation have to be specified in the technical documentation for the control, duly approved.

It is possible to use a conditional to check the sensitivity of standard samples or-1 or-2, or standard samples of the enterprise, specified in the technical documentation for the control, duly approved.

1.7. Permitted to use equipment without auxiliary equipment for compliance with the scan settings if you move the Converter by hand and to measure characteristics of the identified defects.

2. PREPARATION FOR CONTROL

2.1. Weld prepared for ultrasonic testing in the absence of the outer joint defects. The shape and size of the HAZ should allow you to move the transducer within the range that is testing the acoustic axis of the transducer weld or part to be controlled.

2.2. The surface of joint, which moves the transducer should not have dents and irregularities, the surface must be removed spatter, loose scale and paint, dirt.

When machining connections, stipulated by the technological process for manufacturing of welded structures, the surface should not be below 40 µm according to GOST 2789.

Requirements for permissible waviness and surface preparation specified in the technical documentation of the control, duly approved.

The validity of the presence needlewoman scale, paint and dirt in the control of EMA-converters specified in the technical documentation for the control, duly approved.

2.3. Control the heat-affected zone of the base metal within the probe is rotated to the lack of bundles should be done in accordance with the technical documentation for the control, duly approved, if the control of the metal before the welding was carried out.

2.4. The welded joint should be marked and divided into sections to clearly establish the location of the defect along the length of the seam.

2.5. Pipes and tanks in front of the control reflected beam must be freed from liquid. Allowed to control pipes and containers with liquid by the method stipulated in the technical documentation for the control, duly approved.

2.6. The refracted angle and limits movement of the transducer should choose such as to ensure testing of the joint direct and once-reflected rays or only the direct beam.

Direct and once-reflected rays should control the joints, the widths or the lengths of the legs which allow you to check the testing section of the acoustic axis of the transducer.

Allowed to control welded joints is repeatedly reflected beam.

2.7. The duration of the sweep should be mounted so that the highest part of the sweep on the screen of a cathode-ray tube correspond to the path of the ultrasonic pulse in the metal controlled of the weld.

2.8. The main parameters of control:

1) wavelength or frequency of ultrasonic vibrations (flaw);

2) sensitivity;

3) the position of the exit beam (arrow Converter);

4) the incident angle of ultrasonic ray in the metal;

5) the error of the depth gauge (the measurement error of the coordinates);

6) dead zone;

7) the resolution in range and (or) the front;

8) the characteristics of the electroacoustic transducer;

9) conditional minimum defect size, fixed at a predetermined scanning speed;

10) the pulse duration of the flaw.

The list of parameters subject to verification, numerical values, technique and frequency of their inspections should be laid down in the technical documentation for the control.

2.9. The main parameters in accordance with paragraph 2.8, the enumeration 1−6, test on a standard sample so-1 (Fig.1), so-2 (or-2A) (Fig.2 and 3), CO-3 (Fig.4)-4 (Appendix 4) and standard sample of enterprise (Fig.5−8).

Requirements for standard samples of the enterprise, as well as methods for checking the main parameters of the control must be specified in the technical documentation for the control, duly approved.

2.9.1. The frequency of ultrasonic vibrations should be measured by electronic methods of spectrum analysis of the echo signal at the transducer from concave cylindrical surface of the standard sample WITH-3 or measurement of the duration of the period of oscillations in the echo pulse with a broadband oscilloscope.

Allowed to determine the wavelength and frequency of ultrasonic vibrations emitted by the oblique transducer, interference method for sample s-4 in accordance with the recommended Annex 4 according to GOST 18576 (Annex 3).

2.9.2. Conditional sensitivity control echo method should be measured according to the standard model CO-1 in millimeters, or the standard sample s-2 in decibels.

Measurement of the conditional sensitivity for the standard sample WITH-1 performed at a temperature that is installed in the technical documentation for the control, duly approved.

Relative sensitivity in the control of shadow and mirror-shadow methods measured on the defect-free area of the welded connection or on a standard sample of enterprise in accordance with GOST 18576.

2.9.3. Extreme sensitivity of the flaw detector with the transmitter should be measured in square millimeters for square bottom 1 hole in the standard sample of the enterprise (see the devil.5) or to determine the ARD (or SKH)-diagram.

Allowed instead of the standard sample of enterprises with a hole with a flat bottom to apply the standard samples of the enterprise with segment reflectors (see the devil.6) or standard samples of the enterprise with corner reflectors (see the devil.7), or a standard sample of enterprises with a cylindrical hole (see the devil.8).

The angle between the plane of the bottom 1 hole or plane 1 segment and the contact surface of the specimen shall be ()° (see the devil.5 and 6).

Limit deviations of the diameter of the hole in a standard sample of the enterprise features.5 must be ±according to GOST 25347.

1 — the bottom of the hole; 2 — transducer; 3 — block of the monitored metal; 4 — acoustic axis

Damn.5

1 — the plane of the segmented reflector; 2 — transducer; 3 — block of the monitored metal; 4 — acoustic axis

Damn.6

1 — plane corner reflector; 2 — transducer; 3 — block of the monitored metal: 4 — acoustic axis

Damn.7

The height of the segmented reflector must exceed the length of the ultrasonic waves; the ratio of the segmented reflector should be more than 0.4.

Width and height of the corner reflector should be greater than the length of the ultrasonic length; the ratio should be greater than 0.5 and less than 4.0 (see the devil.7).

The sensitivity limit () in square millimeters, measured according to the standard model with a corner reflector area , calculated by the formula

,

where  — coefficient for steel, aluminum and its alloys, titanium and its alloys, which depends on the angle specified in technical documentation for the control, duly approved, taking into account Annex 5.

A cylindrical hole 1 diameter =6 mm for setting the maximum sensitivity should be performed with a tolerance of +0.3 mm at a depth of =(44±0,25) mm (see hell.8).

1 — a cylindrical hole; 2 — transducer; 3 — block of the monitored metal; 4 — acoustic axis

Damn.8

The ultimate sensitivity of the detector for the sample with a cylindrical bore should be determined in accordance with Annex 6.

To determine the limit of sensitivity should be emended, taking into account the difference of surface finish and curvature of the surfaces of a standard sample and a controlled connection.

When using charts as a reference signal using the echo signals from the reflectors in the standard samples or-1 or-2 or-2A, or-3, as well as from the bottom surface or the dihedral angle in the controlled product or the standard sample of the enterprise.

At the control of welded joints with thickness less than 25 mm the orientation and dimensions of a cylindrical hole in a standard sample of enterprises used for sensitivity settings, indicate in the technical documentation for the control, duly approved.

2.9.4. The angle of the input beam should be measured on standard samples of co-2 or-2A, or according to the standard model of the enterprise (see the devil.8). The typing angle more than 70° measured at a temperature control.

The refracted angle in the weld thickness greater than 100 mm, determined in accordance with the technical documentation of the control, duly approved.

2.10. The characteristics of electroacoustic transducers should be checked according to normative-technical documentation for the equipment duly approved.

2.11. Minimum notional size of the defect, fixed at a preset speed control must be determined on a standard sample of enterprise in accordance with the technical documentation of the control, duly approved.

Allowed to determine the minimum of the relative size to use the electronic equipment that simulates the signals from the defects of a given size.

2.12. The pulse duration of the flaw determined by the broadband oscilloscope measurement of the duration of the echo signal at 0.1.

3. CONTROL

3.1. When the weld should be applied to pulse-echo, shadow (mirror of the shadow) or echo and shadow methods.

When the pulse-echo method is used combined (Fig.9) separate (Fig.10 and 11) separately and combined (Fig.12 and 13) of circuit switching converters.

Damn.9

Damn.10

Damn.11

Damn.12

Damn.13

The shadow method used to separate (Fig.14) a diagram of switching converters.

Damn.14

When the echo of the shadow method used dual (damn.15) a diagram of switching converters.

Damn.15

Note. On the heck.9−15;  — output to the generator of ultrasonic vibrations; the output to the receiver.

3.2. Butt welded connections should be proslushivat schemes given on features.16−19, t-connection — schemes shown in hell.20−22, and lap-joints — according to the diagrams given on features.23 and 24.

Damn.16

Damn.17

Damn.18

Damn.19

Damn.20

Damn.21

Damn.22

Damn.23

Damn.24

It is possible to use other diagrams given in the technical documentation for the control, duly approved.

3.3. Acoustic contact of the piezoelectric transducer with controlled metal to establish a contact or immersion (slot) ways of entering of ultrasonic vibrations.

3.4. When you search for defect sensitivity (conditional or marginal) must be less than specified by the value set in the technical documentation for the control, duly approved.

3.5. Testing of welded joints performed by the method of longitudinal and (or) transverse displacement of the transducer at a constant or varying angle of input beam. Scanning method should be installed in the technical documentation for the control, duly approved.

3.6. Steps of the scan (longitudinal or transverse ) is determined based on a predetermined over-scan sensitivity over the sensitivity evaluation, the directivity of the transducer and the thickness of the test weld. The method of determining the maximum of the scanning steps and is given in Annex 7. For the nominal scan step during manual inspection, which must be respected in the process of the control should take values:

.

3.7. Method, key parameters, switching circuits converters, input method, ultrasonic vibrations of the sounding scheme, and recommendations for the separation of false signals and signals from defects to be specified in the technical documentation for the control, duly approved.

4. ASSESSMENT AND REGISTRATION OF TESTING RESULTS

4.1. Evaluation of inspection results

4.1.1. Quality assessment of welded joints according to the ultrasound control should be carried out in accordance with normative-technical documentation for the product, duly approved.

4.1.2. The main measured characteristics of the detected defect are:

1) equivalent defect area or the amplitude of the echo signal from the defect taking into account the measured distance to it;

2) the coordinates of the defect in the weld joint;

3) the relative size of the defect;

4) the relative distance between the defects;

5) the number of defects for a certain length of the connection.

The measured characteristics are used to assess the quality of the connections must be specified in the technical documentation for the control, duly approved.

4.1.3. Equivalent defect area should be determined by the amplitude of the echo signal by comparing it with the amplitude of the echo from a reflector in the sample or by using the design charts provided their convergence with experimental data is not less than 20%.

4.1.4. The conditional size of the defect detected are (Fig.25):

1) conventional length ;

2) conventional width ;

3) conventional height .

Conventional length is measured in millimeters along the length of the zone between the extreme positions of the transducer that is moved along the seam, oriented perpendicular to the axis of the joint.

Conditional width is measured in millimeters along the length of the zone between the extreme positions of the transducer are moved in a plane of incidence of the beam.

Conditional height in millimeters or microseconds is measured as the difference between the values of the depth location of the defect in the extreme positions of the transducer are moved in a plane of incidence of the beam.

4.1.5. In the measurement of conditional dimensions , , for the extreme position of the transmitter accept those in which the amplitude of the echo signal from the detected defect is 0.5 of the maximum value, or decreases to match the specified sensitivity value.

Allowed for extreme position to take those in which the amplitude of the echo signal from the detected defect is specified portion from 0.8 to 0.2 of the maximum value. The adopted values of levels must be specified when placing the results of the inspection.

Conditional width and a nominal height of defect measured in section of a connection where the echo signal from the defect has the greatest amplitude, with the same extreme positions of the transducer.

4.1.6. Conditional distance (see the devil.25) between the defects is to measure the distance between the extreme positions of the transducer, which was determined by conditional length of two adjacent defects.

Damn.25

4.1.7. An additional characteristic of the defect detected is its configuration and orientation.

To assess the orientation and configuration of the defect detected is used:

1) comparison of conventional size and identified defect with the calculated or measured values of conditional dimensions and the non-directional reflector, located at the same depth, and the identified defect.

In the measurement of conditional dimensions , and , in the extreme position of the transmitter accept those in which the amplitude of the echo signal is the specified portion from 0.8 to 0.2 of the maximum values stipulated in the technical documentation for the control, duly approved;

2) comparison of the amplitude of the echo signal reflected from the detected defect back to the middle of the seam from the transmitter, with the amplitude of the echo signal , which had undergone specular reflection from the inner surface of the connection and accept the two transducers (see the devil.12);

3) comparing the ratio of the conditional size of the defect detected with respect to the conventional dimensions of a cylindrical reflector ;

4) comparing the second Central moments of the conditional size of the defect detected, and a cylindrical reflector, located at the same depth, and the identified defect;

5) the amplitude-time parameters of signals of waves diafragmirovanija on the defect;

6), the spectrum of the signals reflected from the defect;

7) determination of the coordinates of the reflecting points of the surface defect;

8) comparison of the amplitudes of the received signals from the defect and from the non-directional reflector in the scoring of the defect from different angles.

The necessity, possibility and methods of evaluating the configuration and orientation of the defect detected compounds for each type and size must be specified in the technical documentation for the control, duly approved.

4.2. The results of the control

4.2.1. The inspection results must be recorded in the journal or prison, or on the scheme of the welded joint, or other document, which must include:

type of controlled connections, the indices assigned to the product and weld, and the length of the controlled area;

technical documentation, in accordance with which they performed the control;

the type of flaw;

reprocentralen or incompletely controlled areas of welds subject to ultrasonic testing;

the results of control;

date of control;

name of radiographer.

Additional information to be logged, and the order of registration and storage of the journal (opinions) should be specified in the technical documentation for the control, duly approved.

4.2.2. Classification of butt welded joints by ultrasonic inspection results produced by the application 8.

The need for a classification specified in the technical documentation for the control, duly approved.

4.2.3. Abbreviated description of the testing results follows each defect or group of defects to specify separately and indicate:

the letter that defines qualitatively the assessment of the acceptability of the defect in the same area (the amplitude of the echo signal) and the conditioned length (A, or D, or B, or DB);

the letter that defines qualitatively the conditional length of the defect, if it is measured in accordance with clause 4.7, listing 1 (G or E);

the letter that defines the configuration of the defect, if it is installed;

a number that defines the equivalent area of the defect detected, mmif it is measured;

number that determines the greatest depth of defect, mm;

a number, defining the conditional length of the defect, mm;

figure defining conditional defect width, mm;

figure defining conditional defect height, mm or µs.

4.2.4. For abbreviating should apply the following notation:

A — defect, equivalent area (the amplitude of the echo signal) and code length of which is equal to or less than the permissible values;

D — defect, equivalent area (the amplitude of the echo signal) exceeds the permissible value;

B — defect, conditional length of which exceeds allowable value;

G — defects, conditional length ;

E — defects, conditional length ;

In a group of defects that are separated from one another at distances ;

The t — defects that can be detected by the transducer at an angle to the axis of the joint and not found at the location of the transducer perpendicular to the axis of the joint.

Conventional length for defects of types G and T are not specified.

In abbreviating numerical values separated from each other and from letters by a hyphen.

The necessity of abbreviating, the applied symbols and the order of entry specifies the technical documentation on the control, duly approved.

5. SAFETY REQUIREMENTS

5.1. When carrying out of works on ultrasonic control of products, the operator should be guided by GOST 12.1.001, GOST 12.2.003, GOST 12.3.002, rules of technical operation of electrical installations and the rules of technical safety for operation of electrical installations* approved by Gosenergonadzor.
________________
* On the territory of the Russian Federation the document is not valid. Apply cross-industry Rules on labor protection (safety rules) when operating electrical installations (SWEAT P M-016−2001, RD 153−34.0−03.150−00). — Note the manufacturer’s database.

5.2. When performing control, the requirements of «Sanitary norms and rules when working with equipment that generates the ultrasound transmitted by contact to the hands working» N 2282−80* approved by the USSR Ministry of health, and safety requirements set out in the technical documentation for the applicable instrument, duly approved.
________________
* On the territory of the Russian Federation the document is not valid. Act SanPiN 2.2.4./2.1.8.582−96. — Note the manufacturer’s database.

5.3. The noise levels generated at the workplace of the operator, shall not exceed the permissible according to GOST 12.1.003.

5.4. At the organization of works on control must be complied with fire safety requirements according to GOST 12.1.004.

ANNEX 1 (reference). EXPLANATION OF TERMS USED IN THE STANDARD

ANNEX 1
Reference

ANNEX 2 (mandatory). A METHOD OF CONSTRUCTING CERTIFICATE-GRAPHICS TO THE STANDARD SAMPLE MADE OF ORGANIC GLASS; EXAMPLES OF APPLICATION CERTIFICATE-GRAPHICS

ANNEX 2
Mandatory

Certificate-schedule communicates the conditional sensitivity () are in millimeters in the original standard sample so-1 with the conditional sensitivity () in decibels for the standard sample so-2 (or 2P GOST 18576) ID reflector with a diameter of 2 mm in the certified sample WITH a-1 at a frequency of ultrasonic vibrations (2,5±0,2) MHz, a temperature of (20±5) °C and the angles of the prism =(40±1)° =(50±1)° for drives of a specific type.

In the drawing, the points marked graph for the source sample so-1.

To construct an appropriate chart to a specific certified sample so-1 that does not meet the requirements of section 1.4.1 of this standard, under the above conditions determine in decibels the difference of the amplitudes from the reflectors 20 and 50 N with a diameter of 2 mm in the certified sample, and the amplitude of the reflector with a diameter of 6 mm at a depth of 44 mm in sample SB-2 (or 2P):

; ,

where  — the value of the attenuator corresponds to the attenuation of the echo signal from a hole with a diameter of 6 mm in sample SB-2 (or 2P) to the level at which to assess relative sensitivity, dB.

 — reading attenuator, in which the amplitude of the echo signal from the test holes with the number in the certified sample reaches a level at which to assess relative sensitivity, dB.

The calculated values mark the points on the chart and connect them by a straight line (an example of the construction see drawing).

EXAMPLES OF APPLICATION OF THE CERTIFICATE-GRAPHICS

The control is implemented by a detector with a Converter to a frequency 2.5 MHz, angle of the prism =40° and a radius of the piezoelectric plate 6 mm made in accordance with the technical specifications approved in the prescribed manner.

The flaw detector is equipped with a model CO-1, the serial number, with certificate the schedule (see drawing).

1. Technical documentation on the control is set to conditional sensitivity of 40 mm.

The specified sensitivity will be played, if you configure a flaw at hole N 45 in the sample so-1, serial number ____________ .

2. Technical documentation on the control is set to conditional sensitivity of 13 dB. The specified sensitivity will be played, if you configure a flaw on hole No. 35 in the sample so-1, serial number __________ .

APPENDIX 3 (reference). DETERMINING THE TIME OF PROPAGATION OF ULTRASONIC OSCILLATIONS IN THE PRISM CONVERTER

APPENDIX 3
Reference

Time in microseconds of propagation of ultrasonic oscillations in the prism Converter still

ISS

where is the total time between the probe pulse and the echo signal from the concave cylindrical surface of the standard sample WITH-3 when mounting the transducer in the position corresponding to the maximum amplitude of the echo signal; and 33.7 µs, the time of propagation of ultrasonic oscillations in the standard sample, calculated for parameters: radius of the specimen is 55 mm, the speed of propagation of transverse waves in the material of the sample — 3,26 mm/µs.

APPENDIX 4 (recommended). SAMPLE SB-4 TO MEASURE THE WAVELENGTH AND FREQUENCY OF ULTRASONIC OSCILLATIONS TRANSDUCERS

ANNEX 4
Recommended

1 — slots; 2 — ruler; 3 — Converter; 4 — the block of steel grade 20 to GOST 1050 or steel grade 3 GOST 14637; the difference between the depth of grooves on the ends of the sample (); sample width ()

The standard sample s-4 is used to measure the wavelengths (frequency), the excited transducers with angles of entry of 40 to 65° and a frequency of from 1.25 to 5.00 MHz.

The wavelength (frequency ) is determined by an interference method as an average of the distances between the four closest to the center of the sample extremes of the amplitude of the echo signal from the parallel grooves with a smoothly varying depth.

,

where is the angle between the reflecting surfaces of the grooves are equal (see drawing)

.

The frequency is determined by the formula

,

where is the speed of propagation of transverse waves in the sample material, m/s.

ANNEX 5 (reference). The DEPENDENCE N=f (Epsilon) FOR STEEL, ALUMINUM AND ITS ALLOYS, TITANIUM AND ITS ALLOYS

ANNEX 5
Reference

Dependence for steel, aluminum and its alloys, titanium and its alloys

APPENDIX 6 METHODS OF DETERMINING THE LIMITING SENSITIVITY OF THE INSTRUMENT AND EQUIVALENT TO THE AREA OF THE DEFECT DETECTED ON THE SPECIMEN WITH CYLINDRICAL HOLE

APPENDIX 6

Extreme sensitivity, in square millimeters of detector with tilted transducer (or the equivalent area of the defect detected) is determined according to the standard model of the enterprise with a cylindrical hole or the standard sample WITH-2A or s-2 in accordance with the expression

,

where  — the value of the attenuator corresponds to the attenuation of the echo from the side drilled hole in a standard sample of the enterprise or the standard sample WITH-2A or-2 to the level at which to assess the ultimate sensitivity, dB.

 — reading attenuator, which evaluate the ultimate sensitivity of the detector or when the amplitude of the echo signal from the investigated defect reaches a level at which to assess the ultimate sensitivity, dB.

 — the difference between the coefficients of transparency of the border prisms of the inverter — controlled metal compounds and opacity of the border of the prism Converter — metal standard sample of the enterprise or the standard sample WITH-2A (or-2), dB (0).

When standardization of the sensitivity for the standard sample of the enterprise, having the form and surface finish the same as the controlled connection =0;

 — the radius of the cylindrical hole, mm;

 — the speed of transverse waves in the material of the sample and the controlled joints, m/s;

is the ultrasound frequency, MHz;

 — the average path of the ultrasound in the prism Converter, mm;

 — the speed of longitudinal waves in the material of the prism, m/s;

and the incident angle of ultrasonic ray in the metal and the angle of the prism Converter, respectively, deg;

depth, for an estimated ultimate sensitivity or which is detectable defect, mm;

 — depth of the cylindrical hole in the specimen, mm;

the attenuation coefficient of shear waves in the metal of the controlled connections and the specimen, mm.

To simplify the determination of the limit of sensitivity and equivalent to the area it is recommended to calculate and graph (linear graph), the linking of limit sensitivity (equivalent area ), the conditional coefficient of the detection of the defect (a) and depth , for an estimated (adjusted) extreme sensitivity or where the defect is located.

The convergence of the calculated and experimental values at a =(50±5)° better than 20%.

Example of constructing a linear graph and determine the maximum sensitivity and the equivalent square

EXAMPLES

Control joints butt welded joints of sheets with a thickness of 50 mm of mild steel performed by means of an angle beam transducer with known parameters: , , . The frequency of ultrasonic vibrations excited by an inverter, is in the range of 26.5 MHz ±10%. Attenuation factor =0.001 mm.

When measured according to the standard sample so-2 found that =50°. SKH-chart calculated for the stated conditions of and =3 mm =44 mm according to the formula given above is shown in the drawing.

Example 1.

Dimension set that =2.5 MHz. Standardization is carried out according to the standard model of the enterprise with a cylindrical hole with a diameter of 6 mm, located at a depth =44 mm; the shape and cleanliness of the sample surface corresponding to the shape and surface finish of a controlled connection.

The value of the attenuator that corresponds to the maximum attenuation, which sound indicator registers the echo-signal from a cylindrical hole in the sample is =38 dB.

It is required to determine the ultimate sensitivity of this setting of the instrument (=38 dB) and the search of defects, depth =30 mm.

The desired value for the maximum sensitivity in SKH-diagram corresponds to the intersection of the ordinate =30 mm line and is 5 mm.

You want to configure the detector at maximum sensitivity =7 mmfor the depth location of the desired defect =65 mm =38 dB.

Specified values and in SKH-diagram corresponds to dB.

Then =-9+38=29 dB.

Example 2.

The measurement established that a =2.2 MHz. Setting is carried out on standard sample SB-2 (=44 mm). By comparing the amplitudes of echo signals from the same cylindrical holes in the leaves of the monitored compounds in the standard sample so-2 set that =-6 dB.

The value of the attenuator that corresponds to the maximum attenuation, which sound indicator fixed echo signal from a cylindrical hole in the SB-2 is =43 dB.

You want to determine the equivalent area of the defect detected. In accordance with the measurement depth location of the defect =50 mm, and the value of the attenuator, which is fixed, the echo signal from the defect, =37 dB.

The value equivalent to the area of the defect detected on SKH-diagram corresponds to the point of intersection of y =50 mm with line =37-(43−6)=0 dB and is 14 mm.

APPENDIX 7 (recommended). THE METHOD OF DETERMINING THE MAXIMUM STEP OF SCAN

ANNEX 7
Recommended

Step scanning with transverse longitudinal movement with parameters 15 mm =15 mm MHz is determined by the nomogram, shown in the drawing (the method of testing).

1 — = 65°; = 20 mm and = 50°; = 30 mm; 2 — a = 50°; = 40 mm; 3 — a = 65°, a = 30 mm; 4 — a =50°, = 50 mm; 5 — a = 50°, = 60 mm

Examples:

1. Set =6 dB, =0, =50°. The nomogram =3 mm.

2. Set =50°, =40 mm, =1, =4 mm. In nomogram 2 dB.

Step scanning with longitudinal and transverse movement is determined by the formula

or

,*

where  — 1, 2, 3, etc. the number of the step;

*- distance from the exit point to the scanned cross-section, normal to the contact surface of the test object.
_______________
* Formula and explication to be consistent with the original. — Note the manufacturer’s database.

The parameter is determined experimentally for a cylindrical hole in the sample co-2 or-2A, or according to the standard model of the enterprise. For this measure the conditional width of the cylindrical hole with the weakening of the maximum amplitude, equal and minimum distance from the projection of the center of the reflector on the working surface of the sample to the point of entry of the transducer in the position at which the determined conditional width . The value is calculated by the formula

,

where  — given the distance from the transducer to the exit point of the beam in the transducer.

ANNEX 8 (obligatory). CLASSIFICATION OF DEFECTS IN BUTT WELDS BY ULTRASONIC INSPECTION RESULTS

ANNEX 8
Mandatory

1. The present application is applicable to butt-welded joints of main pipelines and structures, and establishes a classification of defects in butt welded joints of metals and their alloys with a thickness of 4 mm or more according to the results of ultrasonic testing.

The app is a unified section of the standard of the USSR and the standard East Germany by the following main features:

name and abbreviation of defects in welded joints;

the assignment of defects to one of the types;

the establishment of the degrees of the defect size;

the setting steps of frequency defects;

establishing the length of the assessment phase;

the establishment of a class of defects depending on the type of defects, the step size and step frequency of defects.

2. The main measured characteristics of the detected defects are:

the diameter of the equivalent disk of the reflector;

the coordinates of the defect (a) cross-section (Fig.1);

the conditional size of the defect (see the devil.1);

the ratio of the amplitudes of the echo signal reflected from the detected defect and the echo signal , which had undergone specular reflection from the inner surface (Fig.2);

the angle of rotation of the transducer between extreme positions in which the maximum amplitude of the echo from the edge of the defect detected is halved relative to the maximum amplitude of the echo signal at the location of the transducer perpendicular to the axis of the weld (Fig.3).

Damn.1

Damn.2

Damn.3

The characteristics used to evaluate the quality of a particular weld, the order and precision of their measurements should be established in the technical documentation for the control.

3. The diameter of the equivalent disk of the reflector is determined by using the charts or the standard (test) samples at the maximum amplitude of the echo signal from the identified defect.

4. The conditional size of the defect detected are (see the devil.1):

conventional length ;

conditional width ;

conditional height .

5. Conventional length is measured in millimeters along the length of the zone between the extreme positions of the transducer that is moved along the seam, oriented perpendicular to the axis of the joint.

Conditional width is measured in millimeters along the length of the zone between the extreme positions of the transducer that is moved perpendicular to the seam.

Conditional height in millimeters (or in microseconds) is measured as the difference between the values of the depths (, ) the location of the defect in the extreme positions of the transducer that is moved perpendicular to the seam.

Extreme positions of the transducer are those in which the amplitude of the echo signal from the identified defect is reduced to the equivalent of the specified portion of the maximum value and the established in the technical documentation for the control, duly approved.

Conditional width and a nominal height of defect measured in the cross section of the seam where the echo signal from the defect has the greatest amplitude at the same positions of the transducer.

6. According to the results of ultrasonic inspection of defects is related to one of types:

volume unextended;

bulk long;

planar.

7. For identifying the defect to one of the types (tab.1) is used:

comparison of the conditional length of the defect detected from the calculated or measured values of the conditional length of the non-directional reflector at the same depth, and the identified defect;

Table 1

comparison of the amplitudes of the echo signal reflected from the detected defect back to the middle to the seam the Converter (), with the amplitude of the echo (), which had undergone specular reflection from the inner surface (see hell.2);

comparison relations conditional size of the defect detected with respect to conventional sizes non-directional reflector ;

the comparison of the angle between extreme positions of the transducer corresponding to the decrease in the maximum amplitude of the echo from the edge of the defect twice, with the value established by the technical documentation on the control.

8. Depending on the relationship of the equivalent diameter of the defect detected to the thickness of the weld metal has four stages defect size that is determined by traits.4.

Damn.4

9. Depending on the relationship of the total length of defects on the estimated phase to the length of the assessment phase has four stages the frequency of defects that determine traits.5.

Damn.5

The total length of defects is calculated for each type separately; however, for the bulk of the extended and planar summarize their conditional length , and for large unextended summarize their equivalent diameters .

10. The length of the assessment phase is determined depending on the thickness of the weld metal. At 10 mm, the estimated phase is taken to equal 10 , but not more than 300 mm, at 10 mm is 100 mm.

The choice of this area on the welded seam produced in accordance with the requirements of the technical documentation for the control, duly approved.


If the length of the controlled weld is less than the estimated length of the assessment phase, the length of the assessment area taking the length of the weld.

11. Proven areas of stitches depending on the type of defects, their location in the cross section, the steps of defect size (first digit) and degree of frequency of defects (second digit) refers to one of five classes according to table.2.

Table 2

By agreement between the manufacturer and the customer is allowed to divide the first class into subclasses.

When found on the evaluation section of defects of different types, each type klassificeret separately, and weld refers to a larger room class.

If the two types of defects at the assessment area assigned to one class, then the weld is classified, the sequence number is greater by one.

The results of the classification of welds for defects can be compared, provided that the inspection is made with the same main parameters of ultrasonic testing and the measured characteristics of the defects determined by the same methods.