GOST 6996-66

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  ГОСТ 6996-66

GOST 6996−66 (ISO 4136−89, ISO 5173−81, ISO 5177−81) Welded joints. Methods for determining the mechanical properties (with Amendments No. 1, 2, 3, 4)

GOST 6996−66
(ISO 4136−89,
ISO 5173−81,
ISO 5177−81)

Group B09

INTERSTATE STANDARD

Weld

METHODS FOR DETERMINING THE MECHANICAL PROPERTIES

Welded joints. Methods of mechanical properties determination

ISS 25.160.40
AXTU 0909

Date of introduction 1967−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Academy of Sciences of the Ukrainian SSR

2. APPROVED AND put INTO EFFECT by Decision of the Committee of standards, measures and measuring devices under Council of Ministers of the USSR 03.03.66 N 4736

Change No. 4 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 3 dated 17.02.93)

For the adoption of the changes voted by national standardization bodies of the following States: AZ, AM, BY, GE, KZ, MD, RU, TM, UZ, UA [codes alpha-2 at MK (ISO 3166) 004]

3. REPLACE GOST 6996−54

4. The standard fully complies with ISO 4136−89, ISO 5173−81, ISO 5177−81

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. EDITION (April 2005) with Amendments No. 1, 2, 3, 4, approved in June 1980, September 1983, December 1990, October 2004 (I & C 8−80, 1−84, 5−91, 1−2005)


This standard specifies methods for determining the mechanical properties of the welded joint as a whole and its individual sections, and weld metal in all types of welding metals and their alloys.

(Changed edition, Rev. N 2).

1. TYPES OF TESTS AND APPLICATIONS

1.1. The standard establishes methods of determining mechanical properties under the following types of tests:

a) test of the metal of various parts of welded joints and weld metal in static (short-term) stretching;

b) test of the metal of various parts of a welded joint and weld metal the impact strength (notched samples);

C) test of the metal of various parts of the welded joint resistance against mechanical aging;

g) measurement of metal hardness of various parts of a welded joint and deposited metal;

d) testing of welded joints static tension;

e) testing of welded joints in static bending (bending);

g) testing of welded joints on impact rupture.

1.2. The standard applies to the testing done to determine the quality of products and welding materials, suitability of methods and modes of welding, when establishing the qualification of welders and of indicators of weldability of metals and alloys.

1.3. Types of testing, types of sample and application of the method provided for in the standards and technical specifications for products, establishing technical requirements for it.

(Changed edition, Rev. N 3).

1.4. Allowed to apply samples and test methods according to international standards ISO 4136, ISO 5173, ISO 5177 given in appendices 1, 2, 3.

(Added, Rev. N 4).

2. SAMPLING

2.1. Samples for testing are taken from samples cut directly from a controlled design or from a specially brewed for testing the control connections.

2.2. If the shape of the welded joint eliminates the possibility of manufacturing samples of this type (parts of complex configuration, pipe, etc.), the samples can be selected from specially welded flat control connections.

2.3. When the control compounds the nature of the preparation of welds, grade and thickness of base metal brand of welding materials, the position of the seam in space, the initial temperature of the base metal, welding conditions and heat treatment must fully meet the conditions of manufacture of a controlled product or special purpose tests.

Weld control connections intended for testing of welding consumables (electrodes, welding wires, welding rods, fluxes, etc.), if no special requirements, produce cooling between the overlay of the individual layers. The temperature to which to cool the metal, is established by a standard or other technical documentation.

(Changed edition, Rev. N 2, 3).

2.4. Dimensions of plates for the manufacture of the control compounds are determined by the requirements listed below.

2.4.1. For control connections, operated by arc, electro-slag and gas welding of flat elements, the width of each welded plate, unless otherwise specified in standards or other technical documentation should be not less than:

Width of control joints, made of round or structural shapes should not be less than two diameters or widths of the items.

2.4.2. Length of the welded edges of the plates is determined by the size and number of samples to be subject to re-testing, allowances for width of cut, and the subsequent processing and with the addition of the length of the unused sections of the seam. The size of unused land are equal:

— for manual arc welding with covered electrodes and gas welding not less than 20 mm at the beginning and at least 30 mm at the end of the seam;

— with automatic and semi-automatic welding with any type of protection except a flux, metal thickness up to 10 mm — not less than 15 mm at the beginning and at least 30 mm at the end of the seam, and metal thickness exceeding 10 mm — not less than 30 mm at the beginning and at least 50 mm at the end of the seam;

— with automatic and semi-automatic arc welding under flux on the current up to 1000 A, in electroslag welding and arc welding with forced formation of at least 40 mm at the beginning and at least 70 mm at the end of the seam;

— the automatic submerged-arc welding at more than 1000 But not less than 60 mm at the beginning of the seam. The length of unused area at the end of the seam in this case is taken equal to the length of the crater of the weld (area with partial cross section).

(Changed edition, Rev. N 1).

2.4.3. Insert sizes for the control connection made by the welding methods not listed in paragraph 2.4.1, set the appropriate technical terms.

In the cases of welding of plates with the use of ladders, planks to output the start and end of the seam it is possible to take samples along the entire length of the control connection. Side planks are made of the same material as the plate.

The length of side straps must be at least the size of the unused sections of the weld (see p.2.4.2).

2.5. The dimensions of the samples cut out from a controlled design, are determined by the number and size of samples.

At oxygen cutting samples, their size is determined based on the allowance for subsequent machining to ensure the absence of metal, subjected to heat influence in cutting in the working part of the samples.

(Changed edition, Rev. N 2).

2.6. The cutting blanks for the samples from the samples and control connections it is recommended to run on machine tools. Allowed to cut workpieces by shears, punches, oxygen, plasma, anode-mechanical cutting and other methods.

Allowance for the size of the workpiece, which is provided by the absence in the working part of the sample of metal changed as a result cutting properties, is prescribed depending on the cutting method. The minimum value of the allowance should be:

— metal thickness up to 10 mm: oxygen and plasma cutting 3 mm, mechanical, including anode-mechanical cutting, 2 mm;

— metal thickness over 10 up to 30 mm flame cutting up to 4 mm, plasma cutting — 5 mm, mechanical, including and anode-mechanical cutting, — 3 mm;

— with a thickness of more than 30 to 50 mm: flame cutting — 5 mm, plasma cutting 7 mm mechanical, including and anode-mechanical — 3 mm;

— metal thickness up to 50 mm: flame cutting 6 mm, plasma cutting 10 mm, mechanical, including and anode-mechanical — 3 mm.

When cutting blanks for samples of the metal, which under the influence of cutting does not change the properties of the working part of the specimen allowed the reduction of the above allowances, but not more than twice.

The amount of the allowance for cutting methods not listed above must be specified in normative technical documentation (NTD) for this type of product or method of sampling.

When making samples you must take measures to avoid the possibility of changing the properties of metal by heating or work hardening that occurs during the mechanical treatment.

(Changed edition, Rev. N 2, 3).

2.7. On the samples, control joints and pieces of sheet metal and pipes should indicate the direction of rolling of the base metal against the seam.

(Changed edition, Rev. N 3).

2.8. Edit target compounds or samples taken from a controlled design, is not allowed. You are allowed to edit the finished models out their working parts. When testing of welded joints of pipes of the validity edits of samples specified by standards or other technical documentation.

Unless otherwise specified in standards or in other technical documentation, the deflection on the length of 200 mm (Fig.1) must not exceed 10% of the metal thickness, but not more than 4 mm.

The discrepancy between the plane of the sheets in butt joints (Fig.2) should not exceed 15% of the sheet thickness, but not more than 4 mm.

Damn.1

Damn.2

2.9. Heat treatment, if she agreed NTD, conduct to finishing samples. Heat treatment can be subjected to tests, the test connection or cut out from them blanks for samples. In the case of normalized or quenching heat treatment of blanks for samples is not allowed.

Heat treatment of control joints or blanks for the samples is preferably combined with heat treatment controlled items. The procedure of heat treatment in the manufacture of samples of materials of over 1000 MPa (100 kgf/mm) NTD.

(Changed edition, Rev. N 2).

2.10. Marking samples, test compounds, intermediates and finished samples can be produced by any method so that the brand was located out of the working part of the sample and remained on it after the test.

3. THE TERMS TESTING AND ASSESSMENT OF THEIR RESULTS

3.1. Samples with deviations from the drawing dimensions surface finish, and mechanical damage to the working parts for testing are not allowed and are replaced by the same number of new samples made from the same sample or test compound. If the size of the sample or control joints eliminate the possibility of fabrication of new samples, make new samples cutting or welding of the new control connection.

If the results of the mechanical testing requirements of standards or other technical documentation in all cases except arbitration tests, allowed the use of samples with lower grade surface roughness.

(Changed edition, Rev. N 3).

3.2. Unless otherwise specified in standards or in other technical documentation, tests sec. 4, 8 and 9 is carried out on at least two samples; in sect.5, 6 and 10 — at least three samples; in sect.7 — at least four points for each site weld joint. If the dimensions of the welded joints eliminate the possibility of placing four points, it is allowed to decrease them in accordance with real possibilities.

(Changed edition, Rev. N 3).

3.3. Results for all tests is defined as the arithmetic mean of the results obtained when testing all samples. If there is no indication in the relevant standards or other technical documentation for all types of tests in addition to tests for static bending and hardness measurements allowed reduction of test results for one sample 10% below regulatory requirements, if the average arithmetic result is consistent with the regulatory requirements. The permissible reduction of test results of specimens for static bending and the measurement of hardness shall be as stipulated in the relevant standards or other technical documentation. When tested for impact bending allowable reduced below regulatory requirements is not more than 5 j/cm(0.5 kgf·m/cm).

3.4. Tests referred to in sect.7−10, is carried out at normal temperature (20±10) °C [(293±10)]. The sample temperature is taken equal to the temperature of the room in which you are testing. Tests referred to in sect.4−6, is carried out at normal temperature or at the request stipulated in the relevant standards or other technical documentation, at elevated or low temperatures. When tested at low or high temperatures the sample temperature is taken equal to the temperature of the environment in which carry out heating or cooling. Allow the definition of temperature on samples-witnesses.

(Changed edition, Rev. N 1).

3.5. The tests results are unsatisfactory, if not met the requirements of clause 3.3 or in the fracture of the specimen or on its surface revealed cold crystallization or cracks (except where cracks allowed the corresponding NTD). If unsatisfactory test results repeat twice the number of samples. If the fracture of the sample, the test results which is considered unsatisfactory, the defects of the base metal or welded joints (except for cracks), it is excluded from the estimation and replaced with one new sample.

The overall results of the tests determine the indications obtained in repeated trials. The results of repeated tests are final.

(Changed edition, Rev. N 2, 3).

3.6. The method of determining the sizes of samples, requirements for testing equipment, the testing conditions and calculation of results must comply with:

— when tested in static tension at room temperature GOST 1497, at lower temperatures, GOST 11150, at elevated temperatures, GOST 9651;

— when testing the impact strength at low, room and elevated temperature — GOST 9454;

— when measuring hardness — GOST 2999, GOST 9013, GOST 9012.

Other requirements for the testing, identification of specimen size, testing equipment and calculation of results should be subject to a standard or other technical documentation.

(Changed edition, Rev. N 2).

3.7. Protocol for all types of tests must contain: the designation of this standard, the thickness and grade of the base metal, welding method, connection type, type of heat treatment (if performed), the index of the sample (on the mark), the sample type, the place of his selection, the results of the tests of all samples, the presence of defects in the fracture of the specimen during the testing of welded joints — location of fracture (weld metal, for metal, heat affected zone, base metal). For testing sec. 4−6, further indicate the test temperature; in sect.5 and 6 maximum energy of copra; sec. 7 — layout of measuring points of hardness.

(Changed edition, Rev. N 2, 3).

4. METAL TEST VARIOUS SECTIONS OF THE WELDED JOINTS AND WELD METAL IN STATIC (SHORT-TERM) TENSILE

4.1. When testing metal on the static (short-term) tensile characteristics to determine the following mechanical properties:

— physical yield point , MPa (kgf/mm) or conditional yield strength , MPa (kgf/mm);

— temporary resistance , MPa (kgf/mm);

— relative elongation after rupture (five samples) , %;

contraction ratio after rupture , %.

The test is performed to weld metal, metal various parts of the heat affected zone of the weld metal in all types of welding melting

M.

4.2. The shape and dimensions of samples used for testing must meet the devil.3 or 4, and table.1.

May increase the size of the sample diameter and its height.

Type I, II, III

Damn.3

Type IV, V

Damn.4

Table 1

Dimensions in mm

Note.  — permissible difference between the largest and smallest diameters on the length of the working part of the specimen.


(Changed edition, Rev. N 3).

4.3. For tests conducted at normal or reduced temperature, used samples of all types. When testing at elevated temperatures used samples of types IV and V.

4.4. Allowed the use of proportional short cylindrical samples of different diameter or type according to GOST 1497.

4.5. When testing at elevated temperatures according to the requirement specified in the standard or other technical documentation allowed the use of proportional long cylindrical samples N 2 and 3 according to GOST 9651.

With the appropriate adaptations permitted the use of samples of types I, II and III for testing at elevated temperatures.

4.6. The cross-section samples of all types should completely consist of the metal of the test section. The heads of the sample allowed the presence of other metal sections welded joints. On the surface of the head is allowed one or two (parallel) flats, as well as the presence of a rough surface of the weld or base metal.

The size of the head in the place of flats should be: for samples of types I, II and III not less than +2; for samples of types IV and V — not less .

4.7. Marking the place of cutting of samples produced by the macrosections manufactured at the ends of the workpiece in accordance with the data table.2 and 3. All samples are placed along the longitudinal axis of the test section.

When testing weld metal weld metal with a cross section greater than the cross section of the head of the sample, allowed to produce a layout of places of cuttings samples without etching the workpiece following the external contours of the seam with the requirements of the table.2 and 3.

The scheme of location of samples when testing other parts of the weld metal or the weld metal zone is set by standards or other technical documentation.

Table 2

Table 3

Notes to the table.2 and 3:

1.  — metal thickness, in mm; is the diameter of the head of the sample in mm;  — distance from the weld surface to the axis of the specimen in mm.

2. By single-pass seams, the samples cut from different parts of the seam, have almost identical mechanical properties. In multi-pass joints of the characteristics of the mechanical properties in different parts of the seam are different. Place cuttings samples from multiple-pass weld is specified by standards or other technical documentation. In the absence of special instructions specimens cut from the weld surface.

3. For welded joints executed from round steel, the scheme of sampling remain the same.

4. Of the workpiece at positions 1−3; table 5−7.2 are intended to check the quality of welding materials.

5. If the standards or other technical documentation there are no other indications, both side welding, the samples for testing cut out from the weld made the second.

4.6, 4.7. (Changed edition, Rev. N 3).

5. METAL TEST DIFFERENT AREAS OF A WELDED JOINT AND WELD METAL THE IMPACT STRENGTH (NOTCHED SAMPLES)

5.1. When testing the impact strength to determine the toughness or the impact, or the percentage of brittle and viscous components of the fracture surface of weld metal, weld metal, fusion zones and different areas of the HAZ in the base metal thickness of 2 mm or more.

Impact strength is determined in j/cm(kgf·m/cm) if there is no indication in the relevant standard or other reference document.

(Changed edition, Rev. N 2, 3).

5.2. For tests used samples, shape, size and surface finish indicated on the devil.5 (samples with U-shaped cut) or the devil.6 (samples with V-shaped cut). Preferred are the samples with a V-shaped incision.

 — thickness of base metal mm

Damn.5

According to the requirement specified in the reference document may be used for the samples of type VI (see the devil.5) cut on hell.7 or 8.

5.3. The symbol of toughness or work impact includes: the symbol of toughness (KC) or kick (K); incision (hub) (U, V); test temperature (20 °C not affix); the maximum impact energy of pendulum (the maximum energy of 300 j is not placed); sample type (sample types VI and IX do not affix); the location of the incision (W — seam, ZS — fusion zone, HAZ — heat affected zone  — the distance from the border of fusing to the axis of the incision). The value of negotiated standards or other technical documentation. When the location of the incision across the weld metal, fusion zone or heat affected zone at the end of the notation put the letter P.

Examples of symbols:

1. The impact strength determined on a sample of the type VII, at a temperature of 100 °C, With a maximum impact energy of pendulum 150 j, with a crosscut of U, located at the zone of fusion:

KSI150 UPSS.

2. Impact strength, determined on the sample XI at a temperature of minus 40 °C, With a maximum impact energy of 50 j pendulum, with the incision in the form of a V, located at the heat affected zone distance ( mm) from the boundaries of fusing to the axis of the incision:

КСV50 XI HAZ.

3. The impact strength determined on a sample of type VI, at a temperature of 20 °C, With a maximum impact energy of 300 j pendulum, with a crosscut of the U located at the weld metal:

The КСUШ.

 — thickness of base metal mm

Damn.6

Damn.7

Damn.8

4. The impact strength for sample type IX, at a temperature of 20 °C, With a maximum impact energy of 300 j pendulum, with the incision in the form of a V, located transversely to the weld metal:

КСVШ P.

5.2, 5.3. (Changed edition, Rev. N 3).

5.4. Examples of different types of yield incomparable between the results of tests. For individual cases can be experimentally set to private conversion factors.

5.5. When testing the impact strength to be applied to samples with the maximum possible for the thickness base metal width. In accordance with the thickness of the base metal 11 mm and used samples of type VI or IX, when the thickness of the base metal of 6−10 mm to the samples of a type VII or X, with a thickness of 2−5 mm, the samples of a type VIII or XI. The use of samples of types VII and X is samples of types VI and IX and samples of types VIII and XI is the samples of types VII and X, or VI and IX is allowed only if comparative tests, when one of the objects of the comparison, the use of thin sample due to the thickness of the base metal.

When cutting samples of types VI and IX of welded joints made of base metal with a thickness of 11 mm, and samples of types VII and X — base metal thickness of 6 mm, a tolerance of unprocessed base metal on two surfaces of the sample. The surface of the parent metal specimens in types VIII and XI do not handle.

The bulge of a seam on all samples are removed to the level of the base metal. If the welded connection of the edge offset (see the devil.2) it is removed mechanically.

(Changed edition, Rev. N 2, 3).

5.6. Depending on the purpose of the test cut feature in the weld metal (Fig.9 and 10), the area of fusion (Fig.11) and in different parts of the metal of the weld zone at a distance from the border of the fusion line (Fig.12 and 13). The location of the incision and the distance from the border of fusing to the axis of the incision stipulate in NTD.

Damn.9

Damn.10

During the test of the metal of the weld zone in welding of pressure distance counted from the axis of the joint.

(Changed edition, Rev. N 2, 3).

5.7. The markup for the application of the incision is made on the macrosections located on the faces of the specimen or workpiece for samples. The location of the incision should correspond to p. 5.6. All samples cut out crosswise of the test section of a welded joint. The orientation of the incision for samples of types VI and IX must comply with the devil.9, 11 and 12 for samples of types VII, VIII, X and XI crap.10 and 13. The orientation of the incision for samples of types VI and IX stipulate in NTD. Cutting of samples and preparations for them are at the table.4 and 5.

The scheme of location of samples for testing of the HAZ metal of butt joints and weld metal and heat affected zone when tested t-and lap joints stipulate in the standards or other technical documentation.

Damn.11

Damn.12

Damn.13

Table 4

Table 5

Notes to the table.4 and 5.

1.  — the thickness of the base metal, mm;  — distance from the metal surface to the edge of the sample (blank), mm.

2. The seams in single layer samples, cut out from different sites have almost the same impact strength. Layered seams at the impact toughness of metal of different areas differs from each other. Place the cutting out of samples specified by standards or other technical documentation. In the absence of such instructions, the samples cut out from the weld surface.

3. If the standards or other technical documentation no special instructions, when bilateral joints specimens cut from the weld, the welded second. For two-sided multi-layered seams, performed with varying degrees of overlap of passes, the samples cut from the last of them.

4. Of the workpiece at positions 1−4 table.4 is used for quality control of welding materials.

6. METAL TEST DIFFERENT AREAS OF THE WELDED JOINT RESISTANCE AGAINST MECHANICAL AGING

6.1. Resistance against mechanical aging is characterized by a change in the toughness of the metal is subjected to aging in comparison with the toughness in its original state. On the resistance of metal against mechanical aging is judged by the expressed in percent the ratio of these values or absolute (normative) impact strength after aging. The tests are carried out for weld metal and various sections metal heat-affected zone.

6.2. The workpiece is subjected to artificial aging according to the method: deformation stretching from the calculation of receipt (10±0,5)% residual elongation within the estimated length limited by cores or risks. Recommended on the sample surface every 10 mm to cause risks to verify the uniformity of strain along the length of the design parts.

After lengthening the billet is subjected to uniform heating for 1 h at a temperature of 250 °C (523 °K), followed by cooling in air. Of the working of the workpieces on the devil.14, 15 or 17 selected samples of type VI or IX, and for God.16 — the type VII or X. the axis of the cut must coincide with the axis of symmetry of the seam. The scheme of sampling at the location of the incision in other parts of the welded connection specify standards or other technical documentation.

Under this item, the method of aging used for welded joints of steels. The method of aging for other metals and alloys and different heating temperature or the degree of deformation for connections of steel to stipulate standards or other technical documentation.

Damn.14

Damn.15

Damn.16

Damn.17

(Changed edition, Rev. N 3).

6.3. Mechanical aging is subjected to the procurement taken from the butt joint in accordance with the devil.14 or 15, and table.6. The axis of symmetry of the workpiece must coincide with the longitudinal axis of the seam or with the axis of the future incision (if the test is not carried out for weld metal). The location of the incision for God.15 is used in electroslag welding and in the cases specified in paragraph 5.6. Procurement of hell.16 is used in the testing of welded joints of metal of a thickness less than 12 mm According to the requirement specified by standards or other technical documentation for welded joints performed by electroslag process may be used for procurement of hell.17.

Table 6

Note.  — the thickness of the base metal, mm;  — distance from the surface of the metal to the edge of the workpiece, mm.

6.4. The length of the gripping portion of the workpiece set depending on the design of the testing machine.

6.5. In the symbol of the specimen, specified in paragraph 5.3, add the index «St» (e.g., CS, St W, CS, St W).

7. MEASUREMENT OF METAL HARDNESS OF VARIOUS PARTS OF A WELDED JOINT AND WELD METAL

7.1. The hardness measured in the cross section of the welded joint in accordance with the devil.18, 18a and 19.

Note. The line of measurement of hardness in all cases except for the position of pack* run through all the areas of welded joints.  — from 2 to 4 mm,  — from 10 to 15 mm;  — the thickness of the base metal, mm;  — the thickness of the fillet weld, mm;  — preparation area with a minimum thickness of five layers;  — a plot of hardness measurement with a minimum thickness of six layers. For fillet welds having a concave or convex surface, the value of count from the place of maximum concavity or convexity.
________________
* Consistent with the original. — Note the manufacturer’s database.

Damn.18

Damn.18a

Damn.19

7.2. Hardness is measured by Vickers (HV), Brinell (HB) and Rockwell scales A, B, and C (HRA, HRB and HRC), giving preference to the measurement of the Vickers.

The Vickers hardness is measured according to GOST 2999. The load on the indenter depending on the strength of the metal sections, welded joints, and the width of the heat affected zone must be 98 N (НV10) or 49Н (НV50). If the standards or other technical documentation relevant instructions, measure the Vickers hardness. The load on the indenter when such measurements may vary from 0.04 to 4.9 N.

Brinell hardness number is measured in accordance with GOST 9012, using the steel ball with a diameter of 2.5 or 5.0 mm.

Rockwell hardness is measured in accordance with GOST 9013 with spheroconical diamond indenter (scale A and C) or ball-point steel tip with a diameter of 1,5875 mm.

7.3. The hardness is determined for the joints obtained by fusion welding or pressure of various grades of steel and other metallic structural materials with a minimum thickness of 1.5 mm.

The hardness of the base metal, the various sections of the heat affected zone and weld metal are measured by one or several lines specified by the devil.18. If the connection is made from metal of various grades, the hardness is measured for each of them.

The measurements performed in the vicinity of the boundaries of fusing it is recommended to take 2−3 measurements in accordance with the position of the I devil.18a or more dimensions position II hell.18a.

Allowed measurements in areas of welded joints indicated on the devil.19.

7.4. The Vickers hardness measured on the micro-sections or samples with a polished surface, if the shape of the seam are visible without etching. The surface roughness of such samples should be from 0.40 to 0.63 microns. Hardness Brinell or Rockwell measured on the macrosections or on samples with a polished surface, if the shape of the seam are visible without etching. The surface roughness of such samples should be from 1.25 to 2.00 microns. The samples must be observed that the parallelism of the working and supporting surfaces.

7.5. The hardness of the butt and corner joints made with arc welding, measure thickness of base metal or fillet weld from 1.5 to 9 mm in accordance with the position VIII to hell.18 one dotted line; thickness of 9 to 25 mm — in accordance with items I and III features.18 by two solid lines with a thickness from 26 up to 60 mm in compliance with items II or III hell.18 two solid and one dotted lines.

The scheme of hardness measurement when the thickness of the base metal or fillet weld of more than 60 mm stipulate in the standards or other technical documentation.

The hardness of the welded joints obtained electroslag welding, measured in accordance with the position IV hell.18. The number of points of measurement in the heat affected zone must be at least 10.

The hardness of different areas of the metal deposition rate is measured in accordance with the position of V features.18.

The hardness of the welded joints obtained by the welding pressure, measured in accordance with the position VI to hell.18.

The hardness of the deposited metal in the quality control of welding materials is measured in accordance with the position VII the devil.18.

(Changed edition, Rev. N 3).