By visiting this site, you accept the use of cookies. More about our cookie policy.

GOST R ISO 3183-3-2007

GOST R ISO 3183−3-2007 steel Pipes for pipelines. Specifications. Part 3. Requirements for the pipes class

GOST R ISO 3183−3-2007

Group В62

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

STEEL PIPES FOR PIPELINES

Specifications

Part 3

REQUIREMENTS FOR THE PIPES CLASS

Steel pipes for pipelines. Specifications. Part 3. Requirements for the class With the pipes

OKS 23.040.10
OKP 13 9000

Date of introduction 2008−06−01

Preface


The objectives and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"

Data on standard

1 PREPARED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders», Open joint stock company «Russian scientific research Institute of pipe industry» (JSC «RosNITI») based on the authentic translation of the international standard indicated in paragraph 4, which is the Federal state unitary enterprise «Russian scientific and technical centre of information on standardization, Metrology and conformity assessment» (FGUP «STANDARTINFORM»)

2 SUBMITTED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology dated December 27, 2007 No. 609-St

4 this standard is identical with ISO 3183−3:1999 «the oil and gas Industry. Steel pipes for pipelines. Technical delivery conditions. Part 3. Pipe class» (ISO 3183−3:1999 «Petroleum and natural gas industries — Steel pipes for pipelines — Technical delivery conditions — Part 3: Pipes of requirement class C»). An addition was made to Annex a for ease of reference standard.

The name of this standard changed with respect to names specified international standard for compliance with GOST R 1.5−2004 (subsection 3.5).

In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation, details of which are given in Appendix E

5 INTRODUCED FOR THE FIRST TIME


Information about the changes to this standard is published in the annually issued reference index «National standards», and the text changes and amendments — in monthly indexes published information «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet

Introduction


In the preparation of a series of international standards of ISO 3183, the Technical Committee did not set the task of determining the level of quality of pipelines which have specific application.

However, the Committee recognized that there are several basic quality levels:

First, there is recognition of the need to ensure basic level quality standard ANSI/API Spec 5L [1] corresponding to the tube class, which is discussed in ISO 3183−1.

Secondly, many consumers have additional requirements for pipes, which are used for example for pipelines. These additional requirements correspond to the pipes class and are dealt with in ISO 3183−2.

Thirdly, there are some special requirements for the application, such as acidic environments, operation in the zone of the shelf or at low temperatures, when there are very strict requirements on pipes. They are reflected in the requirements of the class and are dealt with in ISO 3183−3.

The properties of impact strength ISO 3183−3 offers a selection of the necessary test methods, which ensure prevention of brittle fracture or ductile fracture extensive. The test gap by falling cargo is part of the necessary procedures, which are considered usually for gas pipelines.

Job requirements impact Charpy to avoid extended ductile fracture was accepted on the basis of available data in accordance with the recommendations of EPRG (European Pipeline Research Group) [3] for pipes intended for the transportation of depleted dry natural gas. It is recognized that a saturated gas or a two-phase environment can require properties of increased toughness, which can only be determined in individual cases.

The task of the designer is the definition of the necessary requirements for impact resistance in accordance with the intended use and the use of pipes with high toughness and/or the use of mechanical devices to eliminate the formation of cracks.

For pipes of class With the ratio of weld strength of 1.0 may be used in the calculations of pipelines on the basis of the conditions established for the production of these pipes and control joints.

The choice of class requirements depends on many factors. You should consider the properties of the working substance, terms of service, design standards and any statutory requirements. Therefore, the main task of the consumer is to choose the class of pipe for the required application.

Note — this standard applies to the production of a wide range of types, sizes and technical limitations. In some applications the lack of a unified international standard for the design of the pipeline would entail the differences in national rules, and conflicting demands on the consumer that has complicated technical harmonization. Therefore, you may need to change some of the mandatory requirements of this standard in order to achieve compliance with various national design standards. However, this standard remains a key normative document, and such additions should be brought into compliance with the technical conditions at the time of order (e.g. note to 8.2.3.3.1).


The notation used in this standard steels is not consistent with the instructions given in ISO/TR 4949 [3] on the formation of these marks. They were established on the basis of agreed technical committees ISO/TC 67/SC 1 and eciss information/TC 29/SC 2 ISO 3183 and the European standard EN 10208, to avoid misunderstanding that can occur when using different names for the same brand.

1 Scope


This standard specifies the technical delivery conditions for steel welded and seamless pipes of non-alloy and alloy (excluding stainless) steels. This standard specifies more stringent requirements than in ISO 3183−1 and ISO 3183−2. This standard applies to pipes that are used for the transportation of flammable liquids in particularly difficult conditions, such as operation in the area of the shelf, work at low temperatures and/or acidic conditions (3.5).

This standard does not apply to cast steel pipe.

2 Normative references


This standard uses the regulatory references to the following international standards:

ISO 148−1:1983* metal Materials. Impact test pendulum Koper in Sharpie. Part 1. Test method
_______________
* Valid ISO 148−1:2006.

ISO 377:1997 Steel and steel products. Location and preparation of test specimens and samples for specific mechanical tests

ISO 404:1992 Steel and steel billet. General technical delivery conditions

ISO 2566−1:1984 Steel. Conversion chart of relative values of elongation. Part 1. Steel carbon and low alloy

ISO 3183−1:1996 Industry oil and gas. Steel pipes for pipelines. Technical delivery conditions. Part 1. Pipe class A

ISO 3183−2:1996 petroleum and gas Industry. Steel pipes for pipelines. Technical delivery conditions. Part 2. Pipe class

ISO 4885:1996 ferrous metals. Types of heat treatment. Dictionary

ISO 4948−1:1982 Steel. Classification. Part 1. Classification of steels into unalloyed and alloy chemical composition

ISO 4948−2:1981 Steel. Classification. Part 2. Classification of unalloyed and alloy steels according to main quality classes and main property or application

ISO 6507−1:1982* metal Materials. Hardness test by Vickers. Part 1. Test method
_______________
* Valid ISO 6507−1:2005.

ISO 6508−1:1986* metal Materials. Determination of Rockwell hardness. Part 1. Determination method (scales A, b, C, D, E, F, G, H, K, N, T)
_______________
* Valid ISO 6508−1:2005.

ISO 6892:1998 metallic Materials. Tensile test at ambient temperature

ISO 6929:1987 steel Products. Definition and classification

ISO 7438:1985* metal Materials. Test bend
_______________
* Valid ISO 7438:2005.

ISO 7539−2:1989 Corrosion of metals and alloys. The corrosion test under stress. Part 2. Preparation and use of koromislovnaa samples

ISO 8492:1998 metallic Materials. Pipe. Flattening tests;

ISO 8501−1:1988 Preparation of steel substrates before application of paints and related products. Visual assessment of surface cleanliness. Part 1. The degree of rustiness and degree of preparation bare steel surfaces and steel substrates after completely removing previous coatings

ISO 9303:1989 seamless steel Tubes and welded (except tubes produced in arc submerged arc welding) pressure. Ultrasonic inspection of the entire peripheral surface for the detection of longitudinal imperfections

ISO 9304:1989 seamless steel Tubes and welded (except tubes produced in arc submerged arc welding) pressure. The control method of eddy currents for the detection of imperfections

ISO 9305:1989 seamless steel Tubes pressure. Ultrasonic inspection of the entire peripheral surface for the detection of transverse imperfections

ISO 9402:1989 seamless steel Tubes and welded (except tubes produced in arc submerged arc welding) pressure. Testing of pipes of ferromagnetic steel by magnetic flux leakage across the surface for the detection of longitudinal defects

ISO 9598:1989 seamless steel Tubes pressure. Control of the entire peripheral surface of pipes of ferromagnetic steel by magnetic stray fields for the detection of transverse imperfections

ISO 9764:1989 steel Tubes obtained by electric contact welding and induction welding, pressure. Ultrasonic inspection of weld seam for detection of longitudinal imperfections

ISO 9765:1990 steel Tubes of the pressure obtained by arc welding under flux. Ultrasonic inspection of weld seam for detection of longitudinal and/or transverse imperfections

ISO 10124:1994 seamless steel Tubes pressure seamless and welded (except pipe manufactured by arc welding under flux). Ultrasonic testing method for detection of layered imperfections

ISO 10474:1991 Steel and steel products. Documents about control

ISO 10543:1993 seamless steel Pipe and pressure welded, compressed by the hot exhaust. Ultrasonic inspection thickness over the entire peripheral surface

ISO 11484:1994 steel Tubes for pressure. Qualification and certification of personnel for nondestructive testing

ISO 11496:1993 seamless steel Tubes and welded pressure. Ultrasonic testing of tube ends for the detection of layered imperfections

ISO 12094:1994 welded steel Pipes pressure. Ultrasonic testing for the detection of layered imperfections in strip/sheet material used for manufacturing welded pipes

ISO 12096:1996 steel Tubes of the pressure obtained by arc welding under flux. Radiographic inspection of weld seam for the detection of imperfections

ISO 12135:1996* metal Materials. Unified method of test for determination of fracture toughness under the action of quasi-static load
_______________
* Valid ISO 12135:2002.

ISO 13663:1995 welded steel Pipes pressure. Ultrasonic testing of the area adjacent to the weld seam for the detection of layered imperfections

ISO 13664:1997 seamless steel Tubes pressure seamless and welded. Control of pipe ends magnetic particle method for the detection of layered imperfections

ISO 13665:1997 seamless steel Tubes pressure seamless and welded. The pipe body testing magnetic particle inspection method for identifying surface imperfections

ISO 14284:1996 Steel and iron. Selection and preparation of samples for the determination of chemical composition

ANSI/API RP 5L3:1996* test gap by falling cargo for pipes of main pipelines
_______________
* Valid ANSI/API RP 5L3:2003.

ASME Section IX: 1995* Standards ASME boiler and pressure vessel internal
_______________
* ASME Section IX:2004.

ASTM A370−96 (1996) Standard control methods and definitions for mechanical testing of steel products

YONG 288−3:1992 Technical requirements and certification of welding metallic materials. Part 3. Routine tests for arc welding of steel

NACE TM0177:96 (1996) Laboratory measurements of metals in terms of resistance to destruction under the action of stresses in sulfitarea environment and corrosive destruction in hydrogen sulfide environment

NACE ТМ0284:96 (1996) Evaluation of steels for pipelines and pressure vessels for resistance to hydrogen induced cracking

3 Terms and definitions

3.1 General provisions


This standard applies the terminology and definitions for:

— ISO 4948−1 and ISO 4948−2 — classification of steels;

— ISO 6929 — definition of steel products;

— ISO 4885 — types of heat treatment;

— ISO 377, ISO 404, ISO 10474 — alternative procedures for sampling, quality control and document control, as well as the following terms and definitions given in 3.2−3.6.

3.2 Types of pipes and welding

3.2.1 seamless pipe; BT (seamless pipe): Pipe manufactured by the method of hot deformation.

Note — For forming of pipe to get the required size can be followed by cold sizing (6.5) or cold finish (3.3.5).

3.2.2 tube, made by high frequency welding; TWCS (high-frequency welded pipe): Pipe manufactured by forming from strip rolled and welding edges without the use of additional weld metal, and the longitudinal seam obtained with the aid of high frequency current (not less than 100 kHz) is applied by induction or conduction.

3.2.3 pipe manufactured by arc welding under flux; DSF (submerged arc welded pipe): Pipe, which is produced by forming sheet metal and welding the edges with the addition of a filler metal, where the longitudinal (DSFP) and spiral (DSPS) seams get automatic arc welding submerged arc (6.3).

Note — at least one passage do on the inner and outer surfaces of the pipe. Allowed single-pass tack, which precedes the arc welding submerged arc (6.3.3).

3.2.4 butt joint [strip (plate) end of weld] Weld seam, which connects the ends of the roll (sheet) is rolled.

3.2.5 composite pipe (jointer): cut Two pipes connected to the annular weld.

3.2.6 pipe body (pipe body): For welded pipe is the entire pipe, eliminating the seam or seams and heat affected zone, for seamless pipe — all pipe completely.

3.3 processing Conditions

3.3.1 hot deformation at a temperature normalization (normalizing forming): forming Process in which the final phase of deformation is carried out in a temperature range that gives the material properties similar to those characteristic for the material after normalization.

Note 1 — After deformation at the temperature of the normalization of mechanical properties remain the same after the normalization.

Note 2 — Letter designation of the terms of delivery.

3.3.2 thermomechanical treatment (thermomechanical forming): forming Process in which the final phase of deformation in a specific temperature range leading to material properties with the specified parameters that are impossible to achieve or repeat only when the same heat treatment.

Note 1 — Subsequent heating above 580 °C may lower the strength values.

Note 2 — Letter designation of the terms of delivery — M.

Note 3 — thermo-Mechanical processing, which corresponds to the delivery condition M can include processes with an increasing cooling rate and vacation (or no vacation), including semotus, but excluding direct quenching and quenching and tempering.

3.3.3 the quenching and tempering (quenching and tempering): Heat treatment, including hardening of steel by quenching with subsequent tempering.

Note 1-Hardening hardening involves the austenization of the steel, followed by cooling under such condition, when the austenite becomes more or less complete martensite and possibly beynit.

Note 2 — Holidays of steel involves heating one or more times to a temperature which is lower than the recrystallization temperature (AsГОСТ Р ИСО 3183-3-2007 Трубы стальные для трубопроводов. Технические условия. Часть 3. Требования к трубам класса С) and maintain this temperature followed by cooling at a given rate so that the structure was modified and that was achieved the required properties.

Note 3 — Letter designation of the terms of delivery.

3.3.4 cold forming (shaping) (cold forming): the Process, when sheet or hot-rolled coil is formed into a pipe without heating.

3.3.5 cold finishing (cold finishing): the Process of cold treatment (conventional cold drawing) with residual deformation of 1.5%.

Note — This level of residual deformation is different from the level after the cold calibration described in 6.5.

3.4 Imperfections and defects

3.4.1 imperfections (imperfections): the Deviation of the wall thickness or surface quality of the pipe does not meet the requirements of this standard.

Note — the Imperfections, the size and/or distribution density which is within the acceptance criteria defined in this standard are of no practical importance for the intended use of the product.

3.4.2 defects (defects): the Deviation of the geometric dimensions or the surface quality exceeding permissible values defined in this standard.

3.5 operating Conditions


The operating conditions depend on the project pipeline and are determined by the consumer in accordance with the intended use.

Note — In this standard the terms «operating in acidic media», «exploitation in the shelf zone," «operation at low temperatures» determine the conditions of operation.

3.6 Harmonization of requirements


Unless otherwise specified, «agreement» means the agreement requirements between manufacturer and user at the time of order.

3.7 Symbols on the sidelines


The following symbols are used in the margins and tables to denote options conditions of delivery:

OS — mandatory agreement [5.2, enum a)];

US — unless otherwise agreed, is at the discretion of the manufacturer [5.2, enum b)];

PS — random agreement [5.2, enumeration)].

4 Classification and designation of steels

4.1 Classification of steels


For the production of pipes of class With the use of non-alloy and alloy special steel. Their classification in accordance with ISO 4948−1 and ISO 4948−2 are shown in table 1.


Table 1 — Classification and designation of steels

The conditions of heat treatment Grade steel in accordance with ISO 4948−1, ISO 4948−2
Designation of steel*
Normalization or rolling at a temperature normalization Non-alloy special steel L245NC

L290NC

L360NC
Quenching and tempering Non-alloy special steel L290QC
Alloy special steel L360QC

L415QC

L450QC

L485QC

L555QC
Thermomechanical treatment Non-alloy special steel L290MC

L360MC

L415MC
Alloy special steel L450MC

L485MC

L555MC
* The letters N, Q and M represent the conditions of the heat treatment according to 3.3. The letter S must be added to the designation of steel used in sour environment. For example, L450QCS.

4.2 Designation of steels


Designation of steels according to this standard are given in table 1.

Note — the Mapping of the symbols in steels with those specified in API Spec 5L [1] and [4], is given in Appendix A.

5 Information provided by the consumer

5.1 Mandatory information


The user must provide in order the following information:

a) the number of ordered products (i.e. the total mass and total length of the pipes);

b) the shape of the product (pipe);

c) kind of pipe (table 2);

d) designation of this standard;

e) marking of steel (table 1), including conditions of operation in an acidic or non-acidic environments;

f) requirements for toughness (7.3.1);

g) pipe outer diameter and wall thickness in millimeters (7.6.1.1);

h) operation in the zone of the shelf, when using the [table 11, footnote 5), 6) and 7.6.3.4.2];

i) for those pipes that do not operate offshore, the range of lengths or, if required, the exact length in meters (7.6.3.4 and table 13);

j) design operating temperature, if necessary [7.3.1, enum a), b) and 8.2.3.5.];

k) documents required for monitoring (8.1);

I) information about the type of alleged subsequent coating, if necessary;

m) the intended use of the pipe for making the knees, if necessary.

5.2 Additional information


This standard defines the procedure for the negotiation between the consumer and the manufacturer additional information (7.3.1, note 1) or other conditions, in addition to the generally applicable terms of delivery, in accordance with listing a) and C). The need for additional information or additional requirements should be clearly specified when ordering.

Note — Additional information marked with the symbols of the OS, US, PS, as defined in 3.7.


a) Compulsory negotiation (OS) — requirements that must be agreed if necessary:

1) chemical composition of pipes with wall thickness more than 25 mm (tables 3 and 4);

2) mechanical properties of tubes with wall thickness more than 25 mm [table 5, footnote 1)];

3) providing information circular voltage [7.3.1, enum)];

4) requirements for tests for impact bending and impact strength drop-weight (DWTT) for pipes with outside diameter of more than 1,430 mm and/or a wall thickness of 25 mm [table 8, footnote 1); table 9];

5) the diameter tolerances for the pipe ends wall thickness more than 25 mm [table 11, footnote 2)];

6) the tolerances on the diameter for pipe diameters of more than 1,430 mm (table 11);

7) requirements for ovality of pipe, operated in the shelf zone, with D/T greater than 75 (table 11);

8) the party responsible for publishing the document on the control of type 3.2 (8.1);

9) marking of pipe intended for subsequent coating (9.1.4);

10) the frequency and volume of testing for certification of the production process [B. 3 enumeration a) (Appendix C)].

b) Unless otherwise agreed, at the discretion of the producer (US):

1) a method of checking the requirements of geometric dimensions (8.2.3.14.4);

2) select the period non-destructive testing of seamless pipe (D. 2.2, Annex D);

3) x-ray inspection to detect longitudinal imperfections [D. 5.4, the enumeration of a) (Appendix D)].

c) Random coordination (PS) — requirements that can be agreed upon:

1) a method of smelting steel for welded tubes (6.3.3);

2) pipe production DSPP with two longitudinal seams (6.3.3);

3) the rejection of cold ekspedirovanie pipes DSFP (6.5);

4) delivery pipe DSPS with a spiral seam, which contain butt welds the ends of the sheet or strip rolled (6.6);

5) the content of copper and/or molybdenum [table 4, footnote 3), 9)];

6) technical requirements for absorbed the work of destruction (7.3.1);

7) test temperature the impact strength according to Charpy and, if necessary, the temperature of the DWTT, different from the temperature of the standard test are shown in tables 6, 8 and 9 (7.3.1, 8.2.3.3.1, 8.2.3.4);

8) limiting the range of the yield strength [table 5, footnote 2)];

9) increased ГОСТ Р ИСО 3183-3-2007 Трубы стальные для трубопроводов. Технические условия. Часть 3. Требования к трубам класса С[table 5, footnote 3)];

10) data on weldability and testing of welds (7.4.2);

11) application tolerance on inner diameter [table 11, footnote 3)];

12) application tolerance on outside diameter [see table 11, footnote 4)];

13) pipe length different from that specified in (7.6.3.4.1, 7.6.3.4.2, 7.6.3.4.3);

14) special shape and size of the chamfer (7.6.4.2);

15) clean the outside surface of the weld on the pipes DSF (7.6.5.2.2);

16) test transverse tensile specimens for seamless pipes [table 20, footnote 2)];

17) additional tensile test specimens with longitudinal joint for underwater pipelines [table 20, footnote 6)];

18) the use of a cylindrical test specimen (8.2.2.3);

19) use the straightened and heat-treated sample tubes for testing (8.2.2.3);

20) the use of alternative transverse samples for testing the impact strength Charpy (8.2.2.4);

21) the use of hydraulic distribution rings to determine the yield stress (8.2.3.2.3);

22) replacement micrographics control any alternative method of testing (8.2.3.8.1);

23) hardness test during production and the maximum hardness value for TVCS pipes with heat-treated bead (8.2.3.8.2);

24) photomicrography was cracks when testing for hydrogen cracking (8.2.3.9);

25) other test methods for sulfide stress corrosion, and acceptance criteria for certification of the production process (8.2.3.10);

26) the hydraulic pressure test and/or circumferential voltage is higher than the standard value (8.2.3.12.1);

27) a hydraulic pressure test in accordance with ISO 3183−1 (8.2.3.12.3);

28) the use of special means of measurement pipe diameter (8.2.3.14.1);

29) the use of cold branding or viagraviagra (9.1.3);

30) special marking (9.2);

31) temporary protection, including protective coating, primer, varnish factory and other temporary protective measures (section 10);

32) test for hardenability of a metal pipe for the certification of the production process [V. 3, enumeration d) (Appendix C)];

33) test sulphide stress corrosion for certification of the production process [V. 3, enumeration e) (Appendix C)];

34) CTOD — test on the disclosure of top cracks for certification of the production process [V. 3, enumeration, f) (Annex C)];

35) control bundles at the ends of the tubes in the range of 100 mm or chamfer pipe (D. 2.4, Annex D);

36) monitoring of delamination in seamless pipes, used in non-acidic environment [D. 3.3, the enumeration b) (Appendix D)];

37) the increase in control of the wall thickness (D. 3.4, Annex D);

38) application of additional requirements (for seamless pipes) (D. 3.5, app D);

39) limiting the size of individual bundles up to 100 mmГОСТ Р ИСО 3183-3-2007 Трубы стальные для трубопроводов. Технические условия. Часть 3. Требования к трубам класса С(table D. 2, Annex D);

40) the acceptance level L2/C (L2) for non-destructive testing of tubes produced by high frequency welding (D. 4.2, Annex D);

41) application of additional operations for tubes produced by high frequency welding (D. 4.5, app D);

42) using the samples of fixed-depth notches for equipment calibration [D. 5.2.1, enumeration d) (Annex D)];

43) the use of penetrameters hole instead of the wire penetrameters ISO [D. 5.5.1, the enumeration of a) (Annex D)];

44) the use of additional operations for pipe manufactured by arc welding under flux (D. 5.6, Annex D).

5.3 Examples of orders


Preferably, the information when the order was granted as follows:

a) 32000 m pipe DSFP GOST R ISO 3183−3 L415MC 610х12,5 r2, requirements for the amount of work the shock by bending 7.3.1, the enumeration of b), with TD: -10 °C, document control according to ISO 10474 (3.1).

For information: pipes are intended for the subsequent three-layer coatings based on polyethylene.

b) 20000 m pipes BT GOST R ISO 3183−3, L450QC 219,1х12,5, requirements for the amount of work the shock by bending 7.3.1, the enumeration of b), with TD: -10 °C, operated in the area of the shelf, document control according to ISO 10474 (3.1 In);

c) 2000 m of tubes BT GOST R ISO 3183−3 L360NC 88,9х14,2 r2, requirements for the amount of work the shock by bending 7.3.1, enum a), document control according to ISO 10474 (3.1).

For pipe intended for subsequent coating overlaying the outer epoxy coating.

Any additional agreement or additional requirements should be included (section 5.2).

6 Requirements for production technology of pipes

6.1 General

6.1.1 All piping must be manufactured in accordance with the production process, approved by the consumer.

Validation of the manufacturing process can be performed on existing data or after certification in accordance with Annex V.

6.1.2 All transactions control pipe using non-destructive methods (NDT) used in this standard, shall be conducted by professionals certified in the field of nondestructive testing in accordance with ISO 11484 or equivalent.

6.2 steel Fabrication

6.2.1 Steel, referred to in this standard must be obtained in the oxygen Converter or an electric furnace.

6.2.2 the Steel should be fully sedated and fine-grained. For an acidic environment should be used materials that have passed the vacuum degassing or other alternative process. The material can be cleaned from impurities control forms to increase resistance to hydrogen induced cracking (blistering and steps).