GB/T 42677-2023 Non-destructive testing (NDT) methods of steel tubes―Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections (English Version)
Non-destructive testing (NDT) methods of steel tubes―Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections
GB/T 42677-2023 Non-destructive testing (NDT) methods of steel tubes - Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections
1 Scope
This document specifies requirements applicable to liquid penetrant testing of seamless and welded tubes for the detection of surface imperfections.
It is applicable to all or any part of the tube surface as required by the relevant product standards. It can also be applicable to the testing of hollow sections.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3059 Non-destructive testing - Penetrant testing and magnetic particle testing - Viewing conditions
ISO 3452-1 Non-destructive testing - Penetrant testing - Part 1: General principles
ISO 3452-2 Non-destructive testing - Penetrant testing - Part 2: Testing of penetrant materials
ISO 9712 Non-destructive testing - Qualification and certification of NDT personnel
Note: GB/T 9445-2015, Non-destructive testing - Qualification and certification of NDT personnel (ISO 9712:2012, IDT)
ISO 11484 Steel products - Employer’s qualification system for non-destructive testing (NDT) personnel
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3452-1 and ISO 11484 and the following apply.
3.1
tube
hollow long product open at both ends, of any cross-sectional shape
3.2
seamless tube
tube made by piercing a solid product to obtain a tube hollow, which is further processed, either hot or cold, into its final dimensions
3.3
welded tube
tube made by forming a hollow profile from a flat product and welding adjacent edges together, and which, after welding, can be further processed, either hot or cold, into its final dimensions
3.4
manufacturer
organization that manufactures products in accordance with the relevant standard(s) and declares the compliance of the delivered products with all applicable provisions of the relevant standard(s)
3.5
agreement
contractual arrangement between the manufacturer and purchaser at the time of enquiry and order
4 General requirements
4.1 Unless otherwise specified by the product standard or agreed on by the purchaser and manufacturer, this liquid penetrant inspection shall be carried out on tubes after completion of all the primary production process operations (rolling, heat treating, cold and hot working, sizing, primary straightening, etc.).
4.2 The surface of the tube being tested shall be sufficiently clean and free of oil, grease, sand, scale or any other foreign matter which can potentially interfere with the correct interpretation of the indications obtained from liquid penetrant testing. The type of indications, as well as the minimum dimension of the surface imperfections detected, depends on the specific tube manufacturing process and the surface finish.
4.3 This inspection shall be carried out by trained operators, qualified in accordance with ISO 9712, ISO 11484 or equivalent, and supervised by competent personnel nominated by the manufacturer. In the case of third-party inspection, this shall be agreed on between the purchaser and manufacturer.
The operating authorization issued by the employer shall be according to a written procedure. NDT operations shall be authorized by a level 3 NDT individual approved by the employer.
Note: The definition of levels 1, 2 and 3 can be found in appropriate International Standards, e.g. ISO 9712 and ISO 11484.
5 Test method
5.1 General
5.1.1 A liquid penetrant is applied to the surface being examined and allowed to enter the surface imperfections. All excess penetrant is then removed; the surface of the part is dried and a developer is applied. The developer functions both as a blotter to absorb penetrant that has been trapped in imperfections and as a contrasting background to enhance the visibility of penetrant indications. The dyestuffs in penetrants are either colour-contrast (visible under white light) or fluorescent (visible under ultraviolet light). For both penetrant techniques, the following three types of penetrant systems can be used:
a) water washable;
b) post emulsifying;
c) solvent removable.
Note: Where the term “penetrant materials” is used in this document, it is intended to include all penetrants, solvents or cleaning agents, developers, etc., used in the testing process.
5.1.2 For each tube or each part of the tube under test, either a colour-contrast penetrant technique or a fluorescent penetrant technique, both techniques with one of the three types of penetrant systems, shall be used.
The general principles and the methods of verification of liquid penetrant testing as described in ISO 3059, ISO 3452-1 and ISO 3452-2 shall be applied.
5.2 Detection of imperfections and their classification
The liquid penetrant method is an effective means of detecting imperfections which are open to the surface (called surface imperfections in this part of ISO 10893). Typical surface imperfections detectable by this method are cracks, seams, laps, cold shuts, laminations and porosity.
The liquid penetrant method does not make it possible to determine the nature, shape and, more generally, the dimensions of the surface imperfections revealed. The dimensions of the penetrant indication do not directly represent the actual dimensions of the surface imperfection causing this indication. That is why the classification of liquid penetrant indications shall be the following:
a) linear indications - indications where the length of the indication is equal to or more than three times the width of the indication;
b) rounded indications - indications which are circular or elliptical in shape, where the length of the indication is less than three times the width of the indication;
c) accumulated indications - indications which are linear or rounded and are aligned or clustered with a separation of not more than the length of the smallest indication and consisting of at least three indications;
d) non-relevant indications - indications which may result from localized surface irregularities to a particular tube-making process, for example machining marks, scratches and sizing/straightening marks.
The minimum dimension of indications that shall be considered during the evaluation shall be as given in Table 1, in relation to the acceptance level specified.
5.3 Procedure
The liquid penetrant testing shall be in accordance with the following operational conditions:
a) for the choice of the penetrant system, the tube surface condition as well as the test category shall be taken into account;
b) for stainless steel tubes, low halogen (chlorine/fluorine) and low sulphur penetrant materials shall be applied;
c) the temperature of application shall be between 10 °C and 50 °C. When it is not practicable to conduct the liquid penetrant testing within the given temperature range, the testing procedure shall be qualified at the proposed temperature using the liquid penetrant comparator block (e.g. a quench-cracked aluminium block);
d) the penetrant should be applied by brushing or spraying. For parts of tubes, dipping or flooding is less effective but not prohibited;
e) the dwell time shall be not less than that recommended by the manufacturer of the penetrant system; usually it is between 3 min and 30 min;
f) the removal of excess water-washable or post-emulsified penetrant shall be performed with rinsing by water, under black light conditions where appropriate, at a pressure around 200 kPa (2 bar) with a maximum of 350 kPa (3.5 bar). The temperature of the water used for rinsing shall be less than 40 °C. The excess solvent-removable penetrant shall be removed insofar as possible by using wipes of white, Iint-free material that is clean and dry, until most traces of penetrant have been removed. Then the surface shall be lightly wiped with a Iint-free material that has been slightly moistened with solvent, until all remaining traces of excess penetrant have been removed. Flushing the surface with solvent following the application of the penetrant and prior to developing is prohibited;
g) drying of the surface subsequent to washing with water can be assisted by using wipes of white, Iint-free material that is clean and dry or by using a hot-air blast at a pressure below 200 kPa (2 bar) and a temperature below 70 °C. Drying after the solvent-removing process is generally by normal evaporation, therefore no other drying techniques are necessary. The temperature of the tube shall not exceed 50 °C, unless otherwise agreed on by the purchaser and manufacturer;
h) the wet developer shall be applied by spraying, in such a manner as to assure complete coverage of the area being tested with a thin, even film of developer. The dry-powder developer shall be applied either by dipping the tube, or the parts of the tube being tested, into a fluid bed of dry developer or by dusting it with the dry-powder developer through a manual powder bulb or a spray powder gun (conventional or electrostatic), provided the powder is dusted evenly over the entire surface being tested;
i) the development time begins as soon as the wet-developer coating is dry or immediately after the application of the dry-powder developer. Generally, the development time is equal to the penetration time and varies from 5 min to 30 min, and if the bleed out does not alter the inspection results; development periods of more than 30 min are permitted;
j) the inspection of the areas being tested shall be performed after the applicable development time as specified in 5.3 i), to assure proper bleed out of penetrant from the imperfections on to the developer coating. It is good practice to observe the surface while applying the developer as an aid to evaluating indications. For fluorescent penetrant indications, the inspection shall be carried out in a darkened area using a UV-A radiation source with a background of light level not exceeding 20 lx and a black light intensity of at least 10 W/m2 on the surface of the area being inspected. For visible penetrant indications, the illumination of the surface of the area being inspected shall be not less than 500 Ix.
6 Evaluation of indications
6.1 Four acceptance levels, corresponding to four severity levels with maximum permissible number or maximum permissible dimensions (diameter or length) have been established in accordance with Tables 2 and 3.
Standard
GB/T 42677-2023 Non-destructive testing (NDT) methods of steel tubes―Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections (English Version)
Standard No.
GB/T 42677-2023
Status
valid
Language
English
File Format
PDF
Word Count
5500 words
Price(USD)
165.0
Implemented on
2024-3-1
Delivery
via email in 1~3 business day
Detail of GB/T 42677-2023
Standard No.
GB/T 42677-2023
English Name
Non-destructive testing (NDT) methods of steel tubes―Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections
GB/T 42677-2023 Non-destructive testing (NDT) methods of steel tubes - Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections
1 Scope
This document specifies requirements applicable to liquid penetrant testing of seamless and welded tubes for the detection of surface imperfections.
It is applicable to all or any part of the tube surface as required by the relevant product standards. It can also be applicable to the testing of hollow sections.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3059 Non-destructive testing - Penetrant testing and magnetic particle testing - Viewing conditions
ISO 3452-1 Non-destructive testing - Penetrant testing - Part 1: General principles
ISO 3452-2 Non-destructive testing - Penetrant testing - Part 2: Testing of penetrant materials
ISO 9712 Non-destructive testing - Qualification and certification of NDT personnel
Note: GB/T 9445-2015, Non-destructive testing - Qualification and certification of NDT personnel (ISO 9712:2012, IDT)
ISO 11484 Steel products - Employer’s qualification system for non-destructive testing (NDT) personnel
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3452-1 and ISO 11484 and the following apply.
3.1
tube
hollow long product open at both ends, of any cross-sectional shape
3.2
seamless tube
tube made by piercing a solid product to obtain a tube hollow, which is further processed, either hot or cold, into its final dimensions
3.3
welded tube
tube made by forming a hollow profile from a flat product and welding adjacent edges together, and which, after welding, can be further processed, either hot or cold, into its final dimensions
3.4
manufacturer
organization that manufactures products in accordance with the relevant standard(s) and declares the compliance of the delivered products with all applicable provisions of the relevant standard(s)
3.5
agreement
contractual arrangement between the manufacturer and purchaser at the time of enquiry and order
4 General requirements
4.1 Unless otherwise specified by the product standard or agreed on by the purchaser and manufacturer, this liquid penetrant inspection shall be carried out on tubes after completion of all the primary production process operations (rolling, heat treating, cold and hot working, sizing, primary straightening, etc.).
4.2 The surface of the tube being tested shall be sufficiently clean and free of oil, grease, sand, scale or any other foreign matter which can potentially interfere with the correct interpretation of the indications obtained from liquid penetrant testing. The type of indications, as well as the minimum dimension of the surface imperfections detected, depends on the specific tube manufacturing process and the surface finish.
4.3 This inspection shall be carried out by trained operators, qualified in accordance with ISO 9712, ISO 11484 or equivalent, and supervised by competent personnel nominated by the manufacturer. In the case of third-party inspection, this shall be agreed on between the purchaser and manufacturer.
The operating authorization issued by the employer shall be according to a written procedure. NDT operations shall be authorized by a level 3 NDT individual approved by the employer.
Note: The definition of levels 1, 2 and 3 can be found in appropriate International Standards, e.g. ISO 9712 and ISO 11484.
5 Test method
5.1 General
5.1.1 A liquid penetrant is applied to the surface being examined and allowed to enter the surface imperfections. All excess penetrant is then removed; the surface of the part is dried and a developer is applied. The developer functions both as a blotter to absorb penetrant that has been trapped in imperfections and as a contrasting background to enhance the visibility of penetrant indications. The dyestuffs in penetrants are either colour-contrast (visible under white light) or fluorescent (visible under ultraviolet light). For both penetrant techniques, the following three types of penetrant systems can be used:
a) water washable;
b) post emulsifying;
c) solvent removable.
Note: Where the term “penetrant materials” is used in this document, it is intended to include all penetrants, solvents or cleaning agents, developers, etc., used in the testing process.
5.1.2 For each tube or each part of the tube under test, either a colour-contrast penetrant technique or a fluorescent penetrant technique, both techniques with one of the three types of penetrant systems, shall be used.
The general principles and the methods of verification of liquid penetrant testing as described in ISO 3059, ISO 3452-1 and ISO 3452-2 shall be applied.
5.2 Detection of imperfections and their classification
The liquid penetrant method is an effective means of detecting imperfections which are open to the surface (called surface imperfections in this part of ISO 10893). Typical surface imperfections detectable by this method are cracks, seams, laps, cold shuts, laminations and porosity.
The liquid penetrant method does not make it possible to determine the nature, shape and, more generally, the dimensions of the surface imperfections revealed. The dimensions of the penetrant indication do not directly represent the actual dimensions of the surface imperfection causing this indication. That is why the classification of liquid penetrant indications shall be the following:
a) linear indications - indications where the length of the indication is equal to or more than three times the width of the indication;
b) rounded indications - indications which are circular or elliptical in shape, where the length of the indication is less than three times the width of the indication;
c) accumulated indications - indications which are linear or rounded and are aligned or clustered with a separation of not more than the length of the smallest indication and consisting of at least three indications;
d) non-relevant indications - indications which may result from localized surface irregularities to a particular tube-making process, for example machining marks, scratches and sizing/straightening marks.
The minimum dimension of indications that shall be considered during the evaluation shall be as given in Table 1, in relation to the acceptance level specified.
5.3 Procedure
The liquid penetrant testing shall be in accordance with the following operational conditions:
a) for the choice of the penetrant system, the tube surface condition as well as the test category shall be taken into account;
b) for stainless steel tubes, low halogen (chlorine/fluorine) and low sulphur penetrant materials shall be applied;
c) the temperature of application shall be between 10 °C and 50 °C. When it is not practicable to conduct the liquid penetrant testing within the given temperature range, the testing procedure shall be qualified at the proposed temperature using the liquid penetrant comparator block (e.g. a quench-cracked aluminium block);
d) the penetrant should be applied by brushing or spraying. For parts of tubes, dipping or flooding is less effective but not prohibited;
e) the dwell time shall be not less than that recommended by the manufacturer of the penetrant system; usually it is between 3 min and 30 min;
f) the removal of excess water-washable or post-emulsified penetrant shall be performed with rinsing by water, under black light conditions where appropriate, at a pressure around 200 kPa (2 bar) with a maximum of 350 kPa (3.5 bar). The temperature of the water used for rinsing shall be less than 40 °C. The excess solvent-removable penetrant shall be removed insofar as possible by using wipes of white, Iint-free material that is clean and dry, until most traces of penetrant have been removed. Then the surface shall be lightly wiped with a Iint-free material that has been slightly moistened with solvent, until all remaining traces of excess penetrant have been removed. Flushing the surface with solvent following the application of the penetrant and prior to developing is prohibited;
g) drying of the surface subsequent to washing with water can be assisted by using wipes of white, Iint-free material that is clean and dry or by using a hot-air blast at a pressure below 200 kPa (2 bar) and a temperature below 70 °C. Drying after the solvent-removing process is generally by normal evaporation, therefore no other drying techniques are necessary. The temperature of the tube shall not exceed 50 °C, unless otherwise agreed on by the purchaser and manufacturer;
h) the wet developer shall be applied by spraying, in such a manner as to assure complete coverage of the area being tested with a thin, even film of developer. The dry-powder developer shall be applied either by dipping the tube, or the parts of the tube being tested, into a fluid bed of dry developer or by dusting it with the dry-powder developer through a manual powder bulb or a spray powder gun (conventional or electrostatic), provided the powder is dusted evenly over the entire surface being tested;
i) the development time begins as soon as the wet-developer coating is dry or immediately after the application of the dry-powder developer. Generally, the development time is equal to the penetration time and varies from 5 min to 30 min, and if the bleed out does not alter the inspection results; development periods of more than 30 min are permitted;
j) the inspection of the areas being tested shall be performed after the applicable development time as specified in 5.3 i), to assure proper bleed out of penetrant from the imperfections on to the developer coating. It is good practice to observe the surface while applying the developer as an aid to evaluating indications. For fluorescent penetrant indications, the inspection shall be carried out in a darkened area using a UV-A radiation source with a background of light level not exceeding 20 lx and a black light intensity of at least 10 W/m2 on the surface of the area being inspected. For visible penetrant indications, the illumination of the surface of the area being inspected shall be not less than 500 Ix.
6 Evaluation of indications
6.1 Four acceptance levels, corresponding to four severity levels with maximum permissible number or maximum permissible dimensions (diameter or length) have been established in accordance with Tables 2 and 3.
