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GB/T 2521.1-2016 English PDF (GBT2521.1-2016)

GB/T 2521.1-2016 English PDF (GBT2521.1-2016)

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GB/T 2521.1-2016: Cold-rolled electrical steel delivered in the fully-processed state -- Part 1: Grain non-oriented steel strip (sheet)

This Part of GB/T 2521 specifies the terms, definitions, classification, symbols and nameplates, general requirements, technical requirements, test and inspection, determination and re-inspection rules, packaging, mark, quality certificate and content of order of grain non-oriented electrical steel strip (sheet) with the nominal thickness of 0.35 mm, 0.50 mm and 0.65 mm. This Standard is applicable to grain non-oriented electrical steel strip (sheet) [hereinafter referred to as steel strip (sheet)] that is applied to magnetic circuit structure under fully-processed cold-rolled delivered state.
GB/T 2521.1-2016
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 77.140.40
H 53
Partially replacing GB/T 2521-2008
Cold-rolled Electrical Steel Delivered
in the Fully-processed State - Part 1:
Grain Non-oriented Steel Strip (sheet)
(IEC 60404-8-4:2013, Magnetic Materials - Part 8-4: Specifications for
Individual Materials - Cold-rolled Non-oriented Electrical Steel Strip and Sheet Delivered in the Fully-processed State, MOD)
ISSUED ON: JUNE 14, 2016
IMPLEMENTED ON: MAY 1, 2017
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration Committee of the PEOPLE
Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 6
4 Classification ... 6
5 Symbols and Designations ... 7
6 General Requirements ... 8
7 Technical Requirements ... 9
8 Test and Inspection ... 13
9 Determination and Re-inspection Rules ... 17
10 Packaging, Mark and Quality Certificate ... 17
11 Content of Order ... 17
Appendix A (Normative) Repeated Bending Test Method ... 18
Appendix B (Normative) Test Method of Coating Insulation Resistance ... 20 Appendix C (Informative) Mechanical Properties of Grain Non-oriented
Electrical Steel Strip (sheet) ... 21
Appendix D (Informative) Properties and Main Purposes of Various
Designations ... 22
Appendix E (Informative) Comparison Table of Designations in this Part and IEC 60404-8-4:2013 ... 24
Appendix F (Informative) Comparison Table of Chapter Number in this Part and IEC 60404-8-4:2013 ... 25
Appendix G (Informative) Technical Differences and Reasons in this Part and IEC 60404-8-4:2013 ... 28
Cold-rolled Electrical Steel Delivered
in the Fully-processed State - Part 1:
Grain Non-oriented Steel Strip (sheet)
1 Scope
This Part of GB/T 2521 specifies the terms, definitions, classification, symbols and designations, general requirements, technical requirements, test and inspection, determination and re-inspection rules, packaging, mark, quality certificate and content of order of grain non-oriented electrical steel strip (sheet) with the nominal thickness of 0.35 mm, 0.50 mm and 0.65 mm.
This Standard is applicable to grain non-oriented electrical steel strip (sheet) [hereinafter referred to as steel strip (sheet)] that is applied to magnetic circuit structure under fully-processed cold-rolled delivered state.
2 Normative References
The following documents are indispensable to the application of this Standard. In terms of references with a specified date, only versions with a specified date are applicable to this Standard. The latest version (including all the modifications) of references without a specified date is also applicable to this Standard.
GB/T 247 General Rule of Acceptance, Package, Mark and Certification for Steel Plates (sheets) and Strips
GB/T 2522-2007 Methods of Test for the Determination of Surface Insulation Resistance and Lamination Factor of Electric Sheet and Strip (IEC 60404-11:1999, MOD)
GB/T 2900.60 Electrotechnical Terminology - Electromagnetism (GB/T 2900.60- 2002, eqv IEC 60050 (121):1998)
GB/T 3655 Methods of Measurement of the Magnetic Properties of Electrical Steel Sheet and Strip by Means of an Epstein Frame (GB/T 3655-2008, IEC 60404- 2:1996, IDT)
GB/T 9637 Electrotechnical Terminology - Magnetic Materials and Components [GB/T 9637-2001, eqv IEC 60050 (221):1990]
GB/T 13789 Methods of Measurement of the Magnetic Properties of Magnetic Sheet and Strip by Means of a Single Sheet Tester (GB/T 13789-2008, IEC 60404- 3:2002, IDT)
GB/T 17505 Steel and Steel Products - General Technical Delivery Requirements (GB/T 17505-2016, ISO 404:2013: MOD)
GB/T 18253 Steel and Steel Products - Types of Inspection Documents (GB/T 18253-2000, eqv ISO 10474:1991)
GB/T 19289 Methods of Measurement of Density, Resistivity and Stacking Factor of Electrical Steel Sheet and Strip (GB/T 19289-2003, IEC 404-13:1995, MOD) YB/T 4292 Methods of Determination of the Geometrical Characteristics of Electric Steel Sheet and Strip (YB/T 4292-2012, IEC 60404-9:1987, MOD)
3 Terms and Definitions
Those defined in GB/T 2900.60, GB/T 9637 and YB/T 4292, and the following terms and definitions are applicable to this Standard.
3.1 Number of Bends
Number of bends refers to the maximum number of repeated bends before substrate manifests crack (or emits the sound of crack-generating) under visual observation. NOTE: number of bends is utilized to signify the extensibility of a material. 3.2 Nominal Thickness Tolerance
Nominal thickness tolerance refers to the allowable tolerance of nominal thickness in the same acceptance batch.
3.3 Longitudinal Thickness Tolerance
Longitudinal thickness tolerance refers to the thickness tolerance that is parallel to the rolling direction of the previous steel sheet or on a certain length of steel strip. 3.4 Transverse Thickness Tolerance
Transverse thickness tolerance refers to the thickness tolerance that is vertical to the rolling direction.
4 Classification
4.1 In this Part, the grade of steel strip (sheet) can be classified in accordance with the maximum total loss ratio P1.5/50 under the magnetic polarization intensity of 1.5 T and Steel strip (sheet) can be delivered in trimmed or untrimmed condition. Generally speaking, before delivery, steel strip (sheet) shall have insulating coating on a single side or both sides, or steel strip (sheet) can be delivered without insulating coating. The type of insulating coating shall be determined by the supply side and the demand side through negotiation.
6.4 Surface Quality
6.4.1 The surface of steel strip (sheet) shall be smooth and clean; there shall be no corrosion. Scattered defects, such as scratch, bubble and crack, are allowed to exist when they are within the range of thickness tolerance and do not affect the normal utilization of the material.
6.4.2 The insulating coating on the surface of steel strip (sheet) shall be favorably attached; the color of the coating shall be even. The coating shall not be stripped during the operation of shearing. During the process of repeated bending test (please refer to 8.3), the coating shall not manifest stripping after 90?? bending. If the coating is stripped, conduct shear test of the test piece where the sample is taken. During the shear test, large-area stripping of the coating is not allowed. However, slight chippings on the sheared edge of the coating are allowed.
6.5 Shear Adaptability
It shall be convenient to shear or stamp steel strip, which guarantees that steel strip can be sheared into a normal shape in any position. If the demand side has a special demand, the supply side and the demand side shall determine it through negotiation. 7 Technical Requirements
7.1 Magnetic Properties
7.1.1 The magnetic properties of steel strip (sheet) provided under the condition of 6.3 shall comply with the stipulation in Table 2. Timeliness-based sample shall also comply with these properties. In terms of products with coating, the quality of the insulating coating shall be included in the calculation.
7.1.2 The magnetic properties of steel strip (sheet) shall be tested in accordance with GB/T 3655. Through the negotiation between the supply side and the demand side, it can also be tested in accordance with GB/T 13789. Under this circumstance, the tested value shall also comply with the stipulation in Table 2.
NOTE 1: over the past few years, it is a habit to adopt magnetic induction intensity. As a matter of fact, the object of Epstein square and single sheet tester is magnetic polarization intensity. The relation between magnetic induction intensity and magnetic polarization intensity: J=B-???0H
calculation of magnetic properties and stacking coefficient shall comply with the stipulation in Table 2.
7.3.2 Stacking coefficient
The minimum stacking coefficient of steel strip (sheet) shall comply with the stipulation in Table 2. When it is controversial, stacking coefficient is merely applicable to uncoated state.
7.3.3 Number of bends
The minimum number of bends of steel strip (sheet) that is vertical to the rolling direction shall comply with the stipulation in Table 2.
7.3.4 Tolerance of sheared edge triggered by internal stress
Internal stress on steel strip (sheet) shall be minimized. In accordance with the demand side?€?s demand, and it shall be indicated in the contract, the tolerance test of sheared edge that is triggered by internal stress can be conducted on steel strip (sheet) whose width is more than 150 mm. The measured value of welding seam shall not exceed 2 mm.
7.3.5 Insulation resistance of coating
In accordance with the demand side?€?s demand, and through the negotiation between the demand side and the supply side, the test on the insulation resistance of coating can be conducted. In addition, the minimum value of insulation resistance of the coating surface or interlayer resistance shall be indicated in the contract. If steel strip (sheet) needs thermal treatment, it shall be conducted in accordance with the conditions appointed by the manufacturer. Furthermore, it shall be indicated in the contract that insulation resistance of coating shall be tested before or after the treatment.
NOTE: insulation resistance of coating shall be divided into surface insulation resistance and interlayer resistance.
8 Test and Inspection
8.1 General Requirements
8.1.1 When an agreement of ordering is signed in accordance with this Part, users can conduct stipulated test and inspection in accordance with the stipulation in GB/T 17505, or unstipulated test and inspection. However, in terms of unstipulated test and inspection, the manufacturer shall provide the total loss ratio and magnetic polarization intensity of steel strip (sheet).
8.1.2 When the ordered products are tested and inspected in accordance with the stipulation, users shall be clear and definite about the type of inspection files in GB/T 18253.
8.1.3 Steel strip shall be batched in accordance with coil. Generally speaking, a coil shall constitute a batch for acceptance. Steel strip coils of the same grade and the same nominal thickness are allowed to be combined into an acceptance batch. However, its weight shall not exceed 20 t. An individual steel coil whose weight is more than 20 t shall constitute an acceptance batch.
8.1.4 Unless it is otherwise stipulated in an agreement, the stipulation in 8.1.3 is applicable to the tolerance of sheared edge triggered by internal stress, shear adaptability, insulation resistance of coating, geometrical characteristics and tolerance inspection.
8.1.5 When products are delivered in the form of separated coils, the test result of the original acceptance batch is applicable to the separated coils.
8.2 Sampling
8.2.1 General requirements
8.2.1.1 Sampling shall be taken from each acceptance batch.
8.2.1.2 The innermost ring and outermost ring of steel coil shall be deemed as packaging material and shall not represent the quality of the whole steel coil. Sampling shall not be taken from this part. Sampling shall avoid welding seam and splicing area. 8.2.1.3 Through reasonable arrangement of the test sequence, the same sub-sample can be adopted for the test of multiple properties.
8.2.2 Magnetic properties
8.2.2.1 The sample for magnetic properties test shall be respectively taken from steel strip (sheet) longitudinally and transversally. The sampling size shall be separated equally to longitudinal and transversal. Please see the specific requirements below: a) When 25 cm Epstein square is adopted in the test, a set of samples shall be constituted of 4 times of test pieces. The recommended weight is around 0.50 kg. The sampling method, dimension and allowable tolerance of sample shall comply with the stipulation in GB/T 3655;
b) When single sheet tester is adopted, 2 samples shall be taken under general circumstances. If the sample is square, then only 1 sample will be needed. The sampling method, dimension and allowable tolerance of the sample shall
comply with the stipulation in GB/T 13789.
8.2.2.2 When the maximum total loss ratio of timeliness-based sample of steel strip (sheet) is tested, the timeliness-based sample shall receive continuous heat 8.3.2 Magnetic properties
The test method of magnetic properties of steel strip (sheet) shall comply with GB/T 3655 or GB/T 13789.
8.3.3 Geometrical characteristics and tolerance
8.3.3.1 Thickness
The thickness of steel strip (sheet) shall be tested in any position that is at a distance of not less than 30 mm from the edges of steel strip or steel sheet (not less than 45 mm if it is untrimmed). In terms of material whose width is less than 60 mm, the measurement of thickness shall be conducted on the vertical axis of steel strip. The test of thickness shall adopt micrometer whose division value is 0.001 mm. 8.3.3.2 Width
The width of steel strip (sheet) shall be tested along the vertical axis of vertical steel strip or steel sheet.
8.3.3.3 Camber
The camber of steel strip (sheet) shall be tested in accordance with YB/T 4292. 8.3.3.4 Unevenness
The unevenness of steel strip (sheet) shall be tested in accordance with YB/T 4292. 8.3.3.5 Residual curvature
The residual curvature of steel strip (sheet) shall be tested in accordance with YB/T 4292.
8.3.3.6 Burr height
The Burr height of steel strip (sheet) shall be tested in accordance with YB/T 4292. 8.3.4 Technical properties
8.3.4.1 Stacking coefficient
The stacking coefficient of steel strip (sheet) shall be tested in accordance with GB/T 19289.
8.3.4.2 Number of bends
The number of bends of steel strip (sheet) shall be tested in accordance with Appendix A.
Appendix A
(Normative)
Repeated Bending Test Method
A.1 Sample
A.1.1 Along the vertical rolling direction, at a distance of at least 40 mm from the edges or the center of steel strip (sheet), take a rectangular sample whose minimum width is 20 mm (generally 30 mm), and whose length is 250 mm ~ 300 mm. The quantity of the samples shall be at least 2. The samples shall be maintained straight.
A.1.2 If the width of steel strip (sheet) is not sufficient to take a sample in accordance with the stipulated requirement for length, the sample can be taken along the rolling direction. Under this circumstance, the test result shall comply with the stipulation in Table 2.
A.2 Test Method
A.2.1 The test shall be conducted at the temperature of 23 ??C ?? 5 ??C.
A.2.2 The sample shall be fixated with a lower clamp whose corner radius is 5 mm, as it is shown in Figure A.1.
A.2.3 The method of counting repeated bends: bending to 90?? from the initial position and returning to the initial position shall be counted as a bend; bending 90?? from the initial position towards the other direction and returning to the initial position shall be counted as another bend. Count the number of bends in turn.
A.2.4 Continuously bend the sample, until crack emerges (or the sample emits the sound of crack-generating) for the first time under visual inspection, then, stop the test. The last bend shall not be counted into the number of bends.
A.3 Test Device
In order to guarantee that the sample can be bended in a fixed position, impose certain tension on the sample. The recommended tension is approximately 70 N. Please refer to Figure A.2 for the repeated bending test device.
A.4 Test Result
The minimum value of several test results shall be considered as the ultimate test result.

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