GB/T 38090-2019 English PDF (GBT38090-2019)

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GB/T 38090-2019: Technical requirements of permanent magnets for drive motor of electric vehicle
GB/T 38090-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.030
K 14
Technical Requirements of Permanent Magnets for
Drive Motor of Electric Vehicle
ISSUED ON: OCTOBER 18, 2019
IMPLEMENTED ON: MAY 1, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 4 
1 Scope ... 5 
2 Normative References ... 5 
3 Terms and Definitions ... 6 
4 Designation ... 6 
5 Requirements ... 7 
5.1 Magnetic Property ... 7 
5.2 Temperature Coefficient ... 7 
5.3 Resistivity ... 9 
5.4 Bending Strength ... 9 
5.5 Product Magnetic Moment Consistency ... 9 
5.6 High Temperature Irreversible Magnetic Loss ... 9 
5.7 Plating (or coating) Thickness ... 9 
5.8 Corrosion Resistance ... 9 
5.9 Binding Force ... 10 
5.10 Dimensions ... 10 
6 Test Methods ... 11 
6.1 Magnetic Property ... 11 
6.2 Temperature Coefficient ... 11 
6.3 Resistivity ... 11 
6.4 Bending Strength ... 11 
6.5 Product Magnetic Moment Consistency ... 11 
6.6 High Temperature Irreversible Magnetic Loss ... 11 
6.7 Plating (or coating) Thickness ... 11 
6.8 Corrosion Resistance ... 11 
6.9 Binding Force ... 12 
6.10 Dimensions ... 12 
7 Inspection Rules ... 12 
7.1 Inspection Classification ... 12 
7.2 Inspection Items ... 12 
7.3 Exit-factory Inspection Sampling and Group Rules ... 12 
7.4 Inspection Result Determination and Re-inspection Rules ... 13 
8 Marking, Packaging, Transportation and Storage ... 13 
8.1 Marking ... 13 
8.2 Packaging ... 14 
8.3 Transportation and Storage ... 14 
Appendix A (informative) A Comparison of Designations of CGS and SI Unit
System of Sintered Neodymium Iron Boron Permanent Magnets... 15 
Appendix B (normative) Resistivity Measurement Method of Sintered
Neodymium Iron Boron Permanent Magnets ... 16 
Appendix C (informative) High Temperature Irreversible Magnetic Loss
(magnetic attenuation) Measurement Method of Permanent Magnets ... 18 
Bibliography ... 21 
Technical Requirements of Permanent Magnets for
Drive Motor of Electric Vehicle
1 Scope
This Standard stipulates the technical requirements (magnetic property, temperature
characteristics, allowable deviations of magnetic property, allowable deviations of
dimensions and corrosion resistance) of sintered neodymium iron boron permanent
magnets for drive motor of electric vehicle, as well as their test methods, inspection
rules, marking, packaging, transportation and storage, etc.
This Standard is applicable to sintered neodymium iron boron permanent magnets for
drive motor of electric vehicle (hereinafter referred to as permanent magnets).
2 Normative References
The following documents are indispensable to the application of this document. In
terms of references with a specified date, only versions with a specified date are
applicable to this document. In terms of references without a specified date, the latest
version (including all the modifications) is applicable to this document.
GB/T 2828.1-2012 Sampling Procedures for Inspection by Attribute - Part 1: Sampling
Schemes Indexed by Acceptance Quality Limit (AQL) for Lot-by-lot Inspection
GB/T 2900.60-2002 Electrotechnical Terminology - Electromagnetism
GB/T 3217 Methods of Test of the Magnetic Properties of Permanent Magnetic
(magnetically hard) Materials
GB/T 6461-2002 Methods for Corrosion Testing of Metallic and Other Inorganic
Coatings on Metallic Substrates - Rating of Test Specimens and Manufactured Articles
Subjected to Corrosion Tests
GB/T 6462 Metallic and Oxide Coatings - Measurement of Coating Thickness -
Microscopical Method
GB/T 9637-2001 Electrotechnical Terminology - Magnetic Materials and Components
GB/T 10125 Corrosion Tests in Artificial Atmospheres - Salt Spray Tests
GB/T 24270 Method of Measurement of Temperature Coefficient of Magnetic
Properties of Permanent Magnetic Materials
GB/T 29628 Guides for Methods of Measurement of the Magnetic Properties of
5.3 Resistivity
The resistivity of permanent magnets perpendicular to the direction of easy
magnetization shall be not less than 1.22   m; the resistivity of permanent magnets
parallel to the direction of easy magnetization shall be not less than 1.38   m.
5.4 Bending Strength
The bending strength of permanent magnets perpendicular to the direction of easy
magnetization shall be not less than 220 MP; the bending strength of permanent
magnets parallel to the direction of easy magnetization shall be not less than 180 MPa.
5.5 Product Magnetic Moment Consistency
Product magnetic moment consistency (at the temperature condition of 20 °C) shall
satisfy the following requirements: the magnetic moment deviation of permanent
magnets whose mass is above 10 g shall be less than 4%; the magnetic moment
deviation of permanent magnets whose mass is between 5 g ~ 10 g shall be less than
6%; the magnetic moment deviation of permanent magnets whose mass is below 5 g
shall be less than 8%.
5.6 High Temperature Irreversible Magnetic Loss
The high temperature irreversible magnetic loss of permanent magnets shall be
determined by the demand-side and the supply-side through negotiation.
5.7 Plating (or coating) Thickness
After surface treatment, the thickness range of the central plating (or coating) of
permanent magnets is 3 m ~ 70 m; plating (or coating) thickness at the corners is
allowed to be different from the thickness of the magnetic body’s central location, but
this thickness difference shall be not more than 30 m.
5.8 Corrosion Resistance
Corrosion resistance of permanent magnets shall satisfy the requirement of salt spray
test time stipulated in Table 3. After the test, permanent magnets shall reach the
requirements of protection rating and appearance rating Level-10 as stipulated in GB/T
6461-2002.
6 Test Methods
6.1 Magnetic Property
The test of main magnetic properties of permanent magnets shall comply with the
stipulations in GB/T 3217 or GB/T 29628.
6.2 Temperature Coefficient
The test of temperature coefficient of permanent magnets shall comply with the
stipulations in GB/T 24270.
6.3 Resistivity
The measurement method of electrical resistivity of permanent magnets shall comply
with the stipulations in Appendix B.
6.4 Bending Strength
The test of bending strength of permanent magnets shall comply with the stipulations
in GB/T 31967.2.
6.5 Product Magnetic Moment Consistency
The measurement of magnetic moment of permanent magnets shall comply with the
stipulations in IEC 60404-14. Product magnetic moment consistency is the ratio of
sampling product’s magnetic moment range (the difference between the maximum
value and the minimum value) and the average value.
6.6 High Temperature Irreversible Magnetic Loss
The measurement of high temperature irreversible magnetic loss of permanent
magnets shall refer to the method described in Appendix C.
6.7 Plating (or coating) Thickness
The measurement of plating (or coating) thickness of permanent magnets shall comply
with the stipulations in GB/T 6462.
If there are multiple metal plating, then, measure the total thickness of the plating.
6.8 Corrosion Resistance
The test of corrosion resistance of permanent magnets shall comply with the
stipulations in GB/T 10125.
Thickness
6 Corrosion Resistance 3 PCS/batch 5.8 GB/T 10125
7 Dimensions
...