IEC 61631:2001 pdf download

IEC 61631:2001 pdf download.Test method for the mechanical strength of cores made of magnetic oxides.
2 Normative references
The following referenced documents are indispensable for the application of PEC 61631. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 61246:1994, Magnetic oxide cores (E-cores) of rectangular cross-section and associated parts — Dimensions
EN 10002-2:1992. Tensile testing of metallic materials — Part 2: Verification of the force measuring system of the tensile testing machine
ISO 4677-1:1985, Atmospheres for conditioning and testing — Determination of relative humidity — Part 1: Aspirated psychrometer method
ISO 4677-2:1985, Atmospheres for conditioning and testing — Determination of relative humidity — Part 2: Whirling psychrometer method
3 Definitions
For the purpose of this International Standard, the following definition applies.
mechanical strength
the maximum recorded force at the Instant of fracture of a magnetic oxide core when it Is loaded In bending
4 Apparatus
4.1 Test core support and loading wedge
Test cores shall be supported on free moving roller bars or on a flat support depending on their size (see 6.2). The loading wedge and the roller bars or the flat support shall be made of hardened steel with a hardness of 40 HRC to 60 HRC. The loading wedge and the roller bars shall have a radius of 2 mm. The loading wedge shall be connected to a device for rneasunng and recording the load applied.
4.2 TestIng device
The testing device shall be a mechanical testing machine capable of applying a force to the loading wedge high enough to break the test core. The machine shall be capable of applying the force at a constant loading-rate. The machine shall be equipped with a device for recording the peak load applied to the test core. The accuracy of the machine shall be in accordance with EN 10002-2, Grade 1 (accuracy 1 % of the Indicated load). Force calibration of the machine shall be checked in accordance with EN 10002-2.
4.3 Humidity measuring device
A humidity measuring device shall be as specified in ISO 4677.1 or Iso 4677.2 and shall be
capable of measuring relative humidity to an accuracy of ±2 %.
5 Test cores
The test cores shall be selected as agreed between the parties concerned, They may be machined to the specified, dimensions, because any machined surface plays an important role in the mechanical strength (see Introduction).
5.1 Number of test-cores
For material development, characterization or quality checking, the minimum number of test cores shall be five pieces. For statistical evaluation of strength-data (for example. Welbull parameters), the minimum number shall be 30.
NOTE Fot comparison of data for different mat.rials, it is import.anl fiat the numb., of specimens is high enough to ob(ae results with sufficient StatiStical confidence. Since the confidence Ilmitg. In general, depend on the number of test results and their dIsperi’on. Itie number of test specimens should be decided on the basis ot statistical considerations.
5.2 Precautions
The prepared test cores should be handled with care to avoid introduction of additional damage. Test cores should be kept separately at all times, and should be wrapped individually for transport.
6 Testing
6.1 Test conditions
The test shall be carried out at an ambient temperature between 15 °C and 35 °C. The temperature shall not vary by more than 3 C during the course of a test series. The relative humidity shall be between 45 % and 85 % and shall not vary by more than 10 % during the course of a test series.
6.2 Test procedures
6.2.1 General
The test core shall be arranged in the test apparatus in accordance with 6.2.2, 6.2.3, 6.2.4. 6.2.5 or 8.2.6 as applicable (see figures 1 to 5).
The E-test and W-test can be used for material related purposes, while the M-test and T-test can be used for process related purposes. The I-test is only recommended for flat shaped test cores such as antenna rods A preloading force of 5 N to 25 N shall be applied because the upper and lower faces of the test cores are never absolutely parallel. Then the test force shall be applied at a loading rate of between 5 mm/nun and 20 mm/mm until the test core fractures The load at the instant of fracture 5hall be recorded. The fractured fragments shall be identified and preserved for later fractographic examination.