AS ISO 9934.3:2020 – Non-destructive testing— Magnetic particle testing Part 3: Equipment.
4.2.3 Technical requirements
The following requirements shall be satished at an ambient temperature of 30°C and at the rated current I:
— duty cycle: l0 %;
— current “ON” time: 5 s.
NOTE High testing rates will require a higher duty cycle.
4.3 MagnetIc benches
4.3.1 General
Fixed installation benches can include facilities for current flow and magnetic flow techniques. Magnetic flow can be achieved either by an electromagnetic yoke or a fixed coil. The characteristics of the current generator are defined in 4.2.
When facilities for multidirectional magnetization are included, each circuit shall be independently controlled. Magnetization shall be sufficient to achieve the required detection capability In all directions.
The characteristic of the electromagnetic yoke Is the tangential field strength. H1, measured, in kiloamperes per metre. at the nudpoint of the length of a cylindrical bar conforming to C22 (1.0402) of EN 10250-2, of specified dimensions (length and diameter) appropriate to the acceptance range of the equipment.
If the bench is to be used for magnetic flow testing of components longer than 1 m, or segments of the length are magnetized Individually, the supplier shall define how magnetizing capability is determined. This shall include a specification of the tangential field strength for a bar of suitable length and diameter.
4.3.2 TechnIcal data
The following data shall be provided:
— types of magnetization available;
— current wave forms available;
— method of current control and effect on waveform;
— working range and incremental setting steps;
— method of constant current control, if available;
— monitoring of magnetizing current(s);
— magnetizing duration range;
— automated features;
— duty cycle at maximum out put;
— maximum current “ON” time (if other than specified in 4.2);
— tangential field strength, H1 (see 4.3);
— open circuit voltage, Uo (RMS);
— short circuit current Ik (RMS);
— rated current (RMS);
8 Demagnetization
8.1 General
Facilities for demagnetization can be included in the magnetizing equipment, or demagnetizing can be carried out using a separate equipment.
If viewing for indications is carried out after demagnetization, indications shall be preserved by a suitable method.
8.2 Technicaldata
The following data shall be provided:
method(s) of demagnetization;
— type of current regulation;
— field strength (at the centre of the empty demagnetizing coil if applicable);
— residual field bra specified component;
— electrical supply requirements at maximum current output (voltage, phases, frequency, and current) If separate from the general equipment;
— overall dimensions of equipment if separate from the general equipment;
— equipment mass, in kilograms, if separate from the general equipment,
8.3 Technical requirements
The equipment shall be capable of demagnetizing to a specified level (typically 0,4 kA/m to 1.0 kA/m) unless otherwise agreed.
9 Measurements
9.1 General
In connection with this part of Iso 9934, measurements are required for the following:
— determination of the equipment characteristics;
— checking inspection parameters.
For all current and magnetic field measurements, only instruments that respond directly to the waveform shall be used. Instruments that calculate peak or RMS values based on calculation derived from other values shall not be used. Where True RMS meters are used to measure RMS values the specified crest factor of the instrument shall be greater than the crest factor of the waveform being measured and generally not less than 5.
9.2 Current measurement
Pure AC sinusoidal waveforms can be accurately measured using clamp meters or other conventional instruments. Measurements of phase controlled currents can be more complex and it shall be verified that the instrument used has the correct response before use on these waveforms. Measurement systems using shunts with suitable voltage measurement instruments shall be regarded as current meters and conform with the requirements for such instruments.