BS ISO 24497-1 pdf download

BS ISO 24497-1 pdf download Non-destructive testing — Metal magnetic memory — Part 1 : Vocabulary
1 Scope
This part of ISO 24497 specifies terms and definitions for procedures in the sphere of non-destructive testing by the method of metal magnetic memory. The terms specified in this part of ISO 24497 are mandatory for application in all types of documentation and literature in the sphere of non-destructive testing, using the method of metal magnetic memory included in the scope of standardization works and/or using the results of these works.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 metal magnetic memory MMM after-effect which occurs as residual magnetization in components and welded joints formed in the course of their fabrication and cooled down to ambient temperatures under interaction with weak magnetic fields or due to irreversible change of the local magnetization state of components in zones of stress concentration and damage under working NOTE Weak magnetic fields are the geomagnetic field of the planet Earth and other external fields in Rayleigh area.
2.2 self-magnetic-leakage field of the components SMLF magnetic-leakage field occurring on the component’s surface in the zones of stable slip bands of dislocations under operational or residual stresses or in the zones of strong heterogeneity in the microstructure of the material NOTE SMLF characterizes MMM.
2.3 method of metal magnetic memory MMM method non-destructive testing method based on the analysis of SMLF distribution on components’ surfaces for determination of stress concentration zones, imperfections, and heterogeneity in the microstructure of the material and in welded joints
2.4 magneto-dislocation hysteresis hysteresis curve due to the pinning of magnetic domain walls (Bloch walls) at dislocation clusters in weak magnetic fields
2.5 critical size of the local zones of instability of the shell (l cr ) of a component minimal distance between the two nearest stable dislocation slip bands in material layers occurring at the moment of loss of shell stability of the component under the influence of loads NOTE This critical size is characterized by the distance between the two nearest SMLF extreme values normalized on the value of the shell dimension. 2.6 SMLF intensity characteristic value of the magnetic-leakage field intensity measured on the component surface by the method of metal magnetic memory
2.7 SMLF gradient ratio between the difference of the magnetic-leakage field intensity, measured at two adjacent scanning points and the distance between them
2.8 magnetic index (m) of the deformation capability of the material ratio between the maximum value of the SMLF gradient and the average value
2.9 limiting value (m lim ) of the magnetic index of the material deformation capability limiting value for the ratio between the maximum value of the SMLF gradient, corresponding to the metal tensile strength, and the average value of the SMLF gradient, corresponding to the material yield strength 2.10 SMLF measurement channel SMLF intensity measured with a single flux-gate sensor
2.11 base distance between two SMLF measurement channels l b distance between the two SMLF measurement channels installed at the scanning instrument during the sensor adjustment
2.12 SMLF diagram magnetic image of the graph reflecting the SMLF gradient along the scanning path
2.13 discreteness unit of the SMLF intensity recording distance between two adjacent scanning points of the magnetic-leakage field intensity measurements
2.14 calibration of the equipment used to measure the metal magnetic memory adjustment of the sensors for the measurement of the magnetic-leakage field by using a reference coil and of the position-sensing device by using a length-measurement reference standard 2.15 setting of equipment operational mode by the MMM method equipment adjustment according to the instrument main menu and described in the manual