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GB/T 34370 consists of the following six parts under the general title Nondestructive Testing of Amusement Equipments:
——Part 1: General Requirement;
——Part 2: Visual Examination;
——Part 3: Magnetic Particle Testing;
——Part 4: Penetrant Testing;
——Part 5: Ultrasonic Testing;
——Part 6: Radiographic Testing.
This is part 3 of GB/T 34370.
This part is developed according to the rules given in GB/T 1.1-2009.
This part was proposed by and is under the jurisdiction of SAC/TC 250 National Technical Committee on Ropeway and Entertainment Facilities of Standardization Administration of China.
Nondestructive Testing of Amusement Equipments -
Part 3: Magnetic Particle Testing
1 Scope
This part of GB/T 34370 specifies magnetic particle testing methods for amusement equipments such as the yoke method, coil method and galvanization method as well as the requirements for quality grading.
This part is applicable to the testing of surface and near surface flaws of ferromagnetic raw materials, parts and components and welded joints of the amusement equipments.
This part is not applicable to the testing of austenitic stainless steel and other non-ferromagnetic materials.
2 Normative References
The following documents are indispensable for the application of this standard. For dated reference, only the dated editions are applicable to this document. For undated reference, the latest edition (including any amendments) applies.
GB/T 5097 Non-destructive Testing - Penetrant Testing and Magnetic Particle Testing - Viewing Conditions
GB/T 11533 Standard for Logarithmic Visual Acuity Charts
GB/T 12604.5 Non-destructive Testing - Terminology - Terms Used in Magnetic Particle Testing
GB/T 20306 Amusement Devices Terminology
GB/T 20737 Non-destructive Testing - General Terms and Definitions
GB/T 23907 Non-destructive Testing - Shims for Magnetic Particle Testing
GB/T 34370.1 Nondestructive Testing of Amusement Equipments - Part 1: General Requirement
JB/T 6063 Non-destructive Testing - Materials for Magnetic Particle Testing
JB/T 8290 Non-destructive Testing Instruments - Magnetic Particle Flaw Detectors
3 Terms and Definitions
For the purpose of this standard, the following terms and definitions given in GB/T 12604.5, GB/T 20306 and GB/T 20737 as well as the following ones apply.
3.1
excessive background
magnetic particle indication background that hinders the analysis and evaluation of magnetic particle indication due to excessive magnetic field strength and concentration of the magnetic ink which result in the roughness or contamination of the workpiece surface
3.2
relevant indication
relevant indication, also know as flaw indication, refers to magnetic particle indication formed during magnetic particle testing due to adsorption of magnetic particles by magnetic leakage field generated by such flaws as crack, incomplete fusion, pore and slag
3.3
non-relevant indication
magnetic particle indication formed due to adsorption of magnetic particles by magnetic leakage field as a result of abrupt change in section and difference in permeability of materials
3.4
false indication
fade indication
magnetic particle indication that is not formed due to adsorption of magnetic particles by magnetic leakage field
3.5
tangent magnetic field strength
component of the magnetic field strength parallel to the surface of the workpiece to be tested
3.6
ambient visible light
visible light measured from the surface of the workpiece under black light in dark area
4 Method Summary
After the ferromagnetic material workpiece is magnetized, due to the discontinuity, the magnetic field lines on the surface of the workpiece and the near surface are locally distorted to generate a leakage magnetic field, and the magnetic particle applied on the surface of the workpiece is adsorbed to form a visually visible magnetic particle indication under appropriate illumination, thus showing discontinuous position, size and shape. Figures 1 to 3 are schematic diagrams of the yoke method, the coil method, and the axial galvanization method respectively.
Keys:
1——current;
2——iron core;
3——flaw.
Figure 1 Yoke Method (Magnetic Particle Indication)
Keys:
1——current;
2——workpiece;
3——flaw;
4——coil. Keys:
1——current;
2——flaw;
3——workpiece;
4——electrode.
Figure 2 Coil Method
Figure 3 Axial Galvanization Method
5 Safety Requirements
The safety requirements during testing shall include at least:
a) The testing personnel shall observe the safety requirements of the site for the tested workpiece, wear protective clothing and relevant protective equipments as required on the testing site;
b) Care shall be taken to avoid various safety hazards such as bumps, electric shock, falling crush, cutting, tangling, slippery, drowning, and burns, etc.
c) If using hydromagnetic ink to detect amusement equipment, prevent insulation failure or electrical short circuit;
d) If using fluorescent magnetic particle for testing, the filter of the black light lamp shall be free from cracks, and the black light shall be prevented from direct illuminating the human eye;
e) The axial galvanization method shall not be used in occasions liable to flammables or explosives, and it shall be prevented from burning in other places.
This chapter does not list all the safety requirements for testing. Users adopting this part shall establish safety guidelines prior to testing.
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Method Summary
5 Safety Requirements
6 Requirements on Personnel
7 Testing Apparatus and Instruments
8 Testing Technological Procedure
9 Testing
10 Retesting
11 Demagetization
12 Quality Grading of Magnetic Particle Testing
13 Magnetic Particle Testing Report
Annex A (Informative) Various Waveforms of Magnetizing Current, Ammeter Indication and Conversion Relation
Annex B (Informative) Typical Magnetization Methods for Weld
