Questions about magnetic particle testing?
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1. Regarding the process procedure in 4.3.1, does it refer to the general procedure developed by the testing unit, or the process procedure specific to a particular project? 2. Does clause 4.3.2 refer to contrast enhancers for non-conductive surfaces, meaning that the contrast enhancer itself is a non-conductive surface, or does it mean that a contrast enhancer is applied to a non-conductive surface? What is the significance of this, and what is the difference from conductive surfaces? 3. Why are standard test pieces not suitable for the remanent magnetism method? 4. Is the use of a standard test block in the method for magnetizing the central conductor meant to represent the specification for magnetizing the central conductor, or can either an annular test block or a standard test piece be used? 5. Why can’t the magnetization criteria for the remanent magnetism method be verified using standard test pieces? What method is used for verification without standard test pieces? 6. When the L/D ratio of the coil method is less than 2, why is it necessary to use an extension block? Is there experimental evidence or a theoretical basis for this? 7. Why can’t the dry method be used in remanent magnetism testing? 8. Why is the brushing method not suitable for magnetic suspensions? 9. The cross yoke specifies that the gap between the pole and the end face must not exceed 0.5 mm; why is no such specification given for a single yoke?
1. Refers to general procedures. 2. Apply a contrast enhancer to the non-conductive surface. Function: Enhances the magnetization effect. 3. Standard test pieces are mainly used to determine sensitivity; the magnetization strength obtained using the residual magnetism method decreases over time, failing to reflect the true sensitivity.
1. Refers to the general procedures of the testing unit. 2. The standard original text refers to non-magnetism; however, using the contact method, it can also be understood as non-conductivity. It refers to the contrast enhancer forming a non-magnetic surface. 3. This question can be understood as per Floor 3. 4. The original poster is correct. 5. The residual magnetism method can be used to measure the residual magnetism on the surface of a workpiece with a magnetometer. 6. This is an axiom of magnetic particle inspection theory, and there is no need for any justification. 7. The dry method can be used for the remanent magnetism method; you can refer to ASME. But it’s just a special regulation in the country. 8. The brushing method can result in brush marks and potential shedding of fibers, causing false readings. 9. In practical use, the pole spacing and the gap between the poles and the workpiece in a single-yoke design are not constant; if these values are set too strictly, the device will not be able to function, and such settings are then useless.