NDT Magnetic Particle Products 300mm Magnetic Coil Flaw Detector

NDT Magnetic Particle Products 300mm Magnetic Coil Flaw Detector

I. main parameter

II. Function introduction

1, Magnetization - start the electromagnetic field to magnetize the workpiece;

2, Demagnetization - demagnetization field starts to demagnetize the workpiece;

3, Over temperature alarm - the coil has a built-in 75 ℃ temperature sensor. When the set temperature is exceeded, it enters the protection state;

Installation:

1. The equipment shall be installed in a dry environment without metal dust, corrosive gas and inflammable and explosive articles;

2. The temperature of surrounding medium shall not be lower than - 10 ℃ and not higher than + 40 ℃;

3. The relative humidity of the air shall not be greater than 85%;

4. The pipe and wire connection between the installation equipment and each auxiliary facility shall be connected according to the indication sign and plug base;

5. Power supply (power supply, air source, etc., according to equipment installation environment and operation conditions), and the equipment shell is reliably grounded;

Commissioning:

1. After the equipment is installed in place, first check whether all connecting wires and fastening screws are loose and fall off;

2. Use instruments to measure whether the voltage at the upper end of the main switch of the machine meets the requirements of equipment installation environment and operation conditions;

3. Check each function action, manually press or toggle each function switch, and each function action of the equipment shall be executed accordingly;

4. Demagnetization effect inspection: check whether the residual magnetism after demagnetization meets the requirements;

5. After passing the commissioning and inspection, the equipment can be put into production.

IV. Routine maintenance

After the equipment is used, the following operations must be carried out:

1. Turn off the power switch and cut off the power supply of the equipment;

2. Cut off the main switch of external power supply;

3. Clean up the oil stain on the coil surface and keep the whole equipment clean;

4. Check the circuit connecting line, cable and fastener for looseness and aging within one month;

5. Check whether the concentration of magnetic suspension meets the standard every day;

6. Neutral washing must be used to clean the oil stain on the surface of the equipment;

7. If the shell is damaged, it is forbidden to continue to use;

V. Flaw detection principle

Principles of electromagnetism

The magnetizing current forms an electromagnetic field through the surface of ferromagnetic workpiece (AC and half wave DC have skin effect). The existence of defects will cut off the magnetic line of force, form a leakage magnetic field and adsorb magnetic particles. Magnetic particles accumulate to form magnetic marks. The existence of defects can be judged by observing magnetic marks (magnetic marks are actually enlarged defects).

Sensitivity

Sensitivity refers to the precision of magnetic particle flaw detection, usually through the NATIONAL standard TYPE A test to detect. Type A standard test is usually referred to as sensitivity test. Type A standard test sheet has three kinds of sensitivity: high, medium and low. The smaller the fraction value in type A, the higher the effective magnetic induction intensity that can display magnetic mark is required. (A-15/100, A-30/100, A-60/100, A-7/50, A-15/50, A-30/50, six scores, the highest sensitivity of 1# test film includes A-15/100, A-7/50. 2# Test tablets have moderate sensitivity, suitable for most industries, including A-30/100, A-15/50. 3# test tablets have the lowest sensitivity, including A-60/100 and A-30/50.)

Method of use of standard sensitivity test piece (suitable for continuous method), usually using type A standard test piece 2#(30/100 or 15/50) for the selection of magnetization current for flaw detection.

The artificial defects can be clearly displayed on the smooth surface of the test piece by tightly fitting the surface of the test piece with artificial defects with the workpiece under test, slowly flowing magnetic suspension through the workpiece and applying appropriate magnetization current (adjusting circumferential direction and longitudinal direction respectively). The value of magnetization current is the appropriate magnetization specification.