05:05 Jun-11-2003 Nigel Armstrong Engineering, - Specialist services United Kingdom, Joined Oct 2000 1094
Re: magnetic testing HWDC is an MPI bench unit machine setting giving a rectified AC output. This gives a compromise inspection solution between AC which due to the skin effect is very effective at surface flaw detection but with very little sub-surface flaw detection capability and DC where relatively deep-lying defects may be detected though with a concomitant sensitivity loss for surface flaws.
You'll need a pretty hefty 4 turn coil and high output bench unit for an A319/A320 main landing gear axle. Plus I should imagine there will be a requirement for inspection shot for longitudinally oriented flaws as the coil shot will only find circumferential oriented flaws (more specifically flaws oriented parallel to the coil turn direction). If you are not familiar with all of this then may I suggest you sub-contract it to someone who has the right equipment, knowledge, qualifications and experience.
Re: magnetic testing : I found in A319/A320 maintenance manual (aircraft) something about MT on a MLG axle and it says HWDC 4 turn coil .Iwould like to know what is that HW ,DC is probably direct current? HWDC has the penetrating power of single phase full wave DC and the skin effect of AC. The pulse of the rectified wave produces maximum particle mobility with dry particles. The down side is demagnetizing can be difficult.