The development of methods and means of diagnosing local hydrogen damage of structural ferromagnetic elements

The Chart of application of the method magneto-elastic acoustic emission (MAE) for the diagnosis of local hydrogen damage of structural ferromagnetic elements.

1 – is the primary acoustic emission (AE) transducer of MAE (PAE)
2 – is the attachable electromagnet, which generates an alternating magnetic field of intensity H
The frequency of magnetic field is given by the generator 3, and its value by the amplifier 4
The pulses of MAE with amplitudes A are amplified by the pre-amplifier 5 and recorded by the recording device 6, zones I, II, III are the local damage places in ferromagnetic material.

Applications

Technology is developed for non-destructive evaluation and monitoring the existence of places of local damage in ferromagnetic material caused by hydrogen and for diagnosing its conditions by the parameters of MAE signals.

Short Description

Modern methods of non-destructive testing, including ultrasonic and X-ray flaw detection are laborious and non-technological especially for operating equipment. Prospective is the method of AE. However, its application requires an additional mechanical stress applied to the tested object. Taking into account that the level of stress can be significantly higher than the allowable for the structural element, practical use of AE diagnostics is limited, particularly for structural elements that operate in hydrogen contained environments. To improve the efficiency of local diagnostics of structural elements or products it is proposed in the project to initiate MAE signals by external magnetic field, which will initiate an abrupt motion of magnetic domain walls (Barkhausen effect).

Expected properties

New methods and means of nondestructive AE monitoring and diagnostics of ferromagnetic products and structural elements of long-term usage, particularly to identify local places of hydrogen bulk damage without any mechanical action on them will be developed. Will also be designed and manufactured Electronic measuring equipment to record MAE signals, excited by an external magnetic field in different ferromagnetic materials with different degrees of hydrogen concentration are other factors of their degradation will be also developed and produced.

Advantages

MAE method is highly sensitive to the presence of dissolved hydrogen of small concentration in ferromagnetic material, it is easy to use including field conditions, for working equipment. It does not require complex preparation for installing AE transducers .

Competitors

Vallen Systems (Germany),
Physical Acoustic Corporation (PAC) (USA).

Status of the development

The dependences between the parameters of the dynamic displacement fields in the domain structure during Barkhausen jumps in locally damaged by hydrogen ferromagnetic structural materials and an external alternating magnetic field parameters are established. Methodological grounds are developed, samples are manufactured and experimental study of the effect of hydrogen and other factors of degradation of ferromagnetic materials on the generating of MAE signals is investigated.

Intellectual Property

Patent of Ukraine No 88249, G01N29/14; G01N17/00. Method of assessment of degree of hydrogenation of ferromagnetic alloys / Skalskyi V.R, Nazarchuk Z.T., Clym. B.P., Pochapskyy E.P., Mykhalchuk V.B. - Publ. 25.09.2009, Bull. No 18.

Contact Information

Executive: Karpenko Physico-Mechanical Institute of NAS of Ukraine

Project №24 " The development of methods and means of diagnosing local hydrogen damage of structural ferromagnetic elements "

Contact person:

O. Serhiyenko

Е-mail: serhiol@ipm.lviv.ua

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