Disbonding phenomenon takes place in hydroprocessing vessels of petroleum refineries under high pressure-high temperature gaseous hydrogen service.
These reactors are manufactured by weld overlay of stainless steel alloy onto a steel substrate.
The delamination of the stainless surface layer is generated in particular shutdown conditions. This phenomenon is known as Disbonding.
ITMA Materials Technology has an equipment for performing the Disbonding test, which simulates service conditions in refineries, with the following characteristics:
- Testing up to 500ºC of temperature and 200bar hydrogen pressure.
- Total automation of pressure and temperature cycles.
- Cooling rate up to 750ºC/h.
For evaluating the percentage of disbonded area, an ultrasonic device with automated C-Scan mode is used.
A special device consisting of a bucket and two encoders (x, y) has been developed in order to provide, with two focussed immersion transducers, the highest precision of the percentage of such disbonded area.
Several furnaces are available to carry out stress relieve and special post-weld heat treatments.
Testing are always carried out according to ASTM G 146.
ITMA Materials Technology provides a Disbonding test service within a technological offer covering the following fields:
- R&D&I Projects. As an example, they can be focussed on:
- Studying microstructural transformations.
- Influence of cooling rate.
- Study of welding parameters.
- Post weld thermal treatments.
- Influence of wall and weld overlay thickness.
- Influence of the base material.
- Influence of the cladding.
- Temperature-Pressure behaviour.
- Technical Advisory
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