Research Projects

Objective: Development of Giant Magneto-impedance based array sensor for detecting ferromagnetic phase generated in non-magnetic austenitic steel due to carburization in petrochemical reactor components which will comprise of the following: Equipped with various configurations of probes either sensor array or probe with raster scan facility in order to cover larger area of the sample under test. Detection of carburization in austenitic stainless steels. Comparison of the array sensor probe with the single sensor element as regards sensitivity and area coverage. To be used as exclusive research tools for post inspection analysis and long term improvement Development of arrayed GMI sensing device with capability of remote sensing through wireless / internet of things (IOT) so that monitoring group can have real time data during the site inspection carried out by the operator. To develop and incorporate a customized software for smart monitoring & control of the sensing device. Recall of the measured data from files history and comparison with the real time data.

Summary: Petrochemical reactor unit components are made of austenitic stainless steel have high amount of chromium (16 to 20 %) and nickel (8 to 10 %). These steel components are primarily paramagnetic in nature. During naphtha cracking in these reactors, carburization leads to the formation of chromium carbides in the austenitic stainless steel as chromium has more affinity to form carbides than nickel and iron which are present in the material. Due to the formation of these carbides, small chromium depleted areas are formed near to carbide sites and these areas will have high relative concentration of iron and nickel. Such change in composition will transform from paramagnetic component to ferromagnetic one. CSIR-NML has already developed a giant magneto-impedance sensor (MagSys-2) for Indian Oil corporation ltd for detection of carburization in Johnson screens of petrochemical reactor units. The sensor element used in MagSys-2 is about 120 microns thick, leading to lesser area coverage for detection of carburization. The existing system has a direct read out sensor output. The proposed project is targeted to the development of an advanced giant magneto-impedance based sensor wherein the focus will be to incorporate array of sensors for enhancing the area coverage. This development work would include modification in operating parameters like driving current, frequency, configuration of the sensor elements for array design and remote data capture.