Fluorescent dot peen marking for insuring oil steel pipes traceability

“VKO “Simvol” designs and produces marking equipment, reading equipment and traceability software. Fluorescent dot-peen marking (FDMP) is an improved version of dot peen marking (DPM) technology. In FDPM technology information dots are filled with special material – fluorescent composition. Various fluorescent compositions provide high stability of marking in different aggressive media, such as moisture, salt and acid solutions, oils, lubricants or high temperatures. 2D barcode Data Matrix makes the marking machine readable, even if some of the dots are damaged.


Introduction
Oil steel pipes (further -pipes) pass many operations and technological processes during their lifetimetransportation, storage, working in the aggressive media, repair, and disposal. An objective of identification and administrating each pipe's "individual story" during all stages of its life cycle is quite relevant for oil industry.
Manufacturer marking for oil and gas pipes contains product description and all the information for pipes identification. This marking serves to the pipe manufacturer's purposes only, while oil and gas companies needs stay unsatisfied in case of the information loss.
Identification (individual pipe recognition) requires availability of sustainable identification signs during any operations with the pipe. Marking is the most common way of identification. Machine-readable marking (further marking), which helps to trace the entire product's life cycle, is used in modern automated systems.
Pipe traceability provision has a number of features related to the marking's sustainability to various types of mechanic, climate and chemical or media impacts during manufacture, transportation, storage, operation and repair. Therefore there is need for modern methods of marking that are resistant to aggressive environment [1]. Since exposure in oil and gas environment (high pressure, high temperature, CO 2 and H 2 S content) during the operation of pipe or tube causes destruction of equipment [2 -4].
The aim of this study to ability to survive fluorescent dot peen marking (FDPM) the severe tests, modelling the conditions of oil and gas industry.

FDPM reading
Fluorescence of the information dots in FDPM provides better contrast than usual DPM marking. When reading FDPM, the machine records only the fluorescence of the dots, information elements ( Fig. 1). The surface of a marked product and its optical properties have minimal influence on FDPM reading, and. This allows to reduce the influence of marked surface brightness, its curvilinear profile, the color of the coatings, rust, roughness during reading FDPM. In case of damage, FDPM can be recovered.
The high contrast and stability allow to read FDPM after transporting, mounting and operating oil pipes. The photo on Fig. 4 shows fluorescence of FDPM dots on the pipe after high temperature and shot-blasting treatment, the marking remains readable. The developer patented a number of processes, devices and compositions used in his hardware and technology complex, which provides for the application of FDPM, their reading and use for building an automated system of product identification and traceability. Patent list is given in the Literature section [5 -13].
The effect of marking on the mechanical and corrosion properties of pipe and tube material has been studied by several researchers [14]. The requirements for resistance to aggressive media must be applied for FDPM.
It was performed a set of FDPM stability tests on pipe samples. The samples were tested in environments, modelling climate conditions and oil pipe operating media. Tests with 11 different fluorescence compositions were performed, this allowed to find the most persistent compositions.
Test results of the best FDPM fluorescent compositions for pipes are shown in Table 1.  Table 1. Reading FDPM with several fluorescent compositions after aggressive environments tests. "+" -readable, "-"unreadable, the "*" sign means corrosion products removal.

Conclusion
The results show the FDPM ability to survive the severe tests, modelling the conditions of oil pipe lifetime.
Although most of the compositions tested did not show acceptable stability, some of them showed good reading results and should be developed further. According to the results of the laboratory experiments, FDPM based on composition «K» and luminophore «J» was recommended to test on pump-compressor pipes and oil and gas pipes in pilot industrial operation.