High-Sensitivity, Portable Online Measurement of Defects and Anomalies in Coiled Tubing Strings

A high-sensitivity, low-power and portable coiled-tubing (CT) inspection tool is developed based on magnetic flux leakage (MFL) technology. The tool provides enhanced real-time integrity monitoring of CT operations to minimize the risks of unexpected failures and enable efficient management of CT operations. This paper discusses practical design and engineering considerations to enhance the sensitivity of the magnetic inspection head, including magnetic characterization of the CT material, pole-piece separation, parametric calculations of the gap field, eddy currents, and MFL signal bandwidth. Experimental measurements illustrate the capability of detecting defects down to 1 mm in diameter and depth in a 1.5" CT pipe.

Reasons for the formation of crack-like defects in 09Г2С heavy plate steel for tank steel structures

Determination of causes of crack-like defects in the heavy plate steel 09Г2С is a crucial task, the solution of which is aimed at improving the mechanical safety of oil storage steel vertical tanks. In order to determine the causes for the formation of a group of crack-like defects oriented towards rolling, revealed during grinding and magnetic inspection of the tank wall surface near the vertical weld, the analysis of the chemical composition and testing of the mechanical properties of heavy plate steel were carried out, including the determination of the anisotropy of impact toughness in the temperature range from +20 to –75 °С, analysis of metal microstructure in the area of defect formation on transversal sections and rolled surface. Impact bending tests of 09Г2С heavy plate steel after controlled rolling in longitudinal and transverse directions showed no anisotropy of impact toughness, as well as high purity of steel as for sulfur and titanium, which at higher content causes impact toughness anisotropy. The revealed features of metal microstructure near the defects made it possible to conclude that the crack-like defects were formed during the rolling of gas bubbles at the stage of preparing semi-finished rolled products for finishing rolling. One of the possible methods to prevent such defects from getting into finished rolled products is the use of automated systems of visual inspection of rolled products in the manufacturing process.

Choosing and Explaining Methods of Non-Destructive Control of Gear Mechanisms in Imported Excavators

Kuzbass opencast coal mines use foreign produced excavators as basic equipment. Capital repair of these excavators involves complete replacement of all tooth wheel gearing in reduction gear boxes after 2~3 years of work (depending on operating time). The cost of this replacement is practically equal to the cost of new gear boxes. To minimize repair costs and extend service life of gear-tooth systems in gear boxes a methodology for monitoring technical state of gear boxes in imported mining equipment was developed. It allows to obtain reliable information about the level and significance of in-service defects in their elements. The research showed that the most reliable methods of control are visual and dimensional test (67%) and fluorescent-magnetic inspection (32%), and used together these two methods allow to detect up to 100% of significant defects. The most significant among service defects in typical elements of gearing systems are single and multiple cracks.

A Feasibility Study of the Drive-By Method for Damage Detection in Railway Bridges

Damage identification and localization in railway bridges is a widely studied topic. Strain, displacement, or acceleration sensors installed on the bridge structure are normally used to detect changes in the global behavior of the structure, whereas approaches like ultra-sonic testing, acoustic emission, and magnetic inspection are used to check a small portion of structure near localized damage. The aim of this paper is to explore another perspective for monitoring the structural status of railway bridges, i.e., to detect structural damage from the dynamic response of the train transiting the bridge. This approach can successfully be implemented in the case of resonant bridges, thanks to the high level of acceleration generated, but its application becomes more challenging when the excitation frequencies due to train passage do not excite the first mode of vibration of the bridge. The paper investigates the feasibility of the method in the latter case, through numerical simulations of the complete train-track-bridge system. Accelerations on axleboxes and bogies are processed through suitable algorithms to detect differences arising when the train crosses a defective bridge or a healthy one. The results outline the main operational parameters affecting the method, the best placement for sensors, and the best frequency range to be considered in the signal processing, also addressing the issues that are related to track irregularity. Good performance can be achieved in the case of short bridges, but a few practical issues must be tackled before the method could be tested in practice.