Marek Szkodo

Cavitation Erosion Behavior of 18/8 Stainless Steel after Its Laser Alloying of Manganese

The laser surface alloying of 18/8 stainless steel with Mn, was carried out by 6 kW cw CO2 laser. The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, energy dispersive X-ray spectroscopy and Xray diffractometry, respectively. Cavitation behavior of produced layers was investigated in a rotating disc facility. Cavitation properties of laser-processed steel were calculated in the initial stage of erosion, on the surface of about 4 mm2, on which cavitation intensity was constant. As a property characterizing the cavitation erosion resistance of materials was proposed for the depth of strain hardening. It was found that presence of manganese in the amount of 7.31% causes the highest increase hardness after alloying and the lowest depth of strain hardening due to cavitation loading.

Clay Minerals – Mineralogy and Phenomenon of Clay Swelling in Oil & Gas Industry

Abstract Among the minerals found in the earths crust, clay minerals are of the widest interest. Due to the specific properties such as plasticity, absorbing and catalytic properties clay minerals are used in many industries (oil & gas, chemistry, pharmacy, refractory technology, ceramics etc.). In drilling, a phenomenon of swelling clays is frequently observed. It has an important impact on the cementing quality. During the last few decades clays have been the subject of research on a scale unprecedented in the history of mineralogy. This paper presents review literature on mineralogy of clay minerals and phenomenon of swelling in oil and gas industry. Unique ion exchange properties and clay swelling mechanisms are also considered.

The Characteristic of Surface Layers on Austenitic Stainless Steel after Glow-Discharge Nitriding Process

This paper presents investigation of surface layers. The diffusion layers were produced by using different parameters of reactive atmosphere (N2:H2). The research of the surface layers was performed using scanning electron microscope (SEM). The results of energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) analysis are presented. Research reveals the influence of chemical constitution of reactive atmosphere on the change of properties of nitrided layers.

Cavitation erosion of P110 steel in different drilling muds

Abstract The P110 steel specimens were subjected to ultrasonic cavitation erosion in different compositions of drilling muds and surfactant additive. The test procedure was based on ASTM-G-32 standard recommendations. API 5CT-P110 steel is used for pipes in oil and gas industry. The harsh environment and high velocity of flows poses corrosive and erosive threat on materials used there. The composition of drilling fluid influences its rheological properties and thus intensity of cavitation erosion. The erosion curves based on weight loss were measured.

Assessment of FSW Welds Made of Aluminum Alloy AW7075-T651

This paper summarizes the results of experimental studies in which the aluminum alloy AW7075-T651 was friction stir welded (FSW) using various combinations of process parameters (rotational - R and travel speed - T). Mechanical properties of the test welds were assessed by using static tensile test and Vickers hardness measurement. The temperature of the welded plates was monitored during welding by means of thermocouples placed on both sides of the joint line, 15 mm from the weld axis as well as by using thermo camera. The microstructure, chemical composition and phase identification of the welding joints were examined using optical and scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry (XRD). Investigations revealed that the temperatures at the weld center can reach values close to 550 °C and raised with R/T ratio increasing. It was found that tensile strength of welded joints is not correlated with R/T ratio and averages about 60% to 80% of tensile strength of a base material AW7075-T651. XRD analysis demonstrated that there is also deformation texture in the nugget (WN) and the thermo-mechanical affected zone (TMAZ) with strong dependence on process parameters.

A universal NDT method for examination of low energy impact damage in CFRP with the use of TLC film

Abstract The article presents an attempt to use a sheet of laminated thermochromic liquid crystal film (TLC film) for non-destructive testing of the impact damage (energy values: 1J, 2J, 3J and 4J) in carbon fibre-reinforced polymer (CFRP). This is a new, alternative NDT approach based on the thermo-optical effect. The main advantages of this method are a) the low cost of TLC film, b) the low cost of recording devices due to the usage of conventional digital recording equipment and c) the low requirements for tests. The TLC film method was compared with two other conventional NDT methods: computer radiography (CR) and active thermography (thermographic camera). The scatter of results regarding the average crack length (TLC film and active thermography) was ±5% in relation to the CR method. The damage area (impact energy 2J to 4J) showed a similar shape (TLC film vs active thermography) and the scatter of results for the TLC film was ±2% in relation to the active thermography method. Only the CR detected the damage caused by 1J impact energy. The comparative studies have proven that the described method (TLC film) is a full-fledged and accurate tool for NDT method for the diagnosis of impact damage in CFRP.

The Processing Procedure for the Interpretation of Microseismic Signal Acquired from a Surface Array During Hydraulic Fracturing in Pomerania Region in Poland

Abstract Hydraulic fracturing is a procedure of injecting high pressure fluid into the wellbore in order to break shell rock and facilitate gas flow. It is a very costly procedure and, if not conducted properly, it may lead to environmental pollution. To avoid costs associated with pumping fluid outside the perspective (gas rich) zone and improve one’s knowledge about the reservoir rock, microseismic monitoring can be applied. The method involves recording seismic waves, which are induced by fractured rock, by an array of sensors distributed in a wellbore nearby or on the surface. Combining geological and geophysical knowledge of region with signal processing computer techniques, one can locate induced fractures allowing for real-time process monitoring and rock properties evaluation. In Poland perspective shell formation is located very deep, i.e. about 4km from the surface. Additionally overlaying rock formations strongly attenuate and disperse seismic waves. Therefore, signal recorded by a surface array of sensors is very weak. Signal from a seismic event can be orders of magnitude lower than noise. To recover signal connected with fractured rock one needs to use numerical methods utilizing coherence of signals. An example of such a computer procedure is presented in this paper.

Cavitation erosion degradation of Belzona® coatings

Abstract In hydrocarbon and maritime industry there is a constant need of materials and coatings withstanding severe conditions. One of adverse phenomena present there is cavitation erosion. The paper presents evaluation of cavitation resistance of three different steel coatings. Belzona 2141 (ACR-Fluid Elastormer), 1321 (Ceramic S-Steal) and 5831 (ST-Barrier) were deployed on P110 steel and subjected to ultrasound cavitation in distilled water and drilling mud environment. According to mass loss measurements Belzona 2141 shows superior performance comparing to two other coatings and bare p110 steel surface. This is due to its high elasticity comparing to steel.

Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance

Abstract The paper presents properties of surface layers. Surface layers were obtained by using low temperature glow–discharge nitriding process and laser remelting carried out on austenitic stainless steel type X10CrNi18-8. Investigations were done by using an Ultra Nanoindentation Tester (UNHT) in the Warsaw Institute of Fundamental Technological Research. The influence of the above mentioned treatments on obtained surface layers is shown. The values of the Vickers hardness (HV), the irreversible indentation work (Wir), the reversible work (We) and the maximum depth (hmax) during indentation were determined using the method proposed by Oliver and Pharr [1]. On the basis of mechanical properties, the elasticity (Ie) and ductility (Iir) indexes were calculated. Moreover, microstructure cross-section of the austenitic stainless steel after nitriding process and laser remelting was observed using a scanning electron microscope. Cavitation test was performed at a vibratory rig with stationary specimen. On the basis of erosion curves the cavitation resistance was evaluated.

Influence of Spatial Structures of 316L Stainless Steel on its Cavitation Erosion Resistance

Cavitation erosion performance of modified macroscopic internal structure 316L stainless steel was investigated. The samples processed by means of SLM method were subjected to cavitation erosion test. The scanning electron microscope Philips 30/ESEM was used to examine morphology of eroded surface.