74 research outputs found
Statistical analysis of different mathematical models for stress-strain curves of AISI 321 stainless steel
This paper presents statistical analysis of data obtained by uniaxial tensile testing of AISI 321 stainless steel. This data is required as material input in numerical software, such as Abaqus, Ansys, MSC Marc, Nastran, etc. This data can be provided in the software as a set of points (piecewise linear model) that is cumbersome to enter, or it can be provided as a mathematical model, in the case of which the Finite Element Method (FEM) software calculates desired points directly from the mathematical model. Various mathematical models can be used to approximate tensile test data depending on the material loading state (linear, elasto-plastic, plastic). In this paper, the same uniaxial test data is analyzed, and curve fitting parameters are shown for each mathematical model
Analysis of interconnection between physical and protective properties of two-component epoxy primer
This paper presents the research into protective properties of two-component epoxy primer obtained by measurements of the notch corrosion and by testing of the gloss as a physical property. In order to obtain different values of measured response, the first experiment was done by applying the primer in various amounts of the dry film thickness, while the second experiment was based on combining various contents of anti-corrosion pigment. Analysis of the obtained research results proved the interconnection between the two observed properties. It was confirmed that the obtained results were inversely proportional for both experiments. Protective properties of coating could be assessed by measuring the gloss value, which is simpler and faster than measuring the notch corrosion
Quality monitoring at fusion welding of polyethylene high-density pipes
The paper presents the main parameters of fusion welding and their Off - line analysis of Polyethylene high-density (PE-HD) pipes. By direct measurements of voltage and current at the coupler, inductive and the resistant character changes in amplitude modulation waveforms of the measured signal are observed. In early measuring device analyzes the scanned parameters with certain types of fittings and compares them with the tested and measured parameters is done by welding machines. There can be seen the time delay or “dead time” when the system analyzes the parameters and dimensioned regulatory function of the system
Corrosion resistance of the X6CrNiTi18-10 material exposed to a salt spray test
The research was focused on testing the corrosion resistance of the X6CrNiTi18-10 material. This material exhibits good corrosion resistance in the humid atmosphere, but with the occurrence of chloride inclusion in the same atmosphere, its corrosion resistance is drastically reduced. The X6CrNiTi18-10 material is austenitic stainless steel susceptible to pitting corrosion and this can cause problems during exploitation of the construction made of this material. In order to determine the likelihood of pitting corrosion occurrence, a light microscopy was performed on test samples that were exposed to the salt spray test chamber atmosphere, i.e. sprayed with a 5% sodium chloride solution (NaCl) at different time intervals
Analysis of the vehicle exhaust system corrosion and its effect on the ECO-test result
This paper deals with analysis of the vehicle exhaust system quality and its influence on the results of measuring exhaust emissions of the Otto and Diesel motor vehicles. Results of eco-tests obtained from correct and faulty vehicle exhaust systems were compared to conclude that damages caused by corrosion had significant influence on the pass rate of vehicles at eco-test. Referring to vehicles with the Otto engine, damages in the exhaust system increase the oxygen level, which results in the increased λ factor and in failure at the eco-test. On the contrary, vehicles with the damaged Diesel engine exhaust system allow the gas to leak through the damage, so the measurement of blackening is lower, i.e. the eco-test result is better than that of the exhaust system without damage
Influence of surface roughness on the rate of corrosion penetration into the steel
This research analyses the influence of surface roughness on the rate of corrosion penetration into the steel. The test specimens were mechanically treated with fine abrasive jet to make their surface slightly rougher than it was in the initial state. The test specimens were then kept in conditions of atmospheric corrosion for 90 days to be tested afterwards by weighing, i.e. by the mass loss method. The analysis showed that a slight increase in surface roughness facilitated faster development of corrosion mechanisms, thus drastically increasing the rate of corrosion penetration into the material. Changes in surface roughness can be also caused by abrasion or erosion damage, so it is important to choose adequate surface protection technologies for prevention of unwanted wear of the steel
Analysis of plated layer’s effects on the structure resistance to corrosion
This paper presents the laboratory testing of protective effects that the plated layer had on the structure resistance to corrosion by using the weighing method, i.e. the method of mass loss. The described procedure refers to preparation of samples, their exposure to aggressive atmosphere of the salt chamber and analysis of obtained results. According to the properties of the base material and its reduced stability in the experimental conditions, it is confirmed that the use of plated layer was required to improve the structure resistance to corrosion and to protect the base material
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