Claddings produced by welding are commonly used to increase the durability of the working elements of agricultural tools. The working conditions that occur during the cultivation of agricultural soil determine the wear intensity (different soil fractions, biological, and chemical environment). It was found that the tested claddings (Fe-Cr-C-Nb system) is characterized by three different layers: hypereutectic (layer I), near eutectic (layer II), and hypoeutectic (layer III). In layer I, micro-cracking and spalling of hard and brittle primary M7C3 carbides resulted in micro-delamination under the impact of larger soil fractions, which increased the wear intensity. Due to the lower fraction of primary M7C3 carbides in layer II, the share of micro-delamination was less significant in comparison to layer I. It was found that niobium carbides are firmly embedded in the matrix and effectively inhibit wear intensity in layer I and layer II. Layer III contained austenite dendrites, a refined eutectic mixture, and also NbC. In this layer, cracks (caused the unfavorable eutectic mixture morphology) were found in the interdendritic spaces at the worn surface. After the penetration of the cladding, there was a "wash-out effect", which resulted in a significant reduction in the durability of the working elements due to abrasive wear.
This article evaluates two essential non-destructive electromagnetic techniques, magnetic flux leakage (MFL) and eddy current (EC) methods, and their effectiveness in assessing the basic parameters of reinforced concrete (RC). The study compares both systems’ hardware and software components, emphasizing the adaptations implemented to tailor the methods for evaluating RC structures. Subsequently, the measurement results are analyzed, and association rules are extracted to demonstrate the relationships between variations in the physical parameters of the tested structure and the features of the measured waveforms. Finally, similar identification models are implemented, and the obtained identification results are compared. The paper documents and details all phases of this research. The findings indicate that while the operational principles of both methods are similar, the techniques differ significantly in terms of their measurement systems’ complexity and usability. The eddy current (EC) method exhibits superior spatial resolution, whereas the magnetic method is more straightforward and offers a greater effective range and favorable association rules. Consequently, it is recommended that both techniques be utilized for different structures and in varying contexts. The techniques’ advantages, disadvantages, and limitations are discussed in this work and supported by the measurement results.
This paper aims to present a non-destructive magnetic method developed for simultaneously identifying key parameters in reinforced concrete (RC) structures. This method is designed to evaluate concrete structures containing dense reinforcement meshes. The development process of the system is presented step by step. First, the hardware layer of the system is discussed and documented. The proposed modifications to the excitation system enhanced the method’s effectiveness compared to the conventional Magnetic Flux Leakage (MFL) technique. Next, this paper presents the extracted association rules that connect the parameters of the RC structure to the properties of resultant waveforms. The relations are verified with measurement results. Finally, the identification of the model’s design, implementation, and deployment processes are presented. A universal methodology for non-destructive testing investigations was developed and is described throughout the research.
Tribological properties of ploughshares made of pearlitic and martensitic steels were compared in field tests. Sectional ploughshares consisting of separate share-points and trapezoidal parts were subjected to examinations. Contours of the examined parts were similar, but the thickness of the parts made of pearlitic steel was 1 to 3 mm greater for the share-points and 0.5 to 2 mm greater for the trapezoidal parts. Within the tests, sandy loams, loams, and loamy sands with circa (ca.) 13% humidity were cultivated. A greater intensity of thickness reduction and mass wear of the parts made of pearlitic steel was found, which indicates a lower resistance of this steel to wear in soil. However, contour changes of the share-points and the trapezoidal parts made of pearlitic and martensitic steels were comparable, which was probably influenced by the greater thickness of the parts made of pearlitic steel. The roughness of the rake faces of the parts made of pearlitic steel was greater than that for the parts made of martensitic steel, which can be attributed to lower hardness of the former. The largest differences occurred between maximum peak heights of the roughness profile values (Rp), which indicates stronger ridging in the case of pearlitic steel. Scanning electron microscope (SEM) observations of the rake faces showed that martensitic steel was subjected to wear mostly by microcutting, but pearlitic steel was principally worn by microcutting and microploughing. During tillage, only one share-point made of pearlitic steel was broken. However, the main disadvantage of these parts was that their bending was related to the lower mechanical strength of pearlitic steel.
The condition of working surfaces of ploughshares used in two soils with different granulometric condition (one containing large portion of coarse fractions and one containing increased portion of fine fractions) was evaluated. The soil cultivated for the research was characterised by high moisture content. In the tests, divided ploughshares were used, composed of separate parts: a share-points and a trapezoidal part. The aim of the research was to determine, on the grounds of scanning microscopy of working surfaces and their roughness measurements, wear processes occurring during operation of the ploughshare. It was found from the scanning photography that the main mechanism for material wear in soils containing an increased portion of coarse grains was microcutting and grooving, but in soils containing increased portion of fine fractions, microcutting dominated. Surface roughness of ploughshares used in soil with increased portion of coarse grains was higher than that of ploughshares working in soil with higher portion of fine fractions. It was found by statistical analysis that in soil with an increased portion of coarse grains, values of the parameters Ra (arithmetical mean deviation of the assessed profile), Rt (maximum height of the profile), Rv (maximum valley depth) and Rp (maximum peak height), most often occurring on ploughshare rake face, were 1.13, 10.50, 7.60, 2.74 µm respectively and, in soil with an increased portion of fine fractions, these values were 0.80, 6.86, 4.78 and 2.32 µm respectively. On working surfaces of ploughshares operating in both types of soil, higher values Rv in relation to Rp were found. In average, ratio of these parameters for ploughshares in both soils was ca. 2.7. This indicated that microcutting and scratching occurred in the process of material wear of a ploughshare.
Field tribological tests of two design variants of chisels used in the teeth of a cultivation-sowing unit were carried out in this research. A characteristic feature of the first variant of chisels was the reinforcement of their contact surface and almost the entire rake surface by plates made of cemented carbides. On the other hand, the second variant of chisels was reinforced only in the area of the blade by two plates made of cemented carbides, soldered on the rake face of the elements. The use of the first variant of chisels contributed to a significant reduction in the wear rate of elements, especially in terms of thickness and width loss. Effective reinforcement of the rake face, with relatively lower resistance to length reduction in the elements, raises doubts as to the validity of the use of cemented-carbide plates on almost the entire length of their rake face, because the applied variant of chisels contributed to a significantly higher price. However, the second variant of chisels effectively limited the intensity of the loss of the length of the elements, and the cause of the loss of their usefulness as part of the base material wear. It was found that the main wear mechanism of the cemented-carbide plates consisted of matrix removal under the influence of the finest fraction of the soil, which weakened the embedding of carbides, and then crushing or chipping of carbide grains from the matrix, whereas the dominant wear mechanisms of martensitic steel were grooving and micro-cutting.