M. Linda

Modelling of the Anisothermal Phase Transformation of Austenite by Electromagnetic Sensor

The characterization of steel microstructures is an important tool for metallurgists as mechanical properties are controlled by microstructural parameters such as grain size, phase balance and precipitates. This paper describes a model of the phase transformation of tool steel CSN 41 9436. Each of the experimental data was observed by electromagnetic sensor. The mathematic model was developed for an optimizing of tool steel heat treatment. The model was developed from one experiment and next experiments were for an evaluation of the model. A model can be satisfactory used for graphical form of the austenite phase transformation.

Exploitation of Hazelnut (Corylus avellana) Shell Waste in the Form of Polymer–Particle Biocomposite

Abstract Mechanically ground hazelnut (Corylus avellana) shells, a food industry by-product of hazelnuts processing, were tested for use as a composite material filler. Mechanical properties and fracture surface of the composite were evaluated using scanning electron microscopy. Polymer composites, i.e. resins filled with microparticles of hazelnut shells, were tested at various concentrations of the filler (5, 10, 20, 30, and 40 wt%). Hazelnut shell microparticles used at low concentration (5 wt%) increased tensile strength. The filler did not considerably influence hardness of the composite. Adhesive bond strength did not significantly change up to 20 wt%. The hazelnut shell microparticles were well wetted with the resin.

Using the FEM model for design the heat treatment of an agricultural tools

Agricultural tools need mechanical properties such as abrasive wear, hardness and toughness. These mechanical properties are achieved by choosing a suitable steel and subsequent heat treatment of the steel. Phases of the microstructure affects the final steel properties. The phase composition in the steel is influenced with the designing of the heat treatment. 25CrMo4 steel was investigated for the production of agricultural tools. The heat treatments ware designed for different cooling conditions. The salt bath was used to cooling as a medium with subsequent cooling on the water or in the air. The FEM method was used to designing the heat treatment conditions. The Johnson-Mehl-Avrami-Kolmogorov equation and the Koistinen-Marburger equations were used to prediction the microstructure phases. The microstructures were verified with experimental measurements. The ASTM G65 method was using for abrasion resistance tests. The results show that this procedure can be used to designing parameters of heat treatment of agricultural tools.

Utilization of FEM model for steel microstructure determination

Agricultural tools which are used in soil processing, they are worn by abrasive wear mechanism cases by hard minerals particles in the soil. The wear rate is influenced by mechanical characterization of tools material and wear rate is influenced also by soil mineral particle contents. Mechanical properties of steel can be affected by a technology of heat treatment that it leads to a different microstructures. Experimental work how to do it is very expensive and thanks to numerical methods like FEM we can assumed microstructure at low cost but each of numerical model is necessary to be verified. The aim of this work has shown a procedure of prediction microstructure of steel for agricultural tools. The material characterizations of 51CrV4 grade steel were used for numerical simulation like TTT diagram, heat capacity, heat conduction and other physical properties of material. A relationship between predicted microstructure by FEM and real microstructure after heat treatment shows a good correlation.

The effect of microstructure on abrasive wear of steel

Abrasive wear of agricultural tools is one of the biggest problems in currently being. The amount of abrasive wear, depending on the microstructure, has been investigated in this work. Steels 25CrMo4 and 51CrV4 were used in this work to determine the effect of the microstructure on the abrasive wear. These steels are commonly used for components that have to withstand abrasive wear.SEM analysis was used to detect the microstructure. The standardized ASTM G65 method was used to compare the abrasive wear of steels. The results show that the abrasive wear depends on the microstructure of steels.

Application of 3D cameras in agriculture when evaluating the quality of soil tillage

Kříž M., Linda M., Svatoš J., Hromasová M. (2016): Application of 3D cameras in agriculture when evaluating the quality of soil tillage. Res. Agr. Eng., 62: 39–49. The paper deals with the evaluation of data collected by scanning the agricultural surface with a 3D Photonic Mixer Device (PMD) camera with IFM company electronics and a resolution of 64 × 50 pixels in different scanning modes. After short introduction various methods of measuring of soil surface characteristics are presented. These methods are laser, photogrammetric and radar measurement followed by experimental measurement by kinect system and O3D201 3D camera using the Photonic Mixer Device (PMD) technology. For 3D calibration measurements of the camera a quartered pyramid model was used. Measurement results before and after the field testing area soil tillage are presented.

Prediction Of Mechanical Properties Of Quench Hardening Steel

Abstract The present study investigated the application of finite element method for prediction of mechanical properties of quench hardening steel. Based on the experimental results obtained, a numerical model for simulation of continuous cooling of quench hardening steel was developed. For the simulation of the kinetics of diffusion phase transformations, the Avrami equation and additive rule were applied. A new model was also developed for martensitic transformation which was validated using metallographic analysis and hardness tests. Experimental and simulation results indicated a good agreement. The developed model information provided here could be used for simulation of continuous cooling and kinetics phase transformation as well as for prediction of final distribution of microstructures and hardness of alloy steels.