Papers by Author: Bartosz Koczurkiewicz

Abstract: The research presented in the paper was carried out for the experimental steels with modified chemical composition allocated to pipelines for 760÷1180 °C range, strain rate s^–1 s^–1 and different distributions of particular reductions between passes were presented. Physical modeling of the rolling process was carried out upon using the GLEEBLE 3800 simulator. The research was based on the findings of the paper [1].

Abstract: The purpose of the process was to develop the guidelines for the new technological process of producing E635M zirconium alloy bars, including the conditions and schemes of deformations in individual open-die forging operations on a hydraulic press. The determined range of hot plastic deformation parameters (temperature, strain, strain rate) will contribute to the intensification of the plastic flow process in individual technological forging operations at a lower total energy consumption, with simultaneous homogenization of the structure in finished bars. Plastometric modeling of the process of hot forging square cross-section forging for industrial conditions and according to a newly developed scheme was carried out within the study. The examination was performed using the Pocket Jaw module of the plastometric device Gleeble 3800.

Abstract: The Institute of Metal Forming and Safety Engineering has developed technology for manufacturing grade X80 pipeline plates according to European standard EN 10208-2. Experimental chemical compositions ensuring a high level of yield strength have been developed. The article describes a method for selecting chemical composition [1]. The advancement of rolling technology takes much time and many calculations. Thus, using numerical simulations provides a possibility of a theoretical analysis of the plates made from new materials [4], [5]. Preliminary studies [1] have disclosed a large volume of deformations during the rolling process, which causes the distortion of rolls and generates heavy loads. For the theoretical analysis of rolling plates, Forge 2008® was used. The paper presents the obtained results of energy analysis and strength parameters displayed in Figure 1. The article considers a total amount of pressure on metal rollers and changes in the rolling moment.

Abstract: The paper presents the results of the physical and numerical modelling of heat treatment of experimental steels for pipelines. Simulation has been conducted at the Institute of Metal Forming and Safety Engineering of Częstochowa University of Technology. The numerical modelling of heat treatment has been carried using commercial program TTSteel. Based on the results of computer simulation, changes in steel microstructure during continuous cooling have been analysed, and the characteristics of temperature and the diagram of Continuous Cooling Transformation (CCT) have been constructed. Numerical research has been verified running the physical simulation of heat treatment of steel using dilatometer DIL805 A/D. The characteristic temperature of steel and the size of the former austenite grains have been determined. Also, the metallographic examination of the samples was conducted and Vickers hardness was tested. The obtained results have been used for building a real CCT diagram of steel.

Abstract: The requirement for curde oil and natural gas is still increasing. It was observed a growing of interested in the exploration and exploatation of unconventional fuels, including shate gas. There is about 3 to 5 trilion cubic meters resources of that type of gas in Poland. The latest data predicts that in addition to gas in the shale is also petroleum. The development of this branch of mining in our country can cause a significant increase in demand for pipes. The results of basic research of experimental steels for pipe line are presented in this article. Analyse of published materials about steels for pipe line was done. The chemical composition of two types of new steels meeting the requirements for X80 and X100 grade plates according API 5L norm were developed. The heat tratment using dilatometer DIL 805A/D were carried out. The influnce of heat temperature before rolling proces on structure of austenite was defined. The heating schemes were proposed for obtaining a high yield, while not allowing the dissolution of the alloying elements inhibit austenite grain overdevelopment. For samples after tests the structure of primary austenite and the size of former austenite grains were determined. The influence of deformation cinditions on structure were determinated, too. The results obtained from the examinations will be used to develop a technology for rolling sheets of pipelines in the category of X80 and X100 according to the API.

Abstract: The research presented in the current paper was carried out for the experimental steel designed for plate which meets the requirements for grade X100 according to API5L. Physical modeling of the rolling process was carried out using the GLEEBLE 3800 simulator. The tested steel is fine-grained constructional steel for making tubes for gas pipelines with the working pressure higher than 15 MPa. The fine-grained structure guarantees excellent plastic properties as well as high impact toughness. After rolling the steel should obtain the minimal yield point of 690 MPa and tensile strength over 760 MPa.

Abstract: The industrial development require new materials characterized highest mechanical properties. The conditions of thermo-mechanical treatment proved to highest level of mechanical properties for steels. Another method of making strong materials is to reduce the scale of the microstructure using heat treatment [1]. The paper presents the results of investigation into the effect of time and temperature variations during isothermal annealing on the mechanical properties of high carbon (c.a. 0,8%C) bainitic steel. Chemical composition of that steel (addition Si, Mn, Mo and Cr) obtain high level of tensile strength and good plastic properties. The analyzing of published results of researches of high carbon bainitic steels shown, that transformation of bainite can take between 2 to 60 days within the temperature range 125÷325°C [2,3] Based on results of researches of investigated steel a isothermal annealing in temperature range 200÷300°C were done. The experiments were done for 24, 50 and 100 hours of annealing. After that the mechanical tests were done. A Zwick Z100 testing machine was used for tests. The force and elongation values were recorded. On their basis, the proof stress and tensile strength of the steel tested were determined as a function of annealing temperature. The microstructure were determinated too.

Abstract: The fast development of automotive industry effects significantly on aspirations of designers and constructors to reduces the mass-produced cars, affecting meaningly on fuel consumption and gas emition. From the standpoint of automotive industry materials for modern car-body sheets should have high mechanical properties (primarily high tensil strenght) and very good cupping. The required high mechanical and plastic properties steels used in produce of car bodies are dependent on the type of the obtaining structure, witch be shaped by an appropriate heat and thermo-plastic treatment. The modern steels used in automotive industry are multi-phase steels e.g. dual-phase (DP), complex-phase (CP) and transformation induced plasticity (TRIP) steels. In this paper are presented the results of physical and numerical modeling of heat treatment the experimental complex-phase steel, witch be conducted in the Institute of Modeling and Automation of Plastic Working Processing on Częstochowa University of Technology. The numerical modellig of heat treatment were carried with using the commercial programe TTSteel. Based on the results of computer simulation the changes of steel microstructure during continuous cooling were analyzed and the characteristics temperature and CCT diagram was constructed. Numerical research have been verified by the physical simulation of heat treatment by the dilatometer DIL805. The characteristic temperature of investigated steel and the size of initial austenite grains were determined. On the samples was also metallographic examination and Vickers hardness testing conducted. The obtained results were used to build a real CCT diagram of steel.

Abstract: In the present work, low-carbon ultra grained constructional low-alloyed steel were subjected to thermo-mechanical treatment for modification of microstructure. It shows that microstructure after thermo-mechanical treatment is quite dependent on the alloy composition, conditions of hot deformation, grain size of austenite and cooling rate. The research was provide by using the computer program for thermo and thermo – mechanical treatment. The most optimal variant of heat treatment and thermo – mechanical deformation were obtained. The verifications were provided by the dilatometer with possibility of deformation DIL 805A/D.

Abstract: The article presents the results of physical simulations of the process of rolling plates of steel in the strength category 350÷460MPa on the finishing stand of a reversing mill. The simulations were performed for three steel grades and final plate thicknesses 40mm. The purpose of the simulations was to select the conditions of plate deformation to obtain, directly after rolling, structure of material corresponding to the structure obtained from normalizing annealing. Thus, the simulations reflected the normalizing rolling process. The research carried out has allowed to elaborate the new technology of production of rolling plate without an additional thermal treatment like normalization. It allow to decrease a time and total cost of production for this sort of product.