Marcin Knapiński

Theoretical analysis of the asymmetric rolling of sheets on leader and finishing stands

Abstract A theoretical analysis of the asymmetric rolling in The Plates Hot Rolling Mill of Tadeusz Sendzimir Steel Work in Cracow has been performed with finite element software Elroll with an assumed rigid–plastic model of the deformed metal. The theoretical analysis of the asymmetric rolling process, which was performed based on Elroll computer software, required the definition of the mechanical properties of the materials examined. Before making the selection of steel grades for analysis, data deriving from the system of controlling the finishing stand group at the Sendzimir Steel Works of Cracow were reviewed and steel grades defined in the system were analysed, the latter being grouped into sets, each with an assigned code of mechanical properties. Each of these groups is characterised by different coefficients of a general equation that defines the dependence of yield stress on temperature, strain rate, total rolling reduction, and the rolling stand number. On the base of the obtained results of the computer simulation the technology of the asymmetric rolling of plates in a continuous rolling mill has been elaborated. Within this framework results of the computer simulation are presented.

The Individual and Cumulative Effect of C and N on the Hardening and Structure of High-Nitrogen Hot Plastic Worked Steels

Investigation into the effect of carbon and nitrogen contents of steels with an addition of chromium, nickel and manganese on their structure and properties after thermoplastic treatment has been carried out within the present study. For the physical modeling of thermoplastic treatment processes, a DIL 805A/D dilatometer with a deformation capability and a Gleeble 3800 simulator were used. The effect of carbon and nitrogen contents and the sum of these elements (C+N) on the hardening of the material during hot plastic working. The softening of the material depends on the C/N element ratio. The influence of the constituents under analysis on the dynamics of removal of cold work effects is different; C speeds up, while N slows down this process. The influence of the sum of the elements C and N depends on the type of nonmetallic phase precipitates. The structure and properties of such steels are determined by quenching and tempering cycles.

Threats associated with the human factor in the aspect of information security

Published: 15 March 2018 The current publication presents selected risks resulting from the involvement of the human factor. In the opinion of the authors of the paper, it is the human inclination to make mistakes, commit breaches and abuses that can generate losses and damages caused by disclosure, modification, destruction or loss of corporate data. Theoretical considerations on the subject matter have been enriched by the results of conducted empirical research. They answer the following question: What categories of information security threats are associated with the human factor.

Physical Simulations of the Controlled Rolling Process of Experimental Steels with Modified Chemical Composition Allocated to Pipelines

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].

Plastometric Modelling of the E635M Zirconium Alloy Multistage Forging Process

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.

The Physical and Numerical Modelling of Heat Treatment of Experimental Steels for Pipelines

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.

Numerical Simulation of the Rolling Process of Pipeline Sheet

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.

The Study of Heat Transfer Coefficient during Cooling Plates of High Strength

Nowadays methods of hot-rolled sheets should ensure high mechanical and plastic properties of sheets, in-line rolling. Such technologies require application of devices for accelerated cooling of a band after last deformation. The essential thing in this process is selection of an appropriate positioning of the cooling intensity. The paper presents results of the cooling intensity for the selected air-water nozzle. On the basis of the results, the map of distribution of heat transfer coefficient for the nozzle to the surface of the cooling was performed. These tests were carried out for different settings of water and air. The research was carried out for high-strength steel. The obtained results allow executing of computer simulation of the impact of cooling intensity on the final product’s structure.

Physical Simulations of the Controlled Rolling Process of Plate X100 with Accelerated Cooling

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.

The Basic Research of Experimental Steels for Pipelines

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.