The article presents the tests results which tested the possibilities of shaping magnesium alloys. Testing materials were ingots from magnesium alloys with symbols AZ61, WE43. One of the aims of conduction of plastic shaping tests with the use of KOBO method was to achieve a product in the form of flat bars. The paper presents the results of mechanical tests of tested alloys marked in a uniaxial tension test in room temperature and in elevated temperature for achieved flat bars. Fractographic tests were conducted in tension test in order to determine the mechanism of cracking. A microstructure analysis was conducted both in the initial condition and in condition after plastic strain with the use of techniques of light microscopy and scanning microscopy.
The automotive industry is characterized by rapid development, which is the largest effort devoted to maximum production optimization. The article deals with problematics of hemmed joints in the automotive industry when main objective is to reduce production price while maintaining sufficient quality products. During joining two or more sheets of metal plates together is the greatest challenge to ensure dimensional stability of sheet metal parts, which can move against each other. This negative effect can occur during other stages of production, especially during installation, when parts may not be correctly aligned. In the article you can find new innovative solution that should meet these requirements.
Dynamic development of computer technology as well as of computer software for designing of metal forming processes based on the finite element method has triggered demand for a description of mechanical properties of material subject to plastic deformation. Characteristics of material deformation obtained under conditions of plastometric testing provide grounds for developing constitutive equations in the form of σ=f(ε,T).
This paper provides a discussion on results of plastometric tests of selected steel grades used to manufacture pipeline components for the power engineering applications (10CrMoVNb9-1, 14MoV6-3, 10CrMo9-10) as well as for the gas and petroleum industry (L485ME). The formability assessment was conducted under conditions of compression, using a thermal-mechanical Gleeble simulator on stock at the Technical University of Ostrava (Vysoká škola báňská). Studies on the dependence of flow stress from strain were conducted at the temperature ranging from 20 to 1,100 °C and the strain rate of 1 1/s. The deformation characteristics established for the 10CrMoVNb9-1 steel were implemented in numerical simulations of the tube (508 x 55 mm) bending process with application of local induction heating. The results obtained from the numerical process simulations allow for determination of optimum tube bending parameters entailing geometrical parameters of the bend, and they may be applied under industrial conditions, thus making it possible to minimise the costs involved in the technology implementation without the necessity of adjusting the parameters of bending in industrial tests.
In this study, a commercially acquired Ni-rich (50.0~50.8at% Ni) Ni-Ti shape memory alloy sheet having the thickness of 0.9 mm was cut in the shape of a circle with a diameter of 36 mm and placed in a heated chamber at 800°C for one hour and then quenched in water, which served as a solid solution process affiliated to an annealing process. This sheet blank was then stretch formed with a hemispherical punch of 30 mm in diameter to a stroke 1 mm, 2 mm, 3 mm, and 4 mm, respectively. After removing the punch, the formed part was then put into a furnace for aging treatment at 300°C for one hour and subsequently quenched in water. As a result, for smaller punch strokes the sheets could not be well formed, because the maximum strain presented in the alloy was little bit over the elastic region. After the aging process, the heights of the formed sheets were extra shortened because of a further spring-back. The springback after stretch forming and during aging can be compensated by modifying the punch radius, so that a tolerable shape with shape memory effect can be achieved with only one die set. Furthermore, if the sheet part was immersed in liquid nitrogen basin to have its martensitic phase and compressed into a flat shape, the original shape of the part can be fully recovered by returning to room temperature.
High alloy heat resistance steels based on 12% Cr content are characterized by specific structure and properties, which can substantially complicate technological procedure of their forming. These 12 % Cr based steel are characterized by increased resistance to deformation that affects their formability significantly, quit narrow interval of forging temperatures, non uniform formability and high sensitivity to stresses.
Paper deals briefly with effect of various factors on formability, microstructure and mechanical properties. Effect of some chemical elements, grain size and volume of delta ferrite is discussed and compared. Effect of forming temperature is also discussed.
The paper presents plasticity tests results for steel types 23 MnB4, 30MnB4, C45 and C70 meant for rolling wire rods in modern continuous rolling mill. The assessment of plasticity was conducted in hot torsion test with the use of torsion plastometer in temperature range of wire rod rolling from 850 to 1150°C and deformation speed of 0.1; 1 and 10 s-1. The core data for plasticity assessment were the achieved redundancies of yield stress from deformation on the basis of registered torsional moment in function of number of torsions of a sample. On such basis the values which characterise the susceptibility of steel to plastic shaping were determined such as: maximum yield stress, value of deformation corresponding with the maximum stress and deformation till failure. Those values were dependent on temperature and deformation speed. The dependency between maximum yield stress with corresponding deformation and the energy of activation with Zener-Hollomon parameter was elaborated together with marking the yield stress function.
Main goal of our paper is comparison of results obtained using full factorial experiments with different combinations of one factor levels. On the example of multipass wire drawing, we will show how the choice of levels of factors can affect the final result of the experiment, especially in view of the determination of the significant factors and their interactions. We will demonstrate how important is the selection of each factor level on the final result of experiment. The experimental material was a drawn and patented wire of 5.5 mm diameter of C78DP steel. The wire was drawn from the diameter of 5.5 mm to 2.5 mm using straight-through single-block KOCH KGT 25-E wire drawing machine. The total reduction was 79.3 %. The drawing dies of tungsten carbide had approach angles of 8° and 12°. Two ways of descaling (mechanical and chemical) were used. A total of three uniform pass schedules were used with different single-pass reduction (23, 27 and 32,6 %). It gives us in total three individual experimental plans of design of experiments (DOE) with following variations of one-pass strain levels: DOE1 23 – 27 %, DOE2 23-32,6 % and DOE3 27 – 32,6%. Monitored depended variable is number of bendings to fracture during reverse bending test. All DOE were evaluated using graphical methods. The significant factors and his interactions were determined and compared for all DOE mutually.
The work concerns an idea of the expert system for predicting the life of forging tools used in die forging processes, for which the representation and knowledge processing were based on Adaptive Neuro-Fuzzy Inference System (ANFIS). Based on extensive investigations and analysis for the three representative industrial hot forging processes (forging of front wheel, casing of constant velocity joint body, and fastener construction forging) was developed knowledge base. The knowledge base contains elements of both theoretical knowledge about destructive phenomena and empirical knowledge gained from the experience of the authors and industry experts (forge employees) as well as from acquired values of selected forging parameters: the number of forgings, the billets and tools temperature, a loads of tools, contact time, friction distanceand lubrication, were elaborated tabularily in the form of knowledge vectors.Action of the developed system is to quantify the amount of wear, which is a geometric cavity dies for the industrial hot forging process, after entering for this process inputs as some technological parameters.
It is an original approach, as, so far, the thematic literature has not provided any examples of the use of ANFIS to solve the problem faced by the system.
Differences between the results obtained from the system (based on ANFIS) and empirical data derived from the study of worn tools are in the range of 0-10%.
The article describes the influence of a new ECAP forming tool draft (helix) for achieve a very fine grained structure and final properties of magnesium alloy AZ61. It was realized detailed measurements of hardness (HV) distribution and unconventional micro tensile tests for small samples (M-TT) after the individual passes through deformation route Bc and effect of ECAP technology on the structure of AZ61 alloy (optical microscopy and electron microscopy).
The paper deals with visualization of results for simulation of deformation process of sample with mushy zone. The numerical model consist of three basic subsystems: the mechanical, thermal and density changes parts. These describe both solid and semisolid deformation states. Taking into consideration their specific distribution graphical visualization is very helpful for understanding the course of the process. Moreover, three-dimensional presentation is applied in various fields, ranging from medical imaging systems to technological processes assistance to scientific visualizations and entertainment. Among other stereoscopic imaging technique is still being developed. It is based on the idea of showing each eye the same scene from a bit different perspective. As an effect illusion of depths is created due to the way the two images are interpreted by human brain. Stereoscopy is not a new concept, but in the past few years a significant increase in interest in this method of visualization could be observed. It is caused by the computer and audio-visual technology development. In the paper several techniques of creating stereoscopic images are presented together with their physical bases and devices providing such functionality. Utilization of projection equipment and possibilities of its application to visualization of semi-solid steel deformation is discussed. Apart from that a description of an implementation of OpenGL specification for stereoscopic presentation of computer simulation results is provided.
In steel research, as well as in the manufacture of semi-finished metallurgical products and finished formed products, such as forged parts, the material is often heated to high temperatures which leads to surface oxidation and decarburization. Material-technological modelling involves the use of small-size specimens which are treated using schedules identical to those in real-world processing. From these treated specimens, test bars are made for various mechanical tests. If severe decarburization occurs, the affected surface layer may give rise to substantially different results of mechanical testing than testing of a thermomechanically treated material with an intact surface. Therefore, protective barriers were sought by which formation of scale on the surface of test specimens, and decarburization in subsurface layers could be prevented. One of the available options involves deposition of a coating of 10–15 micrometre thickness by electrolytic nickel-plating. By this simple and readily-available technique, very good protection was obtained for specimens exposed to high temperatures.
The paper is aimed on evaluate of effect previous plastic deformation on transformation kinetics of rail steel class IH alloyed with chromium. The CCT and DCCT diagrams were assembled on the basis of dilatometric tests with and/or without an influence of previous deformation. To the experiment execution the dilation module of the plastometer Gleeble 3800 was used. Accuracy of the diagrams was faced with metallographic analysis and measurement of hardness. The obtained results were compared with the results of in-process measurement of rail rolling mill Třinecké železárny Inc. This confirmed the theory that in the case of steels which are intended for rolling rails, no influence of the previous deformation the crucial influence pearlitic transformation in terms of time, but in case of higher cooling rate has deformation an appreciable effect on shift temperature intervals of pearlite formation.
For the evaluation of the quality of drawn wire is necessary to evaluate its fundamental mechanical properties. An important prerequisite for this evaluation is the accuracy and consistency of the results obtained by testing of the drawn wire. In this paper we used the basic techniques for evaluating the quality of non-replicable measurement systems. For this purpose were conducted destructive tests of dynamic stress of samples produced by the straight-through single-block KOCH KGT 25 – E wire drawing machine The test was conducted on 2.5 mm C78DP steel wire drawned from 5.5 mm thick rolled rod. The results of tests of drawn wire were used in the gage repeatability and reproducibility study (GRR). The tests were conducted in accordance with the ČSN ISO 7800 standard Metallic Materials – Wire – Torsion test and ČSN ISO 7801 standard Metallic Materials – Wire – Reverse bend test.
The paper present the concept of a mathematical model for predicting changes in the austenite microstructure of high carbon steel. Based of physical modeling changes of microstructure the mathematical model for predicting changes in the austenite microstructure was buillt. Model is based on the classic Sellars equations developed by taking into account the parameters of plastic forming processes and their impact on the processes occurring in the deformed steel. The coefficients of mathematical equations describing the evolution of deformed austenite microstructure were calculated based on the results of experimental studies carried out in the Institute of Plastic Working and Safety Engineering Czestochowa University of Technology.
For the verification of the accuracy developed model laboratory studies were conducted using a metallurgical processes simulator Gleeble 3800. Comparison of the results obtained in the theoretical and experimental studies have confirmed good agreement developed model of the microstructure evolution for high carbon steel.
The paper presents the results of research on the selection of tool materials, lubricants and self-lubricating coatings in the process of rotary forming of nickel superalloy Inconel type sheets.
The abrasiveness tests of sheets were carried out with roller made of ceramics FRIALIT® F99.7 and steel CALDIE. The discs were covered with single layers of lubrications: WD-40, Loclite 8023, Loclite 8151AS, Bonderite Aquadag18%. In parallel the discs were coated with a self-lubricating coatings: silver, zinc and copper. The properties of friction pairs were determined based on weight loss.
The obtained samples was subjected to detailed research focused on the analysis of the quality of the surface after deformation. The test results are shown in tables, diagrams and
surface profiles.
The paper presents results of numerical and physical modeling of microstructure evolution during 20 mm in diameter round bars rolling process. Presented in the paper research were conducted for one of continuous bars and shapes rolling mill technological conditions. Low carbon 30MnB4 steel grade for cold upsetting was used for the tests. The QTSteel Metallurgical Software for simulating the quench and tempering of steel was used for numerical modeling. For the physical modeling the GLEEBLE 3800 simulator and the STD 812 torsion plastometer were used. The main purpose of this work was comparision of numerical and physical results to check opportunities of QTSteel softwaere for modeling of microstructure evolution during hot rolling processes.
To determine the value of springback coefficient of sheet metal the cylindrical bending tests were conducted. The experimental tests of bending process were carried out using special device which allows to measure the value of sheet springback. As a test material we used the AMS 5604 alloy sheet metal with a sheet thickness of 1 mm. The numerical simulations by finite element method of the cylindrical bending tests were conducted using LS-Dyna program. The simulations were conducted at the ambient temperature (20°C) and at elevated temperatures: 400°C, 500°C, 600°C, 650°C i 700°C. The results indicated that the value of springback coefficient of the sheet decreases with the increasing of temperature. Furthermore, during the bending process at analysed temperature the linear variation in sheet thickness is observed. The forming temperature value influences the value of limit strains of the sheet and determines the final shape of product.
In this article the results of modifications of the forming process of the turbine engine bearing housing are presented. The bearing housing is one of the critical structural element of turbine engine and it is made of AMS 5504 stainless steel. Due to the nature of the element operation, the permissible shape error of housing profile is 0.508 mm. The proposed modification of the element forming process consists in welding of two coupled parts into one and the calibration of the profile. This process is replaced by two steps expanding of the cone-shaped drawpiece with the use of the rubber pad forming process in SAAB hydro-mechanical press. Eliminating one weld allows to reduce manufacturing costs of parts and also improve the strength of the part. To optimize the expanding process of the cone-shaped drawpiece the finite-element-based Impetus Afea system was used. Measurements of shape errors of the drawpiece were carried out using ATOS Core which is optimized for the 3D measurement of small to medium-sized components.
The paper presents experimental results that concern hydromechanical bulging of copper axisymmetric components whose relative wall thickness was s0/D= 0.045. The samples used in investigations were segments of copper tubes having the outer diameter D= 22 mm and wall thickness s0 = 1 mm. The deformation ratio of material in paper was defined as relative upsetting ratio Dl/l0 (where Dl – the punch displacement, l0 – initial length of tube). The investigations aimed to determine the impact of upsetting ratio on microhardness in different zones hydromechanically bulged axisymmetric components. The measurements of microhardness were taken with micro-vickers hardness tester MMT-X3 by Matsuzawa company. The paper gives the comparison of the microhardness distributions in longitudinal sections of hydromechanically bulged copper axisymmetric components with different relative ratios Dl/l0=0.054÷0.109.
The article presents the results of tests of influence of the heat-plastic treatment parameters (such as temperature, cooling conditions) on the mechanical properties and microstructure of steel 23MnB4 indicated for cold-heading. The process of rolling was conducted in simulation in continuous finishing train arrangement of four rolling stands in a laboratory of Faculty of Metallurgy and Materials Engineering VSB Ostrava. Results of presented tests will be applied for optimisation of the rolling process on rolling mill type MORGAN equipped with a system of regulated cooling Stelmor. Achieved results for steel 23MnB4 will be useful for optimisation of heat-plastic treatment in order to achieve products with good mechanical properties.
Prediction capability of a newly derived hot flow stress model is demonstrated on experimental flow curves of steel 38MnVS6. These flow curves were also described by the commonly used equations like Cingara & McQueen, JMAK or Hensel-Spittel. Graphical and statistical comparison proved that flow curve prediction by the newly derived model leads to the best fit with the experimental data. An advantage of the new model was discovered especially in case of the flow curves acquired in very broad range of thermomechanical conditions when shapes of these curves may very differ.
Computation of the springback phenomenon in numerical simulations, together with its prediction, is very complex. Final results of the springback analysis are highly dependent on the initial setting of the numerical simulation, thus the final accuracy of the springback analysis in comparison with the real product can be influenced significantly. There are many possibilities in terms of initial setting of the numerical simulation, for better understanding the possibilities were divided into two major categories. First group defines the element type, mainly BEM type (Bending Enhanced Membrane) or EPS type (Elastic Plastic Shell). Second group defines all meshing parameters (radius penetration, max element angle, master element size, etc.). The article also focuses on verification of the initial setting in the numerical experiment in AutoForm R6. For experiment, outer panel of fifth doors from ŠKODA Yeti was used.
The use of computer programs which are based on FEM becomes the most common method in the design of manufacturing processes. The simulation is possible to perform using the acquaintance of the equations of deformable material properties, in particular the flow stress. The correct description of plasticity of the material, in particular the flow stress is highly dependent on the method of experimental determination of the stress and its plasticizing mathematical form The aim of work was to show the results of plasticity research of X60MnAl20-3 +V steel for manufacturing car components which can absorb high energy. Based on hot compression tests at 800-1100 °C with strain rate 0.1, 1 and 10 s-1 the plasticity evaluation was determined. Screening the registered values of flow stress in strain function with the relationship to Zener-Hollomon parameter and the flow stress function was presented.
Flat cold rolled metal of general use is the most prospective for replacement by hot rolled metal with the thickness of 1,2-2,5 mm. Such kind of steel products may be referred to the category of Mild Steels with the properties Re=210-380 MPa, Rm=380-520 MPa, A=23-42% and it may reach 20% in metal mix cold rolling.
In continuous wide-strip hot mill production the required properties may be achieved by definite chemical steel composition use and providing finishing temperature of rolling and coiling temperature relatively to starting temperature (Ar3 ) and finishing temperature (Ar1 ) of the phase transformation and turn out with the dependence on the volume of carbon content equivalent Ce=C+Mn/6+Si/3.
Specifications of drafting schedule mode and energy-power parameters of rolling strips with the thickness of 1.2-2.5 mm in finishing mill group were revealed. Model of force estimate was presented for developing strip rolling modes of indicated use and hot rolling torque in variations of shape factor within the limit of 3 to 10, which in particular may allow to estimate deformation zone length taking into account the flattening of working rolls with non-iteration procedure.
Overall five steel grades differing by amount of alloy content of Cr, Mo and Ni were investigated. Dilatometric tests realized on the plastometer Gleeble 3800 and evaluated by the CCT software were utilized to determine the martensitic transformation temperature of Ms and Mf. In case of the steels alloyed only by Cr or Mo was possible to graphically locate the encounter temperature of the Ms and Mf curves. Additive of the Ni leads to a significant change because the bainitic region very fluently ties on the martensitic area at low cooling rates and then it is difficult to define their border. Determination of the Ms and Mf temperature is important for proper setting of refinement processes.
Development of production technology of very fine structure is currently very intensively accelerated. Even in scientific research, it is recognized that precisely controlled forming processes, including special processes, enabling control of technological parameters with regard to the structure refinement, and tied with the strengthening of materials, currently has the highest gradient utilization efficiency of scientific research findings into practice. New forming equipment using the process SPD is currently installed in the lab of developing new technologies Faculty of Mechanical Engineering – VSB-TU Ostrava. The paper analyzes the effects of angles value of newly developed forming tools on achieve mechanical properties at selected low carbon steels in the SPD process. Experimentally were verified following types of steel DC01, DD11, S355 and CK55 - strip sheet with dimensions 58 (width) x 2 (thickness) x 1000 (length) mm. The paper also evaluated the influence of severe plastic deformation (SPD) on strengthening these steels at different sizes angle forming tool. The influence of new geometries forming tools for improving mechanical properties, has been unequivocally demonstrated.
Deformation characteristics of the materials used in the engineering industry are mostly determined at the common stress-temperature conditions (frequently loading rate 10 mm/min and temperature 20°C). However in the operating life are materials loaded under conditions which are quite different from these standard conditions. Among such important operating conditions are e.g. operating temperature, state of stress and so on. Last but not least there is also the information about the tested material deformation behavior at the higher strain rates. This paper deals just with the influence of increased strain rate on the deformation distribution and magnitude. That is why there was chosen the bending impact test at the drop tower Instron CEAST 9350. As a tested material was used non-alloyed steel of the common quality acc. to ČSN 41 1373. The first aim of this paper was design of the testing jig. The second aim was subsequently effort to apply high-speed cameras PHOTRON SA3. For the own deformation computation and its distribution on the sample surface was used software ARAMIS 2M. At this point there was also effort to (by the optical measurement) determine the strain rate corresponding to the used impact velocity of the drop tower tool. So as a result there was not only the testing jig for bending impact tests but also evolution and graphical illustration of the deformation distribution with the information about the strain rate magnitude. Subsequently from the measured results arise certain important recommendations for the future direction of such research.
The metal forming technology is (mainly due to the automotive industry) one of the most dynamically developing branch of the engineering industry. Continuous effort to achieve the top technological level and car´s safety factor at keeping the low price level means necessity to still implement into own production process also newest mathematical models of these technological processes. Thus these days represents utilization of numerical simulations an essential part of the car shape lay-out design, determination of the basic technological operations and also e.g. stamping tools shape optimization. Alongside it implementation of the new materials into production reveals necessity to develop new and more precise computational models of materials deformation behavior as well as models determined for the spring-back prediction. Nowadays in the branch of the metal forming technologies there are several truly top software among which also belongs software PAM-STAMP 2G. In this article is evaluated influence of the computational model on the numerical simulation accuracy by PAM-STAMP 2G at the spring-back prediction. For the deformation analysis was chosen corrosion-proof material DIN 1.4301 and for the spring-back prediction were used two anisotropic computational models termed as Hill 48 and Vegter in combination with the hardening kinematic model termed as YOSHIDA UEMORI. Accuracy of the measured results from the individual computational models is evaluated by the compliance of the carried out experiment and results from the numerical simulations. For the own experiment was chosen test where the material is drawn over the drawbead and drawing edge.
In this work the theoretical-experimental analysis of the effect of the drawing speed on force parameters in multipass drawing process of high carbon steel wires has been assessed. Theoretical analysis of the heating of the wire in the high speed multistage drawing process was carried out on software Drawing 2D, in which the longitudinal stresses, drawing forces and drawing stresses has been estimated. Whereas experimental studies consisted in measurement of force parameters in a real multipass drawing process of steel wires. The drawing process of ø 5,5 mm wire rod to the final wire of ø 1,7 mm was conducted in 12 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15, 20 and 25 m/s.
In this work the drawing power measurements carried out in industrial conditions during high speed multipass drawing process creates a unique possibility to verify the theoretical research based on the finite element method. The significant effect of drawing speed force parameters drawing process. Depending on the actual conditions of the drawing, ie. temperature, friction and lubrication, increasing the drawing speed (in range of 5 to 25 m/s) can result in both an increase and a decrease in stress drawing.
The paper presents the results of the bending tests performed on sling hooks. The hooks are produced of S235JR steel for the power industry. Because of the loading mode, the bending was conducted in two directions: along the axis of the hook and perpendicular to the hook axis. The data on the force values allowed determining the capacity of the slings and the maximum values of breaking forces
This paper deals with using of design of experiments (DOE) during evaluation of mechanical properties of the wire for steel ropes. It was given a full factorial experiment with three factors at two levels. Factors are as follows: one-pass strain, approaching angle and way of removing of the scales from the surface of hot rolled wire. The experimental material was a drawn and patented wire of 5.5 mm diameter of C78DP steel. The wire was drawn from the diameter of 5.5 mm to 2.5 mm using straight-through single-block KOCH KGT 25 – E wire drawing machine. The total reduction was 79.3 %. The drawing dies of tungsten carbide had approach angles of 8° and 12°. Two uniform pass schedules were used with different single-pass reduction. Two ways of descaling (mechanical and chemical) were used. Following each pass, an approx. 50-m sample was removed from the wire stock for subsequent testing. The following tests were carried out after each pass: tension test, torsion test to fracture and reverse bend test to fracture. DOE was evaluated using both graphical and analytical methods. The significant factors and his interactions were determined and response surfaces were calculated.
Since the use of cold-rolled steel sections is a standard method in mechanical engineering and steelwork and cost efficiency is always a big issue, it is of great interest to address the highly non convex problem of cross-section optimization. At a first glance classic genetic algorithms already seem to be suitable for this problem, because they are powerful search heuristics for solutions in non convex problems. But in addition to the great number of local optima, which can occur in the optimization process, the problem is also constrained due to constructive needs and limitations in manufacturing.
Constraints highly affect the ability of genetic algorithms to overcome local optima, especially under high selection pressure. This high selection pressure comes from the need to suit the given use case in terms of physical stability. Therefore we had to handle the restrictions more flexible, so that the algorithm can temporarily violate our stability criteria to overcome a local optimum, but will end up with a solution within our given boundaries. To achieve this we negatively coupled the penalty factor for stability criteria violations to the mutation strength, thus allowing adaptive radiation with rather free-wheeling restriction handling, followed by a rigid selection process approaching the optimal solution. Additionally we introduced an inbreed avoiding recombination system to speed-up the exploration of the fitness landscape. This yielded material savings of about 20% with a run time of approximately 3 minutes for a simple example.
The paper deals with the analysis of the ultra-high strength steels at material tests under high strain rates. In the experimental part was tested steel alloyed by the manganese and boron with the predominant martensitic structure. This steel is used in the automotive industry for the car-body design where is necessary to have part that is ensures the safety of passengers. To fulfill these required function is for these parts very important to know their deformation behavior at the dynamic loading (crash conditions) because it can vary in comparison to the low and uniform strain rates. Experiment was carried out on the special device (drop tower Instron CAEST 9350) where is possible to set the magnitude of the impact velocity. High-speed cameras PHOTRON SA3 were used to record the whole test. These cameras monitored the points displacement on the testing sample surface which was loaded under the conditions of the uni-axial tensile stress state. For the own computation of the kinematics quantities was used software PONTOS where the main goal was to determine the evolution of the given strain rate. Moreover there was recorded the impact energy during the test by means of the force sensor under the different impact velocities.
This article introduces a mathematical model describing how certain parameter changes influence the quality level of final products manufactured out of X2CrNi18-9 steel type 1.4307.
Among the examined parameters are: batches of faulty steel sheets, processing not meeting desired standards, erroneously planned processing methods etc. The simulation results obtained with the use of the designed model determine the approach when making the choice on how to maintain the supply level for one of the logistic chains for the examined type of steel. The model utilizes Bernoulli, Poisson, Gauss and the T-student probability distributions as codependent.