Analysis of the technology of rolling 5,5 mm-diameter wire rod of cold upsetting steel in the morgan block mill

The commercial technology of rolling 5,5 mm-diameter wire rod in Poland’s most modern rolling line has been examined within the study. The material used for the investigation was the 20MnB4 steel intended for subsequent cold working. From the performed analysis of the investigation results it has been found that the technology of rolling wire rod of cold upsetting steel, which is used currently in the Rolling Mill under examination, allows the production of finished products that can be deformed with a relative reduction of about 33 %. At larger plastic deformations,cracks occur in the material, which disqualifies it from further cold working

Determination of characteristics of plasticity of selected medium and high carbon steel grades in hot torsion test

This study presents results of the examinations aimed at determination of rheological properties of selected grades of medium and high-carbon steel grades ( C45 and C72D). The examinations were carried out for the hot torsion test using STD 812 torsion plastometer. The results of experimental studies were approximated with the function used for determination of yield stress depending on strain, strain rate and temperature. The study allowed for development of mathematical models of rheological properties of steel grades studied in the analysed scope of parameters of strain and temperature

Physical modelling of the plastic working processes of modified Zr-Nb zirconium alloy bars and tubes

The article presents the results of physical modelling of the processes of plastic working of the modified Zr - 1%Nb (Zr – 1,0 % Nb – 0,7 % Fe – 0,9 % O) zirconium alloy, obtained using different methods of plastometric testing. The ≪Gleeble 3800≫ metallurgical process simulator, a DIL805 A/D dilatometer with a plastometric attachment, and a ≪Setaram≫ plastometer were used for the tests. Based on the obtained testing results, the values of the yield stress and limiting plasticity of the alloy were determined for wide ranges of temperature variation (Т = 20 - 950 °С) and strain rate variation (έ= 0,1 – 15,0 s-1) under continuous loading conditions. It was found that by using different testing methods, different alloy properties, characteristic of a given plastic working process, could be obtained

The analysis of the influence of varying types of shape grooves on the behavior of internal material discontinuities during rolling

The article discusses problems related to the influence of rolling processes on the process of closing of internal discontinuities in continuous castings during rolling in two types of shape grooves. Numerical modelling of the process of rolling 160 x 160 mm continuous C45 steel billets using the Forge 2008® software program. Variations in deformed strip temperature, as well as in the shape of holes simulating material discontinuities were examined

The influence of the shape of grooves on the behavior of internal material discontinuities in continuous S355J2G3 steel strands during rolling

The article discusses problems related to the influence of rolling processes on the process of closing of internal discontinuities in continuous castings during rolling in shape grooves. Numerical modelling of the process of rolling 160 × 160 mm continuous S355J2G3 steel strands was carried out using the Forge 2008R software program. The experimental studies were conducted in a D150 laboratory rolling mill. Holes simulating material discontinuities were examined. In numerical and experimental studies, in steel samples after rolling in the third rolling stand, the defects were closing in 100 % on average. It was stated that the speed of closing of material discontinuities in feedstock is strongly influenced by the shape of the rolling groove

Analitičko i numeričko utvrđivanje prostiranja temperature na traci hlađenoj zrakom

The paper analyzes the distribution of temperature of 60S2A steel strip cooled in air. Both analytical and numerical methods were applied in investigation. From among the known analytical methods of temperature distribution determination, Tselikov’s [1], and the Fourier’s [2] methods were used. The numerical examination of temperature distribution presented in the paper involved carrying out a computer simulation of strip air cooling. For this purpose, the Forge 2D software [3] was employed, which relies on the finite-element method in performing computations. Comparison of results obtained by analytical methods with numerical computation results and for the real technological process has also been made within the study.U radu se analizira prostiranje temperature u čeličnoj traci 60S2A hlađenoj zrakom. Tijekom istraživanja primjenjivala se i jedna i druga metoda. Između poznatih analitičkih metoda utvrđivanja prostiranja temperature koristile su se Tselikova [1] i Fourierova [2] metoda. Numeričko ispitivanje temperature koje je prikazano u radu uključuje i provođenje kompjuterske simulacije hlađenja trake zrakom. U tu je svrhu primijenjen Forgeov software 2D [3] koji se u računanju oslanja na metodu konačnih elemenata. Unutar studije je također provedena i usporedba rezultata dobivenih analitičkim metodama s numeričkim izračunima

Analysis of the temperature change over the continuous ingot length on the parameters of round bar rolling process

The paper presents results of theoretical and experimental studies on the effect of feedstock end overcooling before the first rolling stand on the plastic flow of metal and on the energy and force parameters during bar rolling process. From the obtained investigation results it has been found that the uniform heating of the feedstock in the stepped furnace does not insure the uniform plastic flow of metal over the rolled band length. Therefore, it is necessary to modify the method of feedstock heating in the stepper furnace in order to obtain a uniform temperature over the length of the feedstock before the first rolling stand

The thermomechanical conditions of open die forging of zirconium alloy ingots determined by rheological tests

The article reports the results of investigation into variations in the rheological properties of the Zr-1 % Nb alloy when deformed under the conditions of physical modelling of the process of multi-stage hot open die forging of ingots. The programme for rheological testing of the alloy was developed based on the simplex planning method. Tests were carried out on a „Gleeble 3800” plastometer. Based on the rheological test results, a new scheme of ingot deformation in forging process was developed and the experimental verification of the model study results was made in industrial conditions. From the obtained results, high effectiveness of the method of determining the thermomechanical conditions as applied to the process of forging zirconium alloy ingots has been found