Wyniki 1-6 spośród 6 dla zapytania: authorDesc:"Martin RIDZOŇ"

Analysis of deformation in precision seamless tubes during cold drawing DOI:10.15199/24.2015.9.12


  This paper deals with the analysis of deformation in precision seamless tubes during cold drawing. The tubes were cold-drawn in five technological sequences, undergoing seven drawing passes in total. After each sequence the intermediate annealing took place. The main goal of the experiment was to evaluate the initial stage of the drawing process for E235 hot-rolled steel tube in Železiarne Podbrezová tube drawing plant, going from ∅ 31.8 × 2.6 mm to the final dimension of ∅ 6 × 1 mm while using specified reductions according to technological standards. The influence of selected reductions and the drawing technology on deformation of tubes was evaluated. The experiment described in this article is a part of the research project aimed at whether it is possible to determine the input technological parameters so that the resulting effect makes the tube production more effective. W artykule przedstawiono analizę odkształcenia precyzyjnych rur bez szwu podczas ciągnienia na zimno. W ramach pięciu ciągów zrealizowano łącznie 7 przejść. Po każdym ciągu następowało międzyoperacyjne wyżarzanie. Głównym celem eksperymentu była ocena wstępnego etapu procesu ciągnienia rur ze stali E235 w ciągarni rur 􀃤eleziarne Podbrezová. Walcowane na gorąco rury wsadowe w rozmiarze ∅ 31,8 × 2,6 mm ciągnięto do uzyskania końcowego rozmiaru ∅ 6 × 1 mm, stosując wielkości redukcji przekroju w kolejnych przepustach dobrane zgodnie z normami technologicznymi. Dokonano oceny wpływu wybranych wielkości redukcji przekroju i technologii ciągnienia na odkształcenie rur. Eksperyment przedstawiony w artykule jest częścią projektu badawczego, który ma wskazać, czy możliwe jest określenie wejściowych parametrów technologicznych umożliwiających bardziej efektywną produkcję rur. Key words: reduction, tube drawing, plastic deformation Słowa kluczowe: redukcja przekroju, ciągnienie rur, odkształcenie plastyczne.Introduction. Cold drawing technology used f[...]

The Change of Mechanical Properties of Material Using Various Reductions by Cold-Drawn Precision Seamless Tubes DOI:10.15199/24.2016.8.11


  Zmiana właściwości mechanicznych materiału dla różnych etapów redukcji przekroju poprzecznego w procesie ciągnienia na zimno precyzyjnych rur bez szwu The production of cold-drawn precision seamless tubes has an old tradition in Železiarne Podbrezová a.s. The production itself consists as a final operation of two previous operations, namely: steel plant - production of continued casting billet and hot-rolling plant - production of hot-rolled tubes. At steel plant, steel is produced in electric arc furnace with following continuous casting. The final product is biller with dimensions 200 × 200 × 400 mm. At hot-rolling plant, hot-rolled tubes serve as feed stock for cold-drawing. A hot-rolled tube can be adjusted to feed stock of cold-drawing plant from the material as well as from dimensional point of view. Based on these possibilities, technological process of production - number of passes, heat treatment and percentage of reduction can be altered by technologists. In this paper, we dealt with number of operations in technological processes of cold-drawing plant. As we have already mentioned, passes, reductions and heat treatment can influence the final tube in terms of mechanical properties (Rp0,2, Rm, A5, HV) and microstructural states. W hucie Žleziarne Podbrezová[...]

Numerical simulation of cold drawing of multi-rifled seamless steel tubes DOI:10.15199/24.2016.9.1


  Symulacja numeryczna ciągnienia na zimno rur stalowych bez szwu z wewnętrznym żebrowaniem Multi-rifled precision seamless steel tubes are produced by cold drawing technology, utilizing multiple drawing sequences with intermediate heat treatment. In this paper, numerical simulation of multi-rifled tube drawing is compared with the experiment regarding the dimensions of grooves on the inner surface of the tube. For numerical simulation, DEFORM-3D software was utilized. The numerical model considered drawing of a hollow feedstock with dimensions ∅ 36 mm × 8 mm into the multi-rifled tube with dimensions ∅ 28.6 mm × 6.3 mm. The analysed numerical results turned to be consistent with the dimensions of grooves obtained experimentally and measured by optical 3D scanning. Based on the validated model, further optimization of various technological parameters can be made, providing an effective method for enhancing product quality and lowering production costs. Precyzyjne rury bez szwu z wewnętrznym żebrowaniem są wytwarzane w procesie wielooperacyjnego ciągnienia na zimno z międzyoperacyjną obróbką cieplną. W artykule przedstawiono porównanie wymiarów rowków na wewnętrznej powierzchni rury uzyskanych eksperymentalnie z wynikami symulacji numerycznej przeprowadzonej w programie DEFORM 3D. Symulacja została przeprowadzona dla ostatniej operacji procesu ciągnienia rury żebrowanej o wymiarach ∅ 28,6 mm × 6,3 mm z rury o gładkich powierzchniach i wymiarach ∅ 36 mm × 8 mm. Analizowane wyniki symulacji numerycznych okazały się zgodne z wymiarami żeber uzyskanych eksperymentalnie, które zmierzono metodą przestrzennego skanowania optycznego. Zweryfikowany model może być wykorzystany do optymalizacji różnych parametrów technologicznych, stanowiąc efektywną metodę poprawy jakości wyrobów oraz zmniejszenia kosztów produkcji. Key words: seamless steel tube, FEM, numerical simulation, multi-rifled tube, cold drawing Słowa kluczowe: stalowa [...]

The technology of cold drawing of seamless steel tubes using numerical simulation DOI:10.15199/24.2017.8.17


  Introduction. At Zeleziarne Podbrezova a. s. (ZP), the drawing process of precision seamless steel tubes has a long tradition. Already in 1968, the construction of a new tube plant began. The tubes have been produced at ZP by draw􀀐 ing technology since 1971. After long time, this process has undergone great changes. Today, ZP is a major European producer of hot-rolled and cold-drawn seamless steel tubes. At present, it is possible to talk about high-tech technology. The drawing plant is equipped with 14 drawing benches with drawing force from 250 to 1000 kN. These devices enable to produce tubes with dimensions: outer diameter from Ø4 to Ø120 mm, with a wall thickness of 0,5 - 11mm and length from 2 - 16mm. The tubes are drawn to the final dimensions according to the customer´s requirements. For this particular technology, a hot rolled seamless steel tube serves as a feedstock for multiple cold drawing opera􀀐 tions with intermediate heat treatment. The reduction of the outer diameter and wall thickness must be set correctly for every pass. The aim is determine the lowest number passes because of low economy costs. In this technology, drawing with plug and hollow sinking are used. In the first passes, where the outer diameter and wall thickness is reduced, the drawing with the fixed plug is used. The fixed cylindrical or fixed conical plug is utilized depending on the wall thickness of input feedstock. The conical plug enables to use higher drawing velocity thanks to its geometry which provides better flow of material. Hollow sinking is a final process in which the wall thickness stays the same and the outer dimen􀀐 sion is reduced [1-3]. In general, the drawing process is determined by the mate􀀐 rial properties of the tube being drawn, the lubrication, and the tool ge[...]

Analysis of eccentricity hot rolled tubes DOI:10.15199/24.2016.8.16


  Analiza mimośrodowości rur walcowanych na gorąco The production programme of ironworks Železiarne Podbrezová a.s. deals primarily with the production of seamless steel tubes rolled from billets from company’s foundry. This paper deals with the study of the transverse defects causes of tubes, especially eccentricity that is evaluated at each technological node separately. The problem of tube eccentricity is considered as a p rimary factor of geometrical deviation. The current method of eccentricity evaluation has been examined. Part of the paper comes up also with the continuous evaluation of tube eccentricity in real production runs. This evaluation takes place once a month, with 98% of seamless tubes produced with eccentricity not exceeding 5%. Conclusions in this paper are decisive for taking preventive measures for eccentricity to occur and also for fixing the measurement methodology for eccentric tubes. Program produkcji huty Železiarne Podbrezová a.s. obejmuje głównie wytwarzanie rur stalowych bez szwu walcowanych z wlewków pozyskanych z własnej odlewni [...]

Compare of the Dies and They Influence of Geometry Precision of the Cold Drawing Tubes with Small Dimensions DOI:10.15199/24.2017.8.22


  Introduction. The article deals with production of seam less precision cold drawing tubes drawing without plug and the influence of technological parameters with effect on the mechanical properties of the tubes. The aim of the ex􀀐 periment is to verify the possibility of drawing hot rolled tubes by one pass technology from dimension 18 × 0.9 m with tempering after drawing to dimension 6 × 1 mm by selected reductions which abide by the factory conditions of Železiarne Podbrezová a.s.. At the End of the article is comparison of both of these dies on geometry and mechani cal properties (Rp0.2, Rm, A5.65). Next is the same com parison in software DEFORM 3D. With consideration of specialization on production seamless precision tubes in Železia[...]

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