http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of Roller Die Drawing on Structure , Texture and Other Properties of High Carbon Steel Wires
Pilarczyk, Jan W .,Dyja, Henryk,Golis, Bogdan,Tabuda, Elzbieta 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.4
In the work the effect of application of roller dies in process of drawing of high carbon steel wires for their structure, texture, residual stresses, surface roughness and mechanical properties has been investigated. Among structural features alignment of cementite lamellae to the wire axis by means of SEM and Pericolor 1500 has been quantitatively determined. Degree of cementite lamellae fracture in colonies parallel to wire axis has been estimated by Langford method. Obtained results were compared with those structural features for conventionally and hydrodynamically drawn wires. It has been found that degree of alignment of cementite lamellae in wires drawn in roller dies was smaller than in wires drawn conventionally and hydrodynamically but in the case of fracture degree the opposite result was noticed. Residual stresses were determined by electrochemical reversal pickling in water solution of sulphuric acid. A significant drop of longitudinal residual stresses in surface layer of wires drawn in roller die has been observed as compared to those stresses for conventionally and hydrodynamically drawn wires. Surface roughness of wires was measured with FORM TALYSURF profilographometer. It has been proved thud roller die drawing lass formed very smooth surface with much smaller longitudinal and circumferential roghness parameters that for surface of wires drawn conventionally and hydrodynamically. In the work the tensile, yield and fatigue strength of tested wires were determined. It has been concluded that roller die drawing has many advantages as compared to conventional process and should be implemented in wire industry for larger scale.
Bohdan Węglowski,Marcin Pilarczyk 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3
The aim of this work is to present a method to determine the transient-state spatial temperature distribution in a cylindrical component. The presented method involves solving the inverse heat conduction problem based on the Finite volume method (FVM). This approach enables determination of transient-state temperature fields with boundary conditions known on one surface of the component only. The proposed method is verified using the laboratory installation located at the Cracow University of Technology. The main components of the laboratory stand are, among others, a steam outlet header and a steam boiler. During the experiment, the steam header is heated up abruptly from the inside by contact with dry saturated steam. The spatial transient-state temperature distribution within the steam outlet header is determined using the proposed method, which is based on temperature measurements made by 19 thermocouples located on the outer surface of the component. The temperature histories in three selected nodes are compared with the measurement results obtained from thermocouples located inside the component wall. The exact location of the thermocouples corresponds to the nodal position at selected control volumes. Moreover, the Ansys Mechanical APDL software is used to verify calculations and experimental data. A transient-state simulation is performed. The temperature histories at the inner and outer surfaces are set as the model boundary conditions. In order to enable verification of the temperature measurements, the component discrete model includes nodes at appropriate locations. An error analysis is performed between calculated and measured temperature values. The results obtained from the numerical and experimental validation demonstrate fully satisfactory agreement. Additionally, a stress analysis of the outlet header is performed in the Ansys software based on the transient-state temperature distribution within the steam outlet header. The method proposed in this paper is a convenient and accurate tool for monitoring working conditions of the power boiler thick-walled components.
The Analysis of Microstructure Change during Multi - Pass Rolling of a Steel with Niobium
Korczak, P .,Dyja, H .,Pilarczyk, J . W . 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.4
The present paper describes experimental and numerical analyses for prediction of microstructure changes during hot plate rolling, which was conducted in Metal Forming Department Czestochowa, Technical University. Models describing kinetics of recrystallization of deformed austenite and precipitation of niobium carbon-nitrides were evaluated in semi-industrial conditions. The main objective of simulation using finite element methods was to determine temperature anti strain distributions in the roll gap and parameters of microstructure through thickness of rolled plates. The experimental results were compared with computer simulation results, which showed that retained strains accumulated during the previous passes have a big influence on stability of distribution of mechanical properties.