Marcin Kwapisz

Analysis of the Shape of Stamp on the Distribution of Deformation in the Process of Alternate Pressing and Multiaxial Compression

The paper presents the results of numerical simulations of the alternate indirect extrusion and multiaxial compression process, performed using commercial software designed for the thermomechanical analysis of plastic working processes, Forge 2009. The paper presents selected results on the distribution of deformation in the process of alternating extrusion and multiaxial compression. Examples of modifications to the shape of the die and punch, and their effect on the kinetics of the material flow as well as the likelihood of defects of materials are provided. The results confirm that suitable modifying the shape of the die and punch enables to obtain a material with no internal defects. Iterative process, alternating squeezing and multiaxial compressive strain allows the accumulation of which results in fragmentation of the microstructure.

Theoretical and Experimental Analysis of the Cooling Ability of Device for the Plain Round Bars Accelerated Cooling Process

The paper presents the results of the numerical modelling and industrial research of the cooling ability of the device for the round plain bars accelerated cooling process. Research were carried out for one of the bar rolling mill technological conditions in a few variants. The paper purpose was determination of the cooling ability of device for accelerated cooling process to checking possibility of the using this device in the rolling line, during normalizing rolling process. Investigation results elaborated in the paper made the basis for determination of the heat exchange coefficients between cooled band and water. In the next stage of this paper numerical modeling of the normalizing rolling process with accelerated cooling of band in the final stage of the rolling process was carried out. In this investigation heat exchange coefficients between band and cooling medium (water), which were determinated with allowance of cooling possibilities of investigated device for band accelerated cooling were used. From the obtained results it was found that in the analysed bar rolling mill it is possible to decrease the band average temperature to about 900 °C, which is required during the normalizing rolling process.

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.

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.

Numerical Modelling of the Cooling Ability of Device for the Plates Accelerated Cooling Process

The paper presents results of the numerical modelling of the plates accelerated cooling process after the rolling process. Research were carried out for one of the plate rolling mill technological conditions. Presented in the paper research were done for a few variants for X70 steel grade. As a result of the carried out research temperature distribution on the cross section of the cooled plates for the analyzed variants of the accelerated cooling process were obtain.

Influence of Rolling Reduction, Strip Shape and Asymmetry Factor on the Strip Curvature

In order to improve the quality of plates, an asymmetric rolling process can be introduced, which will help reduce the total roll separating force and increase plate flatness and decrease thickness deviations along the width and length of rolled strip [1÷.

Numerical Analysis in the Process of Alternate Pressing and Multiaxial Compression

This article presents the results of numeric simulation obtained with commercial software for thermo-mechanical analysis of plastic forging processes, Forge 2009, of the process of alternate forced pressing and multiaxial compression. The new method of alternate forced pressing and multiaxial compression suggested by the authors is characterized by the presence in the plastically forged material of the similar states of deformations to those present in the processes of the equal channel angular pressing and cyclic extrusion compressing. From the performed preliminary tests it can be stated that as a result of combining and repeating two alternate operations: pressing and multiaxial compression, strain accumulation and development of deformation state favorable to grain crushing take place.

Analysis of the Plasticity of High-Carbon Alloy Steel in the Conditions of Hot Plastic Working

This research work presented the analysis of plasticity of high carbon alloy constructional steel in the conditions corresponding to plate rolling in a reversing mill. The deformation and temperature conditions occurring in the real process were reproduced during testing. Plasticity of the steel in the temperature range of 800÷1000oC and for three different strain rates of 0.1, 1.0 and 10 /s was determined in the course of experiments. The research was carried out using the Gleeble 3800 physical simulator of metallurgical processes with the Pocket Jaw module, to estimate the steel plasticity in the uniaxial tension test to the failure strain of the sample. The performed research work enables to determine the optimum temperatures and size of the critical deformations which should be taken into consideration when designing the process of the tested steel rolling in order to avoid formation of internal and external cracks.