Papers by Keyword: High Manganese Steel

Abstract: This paper presents a study of three types of Triples steel, where containing 16 to 28 wt.% manganese, 0.8 to 0.89 wt.% Carbon, 9.9 to 11.21 wt.% Aluminum, and with different Nickel content. We investigated the aging effect on properties of Triplex steel by using an optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). The used temperature in the ageing process is 550°C and we take three different times in that process (1min, 1hr, and 5hrs). The microstructure shows one austenite phase of an as-rolled sample without Ni and shows two austenite phases of an as-rolled sample with Ni content. The k-carbide, intermetallic phase (Ni3Al) and annealing twins formation will appear after adding Ni element. Furthermore, those phases will be increased with aging time. X-ray diffraction shows a competitive formation between the k-carbides and intermetallic phase formation during the aging time. It's confirmed that K-carbides will be formed first after that intermetallic phase, where k-carbides were formed at low temperature. Finally, we can conclude from these results that adding Ni in Triplex steel improves the ductility with 1hr aging time.

Abstract: In this paper, the impact of cutting speed and feed amount on cutting deformation and surface quality and cutter wear have been studied by the test of high manganese steel cutting with metal ceramic tool at high speed. The results show that it is feasible by cutting high manganese steel with cermet tool at high-speed cutting (HSC). Chip changes into succession segment from band in macrostate. Sawteeth can be seen on the top surface of chip while high temperature feature in burning color and cold welding form appear on the bottom of the chip. The model of surface roughness built can be used to predict surface quality at HSC, and provided cutting optimized parameters scheme. Further research indicates that high-speed cutting has its special deformation mechanism and plastic chips exhibit hot brittleness which provides a favorable condition for solving the chip breaking problem in the cutting of high manganese steel.

Abstract: The paper investigates the influence of alloying of high manganese steel with various materials on its wear resistance. It describes the results of differential scanning calorimetry and thermo-gravimetric analysis obtained in the process of thermal investigation of high manganese steel alloyed with different materials. The processes taking place in alloyed high manganese steel during heat treatment were considered. Besides, the paper shows the results of investigation of kinetics of oxidation of high manganese steels, temperatures of the start and completion of carbide decomposition and carbon burning; the comparative analysis of these processes was carried out. The research group determined the qualitative characteristics of the steel decarburization process depending on the implemented alloying scheme of high manganese steel. Scientific justification was given to the results obtained in the research work. The technological recommendations, which make it possible to calculate the optimum hardening temperature of high manganese steels, were given. General conclusions were made in the final part of the paper.

Abstract: Applying a specific roughness on steel sheets, to ensure paintability and sufficient lubrication, is a crucial point for the metal forming processes. Due to the strength of high manganese HSD^® steels (X70MnAlSi 15-2.5-2.5), special actions are necessary to obtain the required roughness. At Salzgitter Mannesmann Forschung GmbH skin-pass rolling experiments on high manganese HSD^® steels with different PRETEX^® textured work-rolls were performed to investigate the influence of roll-surface-texture and skin-pass rolling force on the roughness transfer. The roughness and texture parameters of the steel sheets and roll surfaces were determined using optical confocal microscopy measurements. It is clearly shown that the work-roll surface texture has a major influence on the roughness transfer from work-rolls to steel sheet surfaces.

Abstract: The present paper addresses a 3D investigation of a complicated fatigue crack profile and crack growth behavior in cast Hadfield high manganese steel by in-situ X-ray computed tomography (CT) experiments. In-situ loading experiments were performed on fatigue pre-cracked samples at the X-ray beamline BL13W1 of Shanghai synchrotron radiation facility in China, and high-resolution phase contrast imaging technique was applied to obtain the 3D images. Based on the rendered 3D images at varied loading levels, various crack features and the interactions of the fatigue crack with casting pores were identified and analyzed.

Abstract: The aim of this paper is to determine the high-manganese austenite propensity to twinning induced by the cold working and its effect on structure and mechanical properties, and especially the strain energy per unit volume of new-developed high-manganese Fe – Mn – (Al, Si) investigated steel, containing about 24,5 % of manganese, 1% of silicon, 3 % of aluminium and microadditions Nb and Ti with various structures after their heat- and thermo-mechanical treatments. The new-developed high-manganese Fe – Mn – (Al, Si) steel provide an extensive potential for automotive industries through exhibiting the twinning induced plasticity (TWIP) mechanisms. TWIP steel not only show excellent strength, but also have excellent formability due to twinning, thereby leading to excellent combination of strength, ductility, and formability over conventional dual phase steels or transformation induced plasticity (TRIP) steels. Results obtained for high-manganese austenitic steel with the properly formed structure and properties in the thermo-mechanical processes indicate the possibility and purposefulness of their employment for constructional elements of vehicles, especially of the passenger cars to take advantage of the significant growth of their strain energy per unit volume which guarantee reserve of plasticity in the zones of controlled energy absorption during possible collision resulting from activation of twinning induced by the cold working as the fracture counteraction factor, which may result in significant growth of the passive safety of these vehicles' passengers.

Abstract: In this paper, TiC reinforced steel matrix surface composites were prepared by vacuum evaporative casting infiltration process and self-propagating high-temperature synthesis. The effect of original composition, binder types and original coating density on the hardness, wear resistance and microstructure of the coating were also studied. The results showed that the Ti and C content was 80% while added 3% PVA, by pressed at 200MPa pressure leading optimal coating quality. Meanwhile the average hardness was 62.5HRC and the wear rate was 22 % of high manganese steel.

Abstract: In this paper, TiC reinforced steel matrix surface composites were prepared by vacuum evaporative casting infiltration process and self-propagating high-temperature synthesis. The effect of original composition, binder types and original coating density on the hardness, wear resistance and microstructure of the coating were also studied. The results showed that the Ti and C content was 80% while added 3% PVA, by pressed at 200MPa pressure leading optimal coating quality. Meanwhile the average hardness was 48HRC and the wear rate was 40%.

Abstract: New generation high-strength austenitic and austenitic-ferritic manganese steels represent a valid potential in applications for components in the automotive and railway industry due to the perfect combination of high mechanical properties and formability. Applying this new steels with their combination of properties allows for reduce the weight of vehicles by the use reduced cross-section components and thus to reduce fuel consumption. The development and implementation of industrial production and the use as construction materials such interesting and promising steel is conditioned to improve their casting properties and susceptibility to deformation during thermomechanical processes conditions. In this work, applied an new high manganese austenitic-ferritic steel for analysis the influence of the cooling medium in thermomechanical processes on the mechanical properties and structure of researched steel. The steel was hot rolled with finish temperature 900°C and next cooled with different conditions. Change the cooling conditions effect on the changes in the microstructure of the tested steel, observed grain refinement of austenite and ferrite morphology change. Also are changing the mechanical characteristics of the tested steel.

Abstract: In recent years, the leading scientific centres focus their research on improvement of mechanical properties of steels used for car manufacturing. These steels belong to a so-called 2^nd generation of steels showing above-the-average plasticity while maintaining high strength. Thanks to these properties, they may be used successfully in automotive, armaments or railway industries for elements absorbing energy of a collision and ensuring high rigidity of a structure owing to their resistance to breaking. These steels are called TWIP (Twinning Induced Plasticity) steels based on their hardening mechanism. In this paper, results of studies on the influence of parameters of thermo-plastic deformation on selected properties and structure of an X45MnAl20-3V austenitic steel showing the TWIP effect are presented. Moreover, an analysis of influence of the deformation on the structure of the studied steel in tensile tests has been carried out. The studied steel was manufactured by classic casting to a concast mould, obtaining ingots with dimensions of 100×100 mm, then subjected to rolling in 4 roll passes to a final thickness of 12 mm and 3 mm. The finish-rolling temperature was 950°C and the sheets were cooled in 2 media, i.e. in air and in water. It was confirmed that the studied steel belongs to the TWIP group of steels, with mechanical twinning being the prevailing process of hardening during deformation.