Papers by Keyword: Low Carbon Steel

Abstract: TRIP effect containing steel was well reputed by its high mechanical properties among the 1^st generation of Advanced High Strength Steel. High Silicon content was well established as an inhibitor for cementite precipitation at para-equilibrium condition. However, the effect of manganese as a powerful stabilizer for retained austenite was not much studied in TRIP-Steel. Thereby, the effect of high manganese content on the TRIP containing steel is studied in this research. As been observed from OM, and XRD results, it was found that as long as increasing Manganese content, the fraction of retained austenite increases. No doubt that enrichment of retained austenite throughout the matrix, beers a great impact on the plastic deformation character of the investigated steels, which was proved by using a uniaxial tensile test and determining the strain hardening exponent.

Abstract: The aim of this paper is to present the simulation and experiment of the welding butt-joint aluminum alloys to low carbon steel using Visual-weld software and the metal inert gas (MIG) welding process. The workpiece is set up in a virtual environment with an area of 150 x 70 x 5 mm, a welding speed at 3.5 mm/s, and a heating source of 2.5 kW. The finite element method (FEM) is used as a powerful tool in simulating, calculating and predicting the welding stress and distortion at the early stage of the design process and development of welding products. The metallurgical process, deformation, hardness, etc. are investigated using the FEM in Sysweld software. The microstructure of the intermetallic layer is observed using scanning electron microscopy. The hardness of the intermetallic layer is examined using Vickers hardness testing. Tensile strength and bending strength are examined by tensile and compress multimeter equipment. To improve the quality of the aluminum/steel welds, the IMCs layer should be as small as possible. The experimental results are better if the welding current of range of 95 – 100 A and the welding speed is from 3.5 to 4 mm/s.

Abstract: The deformation treatment of Fe360 low carbon steel by extrusion, equal-channel angular pressing, and equal-channel angular pressing with extrusion in one pass at a temperature of 673 K is considered.The strength increase in steel is shown for all methods of hardening. It is noted that in the range of temperature under consideration, the strength characteristics and the relative residual constriction of hardened steel samples are the parameters of low sensitivity to temperature decrease. The material destruction mechanism in various states under uniaxial tension under conditions of room and low temperature is analyzed.

Abstract: The microstructure and mechanical properties of ferritic rolling low carbon steel are investigated by metallurgical microscope, thermal simulation testing machine, electron backscattered diffraction (EBSD) and universal tensile test machine. The finishing temperature of the transition from austenite to ferrite changed from 680°C to740 °C with different cooling rates, which was obvious lower than that of the interstitial free steel. The deformation stress of low carbon steel was larger than that of interstitial free steel. In addition, the deformation stress of the low carbon steel was more sensitive to the deformation rate than that of the interstitial free steel. The microstructure at the surface layer of the hot rolling plate was composed of fully recrystallized grains while the microstructure in the center was composed of fibrous deformed grains. The ferritic rolling low carbon steel has lower yield ratio and higher elongation than that of normal rolling low carbon steel.

Abstract: Influence of chemical composition (C, Mn and Nb) and soaking temperature on the evolution of austenite grain size from a cold-rolled microstructure was studied on several Advanced High Strength Steels. A wide range of soaking temperatures was used to perform the heat treatments. Characterization of prior austenite grain size from the annealed samples using optical and confocal microscopes, Scanning Electron Microscope and Electron Back-Scattered Diffraction. Comparison of different methods was done to validate the methodology and the results were quite satisfactory. Concomitant effects of Manganese, Niobium, Carbon and of soaking temperature on the prior austenite grain size were analyzed and discussed. Important effect of Mn and Nb was underlined.

Abstract: In order to achieve excellent toughness of heat affected zone (HAZ) of low carbon steel plates by welding, several microstructure control techniques using fine particles have been developed. In particular, Ca-oxysulfide inclusions have been used in a lot of steel plate products, because they are thermally stable even in near the fusion line of weld joint and they have grain refining effect in HAZ. In cases where heat input is large (>100kJ/cm) and microstructure of HAZ mainly consists of polygonal ferrite, it has been clarified that Ca-oxysulfide inclusions act as nucleation sites of polygonal ferrite in HAZ during the cooling process after welding. However, in cases where heat input is medium (≈50kJ/cm) and microstructure of HAZ mainly consists of bainite, nucleation effect of Ca-oxysulfide inclusions and that of mechanism have not been clarified. This study investigated the nucleation effect of Ca-oxysulfide inclusions in medium heat input welding by in-situ laser microscope observation and the lattice misfit between Fe-matrix and Ca-oxysulfide inclusions.

Abstract: In this study, mechanical properties development of reinforcing bar steel (rebar) has examined through heat treatment process. This rebar was made from low carbon lateritic steel with the small amount of alloying elements Cr,Mn and Ni. There were 4 rebar steel samples that consisted of rebar steel was applied hot rolled at 1200 °C at the beginning process in factory (sample A) and three others were conducted by quenching (sample B, C and D). The various of cooling media such as water (sample B), oil (sample C) and air (sample D) have applied to obtain different microstructure behavior and also mechanical properties. Initial heating was conducted to B,C and D rebar specimens at the austenitizing temperature (950 °C) for 1 h and followed by quenching. The experimental results showed that water quench exhibited of higher hardness level (50,26 HRC) for rebar steel but decreasing in toughness (34 Joule) and elongation (4%) than as cast because of martensite phase formed. Sample C showed that martensite and the small amount of retained austenite with hardness and tensile strength below the sample B, but elongation and energy absorbed were above. The lowest of hardness and tensile strength were obtained from sample D. It was appropriate with microstructuree formed as follows ferrite-pearlite phase and widmanstatten-bainite cluster. Nevertheless, sample D is suitable treatment for tensile strength and elongation requirements rebar standard, there are 558 Mpa and 26% respectively (min. 440 MPa and 20%).

Abstract: Bioethanol is a clean and sustainable fuel; on the contrary, the addition of bioethanol to gasoline normally creates corrosion on automobile fuel system materials. In this study, corrosion characteristics of low carbon steel normally encountered in gasoline engine fuel system with bioethanol fuel was investigated. Static immersion tests in different fuel blends E0 (gasoline), E10 and E85 were carried out at room temperature for 1320 h. The mechanical, physical and chemical properties of low carbon steel before and after immersion tests were investigated. Moreover, the physical and chemical properties of fuel blends before and after immersion tests were investigated. The results revealed that the usage of E10 blend is considered feasible for gasoline engines in terms of materials compatibility compared to E85.

Abstract: Anodic current-supplying pins (ACP) made of low-carbon steel corrode intensively due to the sulfur contamination of the carbon-based Soderberg anode and iron sulfides formation in the present aluminium production technology. The aluminide coatings produced by the liquid-phase method followed by the fluoride flux treatment of the steel samples were applied for the ACP protection. The protective layer based on α-Al₂O₃ and FeAl₂O₄ was formed on the steel surface in the course of the test run in the industrial Soderberg anode during the aluminium electrolysis. The aluminized ACP wear rates calculated by the linear extrapolation of data obtained during 150 days workout were 4.0 and 5.4 cm/year for the ACP with the aluminide coating and without it, respectively. The current load on the ACP remained almost the same for the aluminized and original uncoated samples with the exception of the initial “heating” period (400-600°C).

Abstract: Increase of soaking time contributed to the effectiveness of case depth formation, hardness properties and carbon content of carburized steel. This paper investigates the effect of different soaking time (7-9 hours) using powder and paste compound to the carburized steel. Low carbon steels were carburized using powder and paste compound for 7, 8 and 9 hours at temperature 1000°C. The transformation of microstructure and formation carbon rich layer was observed under microscope. The microhardness profiles were analyzed to investigate the length of case depth produced after the carburizing process. The increment of carbon content was considered to find the correlation between types of carburizing compound with time. Results shows that the longer carburized steel was soaked, the higher potential in formation of carbon rich layer, case depth and carbon content, which led to better hardness properties for carburized low carbon steel. Longer soaking time, 9 hours has a higher dispersion of carbon up to 41%-51% compare to 8 hours and 7 hours. By using paste carburizing, it has more potential of carbon atom to merge the microstructure to transform into cementite (1.53 wt% C) compare to powder (0.97 wt% C), which increases the hardness of carburized steel (13% higher).