The effects of ferrite grain size on dynamic tensile properties of lowcarbonsteels with various chemical compositions are shown. The strain rate dependence of ﬂ ow stress, represented by the difference between ﬂ ow stresses at high and low strain rates, ¦· , was the highest in the interstitial free (IF) steel having ferrite single-phase microstructure and the 0.1 % C-steel having ferrite cementite (FC) microstructure. The ¦· decreased when P and Mn were added. In all the steels used, the ¦· was almost constant or decreased only slightly when the ferrite grains were re ﬁ ned down to 2 4 µm, and it decreased signi ﬁ cantly by further grain re ﬁ nement down to sub-micrometer region. The FC and ferrite single- phase microstructures strengthened mainly by grain re ﬁ nement of ferrite showed higher dynamic absorbed energy compared with the other steels strengthened by alloy addition. [doi:10.2320 / matertrans.MA201323]
proximately 15 % (Goodman 1984). These findings indicate that the γ fraction is an important point for the nucleation site of γ , and the nucleation site of γ is mainly a high-angle grain boundary when the γ fraction is low. On the other hand, as mentioned above, pearlite colonies should be the nucleation sites for γ when the microstructure before an- nealing consists of ferrite and pearlite (Huang et al. 2004; Speich et al. 1981). Therefore, it appears that the micro- structure before annealing can also affect the nucleation site of γ. Furthermore, it has been demonstrated that the micro- structure before annealing affects the recrystallization behav- ior of α during annealing in cold-rolled low-carbonsteels (Yamaguchi et al. 2011). The influence of the microstructure before annealing on the competition phenomenon between recrystallization of α and formation of γ during annealing is an important issue for further clarification.
The unprecedented global warming process causes the shrinking of sea ice in the polar region every year; hence, in order to withstand the harsh environment of this region as well as to reduce the transportation cost, a large number of high-strength steels are required to build icebreakers. The main objective of the present study was to investigate the corrosion behavior of both water-quenched and air-cooled low- carbonsteels in 3.5% artificial NaCl solution. It was found that after the corrosion of lamellar ferrites in pearlites and martensites, the remaining cementites aggravated the galvanic corrosion and the pitting corrosion in the matrix. Further, dislocation and the presence of large fractions of cementite in the matrix deteriorated the corrosion resistance property of the directly water-quenched sample. However, the air- cooling process significantly improved the corrosion resistance behavior of the sample steel.
In this paper the effect of the mechanical/thermo mechanical processing on the mechanical and metallurgical properties of lowcarbonsteels, viz, Cold Reduced lowcarbon Steel (CRS) and Themo Mechanically Treated (TMT) steel are discussed. These steels are widely used in automobile, railways, naval architecture, petroleum industry, etc, applications with exposure to extreme temperature conditions and subjected to stress and exposed to corrosive environment . The most commonly used type of steel are lowcarbon steel, High Strength Low Alloy Steel (HSLA), Cold Rolled Steel and Hot Rolled steel (HRS). The mechanical properties like ductility, strength and metallurgical properties like microstructure, grain size, etc, influence the properties of the rolled steels. In this paper an effort is made to study the research reported in literature, on the innovations in processing of lowcarbon steel through grain refinement and heat treatment to produce steel possessing good mechanical and metallurgical properties .
A comparative research on the mechanical properties and microstructural studies of locally produced and imported low-carbonsteels have been conducted. These low-carbonsteels have played major roles in the building and fabrication industries in Ghana.Twodifferentbatches of samples (rebars) from local and foreign producers were used. The rods were obtained from the dealers on the open market. The chemical analyses werecarried out at Tema Steel Works Company Ltd.The tensile tests, hardness measurements and microstructural studies were carried on both the local and the imported steels. The results showed that, the imported rods were more ductile, with higher toughness values and percentage elongation than the locally produced samples. The locally produced rods, however, had higher ultimate tensile strength, higher hardness and were more brittle than the imported samples. The differences in the mechanical properties of the samples were attributed to the different elemental compositions and the production methods used.
components in (111)[1 2 1], (111)[0 1 1], (111)[ 11 2], -fibre <110>//RD with main components in (111) and (001), and -fibre <100>//ND with main components in (001) and (001), . In the case of ultrathin sheets of lowcarbonsteels processed by double reduction, the continuous annealing treatments could be highly effective because the sheet deformation process occurs in relatively short time. A strict control during the ultrathin sheet fabrication stages could result in texture that benefits properties of finished products. However, the effect of a double reduction and subsequent annealing on the final texture has not been properly studied yet. Therefore, the goal of this work is to study the texture evolution during the double reduction cold rolling process with application of continuous annealing aiming to suggest process improvements without affecting the finished product quality.
Rolling is the process of plastic deformation of materials by passing them through a set of rolls. During deformation, metal is subjected to compressive stress in its normal direction (ND). The metal sheet is thinned along its ND because of the compressive stress and the extension that takes place along the rolling direction (RD) whereas lateral expansion is restrained along the transverse direction (TD) by friction [24, 25]. The formability of a metal sheet depends on its scheduling during rolling process apart from its alloying elements. In other way the type of texture and microstructure evolves after rolling process, decides the formability of a metal. Plastic anisotropy induced by the formed texture can have both a beneficial and detrimental effect on the formability. In a strong textured sheet, the variation in yield stress can be observed along with the direction in rolling plane as well as in the thickness of a sheet. Such a directional behaviour affects non-uniform material flow in deep drawability of metals. Taking a step towards the importance of texture formation in rolling, this thesis work investigates on the effect of asymmetry in roll diameters on rolling of plain lowcarbonsteels.
For magnetic applications, two classes of steels are involved. One is lowcarbonsteels and the other the ferritic stainless steels. The composition of lowcarbonsteels is typified by AISI C1010, which contains 0.08-0.13% C, 0.3-0.6% Mn, up to 0.04% P and up to 0.05% S. Despite the presence of these elements in steels, little or no sacrifice of magnetic properties is noticed. Since lowcarbonsteels are inexpensive and yet exhibit far higher yield strengths than pure iron, make the lowcarbonsteels attractive for many low frequency magnetic applications such as laminations for relays, pole pieces and pole supports of motors and other electromechanical equipments . Semi-processed lowcarbon (Fe-0.04-0.06%C) steels have permeability of about 2000 and watt losses of 5.5 W/kg, the permeability are usually measured at 15 kG (1.5 Tesla) . Further, for lowcarbon wrought steel with 0.05%C the permeability, coercivity, saturation induction, resistivity and core loss values reported are 5000, 1.0 Oersted, 21.5 kG, 10 micro-ohm- cm and 2.8 W/kg (at 15kG and 60 Hz) respectively .
Two low-carbonsteels with diﬀerent impurity contents were prepared by strip casting to clarify the advantages of the process. The mechanical properties and the plastic anisotropy of the as-cast, the homogenized and the recrystallization annealed strips were investigated and compared. The as-cast strips showed a good strength-ductility balance and a superior plastic anisotropy to the other strips. The largest average ferrite grain oriented in the -ﬁber is concluded to be responsible for the highest normal anisotropy in the as-cast strips. Meanwhile, the orientation volume ratio between the -ﬁber and the -ﬁber showed a roughly linear relationship with the normal anisotropy of the recrystallization annealed strips. The lower planar anisotropy in the as-cast and homogenized samples was related to the orientation distribution on the h114ikND orientation line.
The influence of molybdenum content on the process of stress corrosion of ultra-lowcarbon structural steels with the addition of copper HSLA (High Strength Low Alloy) was analyzed. The study was conducted for steels after heat treatment consisting of quenching and following tempering at 600°C and it was obtained microstructure of the tempered martensite laths with copper precipitates and the phase Laves Fe 2 Mo type. It was found strong influence of Laves phase precipitate on the grain boundaries of retained austenite on rate and
In this paper, a novel arrangement for magnetic Barkhausen noise detection is introduced. Measurements have been performed using two lowcarbon steel plates of 1 mm thickness. The measurements were conducted along the roll- ing and the transverse directions. The new arrangement includes a displace- ment of the detection coil in predetermined steps in while the magnetizing yoke is kept stationary introducing a cyclic magnetization in the rolling direc- tion and transverse to it. In general, the intensity of the Barkhausen signals decreased as a function of coil displacement in both plates. In the temper rolled plate, Barkhausen noise profile shape changed from a single peak to a double peak one when coil has been displaced by 5 mm away in both magne- tizing directions. Peaks are more apparent while magnetizing in the trans- verse direction. The appearance of two peaks profile in the temper rolled plate may be attributed to two stages of magnetization taking place at differ- ent times as a function of the applied field. Magnetization in the transverse direction results in a partition of the internal magnetizations into two main components perpendicular to each other. The internal components of mag- netization involve the magnetic easy axes in the rolling direction and the forced magnetization in the transverse direction due to the applied field. Another assumption to interpret the findings may be due to the internal de- magnetization field in the soft material below surface. The findings support this assumption in such a way that the demagnetizing field is strong enough in the transverse direction than in the rolling direction. This assumption is supported by the experiment on cold rolled plate. In the cold rolled plate, the resultant MBN profiles are composed of one peak throughout the test due to high dislocation density and hence a very weak demagnetizing field.
There are several XLPA methods such as Williamson-Hall, Warren-Averbach, and Multiple Whole Profile (MWP) fitting. The Williamson-Hall method is a simple and direct method so has been used widely in the literature while both Warren-Averbach and MWP are indirect methods and contain complexity to a large extent. Chacraborty et al.  cold-drew pearlitic steel (0.8 wt.% C) up to a strain of 1.4 and investigated the microstructure using XRD. The cementite reflections were detected during the XRD test and this can be attributed to the high volume fraction of cementite in the investigated sample. However, the cementite peaks became weak with increasing strain suggesting that the cementite dissolution increases with strain. Chacraborty et al.  successfully used Rietveld analysis to study the cementite dissolution during the drawing process and concluded that the cementite dissolution was more than 50% at a drawing strain of 1.4. The lattice parameter did not change with strain which suggests that the carbon atoms which left the cementite did not occupy the interstitial sites in ferrite to form solid solution. The authors used the modified Williamson-Hall method to determine the dislocation density and the nature of the dislocation evolved during the drawing process. The authors successfully eliminated the strain anisotropy observed in the classical Willamson-Hall plot (Figure 2.65) by introducing the dislocation contrast factor or plotting the so-called modified Williamson-Hall plot (Figure 2.66). The authors determined the dislocation density in the ferritic-pearlitic sample cold-drawn up to a strain of 1.4 as 810 15 m -2 while the fraction of the screw dislocation was found to be
The effects of the titanium and oxygen concentration on the characteristics of inclusions and microstructure in lowcarbon wrought steels were investigated. Increasing the titanium concentration from 48 to 120 ppm promoted the formation of TiN particles and decreased the prior austenite grain size. The fraction of intragranular ferrite in the microstructure was relatively unchanged. When the oxygen concentration was increased from 50 to 130 ppm, the volume fraction and the number of inclusion increased. However, the fraction of intragranular ferrite in microstructures decreased abruptly above 80 ppm because the allotriomorph ferrite phase at the prior austenite grain boundary began to form.
Abstract: A careful consideration of facts, there is a segment of steel in the world at large. Steel has various realistic applications in each segment of life. Steel with unprecedented properties are the best among the things. Lowcarbon steel has carbon substance of 0.15% to 0.45%. Lowcarbon steel is the most appreciated kind of steel as its gives material properties that are praiseworthy for two or three usages. It is neither remotely sensitive nor bendable in light of its lower carbon content. The various heat treatment outlines are annealing, normalizing, hardening, austempering, hardening and surface hardening. The work is concerned it is basically centered on carburizing which is a case setting process. The cases were prepared for heat treatment process is finished. These cases are attempted under UTM machine. Then diverse mechanical properties are recorded Keywords: Lowcarbon steel, Heat treatment, Mechanical properties, UTM, Carburizing
Martensite, a hardened microstructure, forms from the transformation of austenite when quenching to room temperature in steels, where carbon formerly in the austenite remains in solid solution during the displacive transformation. The crystal structure changes from face-centred cubic (FCC) of austenite to body-centred tetragonal (BCT) of martensite, compared with the body-centred cubic (BCC) of ferrite because of the supersaturated carbon in solid solution, which results in higher hardness but lower toughness and ductility. Two major morphologies of martensite, named as lath martensite and plate martensite, form in alloyed steels based on the different contents of carbon. For lowcarbonsteels (alloyed and plain carbon), such as Q&T plates (S690-based steels) studied here, the microstructures are generally lath-like martensite. The lath boundaries consist of a high density of dislocations arranged as low-angle grain boundaries (LAGBs) with misorientation angles less than 3° (mostly 1-2°) . Whereas, the packet boundaries, where one packet contains several laths, and prior austenite grain boundaries are high- angle grain boundaries (HAGBs) with misorientations ≥ 15° . The low/high angle- grain boundaries can be regarded as disordered two-dimensional regions with only few atomic size thickness (5-10 Å), where solute diffusion along boundaries is generally orders of magnitude faster than that in the bulk, depending on temperature [9, 10].
Recently, forging producers are increasingly using precision forging in which complicated parts can be formed directly in net shape or near-net shape in order to reduce cost. Particularly, in cold forging, materials with high formability are required and lowcarbonsteels are widely used, since they can reduce the formation of cracks on forged parts . In this scenario, stainless steels are an important class of alloys. Their importance is manifested in the plenitude of applications that rely on their use. The application of austenitic stainless steels in food, petrochemical and nuclear industries is due to their combination of good conformability, mechanical and corrosion resistance. In particular, AISI 304L steel is widely used, not only for its high corrosion resistance but also for its excellent formability and mechanical behavior. Many researchers have studied the changes in 304L stainless steel material behavior and microstructure under different conditions; its plastic deformation and corresponding microstructural evolution was found obviously different from static or dynamic loading conditions at high strain rate [5-9]. Another steel grade of great interest in forging industry is the Duplex Stainless Steel (DSS). DSS is a two-phase alloy (ferrite/austenite) which combine the properties of austenitic and ferritic stainless steels. The good combination of its mechanical properties and corrosion resistance makes it of great interest for a wide range of applications especially in the oil, chemical and power industry . During the last years, in views of the great interest of forging industries on these materials, several studies on their formability were conducted. It is noted that its properties strongly depend on the microstructure and substructural changes of α and γ-phase during deformation under low and high strain rate conditions [11,12].
Carburization provides a gradual change in carbon content and carbide volume from the surface to the bulk, resulting in a gradual alteration of mechanical and wear properties of the material. The heat treatment and carburization increases the mechanical and wear resistance of the material In general, carburizing is the addition of carbon to the surface of lowcarbonsteels at temperatures generally between 850 and 950 °C (1560 and 1740 °F) at austenite region that had high solubility for carbon and the stable crystal structure. Hardening is accomplished when the high carbon surface layer is quenched to form martensite so that a high carbon martensitic case will have good wear and fatigue resistance . Carburizing steels for case hardening usually have base carbon contents of about 0.2%, with the carbon content of the carburized layer generally being controlled at between 0.8 and 1% C. However, surface carbon is often limited to 0.9% because too high a carbon content can result in retained austenite and brittle martensite. In addition, Carburizing process increases the grains size due to permanence for a long time in the austenitic region of the phase diagram, and makes necessary a posterior heat treatment to refine the grains. Classic quenching generates a martensitic hard but brittle material. On the other hand, inter critical quenching transforms the outward carbon rich solid solution into martensite, while the internal microstructures present a mixture of martensite, producing a less-brittle material .
Normalised steel will consist of fine ferrite or cementite with grains of pearlite but hardened and tempered steel will be expected to have a bainitic structure or tempered martensite. Tempering reduces brittleness imparted by hardening and produces definite physical properties within the steel. The resultant strength, hardness, and ductility depend on the temperature to which the steel is heated during the tempering process. Slower cooling rates produce coarser microstructures. In the present work, an extensive study was carried out to investigate the effect of hot forging/rolling reduction ratio and different heat treatment on the hardness and impact toughness of different grades of plain carbon and low alloy steels.
Samples were cut perpendicular to the immersion direction using diamond saw and polished for microhardness measurement. The microhardness of carbon-rich layer formed on the surface of pure iron, and cross-sectional hardness variation from the surface of carburized layer to the interior of the sample was measured by an Instron microhardness tester equipped with a Vickers indentation tests (HV10) with a load of 1 kg.