Effect Of Austenitizing Temperature Research Articles

Effect of Austenitization Temperature on Hot Ductility of C-Mn-Al HSLA Steel.

The article aims to investigate the effect of different austenitization temperatures on the hot ductility of C-Mn-Al High-Strength Low-Alloy (HSLA) steel. The thermo-mechanical simulator of physical processes Gleeble 1500D was used for steel hot ductility study. Hot ductility was estimated by measuring the reduction of area after static tensile testing carried out at temperatures in the range 600 °C to 1200 °C with the step of 50 °C. Evaluation of fracture surfaces after austenitization at 1250 °C and 1350 °C with a holding time of the 30 s showed significant differences in the character of the fracture as well as in the ductility. The fracture surfaces and the microstructure near the fracture surfaces of samples at a test temperature of 1000 °C for both austenitization temperatures were analyzed by Scanning Electron Microscopy (SEM), Light Optical Microscopy (LOM), and AZtec Feature analysis (particle analysis of SEM). AlN and AlN-MnS precipitates at grain boundaries detected by the detailed metallographic analysis were identified as the main causes of plasticity trough in the evaluated steel. Moreover, using Thermo-Calc software, it was found that AlN particles precipitate from solid solution below the temperature of 1425 °C.

Effect of the initial austenitization temperature on the structural microheterogeneity during drawing of carbon steel with a pearlite structure

During wire production, strain fields can be distributed inhomogeneously over the section during drawing and cause structural micro-inhomogeneity, which significantly affects the stability of the process. However, during plastic deformation of carbon steel with a pearlite structure, the interlamellar spacing in the ferrite-carbide mixture and the size of pearlite colonies, which determine the deformation behavior of steel, are of great importance. In addition, in the wire manufacturing technology, heat treatment operations are used with heating the steel to the austenitic state, the temperature of which significantly affects the formation of the structure and properties of the steel. The paper investigates the effect of the austenitization temperature on the structural microheterogeneity of a wire made of carbon steel with a pearlite structure after drawing. The results of studying the microstructure, determining the interlamellar spacing, the anisotropy coefficient of pearlite colonies, as well as the distribution of microhardness over the cross section of the sample during drawing after different temperatures of preliminary austenitization are presented. It is shown that after preliminary austenitization at temperatures of 900, 950 and 1000 °C in a wire made of carbon steel with a pearlite structure, microstructural inhomogeneity in the dispersion of the ferrite-pearlite mixture is observed. It manifests itself as a difference of the interlamellar spacing in pearlite at the surface and in the center of the sample cross section and is retained during subsequent drawing with a total reduction of 8 to 15%. It has been established that the temperature of preliminary austenitization has practically no effect on the anisotropy coeffi cient of pearlite colonies in the initial state after austenitization, and it does not change over the cross section of the sample. However, with subsequent drawing with an increase in the total reduction, the anisotropy coefficient increases, while it increases from the surface to the center of the sample. It is revealed that with an increase in the preliminary austenitization temperature from 900 to 1000 °C, the microstructural inhomogeneity in the drawn wire is manifested to a greater extent, which can be associated with an increase in the grain size of the initial austenite, the size of pearlite colonies, and the interlamellar spacing in pearlite. Microstructural inhomogeneity is confirmed by the nature of the distribution of microhardness over the cross section of the sample. The research was carried out with the financial support of the Russian Foundation for Basic Research and DNT within the framework of the scientific project No. 18-58-45008 IND_a.

The influence of austenitization temperature on microstructural developments, mechanical properties, fracture mode and wear mechanism of Hadfield high manganese steel

In this investigation, the effect of austenitization temperature on microstructural evolution, mechanical properties, fracture mode, and wear mechanism of a high carbon Hadfield steel was studied. Four blocks of the Hadfield steel were cast in an induction furnace. One hour austenitization was performed at 1000 °C, 1075 °C, 1150 °C, and 1225 °C on the cast samples followed by quenching in water. Uniaxial tensile test, pin on disk wear test and Vickers hardness measurements were employed on the processed samples. An optical microscope and a field emission scanning electron microscope were used to study the microstructural evolution. Transmission electron microscope was employed to observe the carbides that were formed. Moreover, scanning electron microscopy technique was used to define the mode of fracture on the tensile test samples. Results showed that increasing austenitization temperature reduced carbides and increased austenite grain size. Mechanical properties measurements also showed that increasing austenitization temperature increased yield/tensile strengths, hardness, and wear resistance of this steel. However, these increments were made at the expense of ductility. Fractography results showed a very ductile mode of fracture. The share of the ductile fracture mode was further increased by reducing the austenitization temperature from 1225 °C to 1000 °C.

Effects of Austenitization Temperature and Pre-Deformation on CCT Diagrams of 23MnNiCrMo5-3 Steel.

The combined effect of deformation temperature and strain value on the continuous cooling transformation (CCT) diagram of low-alloy steel with 0.23% C, 1.17% Mn, 0.79% Ni, 0.44% Cr, and 0.22% Mo was studied. The deformation temperature (identical to the austenitization temperature) was in the range suitable for the wire rolling mill. The applied compressive deformation corresponded to the true strain values in an unusually wide range. Based on the dilatometric tests and metallographic analyses, a total of five different CCT diagrams were constructed. Pre-deformation corresponding to the true strain of 0.35 or even 1.0 had no clear effect on the austenite decomposition kinetics at the austenitization temperature of 880 °C. During the long-lasting cooling, recrystallization and probably coarsening of the new austenitic grains occurred, which almost eliminated the influence of pre-deformation on the temperatures of the diffusion-controlled phase transformations. Decreasing the deformation temperature to 830 °C led to the significant acceleration of the austenite → ferrite and austenite → pearlite transformations due to the applied strain of 1.0 only in the region of the cooling rate between 3 and 35 °C·s−1. The kinetics of the bainitic or martensitic transformation remained practically unaffected by the pre-deformation. The acceleration of the diffusion-controlled phase transformations resulted from the formation of an austenitic microstructure with a mean grain size of about 4 µm. As the analysis of the stress–strain curves showed, the grain refinement was carried out by dynamic and metadynamic recrystallization. At low cooling rates, the effect of plastic deformation on the kinetics of phase transformations was indistinct.

Texture development during austempering process of an AISI 4130 steel

In this investigation, microstructural development and mechanical properties of an automotive grade AISI 4130 steel were explored through various heat treatment routes. In that regard, first of all the effect of austenitization temperature and time on the mechanical properties were assessed. Then, an optimum austenitization temperature was obtained for austempering at 400 °C and for the duration of 20, 40 and 60 min. Finally, under the optimum austenitization condition, austempering temperatures from 300 °C to 500 °C, with 50 °C interval, was evaluated in terms of mechanical properties changes and microstructural development. Optical microscope (OM) and Field Emission Scanning Electron Microscope (FE-SEM) equipped with Electron backscattered diffraction (EBSD) detector were employed for microstructural studies. Tensile tests, hardness measurements and Charpy impact tests were done to define the mechanical properties of the steels. Results show that austenitization at 900 °C for 15 min gives the highest hardness value. This was related to the development of bainite microstructure at the expense of martensite. Also, under different austenitization temperatures, austempering time of 20 min at 400 °C provides the highest strength level. As well, austempering temperature of 400 °C was determined as the best temperature to obtain optimum amount of bainite while strength and ductility levels are acceptable. {100} pole figures for some of the austempering steps were gauged and showed a random texture for the initial steel. However, after austempering process at different temperatures and times, textured structures with the main components of Cube ({100}<001>), Copper({112}<111>), S ({123}<634>), and Brass ({110}<112>)were obtained. Texture components were substantially changed with changing the austempering temperature and time. Out of these texture components, non-cube textures were developed for the best combination of austempering temperature and time. This latest finding could explain satisfactory levels of mechanical properties under the optimum condition of heat treatment.

Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti⁻Ca Oxide Particles.

Inclusion-induced acicular ferrite (AF) nucleation has been used for microstructure refinement in steel. Austenitization conditions have a significant influence on AF nucleation ability. In this paper, the effects of austenitization temperature and holding time on the transformation behaviors of low carbon steel containing Ti–Ca oxide particles were studied. A thermal treatment experiment, high temperature in situ observation, and calculation of Mn diffusion were carried out. The results indicate that small austenite grain size under low austenitizing temperature promoted grain boundary reaction products. With an increase in austenitizing temperature, the nucleation sites transferred to intragranular particles and AF transformation was improved. The inclusion particles in the Ti–Ca deoxidized steel were featured by an oxide core rich in Ti and a lesser amount of Ca and with MnS precipitation on the local surface, which showed a strong ability to promote AF nucleation. At a low austenitizing temperature, Mn diffusion was limited and the development of Mn-depleted zones (MDZs) around inclusions was not sufficient. The higher diffusion capacity of Mn at a high austenitizing temperature promoted the formation of MDZs to a larger degree and increased the AF nucleation ability. Boron segregation at large-sized austenite grain boundaries played an important role in AF transformation. Austenite grain size, Mn-depleted zone development, and boron segregation at grain boundaries were the decisive factors influencing the transformation behaviors under different austenitization conditions for the test steel.

Effect of austenitization temperature on microstructure and mechanical properties of low-carbon-equivalent carbidic austempered ductile iron

The wear resistances of austempered ductile iron (ADI) were improved through introduction of a new phase (carbide) into the matrix by addition of chromium. In the present investigation, low-carbon-equivalent ductile iron (LCEDI) (CE = 3.06%, and CE represents carbon- equivalent) with 2.42% chromium was selected. LCEDI was austenitized at two different temperatures (900 and 975°C) and soaked for 1 h and then quenched in a salt bath at 325°C for 0 to 10 h. Samples were analyzed using optical microscopy and X-ray diffraction. Wear tests were carried out on a pin-on-disk-type machine. The effect of austenization temperature on the wear resistance, impact strength, and the microstructure was evaluated. A structure–property correlation based on the observations is established.

Effect of Austenitization Temperature on the Dry Sliding Wear Properties of a Medium Carbon Quenching and Partitioning Steel

Effect of Austenitization Temperature on the Dry Sliding Wear Properties of a Medium Carbon Quenching and Partitioning Steel

Precipitation in a novel maraging steel F1E: A study of austenitization and aging using small angle neutron scattering

The effect of austenitization temperature, aging temperature, and, aging time on the development of precipitates in a novel maraging steel known as F1E was investigated. The investigation primarily employed small angle neutron scattering (SANS) coupled with thermal calculations, atom probe tomography (APT) and electron microscopy (SEM, STEM, TEM). This large scale study investigated austenitization temperatures of 825, 870 and 960°C with aging of 0, 1, 2.5, 5, 7.5, 10 and 24h conducted at 540°C. For austenitization at 960°C, aging at 520°C and 560°C was also conducted for the same aging times. This yielded 32 conditions where the size, shape and volume fraction of three different precipitates were determined, namely a pre-existing laves phase, a developing laves phase, and a developing β phase. Also observed in this study was a significant change in microstructure of the pre-existing laves precipitate as a result of aging time.

Effects of Austenitization Temperature and Compressive Stress During Bainitic Transformation on the Stability of Retained Austenite

The effects of stress and austenitization temperature on the carbon content and morphology of retained austenite (RA) have been investigated. The stability of RA has been analyzed. An interesting finding is that the increase in the amount of bainite is not accompanied by the increase in the carbon content in RA under the effect of stress. This does not match with what is expected from the bainitic transformation theory. The amount of bainitic transformation and stress both affect the carbon content in RA. In addition, the stress during bainitic transformation helps to increase the stability of RA by decreasing the amount of blocky RA, whereas it has little effect on the carbon content in RA. Moreover, the increase in austenitization temperature is beneficial to increasing the stability of RA, whereas it has no significant effect on the morphology of RA.

Effect of Austenitization Temperature on Microstructure and Mechanical Properties of B1500HS Boron Steel in the Hot Stamping

In the paper, a typical part of B1500HS boron steel was formed using the hot stamping tools, and the effect of austenitization temperature on the microstructure and mechanical properties of B1500HS boron steel was studied. The results show that, the temperature of steel plate has a significant effect on the temperature of hot stamping tools, and the temperature of punch rises at a faster speed than that of die in the hot stamping process. The austenitization temperature has a significant effects on the size of martensite. The cooling rate of steel plate has a significant effect on the tensile strength when the austenitization temperature is 870 °C. The fracture of sample austenitized at 870 °C or 900 °C is the dimple, the fracture of sample austenitized at 930 °C or 960 °C is the mixture of quasicleavage and dimple.

Research on hot stamping for a typical part of B1500HS boron steel using experiment and numerical simulation methods

In the paper, a typical part of B1500HS boron steel was formed using the hot stamping tools, and the effect of austenitization temperature on the microstructure and mechanical properties of B1500HS steel was studied by the experiment and finite element methods. The results show that, the temperature of steel plate has a significant effect on the temperature of hot stamping tools, and the temperature of punch rises at a faster speed than that of die in the hot stamping process. The austenitization temperature and time both have significant effects on the size of martensite, but have not obvious effects on the hardness. The cooling rate of steel plate has a significant effect on the tensile strength when the austenitization temperature is 870 °C. The fracture of sample austenitized at 870 °C or 900 °C is the dimple, the fracture of sample austenitized at 930 °C or 960 °C is the mixture of quasicleavage and dimple.

Effect of Austenitization Temperature and Holding Time on Transformation Plasticity in a Three-Point Bending System

Effect of Austenitization Temperature and Holding Time on Transformation Plasticity in a Three-Point Bending System

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)

Effect of Austenitization Temperature on Wear Behavior of Carbidic Austempered Ductile Iron (CADI)