scholarly journals Influence of Coiling Temperature on Microstructure, Precipitation Behaviors and Mechanical Properties of a Low Carbon Ti Micro-Alloyed Steel

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1173
Author(s):  
Mingxue Sun ◽  
Yang Xu ◽  
Wenbo Du
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Tensile Tests ◽  
Alloyed Steel ◽  
Low Carbon ◽  
Coiling Temperature ◽  
Fine Grain ◽  
Transmission Electron ◽  
Rolling Experiment ◽  
Micro Alloyed Steel

The microstructural evolution, nanosized precipitation behaviors and mechanical properties of a Ti-bearing micro-alloyed steel at different coiling temperatures were studied using optical microstructure (OM), scanning electron micrograph (SEM), transmission electron microscopy (TEM), Vickers hardness and tensile tests. When the coiling temperature was 500 °C, the specimen showed mainly bainitic structure, whereas polygonal ferrite was visible as the coiling temperature increased to 650 °C and 700 °C. The Vickers hardness of tested steel reached the maximum, which can be attributed to the largest number of nanosized precipitates in ferrite at the coiling temperature of 650 °C. A coiling temperature of 650 °C was optimal for the formation of TiC because of the high diffusion rate of alloying elements and kinetics of precipitation. In the laboratory rolling experiment, when the coiling temperature was 630 °C, the steel with yield strength of 682 ± 2.1 MPa and tensile strength of 742 ± 4.9 MPa was produced. The fine-grain strengthening and precipitation strengthening were 262 MPa and 268 MPa, respectively.

scholarly journals Mechanical Properties and Microstructure, in welded joints of Low and Medium Carbon Steels, Applying Rotary Friction

2020 ◽  
Vol 8 (6) ◽  
pp. 5176-5185
Keyword(s):  
Mechanical Properties ◽  
Tensile Tests ◽  
Carbon Steels ◽  
Grain Structure ◽  
Mechanical Resistance ◽  
Low Carbon ◽  
Dissimilar Joints ◽  
Fine Grain ◽  
Medium Carbon Steels ◽  
1045 Steel

The effect of friction welding (FRW) in joints of medium and low carbon steels on its mechanical properties and microstructure was studied. AISI 1020 and 1045 steel bars of 12 mm diameter were used. Welding was carried out on a lathe with coupling to control the process parameters. For 1045/1045 joint, the following parameters were used: n = 1400 rpm, Friction pressure Pf = (0.8 - 1.0) MPa; Friction time (Tf) = 8 sec; Upsetting pressure (Pr) = 5 MPa; Upsetting time (Tr) = 5 sec, were used. For 1020/1045 joints the parameters that only varied were: n = (1000 - 1400) rpm; Pf = (0.7-0.8-1.0) MPa. Tensile tests were carried out on the IMSTRON UNIVERSAL machine under ASTM E8 standard. Microhardness tests were carried out on (HV) 0.5 scale, making a longitudinal and transverse scanning profile. Microscopy at the optical (OM) and electronic SEM levels, with analysis (EDS) was revealed. It was found for similar joints: a higher value of (Pf) increases the mechanical resistance (σrm), but for dissimilar joints decreases it. Welding efficiency of similar joints was 94% and for dissimilar joints 97.5% with regard to 1020 and 74% with regard to 1045. For dissimilar joints, a higher speed “n” increases σy, and σrm, with little effect on “ɛ”. In similar joints the microhardness is maximum in the center, and for the dissimilar ones it is not. Longitudinal and transverse microhardness profiles do not follow a defined pattern with respect to Pf. For both types of joints, the microstructure shows, that FDRZ joint zone, has variable thickness and has a fully recrystallized fine-grain structure. TMAZ deformation zone, a structure of deformed grains and dark grains is observed, the latter, due to the excess carbon produced by diffusion. In both cases, no intermetallic compounds have been produced, and perlite colonies is not observed in these two zones.

Effect of Ferrite Status on Mechanical Properties of Hot-Rolled Directly Quenched and Partitioned Steel

2015 ◽  
Vol 816 ◽  
pp. 736-742 ◽  
Author(s):  
Xiao Dong Tan ◽  
Xiao Long Yang ◽  
Yun Bo Xu ◽  
Zhi Ping Hu ◽  
Fei Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Tensile Deformation ◽  
Alloyed Steel ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Low Carbon ◽  
Phosphorus Addition ◽  
High Silicon ◽  
Micro Alloyed Steel

Hot-rolling direct quenching and partitioning (HDQ&P) processes were applied to both low carbon high silicon vanadium micro-alloyed steel and low carbon low silicon steel with phosphorus addition. Proeutectoid ferrite with an area fraction of about 30% was introduced into some of the sheets. Microstructures were characterized using SEM, TEM and XRD. Mechanical properties were investigated by means of uniaxial tensile test. Austenite stabilization, retained austenite stability, tensile deformation and fracture were comprehensively analyzed by making the comparison between the two steels and between the sheets with and without ferrite considering the different precipitation statuses in ferrite. Experimental results showed that the high silicon vanadium micro-alloyed steel contained more retained austenite with higher stability compared with the low silicon phosphorus added steel. Filled with much more carbides with larger sizes, the martensite in the low silicon phosphorus added steel exhibited a much salient tempered feature. The high silicon vanadium added steel possessed higher strength and ductility than the low silicon phosphorus added steel. The introduction of ferrite can result in an extremely obvious post-necking elongation drop in the low silicon phosphorus added steel. The dispersed V-bearing precipitates and high silicon content in ferrite can increase the yield strength and simultaneously diminish the hardness difference between ferrite and martensite, which can improve their compatible deformation capability and then enhance the work hardening ability and finally raise both the UTS and elongation of the steel.

Phase Stability and Mechanical Properties of Ti(Ni, Ru) Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
Masahiro Tsuji ◽  
Hideki Hosoda ◽  
Kenji Wakashima ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Phase Stability ◽  
Hot Forging ◽  
Tensile Tests ◽  
Lattice Parameter ◽  
Solid Solution Hardening ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Transmission Electron

ABSTRACTEffects of ruthenium (Ru) substitution on constituent phases, phase transformation temperatures and mechanical properties were investigated for Ti-Ni shape memory alloys. Ti50Ni50-XRuX alloys with Ru contents (X) from 0mol% (binary TiNi) to 50mol% (binary TiRu) were systematically prepared by Ar arc-melting followed by hot-forging at temperatures from 1173K to 1673K depending on chemical composition. Phase stability was assessed by DSC (differential scanning calorimetry), XRD (X-ray diffractometry) and TEM (transmission electron microscopy). Mechanical properties were investigated using hardness and tensile tests at room temperature. With increasing Ru content, it was found that the lattice parameter of B2 phase increases, the martensitic transformation temperature slightly decreases, and the melting temperature increases monotonously. Besides, R-phase appears for Ti-Ni alloys containing 3mol% and 20mol%Ru but no diffusionless phase transformation is seen in Ti-Ni alloy containing 5mol%Ru. Vickers hardness shows the maximum at an intermediate composition (HV1030 at 30mol%Ru); this suggests that large solid solution hardening is caused by Ru substitution for the Ni-sites in TiNi.

The Structure and Mechanical Properties of Plastically Consolidated Al-Ni Alloy

2016 ◽  
Vol 682 ◽  
pp. 245-251 ◽  
Author(s):  
Grzegorz Włoch ◽  
Tomasz Skrzekut ◽  
Jakub Sobota ◽  
Antoni Woźnicki ◽  
Justyna Cisoń
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Intermetallic Phases ◽  
Scanning Calorimetry ◽  
Porosity Formation ◽  
X Ray ◽  
Ni Alloy ◽  
Thermal Stability Of

Mixed and preliminarily consolidated powders of aluminium and nickel (90 mass % Al and 10 mass % Ni) were hot extruded. As results the rod, 8 mm in diameter, was obtained. As-extruded material was subjected to the microstructural investigations using scanning electron microscopy (SEM/EDS) and X-ray analysis (XRD). The differential scanning calorimetry (DSC) and thermo-mechanical analysis (TMA) were also performed. The mechanical properties of as extruded material were determined by the tensile test and Vickers hardness measurements. In order to evaluate the thermal stability of PM alloy, samples were annealed at the temperature of 475 and 550 °C. After annealing Vickers hardness measurements and tensile tests were carried out. The plastic consolidation of powders during extrusion was found to be very effective, because no pores or voids were observed in the examined material. The detailed microstructural investigations and XRD analyses did not reveal the presence of the intermetallic phases in the as-extruded material. During annealing, the Al3Ni intermetallic compound was formed as the result of chemical reaction between the alloy components. The hardness of the alloy after annealing at the temperature of 475°C was found to be comparable to the hardness in as-extruded state. Annealing of the material at the temperature of 550°C results in hardness decreasing by about 50%, as the consequence of porosity formation and Al3Ni cracking.

scholarly journals Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Jihyun Jun ◽  
Hogeon Seo ◽  
Kyung-Young Jhang
Keyword(s):  
Mechanical Properties ◽  
Nondestructive Evaluation ◽  
Thermal Aging ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Tensile Tests ◽  
Acoustic Nonlinearity ◽  
Transmission Electron ◽  
Heat Treated ◽  
Elongation To Failure

The structures in high-temperature environments are prone to undergo hardening and embrittlement as a result of thermal aging; this can cause variations in their mechanical properties. Because these changes occur at the microstructural level, it is difficult to evaluate them through linear ultrasonic techniques. In this work, a surface acoustic wave (SAW) was used to measure and compare the acoustic nonlinearity and mechanical properties of Al6061 alloys heat-treated at 220 °C for different durations (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, 1000 h). The SAW was generated by a pulsed laser and then received by an interferometer. Moreover, the yield strength, ultimate strength, and elongation to failure were measured by tensile tests. The results demonstrate that the critical variations in the mechanical properties can be detected by monitoring the variation features in the acoustic nonlinearity. Transmission electron microscopy images were captured to observe the microstructural changes, which shows that the acoustic nonlinearity varied according to the change in the precipitation phase. This supports the acoustic nonlinearity measurement using the laser-generated SAW being an effective technique for the fully noncontact nondestructive evaluation of material degradations as well as changes in mechanical properties.

Effect of Nb and V in the Development of Texture and Plastic Strain Ratio in Low Carbon Microalloyed Steels Produced by A.S.T. Technology

2005 ◽  
Vol 500-501 ◽  
pp. 279-286
Author(s):  
Carlo Mapelli ◽  
Roberto Venturini ◽  
Antonio Guindani
Keyword(s):  
Mechanical Properties ◽  
Strain Ratio ◽  
Tensile Tests ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Plastic Strain Ratio ◽  
Steel Technology ◽  
Back Scattering ◽  
Carbon Microalloyed ◽  
Hot Rolled

The effects of Nb and V on the anisotropy and textures featuring the hot rolled low carbon microalloyed steels produced by A.S.T. (Arvedi Steel Technology) have been studied as a function of the final coiling temperatute Tcoiling. Mechanical properties and r-values for twelve steels have been determined through tensile tests performed on three main different directions: 0°, 45°, 90° to the rolling one. The samples have been analysed by EBSD (Electron Back Scattering Diffraction) to identify the textures developed during the process. The relations among the chemical composition of the steels (i.e. C, N, Nb, V contents), the mechanical properties, the temperature during the coiling operations, the textures and the formability properties have been pointed out.

scholarly journals Characterization of Nanobainitic Structure Obtained in 100Crmnsi6-4 Steel after Industrial Heat Treatment/ Charakteryzacja Struktury Nanobainitycznej Wytworzonej W Handlowej Stali Łożyskowej – 100Crmnsi6-4 W Przemysłowej Obróbce Cieplnej

2014 ◽  
Vol 59 (4) ◽  
pp. 1637-1640 ◽  
Author(s):  
J. Dworecka ◽  
E. Jezierska ◽  
K. Rozniatowski ◽  
W. Swiatnicki
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Tensile Tests ◽  
Bearing Steel ◽  
Transformation Kinetics ◽  
Transmission Electron ◽  
Microstructure Parameters ◽  
Static Tensile

Abstract The aim of the work was to produce a nanobainitic structure in the commercial bearing steel - 100CrMnSi6-4 and to characterize its structure and mechanical properties. In order to produce this structure the austempering heat treatment was performed, with parameters that have been selected on the basis of dilatometric measurements of phase transformation kinetics in steel. The heat treatment process was performed in laboratory as well as in industrial furnaces. The obtained structure was characterized using transmission electron microscopy. In order to investigate the effect of the microstructure parameters on the material’s mechanical properties, the hardness, impact strength and static tensile tests have been conducted.

Effect of Heat Treatments on Microstructure and Mechanical Properties of Low Carbon Steel Pipes Welded by Induction Process

2014 ◽  
Vol 887-888 ◽  
pp. 1301-1306
Author(s):  
Zakaria Boumerzoug ◽  
Lakhdar Lakhdari
Keyword(s):  
Mechanical Properties ◽  
Isothermal Annealing ◽  
Pipeline Steel ◽  
Low Carbon Steel ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Low Carbon ◽  
Steel Pipes ◽  
Induction Process ◽  
Isothermal Heat Treatments

In this work, the effect of isothermal heat treatments on microstructure evolution and mechanical properties after welding by induction of A37 pipeline steel have been studied by scanning electron microscopy, hardness measurements, and tensile tests. Microstructural evolution in welded joint was identified after isothermal annealing from 200 until 900 °C.

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