The Effect of Ti-Zr Deoxidation on the Mechanical Properties of High Strength Low Alloy Steels

2010 ◽  
Vol 146-147 ◽  
pp. 1878-1884 ◽  
Author(s):  
Wei Yu Lu ◽  
Ling Dong Meng ◽  
Hong Hong Wang ◽  
Dao Yuan Wang ◽  
Yong Kuan Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Impact Toughness ◽  
High Strength ◽  
Optical Microscope ◽  
Low Alloy Steels ◽  
X Ray ◽  
The Matrix ◽  
Alloy Steels ◽  
The Stability

The uniformity of the mechanical properties, especially elongation and impact toughness, were compared between steel A, which was deoxidized with Ti-Zr, and steel B, which was deoxidized with Al. Microstructural observations, energy dispersive X-ray spectroscopy and X-ray diffraction analyses were conducted using an optical microscope, a scanning electron microscope and a transmission electron microscope, respectively. Results showed that sub-micron and nano-sized complex oxides were obtained by the combined deoxidation of Ti-Zr. The stability of the mechanical properties of steel A was better than that of steel B. The elongation and impact toughness of steel A were enhanced relative to those of steel B. This was attributed to spheroidization and the dispersed distribution of MnS inclusions in the matrix of steel A.

Effect of Thermomechanical Treatment (TMT) on Hardness, Impact Toughness of Different Grades of Low Alloy Steels

2015 ◽  
Vol 1101 ◽  
pp. 212-216
Author(s):  
Mahmoud M. Tash ◽  
Saleh A. Alkahtani ◽  
Khaled A. Abuhasel
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Mechanical Treatment ◽  
Weight Ratio ◽  
High Strength ◽  
Extensive Study ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Thermo Mechanical Treatment

The present study was undertaken to investigate the effect of thermo-mechanical treatment (TMT) on the mechanical behaviour of different grades of low alloy steels. The effect of hot forming (rolling) with different reduction ratios on the hardness and impact toughness properties will be studied. Correlations between different thermo-mechanical treatment parameters, hardness and impact toughness for different grades of low alloy steels were carried out. Different grades of Low alloy steels were selected for the present study. An extensive study will be carried out to investigate the effect of alloying additions and TMT parameters on the hardness and impact toughness of heat-treated low alloy steels. An understanding of the combined effect of TMT and heat treatment on the mechanical properties of the low alloy steels would help in selecting conditions required to achieve optimum mechanical properties and alloy high strength to weight ratio. The scope of the present work is therefore to study the effects of hot rolling reduction ratios on microstructure and mechanical properties of such alloys. By measuring hardness, impact toughness, strength and ductility resulting from different heat treatment following TMT, it is possible to determine which conditions yielded optimum mechanical properties and high strength to weight ratio.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Microstructure characterization and evaluation of mechanical properties of stir rheocast AA2024/TiB2 composite

2019 ◽  
Vol 54 (7) ◽  
pp. 981-997
Author(s):  
Semegn Cheneke ◽  
D Benny Karunakar
Keyword(s):  
Mechanical Properties ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Globular Structure ◽  
Cast Sample ◽  
X Ray ◽  
Weight Percentage ◽  
The Matrix ◽  
Fractured Surface

In this research, microstructure and mechanical properties of stir rheocast AA2024/TiB2 metal matrix composite have been investigated. The working temperature was 640℃, which was the selected semisolid temperature that corresponds to 40% of the solid fraction. Two weight percentage, 4 wt%, and 6 wt% of the TiB2 reinforcements were added to the matrix. The field emission scanning electron microscope micrographs of the developed composites showed a uniform distribution of the particles in the case of the 2 wt% and 4 wt% of the reinforcements. However, the particles agglomerated as the weight percentages of the reinforcement increases to 6%. The optical microscope of the liquid cast sample showed the dendritic structure, whereas the rheocast samples showed a globular structure. The X-ray diffraction analysis confirmed the distribution of the reinforcements in the matrix and the formation of some intermetallic compounds. Mechanical properties significantly improved by the addition of the reinforcements in the matrix. An increase in tensile strength of 13.3%, 40%, 28%, and 5% was achieved for the unreinforced rheocast sample, 2 wt%, 4 wt%, and 6 wt% reinforced rheocast samples respectively, compared to the liquid cast sample. An increase in 20% of hardness was attained for the composite with 2 wt% TiB2 compared to the liquid cast sample. According to the fractography analysis, small dimples were observed on the fractured surface of the unreinforced rheocast sample, whereas small and large voids were dominant on the fractured surface of the 2 wt% composite, which shows the ductile fracture mode.

Hydrogen Compatibility and Suitability of (Ni)-Cr-Mo High-Strength Low-Alloy Seamless Line Pipe Steels for Pressure Vessels for Hydrogen Storage

2018 ◽  
Author(s):  
Akihide Nagao ◽  
Nobuyuki Ishikawa ◽  
Toshio Takano
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
High Strength ◽  
Pressure Vessels ◽  
Hydrogen Gas ◽  
Low Alloy Steels ◽  
Pipe Steels ◽  
Line Pipe ◽  
Alloy Steels ◽  
Pressure Hydrogen

Cr-Mo and Ni-Cr-Mo high-strength low-alloy steels are candidate materials for the storage of high-pressure hydrogen gas. Forging materials of these steels have been used for such an environment, while there has been a strong demand for a higher performance material with high resistance to hydrogen embrittlement at lower cost. Thus, mechanical properties of Cr-Mo and Ni-Cr-Mo steels made of quenched and tempered seamless pipes in high-pressure hydrogen gas up to 105 MPa were examined in this study. The mechanical properties were deteriorated in the presence of hydrogen that appeared in reduction in local elongation, decrease in fracture toughness and accelerated fatigue-crack growth rate, although the presence of hydrogen did not affect yield and ultimate tensile strengths and made little difference to the fatigue endurance limit. It is proposed that pressure vessels for the storage of gaseous hydrogen made of these seamless line pipe steels can be designed.

scholarly journals Effect of Aluminum, Iron and Chromium Alloying on the Structure and Mechanical Properties of (Ti-Ni)-(Cu-Zr) Crystalline/Amorphous Composite Materials

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 874
Author(s):  
Andrey A. Tsarkov ◽  
Vladislav Yu. Zadorozhnyy ◽  
Alexey N. Solonin ◽  
Dmitri V. Louzguine-Luzgin
Keyword(s):  
Mechanical Properties ◽  
Testing Machine ◽  
High Strength ◽  
Alloying Elements ◽  
Solid Matrix ◽  
Complete Suppression ◽  
Structural Investigations ◽  
X Ray ◽  
Composites Materials ◽  
The Matrix

High-strength crystalline/amorphous composites materials based on (Ti-Ni)-(Cu-Zr) system were developed. The optimal concentrations of additional alloying elements Al, Fe, and Cr were obtained. Structural investigations were carried out using X-ray diffraction equipment (XRD) and scanning electron microscope (SEM) with an energy-dispersive X-ray module (EDX). It was found that additives of aluminum and chromium up to 5 at% dissolve well into the solid matrix solution of the NiTi phase. At a concentration of 5 at%, the precipitation of the unfavorable NiTi2 phase occurs, which, as a result, leads to a dramatic decrease in ductility. Iron dissolves very well in the solid solution of the matrix phase due to chemical affinity with nickel. The addition of iron does not cause the precipitation of the NiTi2 phase in the concentration range of 0–8 at%, but with an increase in concentration, this leads to a decrease in the mechanical properties of the alloy. The mechanical behavior of alloys was studied in compression test conditions on a universal testing machine. The developed alloys have a good combination of strength and ductility due to their dual-phase structure. It was shown that additional alloying elements lead to a complete suppression of the martensitic transformation in the alloys.

Mechanical Properties of SA508 Gr.4N Model Alloys as a High Strength RPV Steel

2010 ◽  
Author(s):  
Min-Chul Kim ◽  
Ki-Hyoung Lee ◽  
Bong-Sang Lee ◽  
Whung-Whoe Kim
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Toughness ◽  
Power Plants ◽  
Charpy Impact ◽  
Alloying Elements ◽  
Low Alloy Steels ◽  
Charpy Impact Toughness ◽  
Age Related ◽  
Alloy Steels

Demands of RPV materials with higher strength and toughness are rising to increase the power capacity and the operation life of nuclear power plants. The ASME SA508 Gr.4N specification can give a superior toughness and strength to the commercial low alloy steels such as SA508 Gr.3. However, the SA508-Gr.4N steels have not yet been used commercially due to a lack of information of the productivity and the age related properties. While the irradiation embrittlement studies are going-on, the current paper focused on the effects of alloying elements such as Ni, Cr and Mo on the fracture mechanical properties of the SA508 Gr.4N low alloy steels. Various model alloys were fabricated by changing the contents of alloying elements based on the composition range of the ASME specification. Tensile properties, Charpy impact toughness and fracture toughness of the model alloys were evaluated and those properties were discussed with the microstructural characteristics of each alloy. The strengths of the alloys were increased with increase of the Ni and Mo contents while there was no remarkable change of the yield strength with the Cr addition. The Charpy impact and fracture toughness were considerably improved with the increase of Ni, Cr contents. The Mo addition did not change the toughness properties significantly. The Cr contents were more effective on the fracture toughness through changing the carbides precipitation characteristics and the Ni contents were effective on the Charpy impact toughness through changing the effective grain size.

Microstructures and Properties of HAZ of JB800 Bainite Steel

2014 ◽  
Vol 670-671 ◽  
pp. 65-69
Author(s):  
Jun Sheng Sun ◽  
Hong Quan Wang
Keyword(s):  
Impact Toughness ◽  
Lower Cost ◽  
Welding Process ◽  
High Strength ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Test Results ◽  
Bainite Steel ◽  
Alloy Steels ◽  
Allotriomorphic Ferrite

JB800 steel has grain boundary allotriomorphic ferrite and granular bainite (FGBA/BG), and it is a kind of high strength low alloy steels, which has simple produce procedure, lower cost and excelled property. The law of microstructure transformation in CGHAZ, hardness, and impact toughness in HAZ of JB800 steel were studied by means of thermal simulation. The test results show that under the general condition of welding process (t8/5=5~50s), microstructure of CGHAZ is composed of mixture microstructure of Martensite and Bainite and with the increase of cooling rate, the content of Martensite will decrease, but that of Bainite will increase; when t8/5 is 20s, CGHAZ zone have better impact toughness, which is composed of 95% Martensite and 5% Bainite. Therefore t8/5 should be controlled at about 20s to get better impact toughness.

Metal Dusting Corrosion of Alloy Cr5Mo in H2-CO Gas Mixtures

2009 ◽  
Author(s):  
Guiming Hu ◽  
Changyu Zhou ◽  
Cheng Chen ◽  
Na Lei
Keyword(s):  
Mechanical Properties ◽  
Iron Carbide ◽  
Thick Layer ◽  
Phase Changes ◽  
Homogeneous Layer ◽  
Low Alloy Steels ◽  
Metal Dusting ◽  
X Ray ◽  
Alloy Steels ◽  
Carburized Layer

Metal dusting is a catastrophic phenomena of high temperature corrosion, which occurs in severe carburizing environments (carbon activity aC>1.0) at temperatures 400–900 °C. It causes not only phase changes but also removal of materials (pitting or thinning) and serious material deterioration. The present study focuses on the fundamental understanding of the corrosion of low alloy steels Cr5Mo in carbon-supersaturated environments (50CO-50H2) at 600 °C over different holding times. Scanning-electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), nano-indentation, and nano-scratch tester are used to investigate the microstructure and its mechanical properties. An interesting continuous thick layer composed of Ha¨gg carbide (Fe5C2) and less cementite (Fe3C) was present on top of the samples, which was ever observed in pure iron but not in alloy steels. This layer grew thicker with increasing holding times and showed very different mechanical properties with the carburized layer which was below the Ha¨gg carbide layer. And the carburized layer could not form a continuous and homogeneous layer of Fe3C even in longer holding times. The cementite only formed at grain boundaries. The results show that also as for low alloy steels at very high carbon activities a second iron carbide, Ha¨gg carbide (Fe5C2), forms on the surface instead of the decomposing process of the metastable carbide, cementite (Fe3C).

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