Investigation on the Austenizing Transformation Process in Continuously Heated X65 Microalloyed Pipeline Steels

2013 ◽  
Vol 756-759 ◽  
pp. 72-75
Author(s):  
Dan Tian Zhang ◽  
Zhi Xia Qiao ◽  
Jie Huo ◽  
Yong Chang Liu ◽  
Hui Jun Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Pipeline Steel ◽  
Interface Energy ◽  
Ferrite Matrix ◽  
Transformation Process ◽  
Continuous Heating ◽  
Second Stage ◽  
Fine Carbide ◽  
Two Stages ◽  
Carbide Particles

Austenization is an important stage during the quenching-tempering heat-treatment process of X65 microalloyed pipeline steel, because it can influence the development of final microstructure and mechanical properties. In this paper, a detailed investigation was carried out on the austenizing transformation process in X65 microalloyed pipeline steel using high-resolution dilatometric technique and microstructure observations. According to the obtained dilatometric curve during continuous heating, the austenizing transformation process in X65 steel was apparently composed of two stages, 740-765°C and 765-875°C respectively. In order to clarify the microstructure evolution during the two stages, interrupt heat treatment tests were performed and subsequent microstructural observations showed that the first stage (740-765°C) was corresponding to the dissolution of fine carbides particles and the second stage (765-875°C) was corresponding to αγ phase transformation. Firstly, austenite nucleates at interfaces between fine carbide particles and ferrite matrix due to the high interface energy there and then the carbide particles dissolve into the austenite nucleus, which constitutes the first stage. After the fine carbide particles dissolve completely into the austenite nucleus, the ferrite matrix relatively far from the original carbide particles needs higher thermal driving force to transform to austenite, therefore the major αγ transformation occurs at higher temperature range (the second stage).

Microstructure and Mechanical Properties of A Ultra-High Carbon Steel

2006 ◽  
Vol 324-325 ◽  
pp. 907-910 ◽  
Author(s):  
Wei Ping Lin ◽  
Ya Jun Fan ◽  
Zhan Ling Zhang ◽  
Jie Wu Zhu ◽  
Yong Ning Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
High Carbon Steel ◽  
Ferrite Matrix ◽  
Carbon Steels ◽  
Eutectoid Transformation ◽  
High Carbon ◽  
Fine Carbide ◽  
Carbide Particles

A ultrahigh carbon steels (UHCS) containing 1.6 wt pct carbon was studied. Through spheroidizing process by divorced-eutectoid transformation (DET), the forged microstructure was spheroidized and the microstructure was fine carbide particles distributed in ferrite matrix. Second-time heat treatment included two kinds of technologies: normalizing and quenching + tempering. Finally, the UHCS obtained ideal mechanical properties. The yield strength and tensile strength of the UHCS were higher than that of 40CrNiMo, moreover plasticity of the UHCS was equal to that of 40CrNiMo. So the UHCS was an excellent structural material.

scholarly journals Effect of the Heating Rate on Austenite Formation

2021 ◽  
Vol 100 (10) ◽  
pp. 338-347
Author(s):  
ALEJANDRO HINTZE CESARO ◽  
◽  
PATRICIO F. MENDEZ
Keyword(s):  
Transformation Temperature ◽  
Pipeline Steel ◽  
Continuous Heating ◽  
Microalloyed Steels ◽  
Austenite Formation ◽  
Heating Rates ◽  
X80 Pipeline Steel ◽  
Bainitic Microstructure ◽  
The One ◽  
Two Stages

The extent of the heat-affected zone (HAZ) in welding is typically estimated from thermodynamic considerations of austenization; however, thermodynamics are a poor predictor of the HAZ location in microalloyed steels. This work addresses the problem through the study of austenite formation during continuous heating on a grade X80 pipeline steel with an initial ferritic and bainitic microstructure. The methodology involved dilatometry, electron microscopy, and thermodynamic calculations. A continuous heating transformation diagram was developed for heating rates varying from 1˚ to 500˚C/s. For the slower heating rates, austenite start-transformation temperature was higher than the one dictated by the equilibrium, while for the faster heating rates, start-transformation temperature gradually approached the theoretically calculated temperature at which the ferrite can transform (possibly through a massive transformation) without a long-range diffusion into austenite. Partial-transformation experiments suggested that austenite formation occurs in the following two stages: 1) the transformation of bainitic zones into austenite, and later, 2) the transformation of polygonal ferritic grains.

scholarly journals Nickel(III) containing layered double hydroxides with hydrotalcite structure

2019 ◽  
Vol 57 (2) ◽  
pp. 116-122
Author(s):  
Irina G. Ryltsova ◽  
◽  
Olga V. Nestroinaia ◽  
Olga E. Lebedeva ◽  
◽  
...  
Keyword(s):  
Heat Treatment ◽  
Layered Double Hydroxides ◽  
Reaction System ◽  
Second Stage ◽  
Transmission Electron ◽  
Crystalline Water ◽  
Two Stages ◽  
Double Hydroxides ◽  
Synthesized Materials ◽  
Thermal Stability Of

Synthesis of layered double hydroxides (LDH) was carried out by the method of coprecipitating of components from the solution at room temperature and variable pH, followed by aging at 98 °C for 2 days. During the synthesis the following compositions were specified: M2+6M3+1.5Ni3+0.5, where M2+ is Mg, Cu or Ca, M3+ is Al, Fe, or Co. In order to convert nickel cations to oxidation state +3, an oxidizing agent – sodium hypochlorite – was introduced into the reaction system. It is shown that the use of this method of synthesis allows to obtain layered double hydroxides containing aluminum and nickel or iron and nickel in the positions of triply charged cations in the structure of brucite-like layers. The formation of hydrotalcite-like structure was confirmed by XRD. The synthesized materials had morphology typical for layered double hydroxides. According to transmission electron microscopy, the samples consisted of aggregates of plate-like particles. The behavior during heat treatment was studied by thermogravimetric analysis. It was shown that the replacement of aluminum with iron cations in the structure of nickel-containing LDH led to a slight decrease in thermal stability of LDH. The thermal destruction of the obtained samples occured in two stages. The first stage, observed in the temperature range from 20 to 220 °C, included the loss of physically sorbed and crystalline water. In the second stage, when heated above 220 °C, simultaneous dehydroxylation of brucite-like layers and removal of carbonate anions from the interlayer space were observed, which resulted in the destruction of the layered structure. Heat treatment at 500 °C led to the transformation of layered double hydroxides into a mixture of corresponding oxides.

scholarly journals Phase Transformation Kinetics of High Nb-TiAl Alloy during Continuous Heating

2021 ◽  
Vol 2133 (1) ◽  
pp. 012029
Author(s):  
Ying Li ◽  
Lian Zhou ◽  
Junpin Lin ◽  
Hui Chang ◽  
Jianglei Fan ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Tial Alloy ◽  
Transformation Process ◽  
Continuous Heating ◽  
Heating Process ◽  
Transformation Kinetics ◽  
Transformation Behavior ◽  
Α Phase ◽  
Two Stages ◽  
Kinetics Of

Abstract In this work, the phase transformation behavior of Ti-45Al-8.5Nb-(W, B, Y) alloy during continuous heating was investigated using dilatometer and optical microscopy. Results indicated that the phase transformation process of high Nb-TiAl alloy during continuous heating included two stages: ordered α2 → disorder α and tetragonal γ → hexagonal α. According to the microstructure analysis, the initial α2/γ lamellar structure transformed into the massive γ phase and α phase (retained as α2) during the heating process. The activation energy of α2 → α and γ → α was 989.65 kJ/mol and 995.30 kJ/mol, respectively. Moreover, the lower the heating rate was, the faster the phase transformation reached the equilibrium state.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

TEM study on fine carbide precipitates and dislocation cell structure

1990 ◽  
Vol 48 (4) ◽  
pp. 904-905
Author(s):  
Mengzhe Chen ◽  
Siqin Wang ◽  
Jun Ke
Keyword(s):  
Carbide Particle ◽  
Cell Structure ◽  
Ferrite Matrix ◽  
Dislocation Cell ◽  
Isothermal Treatment ◽  
Particle Sizes ◽  
Dislocation Cell Structure ◽  
Thin Foils ◽  
Hsla Steels ◽  
Fine Carbide

A series of investigations have been conducted into the nature and origin of the dislocation cell structure. R.J.Klassen calculated that the dislocation cell limiting size in pure ferrite matrix is about 0.4 μm. M.N.Bassion estimated the size of dislocation cell in deformed ferrite of HSLA steels to be of the same order.In this paper, TEM observation has been concentrated on the interaction of fine carbide precipitates with dislocation cell structure in deformed Fe-C-V (0.05%C, 0.13% and 0.57%V) and Fe-C-Nb (0.07 %C and 0.04%Nb) alloys and compared with that in Fe-C (0.05%). Specimens were austenitized at 1500 “C/20 min and followed by isothermal treatment at 750 °C and 800 “C for 20, 40 and 120 minutes . The carbide particle sizes in these steels are from 9 to 86nm measured from carbon extraction replicas. Specimens for TEM were cut from differently deformed areas of tensile specimens deformed at room temperture. The thin foils were jet electropolished at -20 C in a solution of 10% perchloric acid and 90% ethanol. The TEM observation was carried out in JEM 100CX , EM420 at 100kv and JEM 2000FX at 200kv.

Distributed Entropy Energy-Efficient Clustering algorithm for cluster head selection (DEEEC)

2020 ◽  
Vol 39 (6) ◽  
pp. 8139-8147
Author(s):  
Ranganathan Arun ◽  
Rangaswamy Balamurugan
Keyword(s):  
Energy Efficient ◽  
Clustering Algorithm ◽  
Cluster Head ◽  
Residual Energy ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Second Stage ◽  
Energy Efficient Clustering ◽  
Two Stages ◽  
Ch Selection

In Wireless Sensor Networks (WSN) the energy of Sensor nodes is not certainly sufficient. In order to optimize the endurance of WSN, it is essential to minimize the utilization of energy. Head of group or Cluster Head (CH) is an eminent method to develop the endurance of WSN that aggregates the WSN with higher energy. CH for intra-cluster and inter-cluster communication becomes dependent. For complete, in WSN, the Energy level of CH extends its life of cluster. While evolving cluster algorithms, the complicated job is to identify the energy utilization amount of heterogeneous WSNs. Based on Chaotic Firefly Algorithm CH (CFACH) selection, the formulated work is named “Novel Distributed Entropy Energy-Efficient Clustering Algorithm”, in short, DEEEC for HWSNs. The formulated DEEEC Algorithm, which is a CH, has two main stages. In the first stage, the identification of temporary CHs along with its entropy value is found using the correlative measure of residual and original energy. Along with this, in the clustering algorithm, the rotating epoch and its entropy value must be predicted automatically by its sensor nodes. In the second stage, if any member in the cluster having larger residual energy, shall modify the temporary CHs in the direction of the deciding set. The target of the nodes with large energy has the probability to be CHs which is determined by the above two stages meant for CH selection. The MATLAB is required to simulate the DEEEC Algorithm. The simulated results of the formulated DEEEC Algorithm produce good results with respect to the energy and increased lifetime when it is correlated with the current traditional clustering protocols being used in the Heterogeneous WSNs.

Analisis Kebutuhan Petunjuk Praktikum Berbasis Keterampilan Proses Sains untuk Mencapai Kemampuan Merancang Eksperimen

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fitriah Khoirunnisa ◽  
Friska Septiani Silitonga ◽  
Veri Firmansyah
Keyword(s):  
Core Competence ◽  
Process Skills ◽  
Learning Materials ◽  
Science Process Skills ◽  
Second Stage ◽  
The Core ◽  
The Core Competence ◽  
Two Stages ◽  
Practical Instruction ◽  
Design Experiments

Penelitian ini bertujuan menganalisis kebutuhan petunjuk praktikum berbasis Keterampilan Proses Sains (KPS) untuk mencapai kemampuan merancang eksperimen pada materi kalor reaksi kalorimetri. Penelitian dilakukan terhadap peserta didik kelas XI SMA Negeri 2 Kota Tanjungpinang. Variabel penelitian mencakup analisis kebutuhan bahan ajar dan analisis kesesuaian Kompetensi Inti (KI) dan Kompetensi Dasar (KD). Jenis penelitian yang dilakukan adalah penelitian deskriptif kualitatif. Tahapan pertama dalam penelitian ini adalah menganalisis kebutuhan bahan ajar dengan cara membandingkan dua petunjuk praktikum yang selama ini telah digunakan di sekolah tersebut, ditinjau dari aspek struktur format penulisan, aspek kreativitas, dan aspek keterampilan proses sains yang terdapat dalam petunjuk praktikum. Sehingga didapatkan kesimpulan bahwa petunjuk praktikum yang selama ini digunakan tidak memberikan kesempatan kepada peserta didiknya untuk merancang eksperimen yang telah ditentukan. Tahapan kedua yaitu menganalisis kesesuaian kompetensi inti dan kompetensi dasar, yang bertujuan untuk menentukan indikator pencapaian kompetensi (IPK) yang akan menjadi acuan dalam mengembangkan petunjuk praktikum berbasis keterampilan proses sains. Dari kedua tahapan yang telah dilakukan maka dapat disimpulkan bahwa peserta didik memerlukan petunjuk praktikum yang mampu mengonstruksi pikiran dan mengaktifkan kinerja mereka, sehingga pendekatan Keterampilan Proses Sains menjadi pilihan dalam mengembangkan petunjuk praktikum yang sesuai dengan karakteristik kurikulum 2013.   This research aims to analyze the needs of Science Process Skills based Practical Instruction to achieve the ability to design experiments on the calor of reaction. This research was done to the students of class XI SMA Negeri 2 Tanjungpinang City. Research Variable includes the analysis of the needs of the learning materials and analysis of the suitability of the Core Competence (KI) and Basic Competence (KD). The type of research conducted is descriptive qualitative research. The first stages in this research is to analyze the needs of learning materials by comparing two practical instructions that had been implementing in the school, from the aspects of the structure of writing format, creativity, and science process skills embedded in practical instructions. The conclusion of this research that current practical instructions does not give an opportunity to the participants to design determined experiments. The second stage, namely analyzing the suitability of core competence and basic competence, which aims to determine the indicators of achievement of the competencies (GPA) which will be a reference in developing process skills-based teaching instructions science. Of the two stages that has been done then it can be concluded that learners need practical instructions to construct  thinking and and their performance, so the Science Process Skills approach is an option in developing practical instruction suitable for the characteristics of the curriculum of 2013.

ESTIMATING GAS AND ROCK OUTBURST RISK ON THE BASIS OF KNOWLEDGE AND EXPERIENCE – THE EXPERT SYSTEM BASED ON FUZZY LOGIC

2014 ◽  
Vol 59 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Norbert Skoczylas
Keyword(s):  
Fuzzy Logic ◽  
Expert System ◽  
Mining Industry ◽  
Automatic Assessment ◽  
Science Field ◽  
Second Stage ◽  
Two Stages ◽  
Outburst Hazard

Abstract The Author endeavored to consult some of the Polish experts who deal with assessing and preventing outburst hazards as to their knowledge and experience. On the basis of this knowledge, an expert system, based on fuzzy logic, was created. The system allows automatic assessment of outburst hazard. The work was completed in two stages. The first stage involved researching relevant sources and rules concerning outburst hazard, and, subsequently, determining a number of parameters measured or observed in the mining industry that are potentially connected with the outburst phenomenon and can be useful when estimating outburst hazard. Then, the Author contacted selected experts who are actively involved in preventing outburst hazard, both in the industry and science field. The experts were anonymously surveyed, which made it possible to select the parameters which are the most essential in assessing outburst hazard. The second stage involved gaining knowledge from the experts by means of a questionnaire-interview. Subjective opinions on estimating outburst hazard on the basis of the parameters selected during the first stage were then systematized using the structures typical of the expert system based on fuzzy logic.

Integrated assessment and mapping of the environmental situation in the Russian Federation regions

2017 ◽  
Vol 924 (6) ◽  
pp. 6-16
Author(s):  
V.S. Tikunov ◽  
O.Yu. Chereshnia
Keyword(s):  
Russian Federation ◽  
Pollution Index ◽  
Pollution Level ◽  
Anthropogenic Pressure ◽  
Environmental Capacity ◽  
Environmental Friendliness ◽  
Second Stage ◽  
Environmental Situation ◽  
The Russian Federation ◽  
Two Stages

The article presents a methodology for a comprehensive assessment of the environmental situation in Russian Federation regions based on the pollution index and the index of the ecological tension. The evaluation was carried out in two stages. At the first stage, the degree of pollution of the atmosphere, hydrosphere and lithosphere of the regions was estimated on the basis of the emission of pollutants into the atmosphere, departing from stationary sources, the formation of solid domestic wastes (SDW) and the discharge of contaminated wastewater. Based on these three indicators, a pollution index was constructed that estimates aggregate pollution level. In the second stage, the authors made the estimation of loads generated by atmospheric emissions, solid waste and waste water discharged into the territory of each region, per capita and in relation to the environmental capacity of the economy. This allows us to take into account the area of pollution, anthropogenic pressure and environmental responsibility of the population, as well as the environmental friendliness of production. On the basis of relative indicators, the index of ecological tension was created.

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