scholarly journals Quantitative assessment of microstructural inhomogeneity by thickness of hot-rolled plates made of cold-resistant low-alloy steel for Arctic applications

2020 ◽  
pp. 41-49
Author(s):  
A. A. Kazakov ◽  
D. V. Kiselev ◽  
O. V. Sych ◽  
E. I. Khlusova
Keyword(s):  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Rolling Direction ◽  
Accelerated Cooling ◽  
Subgrain Structure ◽  
Plate Steel ◽  
Long Distance ◽  
Microstructural Heterogeneity ◽  
Hot Rolled ◽  
Rolled Plates

A technique to assess microstructural anisotropy assessing by the thickness of the plate steel based on the texture analysis of the image has been developed. This technique provides for the anisotropy assessment at two dimensional levels: in the short-distance and long-distance neighborhoods, which characterize the elongation along the rolling direction of fine and coarse structural constituents, respectively. The practical approval results of this technique in the study of the microstructural heterogeneity of ferritic-bainitic steels over the thickness of 25–70 mm hot-rolled plates have been presented. It has been shown that the proposed anisotropy criteria in combination with the volume fraction of coarse packet-block regions of lath bainite as well as regions of bainite without an internal developed subgrain structure adequately estimate the microstructural heterogeneity over the thickness of plate steel and can be used for a detailed interpretation of the two-stage thermomechanical processing technology with accelerated cooling including taking into account the metallurgical inheritance of the slab.

Quantitative assessment of structural inhomogeneity in cold-resistant low-alloy steel sheets for interpretation of technological features of their manufacturing

2020 ◽  
pp. 4-14
Author(s):  
A. A. Kazakov ◽  
◽  
D. V. Kiselev ◽  
O. V. Sych ◽  
E. I. Khlusova ◽  
...  
Keyword(s):  
Quantitative Assessment ◽  
Complex Analysis ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Granular Bainite ◽  
Accelerated Cooling ◽  
Subgrain Structure ◽  
Long Distance ◽  
Lath Bainite ◽  
Detailed Interpretation

Microstructural inhomogeneity comparative automated complex analysis of plate low-alloy cold-resistant steels for Arctic application with a thickness of 25, 50 and 70 mm, produced by thermomechanical processing technology with various temperaturedeformation parameters, has been performed. The inhomogeneity of the microstructure over the plates thickness was estimated by the volume fraction of coarse packet-block regions of lath bainite and regions of bainite that does not have a developed internal subgrain structure (conventionally called “non-granular” bainite), as well as anisotropy of the microstructure at different dimensional levels: short and long distance neighborhoods. The obtained results of microstructural heterogeneity quantitative assessment over the plates thickness were used for its detailed interpretation, taking into account the metallurgical inheritance of the slab and special features of two-stage thermomechanical processing with accelerated cooling.

scholarly journals Control of Laves Precipitation in a FeCrAl-based Alloy Through Severe Thermomechanical Processing

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2939
Author(s):  
Jiyun Zheng ◽  
Yuzhen Jia ◽  
Peinan Du ◽  
Hui Wang ◽  
Qianfu Pan ◽  
...  
Keyword(s):  
Thermomechanical Processing ◽  
Shear Bands ◽  
Rolling Direction ◽  
Heat Stability ◽  
Structure Type ◽  
Fecral Alloy ◽  
Cell Structures ◽  
The Matrix ◽  
Deformation Textures ◽  
Hot Rolled

In recent years, the development of nuclear grade FeCrAl-based alloys with enhanced accident tolerance has been carried out for light water reactor (LWR) fuel cladding to serve as a substitute for zirconium-based alloys. To achieve excellent microstructure stability and mechanical properties, the control of precipitation particles is critical for application of FeCrAl-based alloys. In this paper, the effect of thermomechanical processing on the microstructure and precipitation behavior of hot-rolled FeCrAl alloy plates was examined. After hot rolling, the FeCrAl alloy plates had typical deformation textures. The rolling direction (RD) orientation gradually rotated from <100> to <110> along with increasing reduction. Shear bands and cell structures were formed in the matrix, and the former acted as preferable nucleation sites for crystallization. Improved deformation helped to produce strain-induced precipitation. The plate with 83% reduction had the most homogeneous and finest precipitation particles. Identification results by TEM indicated that the Laves precipitation was of the Fe2Nb-type crystal structure type, with impurities including Mo, Cr, and Si. The plate with uniform Laves particles displayed favorable heat stability after a long period of aging at 800 °C. The microstructure evolution of the aged sample was also observed. The deformation microstructure and the strain-induced precipitation mechanism of FeCrAl alloys are discussed.

Microstructure and Property Control of Hot Rolled DP600 Steel

2011 ◽  
Vol 415-417 ◽  
pp. 938-942
Author(s):  
Le Yu Zhou ◽  
Ya Zheng Liu ◽  
Lian Hong Yang ◽  
Dan Zhang
Keyword(s):  
Dual Phase Steel ◽  
Volume Fraction ◽  
Ferrite Matrix ◽  
Accelerated Cooling ◽  
Dual Phase ◽  
Dp Steel ◽  
Fine Grain ◽  
Mechanical Experiment ◽  
Property Control ◽  
Hot Rolled

Thermal mechanical experiment of step-cooling of 600MPa hot-rolled DP steel after compressed was carried out on Gleeble-1500 thermal mechanical simulator, using design of butterfly-shaped sample. Microstructure evolution during step-cooling and its effect on mechanical property of tested steel were analyzed. It is shown that, dual phase microstructure which martensite islands disperses in fine grain ferrite matrix is obtained by holding for 8~10s at 670°C followed accelerated cooling to 200°C. With increasing of holding time, grain size of ferrite coarsens, and volume fraction of ferrite has few changes. Meanwhile, tensile strengths of tested steel are all near 600MPa. That is to say, ferrite transformation is adequate during holding for 8~10s at 670°C and tensile strength of dual phase steel is stable accordingly.

Microstructure and Microtexture Evolution of Invar Alloy after Cross Accumulative Roll Bonding (CARB) Compared to ARB

2016 ◽  
Vol 879 ◽  
pp. 744-749 ◽  
Author(s):  
Kamel Tirsatine ◽  
Hiba Azzeddine ◽  
Thierry Baudin ◽  
Anne Laure Helbert ◽  
Francois Brisset ◽  
...  
Keyword(s):  
Accumulative Roll Bonding ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Rolling Direction ◽  
Grain Structure ◽  
Subgrain Structure ◽  
Roll Bonding ◽  
Ni Alloy ◽  
Backscatter Diffraction ◽  
Microstructure And Microtexture

The microstructure and microtexture evolution of a Fe-36%Ni alloy processed by cross accumulative roll-bonding was investigated using Electron BackScatter Diffraction. Deformation led to the development of elongated ultrafine grains parallel to the rolling direction that subsequently became more equiaxed. The grains were more effectivelly refined after CARB than after ARB processing. The grain aspect ratio (l/L) decreased (which means a trend towards elongated sub-grain structure) after 2 and 3 CARB processing cycles and then increased (which means a trend towards equiaxed subgrain structure) from 4 to 5 cycles. The fraction of HAGB, CSL boundaries and the estimated deformed volume fraction gradually increased with increasing number of CARB cycles. Copper-type texture was observed after CARB odd cycles (RD//RD), while after even cycles (RD//TD) a new texture component named H ({012}<221>) was observed.

Precipitation Behavior and Microstructure Evolution of Mg-Zn-Zr-Er Alloy Processed by Secondary Deformation and Heat Treatment

2013 ◽  
Vol 747-748 ◽  
pp. 377-382
Author(s):  
Bao Xiang Zhang ◽  
Jing Zhang
Keyword(s):  
Microstructure Evolution ◽  
Hot Rolling ◽  
Volume Fraction ◽  
Rolling Direction ◽  
Hardness Test ◽  
Secondary Phase ◽  
Rolling Process ◽  
Second Phase ◽  
Precipitation Behavior ◽  
Hot Rolled

Preheated at 673K for 3h and 6h respectively, as-extruded Mg-9Zn-0.6Zr-2Er (wt.%) slabs with starting thickness of 8mm were hot-rolled at 673K to 2mm. The hot-rolled alloys were then solution treated at 673K for1.5h and aged at 473K for 10h. Microstructure evolution and second phase precipitation behavior during hot rolling and subsequent heat treatments were examined by optical microscopy (OM), scan electron microscopy (SEM) and micro hardness test. Mg-9Zn-0.6Zr-2Er alloy were fully recrystallized with fine equiaxed grains after preheating for 3 hours, prolonging heating time leads to a higher degree of dissolution of secondary phase into Mg matrix but a coarsening of the microstructure. During hot rolling process, the volume fraction of the DRX grains increased gradually with increasing reduction ratio, shearing bands became visble in the final pass. Thermal stable Mg-Zn-Er intermetallic compounds distributed along rolling direction at the first rolling passes and became more homogenous in the final pass. More nanosized MgZn2 precipitated during hot rolling in the alloy preheated for 6h than that for 3h, leading to an enhanced precipitation hardening effect in the former.

Effects of Alloying on Deformation Behavior of Low Carbon Steels in the Intercritical Temperature Range

2007 ◽  
Vol 539-543 ◽  
pp. 12-19 ◽  
Author(s):  
Evgueni I. Poliak ◽  
D. Bhattacharya
Keyword(s):  
Deformation Behavior ◽  
Thermomechanical Processing ◽  
Steel Strip ◽  
Carbon Steels ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Technical Problems ◽  
Precise Control ◽  
Hot Rolled ◽  
Hot Rolled Steel

Industrial thermomechanical processing of hot rolled steel strip products with rolling operations in the austenite + ferrite (γ + α) range offers, on one hand, unique possibilities for more precise control of microstructure and mechanical properties of as hot rolled products after accelerated cooling. On the other hand, there are significant technical problems related to the rolling stability induced by steel grade dependent non-monotonous variations in deformation resistance and its sensitivities to temperature and strain rate within the γ + α range. Based on laboratory results, the deformation behavior of low carbon (up to 0.2 %) steels alloyed with Mn, Si, Al and their combinations, as well as microalloyed with Nb at the intercritical temperatures is discussed.

Scientific and technological bases for creation of cold-resistant steel with a guaranteed yield strength of 315–750 MPa for the Arctic. Part 2. Technology of production, structure and properties of sheet hire performance

2019 ◽  
pp. 14-41
Author(s):  
O. V. Sych
Keyword(s):  
Yield Strength ◽  
Thermomechanical Processing ◽  
The Arctic ◽  
Accelerated Cooling ◽  
Low Alloy Steels ◽  
Hot Plastic Deformation ◽  
Metal Thickness ◽  
Alloy Steels ◽  
Technology Of Production ◽  
Technological Methods

On the basis of the conducted research, a complex of scientific and technological methods has been developed for various technological processes (thermomechanical processing with accelerated cooling, quenching from rolling and separate furnace heating with high-temperature tempering). The developed method provides the formation of the structure of acceptable heterogeneity and anisotropy according to different morphological and crystallographic parameters throughout the thickness of rolled products up to 100 mm from low alloy steels with a yield strength of at least 315–460 MPa and up to 60 mm from economically alloyed steels with a yield strength of at least 500–750 MPa. The paper presents results of the industrial implementation of hot plastic deformation and heat treatment schemes for the production of cold rolled steel sheet with yield strength of at least 315–750 MPa for the Arctic. The structure of sheet metal thickness is given, providing guaranteed characteristics of strength, ductility, cold resistance, weldability and crack resistance.

Modeling of steel hardening process at thermal and mechanical treatment

2019 ◽  
pp. 7-13
Author(s):  
A. S. Oryshchenko ◽  
V. A. Malyshevsky ◽  
E. A. Shumilov
Keyword(s):  
Mechanical Treatment ◽  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Accelerated Cooling ◽  
Rolling Mills ◽  
Hardening Process ◽  
Deformation Parameters ◽  
Research Complex ◽  
Steel Hardening

The article deals with modeling of thermomechanical processing of high-strength steels at the Gleeble 3800 research complex, simulating thermomechanical processing with various temperature and deformation parameters of rolling and with accelerated cooling to a predetermined temperature. The identity of steel hardening processes at the Gleeble 3800 complex and specialized rolling mills, as well as the possibility of obtaining steels of unified chemical composition, are shown.

Strength Properties and Chemical Composition of Materials Used in Weathering Steel Bridges

2013 ◽  
Vol 739 ◽  
pp. 292-297 ◽  
Author(s):  
Vit Křivý ◽  
Petr Konečný ◽  
Viktor Urban
Keyword(s):  
Chemical Composition ◽  
Statistical Evaluation ◽  
Strength Properties ◽  
Weathering Steel ◽  
The Czech Republic ◽  
Analysis And Evaluation ◽  
Real Material ◽  
Materials Used ◽  
Hot Rolled ◽  
Rolled Plates

The paper deals with a statistical evaluation of the real material properties of weathering steels used for the construction of motorway bridges in the Czech Republic between 2001 and 2007. The statistical analysis and evaluation is carried out for a range of hot rolled plates made of S355J2W weathering steel. The paper contains an evaluation of the strength properties of the steel and its chemical composition. The paper also contains derived real values of partial factors of materials corresponding to the relevant reliability classes RC1 to RC3 pursuant to the European standard EN 1990.

The production of hot-rolled plate steel with reduced tolerances

Metallurgist ◽  
1974 ◽  
Vol 18 (11) ◽  
pp. 853-854
Author(s):  
Yu. V. Konovalov ◽  
L. B. Gorskii ◽  
A. E. Rudnev ◽  
V. P. Samoilov ◽  
G. I. Manshilin ◽  
...  
Keyword(s):  
Rolled Plate ◽  
Plate Steel ◽  
Hot Rolled
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