Numerical Simulation of Intermediate Cooling Temperature Field in Controlled Rolling

2010 ◽  
Vol 148-149 ◽  
pp. 359-362
Author(s):  
Wen Feng Huo ◽  
Xian Lei Hu ◽  
Bing Xing Wang ◽  
Xiang Hua Liu
Keyword(s):  
Cooling Rate ◽  
Controlled Rolling ◽  
Holding Time ◽  
Air Cooling ◽  
Thickness Direction ◽  
Cooling Mode ◽  
Cooling Strategy ◽  
Profile Characteristics ◽  
Intermediate Cooling ◽  
Rolling Efficiency

Air cooling may decrease rolling efficiency in controlled rolling for needing long holding time to obtain the correct rolling temperature because of small cooling rate. The intermediate cooling can increate the cooling rate, and improve rolling efficiency. Experiment was carried out to research the effect of intermediate cooling on rolling efficiency. The influence of different cooling mode on the temperature distribution and the temperature profile characteristics of different cooling strategy are analyzed with FEM. It shows that intermediate cooling can decrease the holding time effectively, and improve rolling efficiency; the temperature homogeneity in thickness direction can be improved by opening the header one after another and cooling the plate by oscillating cooling.

scholarly journals Development of Intermediate Cooling Technology and Its Control for Two-Stand Plate Rolling

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Fei Zhang ◽  
Wei Yu ◽  
Tao Liu
Keyword(s):  
Steel Plate ◽  
Cooling System ◽  
Chromatic Aberration ◽  
Rolling Process ◽  
Controlled Rolling ◽  
Plate Surface ◽  
Plate Rolling ◽  
Intermediate Cooling ◽  
Rolling Efficiency ◽  
The Impact

In a plate rolling production line, thermomechanically controlled processing is critical for plate quality. In this paper, a set of intermediate cooling equipment of a two-stand plate mill with super density nozzles, medium pressure, and small flow is developed. Based on a simplified dynamic model, a cooling control scheme with combined feedforward, feedback, and adaptive algorithms is put forward. The new controlled rolling process and the highly efficient control system improve the controlled rolling efficiency by an average of 17.66%. The proposed intermediate cooling system can also effectively inhibit the growth of austenite grain, improve the impact toughness and yield strength of Q345B steel plate, reduce the formation of secondary oxide scale on the plate surface and the chromatic aberration of the plate surface, and greatly improve the surface quality of the steel plate.

Effects of cooling rate and isothermal holding on the characteristics of MnS particles in high-carbon heavy rail steels

2020 ◽  
Vol 117 (1) ◽  
pp. 110 ◽  
Author(s):  
Xuewei Zhang ◽  
Caifu Yang ◽  
Lifeng Zhang
Keyword(s):  
Cooling Rate ◽  
Isothermal Holding ◽  
Average Diameter ◽  
Holding Time ◽  
Area Fraction ◽  
Air Cooling ◽  
Steel Matrix ◽  
Number Density ◽  
3D Morphology ◽  
Holding Temperature

The characteristics of MnS particles were intensively investigated at three different cooling rate of 80.4 K · s−1 (water cooling), 3.8 K · s−1 (air cooling) and 1.8 K · s−1 (furnace cooling) as well as the different isothermal holding temperature and time in laboratory experiments. The three-dimensional (3D) morphology of MnS particles was extracted from steel samples using non-aqueous solution electrolysis. The results showed that the 3D morphology of MnS changed from a nearly spherical into rod-like and the area fraction and average diameter of MnS increased with decreasing cooling rate. During isothermal holding process, the morphology of MnS changed little at 1473 K (1200 °C), but their shape profiles varied from a nearly spherical and spindle-like to irregular at higher holding temperature 1673 K (1400 °C) when the holding time exceeded 60 min. Moreover, the number density and area fraction of MnS decreased with increasing holding time at 1573 K (1300 °C) and 1673 K (1400 °C), respectively. Especially at 1573 K (1300 °C), the 1 ∼ 3 µm MnS inclusions were dissolved and lead to decreasing of number density, but that > 3 µm one occurs growth and resulted in increasing of average diameter. The calculation results show that the starting temperature of precipitation of MnS was about 1627 K (1354 °C) and effect of cooling rate on the segregation of Mn and S is insignificant. Considering the segregation of solutes, MnS formation and growth takes place in the solid/liquid interface of steel when the solid fraction is close to 0.9567 during solidification. It has been found that the increase of cooling rate gives rise to the decreased of MnS diameter because the growth time of MnS is short. Furthermore, thermodynamic calculations of MnS solid solubility product were carried out to reveal the high holding temperature and long holding time favors the dissolution of MnS particles. It is necessary to decrease the sulfur content by less than 16 ppm in order to assure that the larger MnS which formed during solidification redissolves in the steel matrix, rather than relying on increasing the heating temperature which is above 1649 K (1376 °C). Subsequent, the MnS will precipitate again in a finely dispersive state during rolling process, and it can hinder annealing grain growth and finally make for the improvement of the toughness property of the steel.

Microstructural Aspects of Recrystallization-Controlled Rolling in V-Ti-N Steels

1985 ◽  
Vol 43 ◽  
pp. 334-335
Author(s):  
M.G. Burke ◽  
R.M. Fix ◽  
A.J. DeArdo
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Steel Industry ◽  
Room Temperature ◽  
Controlled Rolling ◽  
Accelerated Cooling ◽  
Air Cooling ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Processing Treatment

Recrystallization controlled rolling (RCR) has been developed as an economically viable alternative to conventional controlled rolling, a thermomechanica1 processing treatment currently employed in the steel industry. RCR processing involves deformation below the austenite grain coarsening temperature of the steel, followed by accelerated cooling to an intermediate temperature and air cooling to room temperature. The V-Ti-N system is well-suited to RCR processing because Ti (in the form of TiN precipitates) promotes a fine reheated austenite grain size while the V in solution in the austenite will be available for subsequent precipitation in the ferrite. The precipitation potential of V-Ti steels has been shown to increase with increasing N content and cooling rate.

scholarly journals On the influence of basic thermodynamics on thermal cracking resistance of asphalt mixtures in cooling tests

2018 ◽  
Vol 3 ◽  
pp. 1-7
Author(s):  
Daniel Steiner ◽  
Bernhard Hofko
Keyword(s):  
Tensile Strength ◽  
Cooling Rate ◽  
Thermal Cracking ◽  
Radiation Condition ◽  
Asphalt Mixtures ◽  
Air Cooling ◽  
Laboratory Assessment ◽  
Cracking Resistance ◽  
Viscoelastic Parameters ◽  
The Impact

The cooling test or Thermal Stress Restrained Specimen Test (TSRST) simulates fully restrained pavements, as they occur in field for laboratory assessment of the thermal cracking resistance of asphalt mixtures. In the TSRST, cryogenic stress builds up due to cooling and prevented shrinkage until the tensile strength of the specimen is exceeded and the specimen fails by cracking. By carrying out TSRST various viscoelastic parameters, e.g. relaxation, evolution of tensile stresses, and tensile strength can be analyzed. Thus, a comprehensive view on the low temperature performance is possible. Standard TSRST is controlled by setting the cooling rate of the air within the chamber at a fixed value, e.g. -10°C/h. In thermodynamics, the actual cooling rate of objects is not only influenced by the cooling but also by external conditions like humidity, air velocity, radiation condition, etc. A current study investigates the impact of additional cooling parameters rather than just the air cooling rate. Two test machines of the same manufacturer that differ in the year of production and the setup of the climate chamber are compared. An initial wide scatter of test results from the two devices could be explained by taking thermodynamics into account and the reproducibility could be significantly enhanced.

Microstructure and Melting Behavior of Rapid Solidified Au-Ag-Ge Alloy

2012 ◽  
Vol 531-532 ◽  
pp. 618-622
Author(s):  
Da Tian Cui ◽  
Wen Hui Liu ◽  
Long Fei Liu
Keyword(s):  
Grain Boundaries ◽  
Cooling Rate ◽  
Melt Spinning ◽  
Melting Behavior ◽  
Exothermic Peak ◽  
Minimum Size ◽  
Thickness Direction ◽  
Liquid Temperature ◽  
Alloy Ingot ◽  
Precipitated Phase

Rapid solidified Au-Ag-Ge alloy was prepared by the melt spinning method，microstructure and melting behavior of the rapid solidified alloy was investigated by means of SEM, TEM and DSC. DSC results show that liquid temperature of the rapid solidified alloy is about 3～4°C lower than that of the alloy ingot, melting interval is also smaller. Minimum size of 40nm nanocrystalline has formed when the cooling rate is 1.293×106K/sec. Metastable supersaturated precipitated Ge-rich phases have been found at the grain boundaries, a structure mutation was found in the thickness direction of the rapid solidified alloy. Meanwhile, due to the stabilization transition of the supersaturated precipitated phase of the rapid solidified alloy, an exothermic peak has formed in the DSC curve, temperature of the exothermic peak becomes much lower when the cooling rate increases.

Thermomechanical Controlled Rolling of Hot Coils of Steel Grade S355MC at the Wide-Strip Rolling Mill 1700

2019 ◽  
Vol 291 ◽  
pp. 63-71 ◽  
Author(s):  
Oleksandr H. Kurpe ◽  
Volodymyr V. Kukhar ◽  
Eduard S. Klimov ◽  
Andriy H. Prysiazhnyi
Keyword(s):  
Surface Quality ◽  
Hot Rolling ◽  
Rolling Mill ◽  
Controlled Rolling ◽  
Steel Grade ◽  
Air Cooling ◽  
Strip Rolling ◽  
Integrated Technology ◽  
Wide Strip ◽  
Process Constraints

Тhere has been developed technology, and pilot batch of hot rolling coils (6×1500 mm, steel grade S355MC) has been produced using thermo-mechanical controlled process (TMCP) for the wide-strip rolling mill 1700. The integrated technology for TMCP coil production (steel grade S355MC) has been firstly developed for the rolling mill 1700 in accordance with EN 10149-2. Air cooling for coils to 450°C after coiling has been firstly used in the developed technology, which provides for decrease in air scale and improvement of surface quality for the customers. It is possible to manufacture rolled products up to 6×1500 mm (steel grade S355MC) in accordance with EN 10149-2 using the existing equipment without exceeding the existing process constraints during its operation and without upgrading. It is possible to further master the rolled products, which are manufactured according to the TMCP technology.

Effect of Sintering Parameter on the Microstructure and Electrical Properties for Bi2Se3 Topological Insulator Crystals

2013 ◽  
Vol 709 ◽  
pp. 172-175
Author(s):  
Li Lv ◽  
Min Zhang ◽  
Li Qin Yang ◽  
Xin Sheng Yang ◽  
Yong Zhao
Keyword(s):  
Electrical Properties ◽  
Cooling Rate ◽  
Single Crystals ◽  
Carrier Concentration ◽  
Topological Insulator ◽  
Layered Structure ◽  
Phase Structure ◽  
Lattice Parameter ◽  
Holding Time ◽  
Type Conductivity

Single crystals of Bi2Se3 topological insulators have been prepared though melt-grown reaction. The sintering parameters of holding time and cooling rate obviously affect the phase structure and electrical properties. The samples with layered structure can be perpendicular cleaved with (0 0 L) axis. All the samples show n-type conductivity caused by the existence of Se vacancies. For low cooling rate, more Se atoms anti-occupy Bi lattice sites, which decreases c-axis lattice parameter and increases carrier concentration n; high cooling rate increases c and decreases n because of less Se atoms occupying Bi lattice sites. Increasing holding time firstly decreases the ratio of Se atoms occupying Bi lattice sites and then increases it, which gives rise to c firstly increase then decrease and n firstly decrease then increase.

Effect of Austenitizing Temperature and Air Cooling Rate on Microstructure and Properties of the Low Carbon Mn-Si-Cr Steel

2008 ◽  
Vol 33-37 ◽  
pp. 527-532
Author(s):  
Dong Yu Liu ◽  
Shi Xiang Hou ◽  
Ye Yuan ◽  
Bing Zhe Bai ◽  
Zong De Liu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Charpy Impact ◽  
Optical Microscope ◽  
Experimental Result ◽  
Air Cooling ◽  
Low Carbon ◽  
Austenitizing Temperature ◽  
Austenite Grain Size ◽  
Hardness Tester ◽  
Mixed Microstructure

The air cooling rate of the Low Carbon Mn-Si-Cr steel bar with different diameter after austenitizing at 910oC and 960oC was simulated by Formaster-F Phase transforming instrument and Gleeble-1500 thermal /mechanical simulating machine. Microstructure of the specimen was observed by OLYMPUS PME3 optical microscope and FEI QUANTA200F scanning electron microscope. The hardness and impact toughness of the steel was tested by HBRV-187.5 hardness tester and JCSJ300-I instrumented Charpy impact tester. The experimental result showed that with the amount of CFB in CFB+M mixed microstructure increasing the combination of strength and toughness of the steel was improved. The higher the austenitizing temperature of the steel, the wider the air-cooling rate range obtaining CFB+M mixed microstructure. However, the steel produces mixed grain after austenitizing at 960 oC. For obtaining fine prior austenite grain size, Ti and Nb alloying element need to be added.

Improvement of the Ductility of Press-Hardened Plane Sheets through a Modified Heat Treatment

2015 ◽  
Vol 639 ◽  
pp. 243-248 ◽  
Author(s):  
Tobias Konrad ◽  
Peter Feuser
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cooling Rate ◽  
Material Properties ◽  
Sheet Thickness ◽  
The Body ◽  
Intermediate Temperature ◽  
Holding Time ◽  
Production Costs ◽  
Press Hardening

Tailored press-hardening processes are used to reduce both production costs and component weight. The aim of these development methods is to generate regions zones in the component with both high and low tensile strengths. The B-pillar, for instance, needs high tensile strength in the region of the roof frame to prevent deformation. However, the connection to the body should have lower tensile strength to absorb the energy of a crash.Regarding the production process for tailored welded blanks, the tailored press-hardening processes for monolithic sheets need no joining operation. As an addition to recent publications, this paper presents a modified tailored press-hardening process, with a modified time-temperature process. Starting from the required tailored material properties of the part, with a sheet thickness of 1.5 mm, research has been done on the process window and process design.This contribution concentrates on modifications to the time-temperature profile. After heating the hot-dip galvanized, heat-treatable 22MnB5 steel above its austenitic temperature, the aim is to adjust the material’s mechanical properties within the cooling process.Based on the continuous TTT diagram, the cooling rate has an impact on the material’s mechanical material properties. Different proportions of constituents such as Bainite, Ferrite or Perlite are created by varying the cooling rate. Furthermore, during an intermediate stage in the cooling-down period, the holding temperature has an even stronger effect on the material’s microstructural composition and the corresponding mechanical properties. The rate of the transformation process changes, depending on the intermediate temperature. The third parameter investigated is the holding time at this intermediate temperature. As the holding time is increased a transformation, progressing from austenite to other constituents, can be observed.The results of this parametric study could be transferred to a prototype environment.

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