Influence of Annealing Temperature on Microstructure and Properties of the Hot-Stamping Boron Steel

2012 ◽  
Vol 602-604 ◽  
pp. 385-389
Author(s):  
Kuan Hui Hu ◽  
Xiang Dong Liu ◽  
De Xin Tian ◽  
Guan Wen Feng ◽  
Fang Yi Sun
Keyword(s):  
Yield Strength ◽  
Annealing Temperature ◽  
Hot Stamping ◽  
Phase Region ◽  
Boron Steel ◽  
Two Phase ◽  
Microstructure And Properties ◽  
Significant Downward Trend ◽  
Test Steel ◽  
Higher Temperature

The effect of different annealing temperature on microstructure and properties of the hot-stamping boron steel were studied.The results show that the yield strength of the test steel is reduced with increasing annealing temperature, only at 790°C,the specimen yield strength increased slightly, and showed a significant downward trend after 790°C.The specimen tensile strength and hardness with the change of the same trend when annealing temperature changes.And through the test we can see,at 760°C ,the test steel has entered a two-phase region,the test steel gain ferrite and pearlite when it is annealed below the temperature,it is easy to appear martensite microstructure when it is annealed in the higher temperature,and lead to the strength and hardness of the rise.

scholarly journals Wear in Hot Stamping by Partition Heating

2020 ◽  
Vol 4 (1) ◽  
pp. 18 ◽  
Author(s):  
Yanhong Mu ◽  
Enrico Simonetto ◽  
Marco Scagnolari ◽  
Andrea Ghiotti
Keyword(s):  
Mechanical Characteristics ◽  
Adhesive Wear ◽  
Heating Temperature ◽  
Hot Stamping ◽  
Boron Steel ◽  
Steel Sheets ◽  
Body In White ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Pin On Disk

Hot stamping by partition heating of Al–Si coated boron steel sheets is currently utilized to produce parts of the car body-in-white with tailored microstructural and mechanical characteristics. This paper investigates the evolution of the Al–Si coating and its tribological and wear performances in the case of direct heating at the process temperatures of 700 °C, 800 °C, and 900 °C, skipping the preliminary austenitization as it may happen in the case of tailored tempered parts production. A specifically designed pin-on-disk configuration was used to reproduce at a laboratory scale the process thermo-mechanical cycle. The results show the morphological and chemical variation of the Al–Si coating with heating temperature, as well as that the friction coefficient, decreases with increased temperature. Furthermore, the results proved that the adhesive wear is the main mechanism at the lower temperature, while abrasive wear plays the major role at the higher temperature.

Rheological and structural studies on heat-induced gelation of concentrated skim milk

1995 ◽  
Vol 62 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Atsumi Tobitani ◽  
Haruyoshi Yamamoto ◽  
Toshiaki Shioya ◽  
Simon B. Ross-Murphy
Keyword(s):  
Phase Diagram ◽  
Laser Light ◽  
Skim Milk ◽  
Phase Region ◽  
Polymer Physics ◽  
Phase Behaviour ◽  
Two Phase ◽  
Effects Of Ph ◽  
Higher Temperature ◽  
Temperature Side

SUMMARYHeat-induced gelation of milk was studied using both rheological and structural techniques. The sample was a conventional skim milk, concentrated with an ultrafiltration membrane, which formed gels when heated at appropriate pH. We investigated some factors that are considered to affect the gelation, such as concentration, pH and rennet treatment. The gelation process was monitored with a high precision oscillatory shear rheometer and the structure of gels was evaluated with quasi-elastic laser light scattering. From these results the gelation and phase separation behaviour were determined. By combining the results for different concentrations a phase diagram was obtained, which indicated that skim milk had a two-phase region on the higher temperature side. The effects of pH and rennet treatment were also evaluated with the aid of this phase diagram. The results were discussed on the basis of concepts of the phase behaviour of polymers, which were successfully developed in polymer physics.

Decarburization of 0.21C-1.3Mn-0.2Si Steel for Hot Stamping at Various Heating Temperatures

2011 ◽  
Vol 172-174 ◽  
pp. 887-892 ◽  
Author(s):  
Koutarou Hayashi ◽  
Toshinobu Nishibata ◽  
Nobusato Kojima ◽  
Masanori Kajihara
Keyword(s):  
Annealing Time ◽  
Single Phase ◽  
Annealing Temperature ◽  
Volume Diffusion ◽  
Hot Stamping ◽  
Ambient Atmosphere ◽  
Uniform Thickness ◽  
Two Phase ◽  
Annealing Conditions ◽  
Parabolic Relationship

In order to examine the decarburization behavior in the hot stamping (HS) method, the dependence of the microstructure evolution on the annealing temperature was experimentally studied using a Fe-0.21 mass% C-1.3 mass% Mn-0.2 mass% Si steel. The steel was isothermally annealed in the temperature range ofT= 773-1173 K for various times oft= 100-12800 s in an ambient atmosphere. Here, the steel possesses the ferrite (α) + cementite (θ) two-phase microstructure atT= 773-923 K, the α + austenite (γ) two-phase microstructure atT= 1013-1073 K, and the γ single-phase microstructure atT= 1093-1173 K. During annealing atT= 1013-1073 K fort= 1600 s, however, the α layer with a uniform thickness is formed at the surface of the steel due to decarburization and gradually grows into the inside. Such formation of the a layer was not clearly observed atT973 K and T1093 K. Thus, the formation of the α layer hardly occurs under the HS annealing conditions. AtT= 1033 K, the thickness of the α layer is mostly proportional to the square root of the annealing time. Such a relationship is called the parabolic relationship. Furthermore, the grain size of the α layer monotonically increases with increasing annealing time. Hence, the parabolic relationship guarantees that the growth of the α layer is controlled by volume diffusion.

Investigating Fuel Condensation Processes in Low Temperature Combustion Engines

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Lu Qiu ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Load Condition ◽  
Phase Region ◽  
Low Temperature Combustion ◽  
Two Phase ◽  
Temperature Combustion ◽  
Real Gas Effects ◽  
Unburned Hydrocarbons ◽  
High Load Condition ◽  
Higher Temperature

Condensation of gaseous fuel is investigated in a low temperature combustion (LTC) engine fueled with double direct-injected diesel and premixed gasoline at two load conditions. Possible condensation is examined by considering real gas effects with the Peng–Robinson (PR) equation of state (EOS) and assuming thermodynamic equilibrium of the two fuels. The simulations show that three representative condensation events are observed. The first two condensations are found in the spray some time after the two direct injections (DI), when the evaporative cooling reduces the local temperature until phase separation occurs. The third condensation event occurs during the late stages of the expansion stroke, during which the continuous expansion sends the local fluid into the two-phase region again. Condensation was not found to greatly affect global parameters, such as the average cylinder pressure and temperature mainly because, before the main combustion event, the condensed phase was converted back to the vapor phase due to compression and/or first stage heat release. However, condensed fuel is shown to affect the emission predictions, including engine-out particulate matter (PM) and unburned hydrocarbons (UHCs). Specifically, it was shown that the condensed fuel comprised more than 95% of the PM in the low load condition, while its contribution was significantly reduced at the high load condition due to higher temperature and pressure conditions.

Effect of Composition System on Microstructure and Properties of 1000-MPa Grade Cold Rolled DPSteel

2020 ◽  
Vol 993 ◽  
pp. 534-540
Author(s):  
Xiao Long Zhao ◽  
Dong Liang Zhao
Keyword(s):  
High Efficiency ◽  
Phase Region ◽  
Element Content ◽  
Continuous Annealing ◽  
Two Phase ◽  
Microstructure And Properties ◽  
Fine Grained ◽  
Fine Grain ◽  
Duplex Steel ◽  
Cold Rolled

1000 MPa grade cold-rolled duplex steel with 5 component systems was trial-produced in the laboratory. After hot rolling, pickling and cold rolling, the test steel was simulated continuous annealing on Gleeble-3800 thermal simulator. The microstructure and properties of 5 kinds of experimental steels after simulated annealing were analyzed. The results show that C and Mn elements are the basic alloy systems of all duplex steels. In the case of low Si element, the C element content of the 1000 MPa grade dual phase steel should be 0.15 % or higher, and the Mn element content should be higher than 1.8 %. Si element increased to the A3 point, while the amount of austenite was less in the two-phase region during annealing, and the volume fractionof martensiteafter the rapid cooling is insufficient; Nb element is a high-efficiency fine-grain strengthening element, which greatly improvedthe uniformity of the steel species. The fine-grained martensite islands have enhance the tempering stability of martensite and thereby to reduce the adverse strength effect from over-aging temperature.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Solution Properties and Phase Behavior of Ammonium Hexylene Octyl Succinate in Water and Water-Oil System

1970 ◽  
Vol 3 (1) ◽  
Author(s):  
Md. Hamidul Kabir ◽  
Ravshan Makhkamov ◽  
Shaila Kabir
Keyword(s):  
Critical Micelle Concentration ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Carbon Number ◽  
Phase Region ◽  
Solution Properties ◽  
Middle Phase ◽  
Two Phase ◽  
Lamellar Liquid Crystal ◽  
Drug Ingredient

The solution properties and phase behavior of ammonium hexylene octyl succinate (HOS) was investigated in water and water-oil system. The critical micelle concentration (CMC) of HOS is lower than that of anionic surfactants having same carbon number in the lipophilic part. The phase diagrams of a water/ HOS system and water/ HOS/ C10EO8/ dodecane system were also constructed. Above critical micelle concentration, the surfactant forms a normal micellar solution (Wm) at a low surfactant concentration whereas a lamellar liquid crystalline phase (La) dominates over a wide region through the formation of a two-phase region (La+W) in the binary system. The lamellar phase is arranged in the form of a biocompatible vesicle which is very significant for the drug delivery system. The surfactant tends to be hydrophilic when it is mixed with C10EO8 and a middle-phase microemulsion (D) is appeared in the water-surfactant-dodecane system where both the water and oil soluble drug ingredient can be incorporated in the form of a dispersion. Hence, mixing can tune the hydrophile-lipophile properties of the surfactant. Key words: Ammonium hexylene octyl succinate, mixed surfactant, lamellar liquid crystal, middle-phase microemulsion. Dhaka Univ. J. Pharm. Sci. Vol.3(1-2) 2004 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

scholarly journals Revisiting the Bøggild Intergrowth in Iridescent Labradorite Feldspars: Ordering, Kinetics, and Phase Equilibria

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Shiyun Jin ◽  
Huifang Xu ◽  
Seungyeol Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Phase Region ◽  
Two Phase ◽  
Subsolidus Phase ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The enigmatic Bøggild intergrowth in iridescent labradorite crystals was revisited in light of recent work on the incommensurately modulated structures in the intermediated plagioclase. Five igneous samples and one metamorphic labradorite sample with various compositions and lamellar thicknesses were studied in this paper. The lamellar textures were characterized with conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The compositions of individual lamellae were analyzed with high-resolution energy-dispersive X-ray spectroscopy (EDS) mapping and atom probe tomography (APT). The average structure states of the studied samples were also compared with single-crystal X-ray diffraction data (SC-XRD). The Na-rich lamellae have a composition of An44–48, and the Ca-rich lamellae range from An56 to An63. Significant differences between the lamellar compositions of different samples were observed. The compositions of the Bøggild intergrowth do not only depend on the bulk compositions, but also on the thermal history of the host rock. The implications on the subsolidus phase relationships of the plagioclase feldspar solid solution are discussed. The results cannot be explained by a regular symmetrical solvus such as the Bøggild gap, but they support an inclined two-phase region that closes at low temperature.

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