Galvanized Sheet Market In Guangdong

The galvanized sheet price in Guang-dong province soared during Juneand July this year.The price forJapanese 0.28-0.35x1000xC sheetwas high at 13,00-9,500 yuan pertonne,and that of Wuhan Iron andSteel Complex's 0.5x1000xC quoted at9,000 yuan per tonne.     

Hot-Dip Galvanized Sheet Production and Application

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The Research on Micro Electronic-Magnetic Forming of Sheet Metal

Micro channel of T2 copper were molding through electronic-magnetic forming experiments.Laser scanning confocal microscope and contourgraph were used to measure the section profile and sheet thickness.The effects of voltage,shape of channel and discharge cycles on laws of metal flow were studied.Results showed that forming depth of micro channel and thinning of sheet thickness increased as the increasing of the voltage.Mold-filling capacity of components formed by two molds with different structures had been increased when the voltage was increased.Mold with semicircle structure facilitate the material flow and the forming depth of parts was relative large.Semicircle structure was better than taper structure in mold-filling capacity.A number of small pulse discharges can improve the forming quality and deformation,but local thinning in sheet metal leads to non-uniform distribution of thickness.     

Influence of Surface Roughness of Galvanized Steel Sheet on Self-lubricated Coating

Three different thicknesses of self-lubricated coatings were prepared on galvanized steel sheets with different surface roughness(Ra).Performances of the coatings were evaluated by various laboratory tests.Scanning electron microscopy(SEM),atomic force microscope(AFM),neutral salt spraying test(NSST),reciprocating friction and wear test were taken in order to characterize the coatings.Results show that the self-lubricated coating has good corrosion resistance and lubricating property.In 0.857-1.629μm of Ravalue,the relationship between friction coefficients of the self-lubricated steel sheets and the surface roughness of the galvanized steel sheets likes a parabolic curve,and has a peak value of friction coefficient in certain range of Ra.Affected by the hereditary surface topography of the galvanized steel sheet,dents on the surface of self-lubricated steel become deeper and larger with the increase of the surface roughness of the galvanized steel sheets.The influence of the surface roughness of the galvanized steel sheet on the corrosion resistance of the self-lubricated coating steel is similar to that on friction coefficient of self-lubricated coatings,like a parabolic curve.     

Using REE Tracers to Measure Sheet Erosion Changing to Rill Erosion

Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet ero-sion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amount increases with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percent-age increases with time. At the end of the rainfalls, the total rill erosion amounts are 4.3 and 5 times more than sheet ero-sion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amount. The new REE tracer method should be useful to future studying of erosion processes on slope lands.     

Effect of Impurities and Ce on the Anisotropic Behavior of 8090 Alloy Sheet

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Analytical Solution for Fracture Analysis of CFRP Sheet–Strengthened Cracked Concrete Beams

Fiber-reinforced polymer (FRP) composite materials have been widely used in the field of retrofitting. Theoretical analysis of FRP plate- or sheet-strengthened cracked concrete beams is necessary for estimating service reliability of the structural members. In previous studies, the effect of a perfectly bonded FRP plate or sheet was equivalent to a cohesive force acting at the bottom of crack to delay the crack propagation in concrete and reduce the crack width. However, delamination between FRP and cracked beam is inevitable due to interfacial shear stress concentration at the bottom of crack. The intention of this paper is to present an analytical solution for fracture analysis of carbon FRP (CFRP) sheet–strengthened cracked concrete beams by considering both vertical crack propagation in concrete and interfacial debonding at CFRP-concrete interface. The interfacial debonding is modeled as the interfacial shear crack propagation in this paper. Four different stages are discussed after initial cracking state of the concrete. At the first stage, only fictitious crack propagation occurs in the concrete. At the second stage, macrocrack propagates in the concrete without interfacial debonding. At the third stage, both vertical macrocrack propagation in the concrete and horizontal shear crack propagation at the CFRP-concrete interface occur in the strengthened beam. The tensile stress in the CFRP sheet and interfacial shear stress along the span are formulated based on the deformation compatibility condition at the CFRP-concrete interface at this stage. Finally, macroshear crack propagates at the interface until the CFRP sheet is completely peeled out from the beam, and then the member is fractured. The applied load is determined as a function of the referred two crack lengths at different stages. At the beginning, the applied load increases to one peak value with the full propagation of fictitious crack at the first stage. At the third stage, the applied load is improved to another peak value due to the relatively high cohesive effect of the CFRP sheet. Then the two peak values are determined by the Lagrange multiplier method. The validity of the proposed analytical solution is verified with the experimental results and numerical simulations. It can be concluded that the proposed analytical solution can predict the load-bearing capacity of CFRP sheet-strengthened cracked concrete beams with reasonable accuracy.     

Numerical and Experimental Investigation of Electromagnetic Free Bulging of AZ31 Magnesium Alloy Sheet

The electromagnetic free bulging experiment and the coupled-field numerical simulation of the EMF process were carried out to determine the possibility to improve the formability of magnesium alloy AZ31 sheets(1 mm thick)at room temperature.Formability data were examined using strain measurements.The numerical simulation for the electromagnetic sheet free bulging is performed by means of ANSYS FEA software.Compared with quasi-static FLD results,increase in the major and minor principal strains of approximately 87%and 39%were achieved,respectively.The effects of various process parameters on electromagnetic bulging of AZ31 magnesium alloy sheets were evaluated.Three-dimensional(3D)FE model is established to predict the electromagnetic bulging of the sheet.The simulation results agreed well with experimental observations.     

Effect of Prestrain on Microstructures and Properties of Si-Al-Mn TRIP Steel Sheet with Niobium

Paint baking treatment was carried out in a silicon oil bath at 170℃ for 20min for Si-Al-Mn TRIP Steel sheet with different prestrains,and effect of prestrain on microstructures and properties was studied before and after baking.The results show that with the increasing of prestrain amount during prestraining and baking,the volume fraction of retained austenite decreases,and the volume fraction of martensite and bainite increases as well as yield strength increases;as prestrain ranges from 0 to 4%,the baking-hardening(BH)value increases;while the prestrain ranges from 4% to 16%,the BH value decreases;when the prestrain amount is 4%,the highest BH value is about 70MPa for Si-Al-Mn TRIP steel sheet with niobium,which displays excellent baking-hardening behavior.     

Effect of Asymmetric Friction on Front end Curvature in Plate and Sheet Rolling Process

 In this paper a formula of calculating curvature radius was deduced according to the theory of rolling combining with the characteristic of rolling process; moreover, the simulation of producing process is represented. Simulating results indicate that the curvature radius could be diminished by increasing friction coefficient, friction coefficient ratio, reduction ratio or roller radius, while be augmented by increasing the thickness of plate. Furthermore, increasing the thickness of plate would cause more effects on front end curvature, whereas reducing ratio would do less. It provides theoretic gist to eliminate the front end curvature in plate and sheet rolling industry, and it is important to protect scene controlling equipment and increase forming ratio as well.     

Development of Strong η Fiber Recrystallization Texture in Rolled Fe81Ga19 Thin Sheet

The 0.50-mm-thick Fe₈₁Ga₁₉ sheets were produced by rolling procedure, and texture evolution was investigated using macro- and microtexture analyses. The recrystallization texture dominated with strong η fiber (〈001〉//RD) was successfully obtained through sheet thickness by primary recrystallization annealing. The η fiber development can be attributed to the advantage in both grain number and grain size derived from the specially applied rolling process.     

Comparative Study of Pseudo-α and Pseudo-β Class Titanium Alloy Sheet Set of High-Tech Properties

Metallurgist - A forming operations for the pseudo-α titanium alloys OT4-1, OT4-1V, OT4V that are used traditionally in aviation and aerospace transport structures, and a new advanced...     

Effect of Rare Earth Cerium on Yield Strength Anisotropy of Al-Li Alloy Sheet and Its Theoretical Prediction

Traceadditionofrareearthinto 2 0 90Al Lialloyisoneofthemeasurestoimproveitslowductilityandtoughness .Al Lialloysheetwithstrongcrystallo graphictexturehasbeenknowntohaveunusuallyhigheryieldstrengthanisotropythanconventionalalu minumalloys[1～3] .However ,ithasnotbeennormallyrecognizedsofarabouttheeffectofceriumonthisanisotropyofAl Lialloy .Someinvestigationsonheat treatableAl Lialloysshowthattheyieldstrengthanisotropyof 2 0 90sheetalloyisdefinitelyassociatedwiththevolumefractionofT1precipita…     

Effect of Baking Process on Microstructures and Mechanical Properties of Low Silicon TRIP Steel Sheet with Niobium

After 2% predeformation,the baking treatment with different schedule was carried out for low silicon TRIP steel sheet with niobium.The effects of baking temperature and time on microstructures and mechanical properties were investigated.The results showed that with increasing the baking temperature and time,the volume fraction of retained austenite decreases,and the volume fraction of tempered martensite increases;as baking temperature ranges from 80 ℃ to 170 ℃,the bake-hardening(BH)value increases obviously,while from 170 ℃ to 230 ℃,the variation of BH value is very slight;as baking time ranges from 2 min to 20 min,the BH value increases significantly,while the BH value decreases when baking time exceeds 20 min.So that when the baking temperature is 170 ℃ and the baking time is 20 min,the low silicon TRIP steel sheet exhibits good bake-hardening behavior,and the highest BH value is above 70 MPa.     

In-Situ Annealing Study of Transformation of α and γ Texture of Interstitial-Free Steel Sheet by High-Energy X-Ray Diffraction

 High-energy synchrotron diffraction offers great potential for experimental study of recrystallization kinetics. An experimental design to study the recrystallization mechanism of interstitial-free (IF) steel was implemented. The whole annealing process of cold-rolled IF steel with 80% reduction was observed in situ using high-energy X-ray diffraction (HEXRD). The results show how the main texture component of IF steel change, i. e. the α ［<110>∥rolling direction (RD)］ fiber texture decreases and the γ ［<111>∥normal direction (ND)］ fiber texture increases. The important part of the α fiber texture is that both the {100}<011> and {112}<011> texture decrease at the beginning of recrystallization. The γ fiber texture increases at the early stage of recrystallization which stems from the increase of {111}<112>. Nevertheless, the {111}<110> does not change after recrystallization. The dynamic evolution of the main texture components {100}<011>, {112}<011>, {111}<112> and {111}<110> is given by in-situ HEXRD.     

Transport Behaviour of La~（3＋） with Flat－Sheet－Sandwich Supported Liquid Membrane Extraction System

ＴｒａｎｓｐｏｒｔＢｅｈａｖｉｏｕｒｏｆ Ｌａ~（３＋） ｗｉｔｈ Ｆｌａｔ－Ｓｈｅｅｔ－ＳａｎｄｗｉｃｈＳｕｐｐｏｒｔｅｄ ＬｉｑｕｉｄＭｅｍｂｒａｎｅＥｘｔｒａｃｔｉｏｎＳｙｓｔｅｍＹｉＴａｏ（易涛）；ＹａｎＣｈｕｎｈｕａ（严纯华）；ＬｉＢｉａｏｇｕ?..     

Investigation into the Fabrication Possibility of the Boron–Aluminum Sheet Rolling of Increased Strength without Using Homogenization and Quenching

Al–Cu–Mn (Zr) aluminum alloys possess high strength and manufacturability without operations of thermal treatment (TT). In order to investigate the fabrication possibility of the aluminum boron-containing alloy in the form of sheet rolling with an increased strength without TT, Al–2% Cu–1.5% Mn–2% B and Al–2% Cu–1.5% Mn–0.4% Zr–2% B alloys are prepared. To exclude the precipitation of refractory boride particles, smelting is performed in a RELTEK induction furnace providing intense melt stirring. The smelting temperature is 950–1000°C. Pouring is performed into graphite molds 40 × 120 × 200 mm in size. It is established using computational methods (Thermo-Calc) that manganese forms complex borides with aluminum and zirconium at the smelting temperature; herewith, a sufficient amount of manganese remains in liquid, while zirconium is almost absent. The formation of AlB₂Mn₂ complex boride is proven; however, the amount of manganese remaining in the solid solution is sufficient to form the particles of the Al₂₀Cu₂Mn₃ phase in amounts of up to 7 wt %. Boron stimulates the isolation of Al₃Zr primary crystals in the alloy with zirconium; in connection with this, an amount of zirconium insufficient for hardening remains in the aluminum solid solution. The possibility of fabricating thin-sheet rolling with a thickness smaller than 0.3 mm with homogeneously distributed accumulations of the boride phase with a particle size smaller than 10 μm is shown. A high strength level (up to 543 MPa) is attained without using quenching and aging due to the precipitation of dispersoids of the Al₂₀Cu₂Mn₃ phase during hot deformation (t = 450°C).     

Revealing Microstructural,Textural, and Hardness Evolution of Ti–6Al–4V Sheet Cooled From Sub β-Transus Temperature at Different Rates

Metallurgical and Materials Transactions A - A hot-rolled Ti–6Al–4V sheet was annealed at 960 °C (sub β-transus temperature) and then subjected to different coolings [in water...     

Effect of the Removal of a Surface Layer on the Mechanical Properties and the Static Stress–Strain Curves of an Austenitic–Martensitic Sheet TRIP Steel

The influence of the removal of a surface layer with a high strain-induced martensite content on the mechanical properties and the shape of stress–strain curves of austenitic–martensitic VNS9-Sh TRIP steel is studied by room-temperature tests. The removal of a surface layer 5–20 μm thick by electropolishing is shown not to decrease the mechanical properties of this steel and not to change the shape of its stress–strain curves, which have a developed yield plateau. This effect can be related to the presence of a long (up to 1%) stage of microyield in this steel. The existence of a yield plateau in the stress–strain curves of VNS9-Sh steel in the initial state and after the removal of a surface layer can also be explained by the simultaneous operation of three plastic deformation mechanisms, namely, slip, twinning, and martensitic transformation, during deformation.