Cold-rolled Sheet Research Articles

The Structure and Properties of Wrought Al–Mg–Sc Aluminum Alloys with Different Scandium Content

Round ingots 110 mm in diameter and cold-rolled sheets 2 mm in thickness, which were made of experimental Al–Mg–Sc alloys containing different scandium content (0.07, 0.20 wt %), have been studied. Transmission electron microscopy and thermodynamic simulation have been used to investigate the peculiar-ities of the structural-phase state of the material. A reduction in scandium content from 0.20 to 0.07% has been found to result in a twofold increase in the grain size in ingots, a 46% drop in hardening of ingots after homogenization, and a 10–20% decrease in the strength of annealed sheets, which has been caused by a smaller amount of the key phase, Al3(Sc, Zr). A good level of strength characteristics of experimental annealed sheets made of alloy with low scandium content 0.07 wt % (σu 400 MPa, σ0.2 300 MPa) has been achieved and it is higher than that of the traditional AMg6 alloy (σu 350 MPa, σ0.2 150 MPa).

Effect of Proportions of Γ and Iron–Zinc Solid Solution Phases on the Corrosion Prevention Performance of Mixed Coating Layers on Heated Galvannealed Steel Sheets

Coating layers having different ratios of a Γ phase to an Fe–Zn solid solution phase were produced on galvannealed steel sheets by heat treatment. The corrosion prevention characteristics of these layers were then investigated using combined cyclic corrosion test, electrochemical measurements and analyses of corrosion products. A coating layer with a larger proportion of the Γ phase showed better corrosion prevention properties along with a smaller corrosion mass loss. The Γ phase exhibited a sacrificial corrosion protection effect with regard to both the Fe–Zn solid solution and the steel substrate while the Fe–Zn solid solution showed a sacrificial corrosion protection effect on the steel substrate. The corrosion products formed from the Γ phase comprised Zn5(OH)8Cl2·H2O, Zn5(CO3)2(OH)6, ZnO and various amorphous compounds, while the Fe–Zn solid solution generated Zn-containing ferrihydrite and amorphous compounds. The presence of Zn evidently stabilized the ferrihydrite and delayed the formation of crystalline iron oxyhydroxide based on comparisons with corrosion products formed on cold-rolled steel sheets. These effects improved the corrosion prevention performance of the Fe–Zn solid solution. The zinc-based corrosion products formed from the Γ phase provided even better corrosion prevention performance by delaying the formation of crystalline iron oxyhydroxide and were also themselves resistant to reduction.

Static recrystallization behavior of the cold-rolled Mg-1Al-1Zn-0.1Ca-0.2Y magnesium alloy sheet

In this study, we investigated the static recrystallization behavior and basal texture change from rolling direction (RD)-split (c-axes of grains toward the RD) to transverse direction (TD)-split (c-axes of grains toward the TD) of the cold-rolled Mg-1Al-1Zn-0.1Ca-0.2Y (AZXW1100) alloy during annealing. The cold-rolled AZXW1100 alloy sheet contained highly deformed shear bands (SBs), corresponding to 58 % of the total area, which caused rapid recrystallization at the beginning of annealing. The fine recrystallized grains nucleated in the SBs, and the intersection of the twins grew larger while consuming the deformed matrix grains, which did not recrystallize even at the late stage of annealing and were consumed by the surrounding recrystallized grains nucleated on the SBs. Owing to the difference in the recrystallization initiation time between the SB and deformed matrix grains, the recrystallized grains nucleated in the SBs guided the overall recrystallization behavior. Additionally, quasi-in-situ electron backscattered diffraction analyses clearly showed that among the recrystallized grains nucleated at the SBs, the grains with TD texture components became larger through preferential growth, whereas those with RD texture components did not grow and disappeared. Owing to this preferential grain growth, the texture intensity in the RD decreased and that in the TD was maintained, resulting in the formation of a diamond-like or TD-split texture. In this study, the co-segregation of Al, Zn, and Ca atoms along the grain boundaries and the formation of nanoscale Al8Mn5 particles were found to reduce boundary mobility and, consequently, hinder grain growth. These results can explain the texture change from a strong RD-split to a weak TD-split during annealing.

Achieving ultra-high elongation of 1401% in a warm-rolled medium Mn lightweight steel with dual-phase lamellar structure

The present work reports a dual-phase lamellar structure to combine ultra-high superplastic elongation and relatively low deformation temperature in a novel Al-added medium Mn lightweight steel. The specimens were controlled rolling in a two-phase zone; Hence the microstructure contained a high-volume fraction of residual austenite in the ferrite matrix. The ultra-high elongation of 1401% was obtained at the deformation temperature of 775 °C, which is more than 50 °C lower than others reported of the cold-rolled sheets. Interestingly, near 800 °C, due to the enhanced DIFT effect, the ductility was reduced by temperature rise, which is opposite to the condition of the cold-rolled sheets. The ultrahigh elongation at 775 °C was ascribed to the continued recovery and recrystallization of the deformation-induced ferrite, which not only achieves dynamic grain refinement but also maintains the balance of stress distribution between the two phases.

Experimental and Numerical Analyses of a Novel Magnetostatic Force Sensor for Defect Inspection in Ferromagnetic Materials

An innovative magnetostatic force sensor consisting of a laser source, a tiny cantilever beam, and a small permanent magnet was developed and used for defect inspection in ferromagnetic samples in the present article. The penetrating zone within a ferromagnetic material under the magnetic field provided by a permanent magnet was called the magnetic sensing zone (MSZ), and surface or internal defects within the MSZ were inspected by measuring the change in the magnetostatic force. This magnetostatic force could be calculated by the Maxwell tensor integrating over the surface and interface of a ferromagnetic material. Numerical and experimental results demonstrated that this sensor was reliable and could precisely inspect the defects of different sizes in ferromagnetic samples. In summary, the sensor proposed in this paper has the potential for industrial applications to detect surface and sub-surface tiny defects on ferromagnetic steel thin sheets, such as the zinc slag defect of hot galvanized sheets, cracks on cold-rolled sheets, and the ferromagnetic oscillation marks of continuous casting.

Influence of Cu content on the hardenability of Al-xCu-1.1Li alloys

The influence of Cu content (3.7 wt%, 4.1 wt% and 4.3 wt%) on the hardenability of Al-xCu-1.1Li alloys was evaluated through a novel end quenching method by using cold-rolled thin sheets combined with strength measurement after subsequent T8 aging. The yield strength of all three aged alloys decreases with the increase of the distance away from the quenching end. The quenching depth decreases with the increase of the Cu content, which was described by the distance of 95% strength retention value of the samples at the quenching end. The intragranular coarse Cu-enriched phase particles formed during the end quenching process impede the precipitation of T1 precipitates and then lead to the strength reduction. The higher Cu content alloy with more and larger Cu-enriched particles inside the grain causes the more decrease in T1 precipitation, which consequently leads to more reduction in strength. The alloy with higher Cu content therefore has lower quenching depth. The coarse Cu-enriched grain boundary phase particles cause the solute depletion around the grain boundary and create PFZ. Based on the time-temperature-properties (TTP) curves, the quench sensitivity increases and the stability of the supersaturated solid solution of the alloy decreases with the rise of the Cu content. Additionally, the coarse Cu-enriched particles within the grain might be coarse Al2Cu particles, which tend to nucleate at the Al3Zr particles.

Enhanced phosphatability by decorating ferrite layer on the surface of a multi-phase steel

The poor phosphatability in the multi-phase steel is a critical issue to be solved to enhance the life of steel under the corrosion environment. The strategy of decorating the ferrite layer on the surface through decarburization annealing is applied to improve the phosphatability in the multi-phase steel. Different surface states are achieved by controlling dew points at −40, 30, and 60 °C during the annealing of cold-rolled sheets. Higher dew point results in thick external oxide on the top surface and deep decarburized ferrite layers around the sub-surface. The effect of the external oxidation and the decarburized matrix on the phosphatability is investigated by systematic analyses of the decarburized and phosphate-coated specimens. The external oxide layer on the steel surface degrades the phosphate coverage. On the other hand, more than 90% of phosphate coverage is realized with the decarburized matrix after pickling removes the external oxide layer. The enhanced phosphatability after the decarburization annealing and pickling can be understood by the improved dissolution rate of the ferrite layer. The study gives a way to overcome the intrinsic limitation of poor phosphatability in multi-phase steel. • The enhanced phosphatability has been achieved by the decarburization annealing in multi-phase steel. • The dew point-controlled annealing decorates the C-lean ferrite layer in the sub-surface of the steel sheet. • The effect of the external oxide and the decarburized matrix on the phosphatability is quantified in multi-phase steel.

Effect of the Strength of Initial Aluminium on the Bonding Properties and Deformation Coordination of Ti/Al Composite Sheets by the Cold Roll Bonding Process

Ti/Al composite sheets were prepared using the cold rolling process, and different initial aluminium strengths were considered. The results showed that the peel strength of the Ti/Al composite sheet increased with the increasing initial strength of aluminium under the same reduction. A higher strength of the initial aluminium corresponds to better deformation coordination between titanium and aluminium, where the strain hardening of titanium and aluminium plays an important role. The change degree of the components of twins on the titanium side for the Ti/Al composite sheet with a low aluminium strength is stronger than that for the Ti/Al composite sheet with a high aluminium strength. The strong change in the components of twins may result in the low uniformity of the microstructure on the titanium side. The analysis of the peeling surface shows aluminium residue on the titanium side, while there was almost no titanium residue on the aluminium side. At the same reduction, a higher strength of aluminium corresponds to less aluminium residue on the titanium side. The bonding properties of Ti/Al cold-rolled composite sheets were determined by four strong bonding areas. The strength of the initial aluminium was the main factor, and the residual amount of aluminium on the titanium side of the peeling surfaces was a secondary factor.

Influence of microstructure on fatigue crack propagation behaviors of Al-xCu-1.5Li-X alloys

The fatigue crack propagation (FCP) behaviors of Al-Cu-Li cold-rolled sheets with different Cu contents were assessed systematically. The increase of Cu contents significantly reduces the threshold value of fatigue crack growth as secondary particles induce the initiation of microcracks, and provides more opportunities for crack deflection due to finer recrystallized grains. Moreover, Brass-orientated grains with low Schmid factor force the crack to change the direction of propagation, which prevents further crack propagation. Compared to Goss-orientated grains with small tilt and twist angle, cracks prone to deflect at its boundaries with large tilt angles difference between the adjacent grains.

Effect of Cold-Rolling Reduction on Recrystallization Microstructure, Texture and Corrosion Properties of the X2CrNi12 Ferritic Stainless Steel.

X2CrNi12 ferritic stainless steel has a wide range of application prospects in the railway transportation, construction, and automobile fields due to its excellent properties. The properties of X2CrNi12 ferritic stainless steel can be further improved by cold-rolling and subsequent annealing treatment. The purpose of this work is to investigate the effect of cold-rolling reduction on the microstructure, texture and corrosion properties of the recrystallized X2CrNi12 ferritic stainless steel by using SEM, TEM, EBSD and electrochemical testing technology. The results show that the crystal orientation characteristics of the cold-rolled sheet could be inherited into the annealed sheet. The higher cold-rolling reduction could promote the deformed grains rotating into the {111}<uvw> orientation, increasing storage energy and driving force for recrystallization, which could reduce the recrystallized grain size. The orientation densities of α-fiber and γ-fiber were low at 50% cold-rolling reduction. After recrystallization annealing, a large number of grains with random orientation could be produced, and the texture strength was weakened. When the cold-rolling reduction rose to 90%, the γ-fiber texture at {111}<110> was strengthened and the α-fibers, particularly the {112}<110> component, were weakened after recrystallisation annealing, which could improve the formability of the steels. The proportions of special boundaries, i.e., low-angle grain boundaries and low-Σ CSL boundaries, among the grain boundary distribution of the recrystallized X2CrNi12 stainless steel were higher when the reduction was 90%, especially when the annealing temperature was 770 °C. Additionally, the proportion of LAGBs and low-Σ CSL boundaries were 53% and 7.43%, respectively, which improves the corrosion resistance of the matrix, showing the best corrosion resistance.

Effect of calcium on electrical resistance and phase composition of Al – 1.5 % Mn alloy

The authors used experimental and modelling techniques to look at the specific electrical resistance and phase composition of low-alloy Al &ndash; Ca &ndash; Mn alloys after they had been subjected to various annealing regimes. The study focused on four alloys in the form of ingots and cold-rolled sheets containing 1.5% Mn and up to 1% Ca. Templates cut out of ingots and sheets were annealed in a muffle furnace using multi-stage modes in the temperature range of 300 to 600 oC. They were soaked for 3 hours at each stage of the process and air cooled after each stage. It was found that, in the as-cast state, all manganese in all four alloys makes a part of the aluminium solution (Al), whereas calcium is comprised in the (Al) + Al4Ca eutectic, which agrees with the Sheil-Gulliver non-equilibrium solidification simulation. Annealing of cold-rolled sheets for 3 hours at 600 oC results in an equilibrium phase composition and a uniform structure &ndash; i. e. globular submicron particles evenly distributed throughout the aluminium matrix. In their initial state, when almost all Mn is comprised in (Al), the ingots and coldrolled sheets of all the studied alloys have little to no difference between each other in terms of specific electrical resistance. On the other hand, Ca helps to significantly lower the specific resistance (by 6 &mu;&Omega;&middot;mm) compared with the base alloy after cold-rolled sheets have been annealed at 350&ndash;400 oC. It may be attributed to a higher rate of aluminium solution breakdown, which is associated with a dropping concentration of Mn in (Al) and Al10CaMn2 particles forming in line with the Al &ndash; Ca &ndash; Mn phase diagram.This research was funded under Grant of the Russian Science Foundation&nbsp;N 20-19-00746.

Effect of Microstructure Morphology of Q&amp;P Steel on Carbon and Manganese Partitioning and Stability of Retained Austenite

In this study, we used 0.2C-1.7Si-1.9Mn wt% cold-rolled sheet as the experimental material to prepare the Q&amp;P sample with blocky microstructures and the QQ&amp;P sample with lath-shaped microstructures through the Q&amp;P and QQ&amp;P processes, respectively. The partitioning behavior of carbon and manganese in the two samples after intercritical annealing and partitioning were studied. During the intercritical annealing, the partitioning of carbon and manganese in the Q&amp;P and the QQ&amp;P samples occurred, resulting in the contents of carbon and manganese being significantly higher than those in the ferrite. Meanwhile, due to the migration of the ferrite–austenite interface during the formation of the austenite, the distributions of carbon and manganese in the lath-shaped and blocky austenite were both homogenous. The morphology of the microstructures had little influence on the distribution of carbon and manganese in metastable austenite during intercritical annealing. In the partitioning, the migration of the ferrite–austenite interface and diffusion of manganese can be ignored. Carbon first diffuses from the ferrite grains to the ferrite–austenite interface and then diffuses in the austenite grains. The morphology of the microstructures has a great effect on the homogenization of carbon in austenite grains. Compared with coarse blocky austenite, lath-shaped austenite can shorten the diffusion path of carbon in austenite grains and increase the homogeneity of carbon in austenite grains, thereby improving the thermal stability of lath-shaped austenite. Compared with the Q&amp;P sample, the QQ&amp;P sample has higher content of retained austenite (14.74% vs. 13.96%), better elongation (25.9% vs. 19.2%), and higher product of strength and elongation (27.5 GPa% vs. 24.4 GPa%).

Study the influence of scandium content and annealing regimes on the properties of alloys 1580 and 1581

The effect of scandium content and annealing regimes on the properties of cold-rolled sheets from 1580 to 1581 alloys has been studied. The relevance of research is caused by the need to reduce the cost of alloys of the Al–Mg system with the addition of Sc by reducing the concentration of this element in them without a significant decrease in strength. The initial workpieces for research were ingots of three compositions of alloy 1580 with scandium content from 0.05 to 0.1% (wt.), an ingot of alloy 1581 with 0.03% (wt.) scandium, as well as an ingot of alloy 5083, which is an analogue of alloys 1580 and 1581, but without scandium. Ingots with a cross section of 60 × 200 mm were obtained on a physical model of a semi-continuous casting unit (SCCU) in the laboratory of the Siberian Federal University. Then, according to the regime obtained at the semi-continuous casting unit, a large-sized ingot with a cross section of 560 mm × 1310 mm was cast under industrial conditions. Ingots of the same size 40 mm × 120 mm × 170 mm were cut from laboratory and industrial ingots, and annealed according to a two-stage regime: the first heating at 350 °C, 3 h, the second heating at 425 °C, 4 h, and subjected to hot rolling with heating up to 450 °C to thickness 5 mm. Then the strips were annealed at 380 °C for 1 h, rolled at room temperature to a thickness of 3 mm, and annealed at temperatures of 250, 275, 300, and 350 °C. Tensile tests of samples made from sheets of 1580 and 1581 alloys after annealing in the temperature range of 250–300 °C showed that they surpass alloy 5083 in strength properties by no less than 10%. Studies of the cast and deformed structure of alloys 1580 and 1581, carried out by the methods of light, scanning and transmission electron microscopy revealed that during annealing dispersed particles of the Al3(Sc, Zr) phase precipitate from the solid solution of ingots, which, during deformation of the alloys and subsequent technological heating associated with hot rolling and annealing, contribute to the formation and preservation of a subgrain structure in sheet semi-finished products. This factor prevents the occurrence of recrystallization and ensures the strengthening of deformed semi-finished products.

Combination of high-speed softening heat treatment and aluminizing blanks for the manufacture of steam heater tubes in a single technological process

Problem. At domestic metallurgical plants, recrystallization annealing in hood furnaces is used to weaken cold-rolled sheet steel from low-gauge steels, which does not allow obtaining the required level of properties in blanks for electrically welded tubes of steam heaters. Goal. The purpose of this work is to provide 08kp steel blanks with sufficient strength while increasing technological plasticity and preventing deformation aging for defect-free production of tubes. Solving this issue is relevant and has an undeniable practical significance. Methodology. Cold-rolled 08kp sheet steel with a thickness of 0.6 mm was studied, which had a textured structure with a grain size of 70–80 μm and the following mechanical properties: ϬВ = 810 MPa, ϬТ = 640 MPa, δ = 2 %. To ensure technological plasticity, the tube blanks were subjected to high-speed (80 ºС/s) one-time and cyclic two-time recrystallization annealing by means of contact electric heating. During single heating, the temperature varied from 650 to 750 °C with a holding time of 10, 15, and 20s, and during cyclic heating it was equal to 680, 700, and 720°C with the same holding time. Cooling after one-time heating was in air, between cycles and final cooling to 400°C in air and then in water. After annealing, the steel was subjected to aging at a temperature of 400 °C with periods from 2s to 2 min. The effectiveness of the results was evaluated by the microstructure. Results. Recrystallization annealing at 700ºC with a holding time of 20s provided a complex of mechanical properties, which in terms of level practically corresponds to the values after cap annealing. Natural aging within 5 days leads to a significant drop in plasticity. Two-stage heat treatment: annealing at 680 ºС with a holding time of 10s and cooling between cycles and final in air to 400ºС, and further in water, and aging at 400ºС for 2 min. significantly improved the level of properties: Ϭв = 350 MPa, Ϭт = 250 MPa, δ = 34.5% and ensured the absence of natural aging within a month. The technology of high-speed alitization of the sheet surface, which is combined in a single cycle with weakening heat treatment, has also been developed. Originality. For the first time, high-speed cyclic annealing was used as a softening heat treatment of a cold-rolled sheet. Practical value. The obtained results satisfy thecustomer's requirements for high-quality defect-free production of steam heater tubes that work in conditions of high temperatures, aggressive environment and significant pressure. The tubes have passed 100 % industrial control for stretching, flattening and corrosion resistance.

Effect of reduction ratio during cold rolling and final annealing temperature on the properties and microstructure of Al–Mg–Sc alloy sheets

The study covers the effect of the reduction ratio during cold rolling (εh) and the final annealing temperature of sheets rolled with different reduction ratios on the microstructure and the complex of mechanical and processing properties of cold-rolled sheets made of the V-1579 aluminum alloy of the Al–Mg–Sc system. It was established that as εh increases, the nature of plastic anisotropy changes slightly, and an increase in tensile strength and yield strength with a decrease in relative elongation is observed. In this case, the ultimate strength and yield strength anisotropy is practically absent. As the reduction ratio increases to 30–40 %, the relative elongation anisotropy increases, and its value in the rolling direction decreases more rapidly. However, after rolling with εh &gt; 50 %, the relative elongation anisotropy practically disappears. Regardless of the annealing temperature, samples rolled with a higher reduction ratio have better strength properties. It was found that as the annealing temperature increases, the ultimate strength and yield strength decrease, and the relative elongation increases. In this case, softening with an increase in the annealing temperature occurs more intensively for samples rolled with a lower reduction. After annealing, the distribution nature of anisotropy indices in the sheet plane does not decrease and corresponds to the deformation type of textures for all analyzed modes. Moreover, the value of the in-plane anisotropy coefficient decreases in comparison with a cold-rolled sample. At the same time, processing properties of samples rolled with a higher degree of deformation after annealing are higher than those of samples rolled with a lower reduction, regardless of the annealing temperature.

Comparative study on microstructures and mechanical properties of Q&P steels prepared with hot-rolled and cold-rolled C–Si–Mn sheets

In this study, we investigate the microstructures and mechanical properties of quenching and partitioning (Q&P) steels prepared with hot-rolled (HR) and cold-rolled (CR) sheets at different annealing temperatures (partial austenitisation). The ferrite and retained austenite are present in laths and blocks in HR-Q&P samples but are mainly blocky in CR-Q&P samples. Compared with CR-Q&P, the HR-Q&P samples have higher content of retained austenite, better elongation and higher product of strength and elongation (PSE). The lath-shaped retained austenite in HR-Q&P samples with a higher ratio of surface to volume is conducive to homogenization of carbon in austenite grains, thus improving the thermal stability and content of retained austenite. The lath-shaped retained austenite transforms into martensite obviously until the strain exceeds 5% and exhibits higher mechanical stability than coarse blocky retained austenite. When annealed at 810 °C, HR-Q&P and CR-Q&P samples present best PSEs. Indeed, the PSE of HR-810°C-Q&P sample is 62.8% higher than that of CR%-810°C-Q&P. The better elongation and higher PSE possessed by HR-810°C-Q&P sample are linked with the higher content of retained austenite and the presence of two kinds of retained austenite with different mechanical stability. The retained austenite with different mechanical stability in HR-810°C-Q&P sample, contributes to continuous transformation during tensile deformation, thereby improving the elongation. Meanwhile, the lath-shaped structures can delay the formation of voids and microcracks, thereby improving the elongation.

Correlation of the anisotropic hardening behavior and texture features of cold rolled Zr-4 sheet under uniaxial tension

The strongly anisotropic mechanical behaviors commonly observed in Zr-4 sheets typically lead to inferior formability. In this study, the mechanical behavior and texture evolution of a cold-rolled Zr-4 sheet under uniaxial tension in various directions were systematically investigated, and the results showed both anisotropic yielding and hardening behavior in the Zr-4 sheet. The microstructure and texture features revealed by electron backscattered diffraction (EBSD) method indicate that this anisotropic mechanical behavior is closely related to the initial texture and its evolution during plastic deformation. In conjunction with experimental observations, a visco-plastic self-consistent (VPSC) model was employed to quantitatively analyze the relationship between the mechanical anisotropy and the texture features and activation of deformation modes. It was found that the yield anisotropy is affected by the distinct activity of prismatic <a> slip, while the different activities of basal <a> slip and extension twinning (ETW) result in anisotropic hardening. The distinct activation of deformation modes is mainly caused by differences in the evolution of the Schmid factor (SF) and critical resolved shear stress (CRSS) with increasing strain. Additionally, the results prove that the limited twinning activation with a fraction of less than 3% plays a non-negligible role in the hardening behavior during tension along the transverse direction. The latent hardening effect caused by the interaction between prismatic slip and tensile twinning is considered to successfully capture the anisotropic hardening behavior of the Zr-4 sheet. The implementation and insights from the predictions are presented and discussed in this work.

Deep-Drawing of Commercially-Pure Niobium Sheet

Pure Niobium is a material of interest for high-energy-physics applications including superconducting accelerators. Cold-rolled sheets of Nb exhibit significant plastic anisotropy. Here we report on the mechanical and forming properties of 99.95% pure, 1.02 mm thin, cold-rolled sheet. Uniaxial tension, biaxial tension and disc compression experiments are performed, the first two at multiple angles to the rolling direction of the sheet. The material is very ductile (uniform elongation ~30%), and exhibits significant plastic anisotropy (e.g., the R-values range from 1.2 in 45o to 2.5 in 90o). The results are used to calibrate the Yld2000-2D anisotropic yield function, with an exponent of 6 as Nb is BCC. They are also used to extract the hardening curve beyond the limit load in uniaxial tension. Deep-drawing experiments are performed using a die of 27.6 mm dia. and a punch of 25.4 mm dia. Blanks of various diameters are used. The successfully drawn cups exhibit significant earing. The experiments are simulated using Abaqus/Standard and shell elements. It is shown that a properly calibrated material model enables the numerical simulations to match the experiments.

Good combination of strength and mechanical isotropy in AA6082 alloy processed by high temperature intermediate annealing

The microstructure, textures and mechanical property anisotropy of AA6082 alloy sheets after intermediate annealing were investigated. The result shows that the anisotropy of final cold-rolled and T6 alloy sheets decrease and the strengths increase as the intermediate annealing temperatures rise from 400 °C to 550 °C. Higher intermediate annealing temperature promotes the coarsening of soluble Mg2Si particles, which influences subsequent recrystallization and precipitation. The final cold-rolled sheet intermediately annealed at 550 °C presents weak rolling textures, thereby decreasing in-plane anisotropy (IPA) of yield strength from 4.4% to 2.5%. The T6 sheet intermediately annealed at 550 °C exhibits high yield strength (326 MPa), which is ascribed to the synergistic effects of precipitation strengthening, texture strengthening and grain refinement. Meanwhile, it presents high volume fractions of CubeND and random textures. This causes that r̅ value increases by 9.2% and ∆r value decreases by 80%.

Primary diagnosis of energy efficiency in an integrated steel plant, based on intensive energy-saving methodology. Part 2

The energy efficiency of the integrated steel plant is studied basing on the intensive energy conservation methodology. The primary diagnostics of the energy efficiency of the integrated steel plant is carried out. The boundaries of the research object are established from iron ore deposits to finished cold-rolled steel sheet. The thermophysical heat absorption of materials and intermediates within the boundaries of a closed heat engineering complex has been estimated. The energy intensity of the cold-rolled steel sheet within the same boundaries has been calculated. Efficiency of production was estimated by comparing heat consumption and energy intensity. The complete intensive energy conservation reserve in the complex has been determined. Reserve structure is studied and directions of its implementation are discussed. It is shown that the most complete implementation of the energy-saving reserve is possible only with the transition of a new generation of steel engineering and technology.