Robust adaptive polarization analysis method for eliminating ground roll in 3C land seismics

To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component （3C） seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the ground- roll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good ground- roll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals.

Thermal Behaviors of Work Roll in Finishing Trains of Hot Rolling

In order to analyze the thermal field and thermal contour of work roll in finishing trains of hot rolling in rolling process, a quasi two-dimension implicit finite difference model is developed. To improve the calculating speed and precision, some special solutions are introduced, including the development of this model, the simplification of boundary conditions and the computation of heat transfer coefficients. The results show that these solutions of thermal behaviors of work roll are very much efficient and the model can be used as an on-line profile and fatness control model of large industrial mills.

NBCM with Flat Roll in the Finish Stand

With the development of the market, it becomes a demanding task for producers to make flexible production schedules to shorten production cycle. Schedule-free rolling is needed. If the CVC work roll of the F6 and F7 stands in certain 2050 mm hot rolled strip mill are substituted by flat roll (aim to SFR) and the strip profile is controlled by the existing bending force, the control ability is not adequate. This fact has been tested through on-line experiment and has been given in this article. The NBCM (new backup roll crowning method) is recommended to improve the profile control ability. Finally the plastic deformation of the strip and the elastic deformation of the roll are analyzed by employing coupled calculation of rigid-plastic finite element method and G-function method, and the optimal range of the crown of backup roll is given theoretically.

Pulsed current-assisted twelve-roll precision rolling deformation of SUS304 ultra-thin strips with exceptional mechanical properties

Innovative pulsed current-assisted multi-pass rolling tests were conducted on a 12-roll mill during the rolling deformation processing of SUS304 ultra-thin strips.The results show that in the first rolling pass,the rolling reduction rate of a conventionally rolled sample(at room temperature)is 33.8%,which can be increased to 41.5%by pulsed current-assisted rolling,enabling the formation of an ultra-thin strip with a size of 67.3μm in only one rolling pass.After three passes of pulsed current-assisted rolling,the thickness of the ultra-thin strip can be further reduced to 51.7μm.To clearly compare the effects of a pulsed current on the microstructure and mechanical response of the ultra-thin strip,ultra-thin strips with nearly the same thickness reduction were analyzed.It was found that pulsed current can reduce the degree of work-hardening of the rolled samples by promoting dislocation detachment,reducing the density of stacking faults,inhibiting martensitic phase transformation,and shortening the total length of grain boundaries.As a result,the ductility of ultra-thin strips can be effectively restored to approximately 16.3%while maintaining a high tensile strength of 1118 MPa.Therefore,pulsed current-assisted rolling deformation shows great potential for the formation of ultra-thin strips with a combination of high strength and ductility.

Microstructure evolution and strengthening mechanism of high -performance powder metallurgy TA15 titanium alloy by hot rolling

Hot deformation of sintered billets by powder metallurgy(PM)is an effective preparation technique for titanium alloys,which is more significant for high-alloying alloys.In this study,Ti–6.5Al–2Zr–Mo–V(TA15)titanium alloy plates were prepared by cold press-ing sintering combined with high-temperature hot rolling.The microstructure and mechanical properties under different process paramet-ers were investigated.Optical microscope,electron backscatter diffraction,and others were applied to characterize the microstructure evolution and mechanical properties strengthening mechanism.The results showed that the chemical compositions were uniformly dif-fused without segregation during sintering,and the closing of the matrix craters was accelerated by increasing the sintering temperature.The block was hot rolled at 1200℃ with an 80%reduction under only two passes without annealing.The strength and elongation of the plate at 20–25℃ after solution and aging were 1247 MPa and 14.0%,respectively,which were increased by 24.5%and 40.0%,respect-ively,compared with the as-sintered alloy at 1300℃.The microstructure was significantly refined by continuous dynamic recrystalliza-tion,which was completed by the rotation and dislocation absorption of the substructure surrounded by low-angle grain boundaries.After hot rolling combined with heat treatment,the strength and plasticity of PM-TA15 were significantly improved,which resulted from the dense,uniform,and fine recrystallization structure and the synergistic effect of multiple slip systems.

Tailoring the texture and mechanical properties of 3%Y_(2)O_(3)p/ZGK200 composites fabricated by unidirectional and cross rolling followed by annealing

3%Y_(2)O_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 h.The microstructure,texture and mechanical properties of rolled and annealed composites were systematically studied.The rolled composites exhibited a heterogeneous microstructure,consisting of deformed grains elongated along rolling direction(RD)and Y_(2)O_(3)particles bands distributed along RD.After annealing,static recrystallization(SRX)occurred and most deformed grains transformed into equiaxed grains.A non-basal texture with two strong T-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR,indicating that rolling path had great influences on texture of the composites.After annealing process,R-texture component disappeared or weakened,as results,a non-basal texture with double peaks tilting from normal direction(ND)to transverse direction(TD)and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites,respectively.The yield strength of rolled composites after UR showed obvious anisotropy along RD and TD while a low anisotropic yield strength was obtained after CR.Some Y_(2)O_(3)particles broke during rolling.The fracture of the composites was attributed to the existence of Y_(2)O_(3)clusters and interfacial debonding between particles and matrix during tension,as a result,the ductility was not as superior as matrix alloy.

Effect of annealing temperature on microstructure and mechanical properties of Mg-Zn-Zr-Nd alloy with large final rolling deformation

In this study,the Mg-3Zn-0.5Zr-χNd(χ=0,0.6)alloys were subjected to final rolling treatment with large deformation of 50%.The impact of annealing temperatures on the microstructure and mechanical properties was investigated.The rolled Mg-3Zn-0.5Zr-0.6Nd alloy exhibited an ultimate tensile strength of 386 MPa,a yield strength of 361 MPa,and an elongation of 7.1%.Annealing at different temperatures resulted in reduced strength and obviously increased elongation for both alloys.Optimal mechanical properties for the Mg-3Zn-0.5Zr-0.6Nd alloy were achieved after annealing at 200℃,with an ultimate tensile strength of 287 MPa,a yield strength of 235 MPa,and an elongation of 26.1%.The numerous deformed microstructures,twins,and precipitated phases in the rolled alloy could impede the deformation at room temperature and increase the work hardening rate.After annealing,a decrease in the work hardening effect and an increase in the dynamic recovery effect were obtained due to the formation of fine equiaxed grains,and the increased volume fraction of precipitated phases,which significantly improved the elongation of the alloy.Additionally,the addition of Nd element could enhance the annealing recrystallization rate,reduce the Schmid factor difference between basal and prismatic slip systems,facilitate multi-system slip initiation and improve the alloy plasticity.

Reshaping force for deformed casing repairing with hydraulic rolling reshaper and its influencing factors

Hydraulic rolling reshaper is an advanced reshaping tool to solve the problem of casing deformation,which has been widely used in recent years.When it is used for well repair operation,the reshaping force provided by ground devices is generally determined by experience.However,too large reshaping force may destroy the deformed casing,and too small reshaping force may also prolong the construction period and affect the repairing effect.In this paper,based on Hertz contact theory and elastic-plastic theory,combined with the process parameters of shaping,and considering the structural characteristics of the deformed casing and reshaper,we propose a mathematical model for calculating the reshaping force required for repairing deformed casing by hydraulic rolling reshaper.Meanwhile,the finite element model and numerical method of hydraulic rolling reshaper repairing deformed casing are established by using the finite element method,and the reliability of the mathematical model is verified by several examples.On this basis,the control variable method is used to investigate the influence of each parameter on the reshaping force,and the influence degree of each parameter is explored by orthogonal simulation test and Pearson correlation analysis.The research results not only provide an important theoretical basis for the prediction of reshaping force in on-site construction,but also provide a reference for the subsequent improvement of the shaping process.

Unveiling the rolling texture variations ofα-Mg phases in a dual-phase Mg-Li alloy

LZ91 Mg-Li alloy plates with three types of initial texture were rolled by 70%reduction at both room temperature and 200℃to explore the rolling texture formation ofα-Mg phase.The results showed that the rolling texture is largely affected by the initial texture.All the samples exhibited two main texture components as RD-split double peaks texture and TD-split double peaks texture after large strain rolling.The intensity of the two texture components was strongly influenced by the initial orientation and rolling temperature.Extension twinning altered the large-split non-basal orientation to a near basal one at low rolling strain.The basal orientation induced by twinning is unstable,which finally transmitted to the RD-split texture.The strong TD-split texture formed due to slip-induced orientation transition from its initial orientation.The competition between prismatic and basal slip determined the intensity and tilt angle of the TD-split texture.By increasing the rolling temperature,the TD-split texture component was enhanced in all three samples.Limitation of extension twinning behavior and the promotion of prismatic slip at elevated temperature are the main reasons for the difference in hot and cold rolling texture.

Design,preparation,microstructure and mechanical property of the lightweight radiation-shielding Mg-Ta-Al composites basing differential temperature hot rolling

A novel lightweight,radiation-shielding Mg-Ta-Al layered metal-matrix composite(LMC)was successful designed by doping the extremely refractory metal(Ta)into Mg sheets.These Mg-based LMCs sheets shows excellent radiation-dose shield effect,about 145 krad·a^(−1),which is about 17 times of traditional Mg alloy,while its surface density is only about 0.9 g·cm^(−2),reducing by 60%than that of pure Ta.The quantitate relationship between radiation-dose and the materials’thickness was also confirmed to the logistic function when the surface density is in the range of 0.6-1.5 g·cm^(−2).Meantime,the rolling parameters,interface microstructure and mechanical properties in both as-rolled and annealing treated samples were evaluated.The sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface,as well as a thin Al film with a thickness of about 10μm.The special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al LMCs.The interface bonding strength reaches up to 54-76 MPa.The ultimate tensile strength(UTS)and yield strength(TYS)of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa,respectively,along with an elongation of 5.8%.The molecular dynamics(MD)analysis results show that the two interfaces exhibit different formation mechanism,the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement,while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

Carbon Fiber Breakage Mechanism in Aluminum(Al)/Carbon Fibers(CFs) Composite Sheet during Accumulative Roll Bonding(ARB) Process

We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.

Online task planning method of anti-ship missile based on rolling optimization

Based on the wave attack task planning method in static complex environment and the rolling optimization framework, an online task planning method in dynamic complex environment based on rolling optimization is proposed. In the process of online task planning in dynamic complex environment,online task planning is based on event triggering including target information update event, new target addition event, target failure event, weapon failure event, etc., and the methods include defense area reanalysis, parameter space update, and mission re-planning. Simulation is conducted for different events and the result shows that the index value of the attack scenario after re-planning is better than that before re-planning and according to the probability distribution of statistical simulation method, the index value distribution after re-planning is obviously in the region of high index value, and the index value gap before and after re-planning is related to the degree of posture change.

Bonding enhancement of cold rolling TA1 P-Ti/AA6061 composite plates via surface oxidation treatment

TA1 P-Ti/AA6061 composite plate was produced by oxidizing the surface of the titanium plate and adopting a cold roll bonding process.The results revealed that the oxide film(Ti6O)prepared on the surface of TA1 pure titanium was easy to crack during the cold roll bonding,thereby promoting the formation of an effective mechanical interlock at the interface,which can effectively reduce the minimum reduction rate of the composite plates produced by cold rolling of titanium and aluminium plates.Moreover,the composite plate subjected to oxidation treatment exhibited high shear strength,particularly at a 43%reduction rate,achieving a commendable value of 117 MPa.Based on oxidation treatment and different reduction rates,the annealed composite plates at temperatures of 400,450,and 500°C displayed favorable resistance to interface delamination,highlighting their remarkable strength-plasticity compatibility as evidenced by a maximum elongation of 31.845%.

Intelligent Fault Diagnosis Method of Rolling Bearings Based on Transfer Residual Swin Transformer with Shifted Windows

Due to their robust learning and expression ability for complex features,the deep learning(DL)model plays a vital role in bearing fault diagnosis.However,since there are fewer labeled samples in fault diagnosis,the depth of DL models in fault diagnosis is generally shallower than that of DL models in other fields,which limits the diagnostic performance.To solve this problem,a novel transfer residual Swin Transformer(RST)is proposed for rolling bearings in this paper.RST has 24 residual self-attention layers,which use the hierarchical design and the shifted window-based residual self-attention.Combined with transfer learning techniques,the transfer RST model uses pre-trained parameters from ImageNet.A new end-to-end method for fault diagnosis based on deep transfer RST is proposed.Firstly,wavelet transform transforms the vibration signal into a wavelet time-frequency diagram.The signal’s time-frequency domain representation can be represented simultaneously.Secondly,the wavelet time-frequency diagram is the input of the RST model to obtain the fault type.Finally,our method is verified on public and self-built datasets.Experimental results show the superior performance of our method by comparing it with a shallow neural network.

Study of the Characteristics of Large-Diameter Iron Bars Obtained by Rolling at the ODHAV Foundry in the Republic of Guinea

This work consists of evaluating the quality of the mechanical parameters of large-diameter steels, i.e. 20, 25, 28 and 32, through a process of recycling scrap metal that fills garages, rubbish dumps, gutters and other abandoned sites, as well as imported concrete reinforcing steel sold in the Republic of Guinea. To carry out this important work, a number of mechanical tensile and bending tests and a microscopic analysis combining two devices, an electron microscope and a photographic camera, were carried out. The samples were taken from sampling areas in the major communes of Conakry, namely: Casse Sonfonia, Matoto and Kagbélen. The tensile strength values of the large dimensions 20, 25, 28 and 32 are given in the tables.

Influence of Production Sequence of Aluminum Alloy Hot Rolling on Strip Surface Quality

With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling production.This paper studied the effect of the hot rolling order of aluminum alloy on the surface quality of strip,such as roll printing,color difference,anodic oxidation,etc.,reasonable discharge sequence and corresponding optimization measures were formulated.

Improvement of Temperature Drop Model Parameters for 4200mm/3500mm Rolling of Baosteel Medium and Thick Plate

Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from the perspective of heat transfer theory and the temperature change law during the rolling process.The temperature loss during the four rolling processes is tracked on site,and the temperature drop model parameters during the rolling process of 4200mm/3500mm medium and thick plates at Baosteel are quantitatively provided.It is applied to actual rolling production and has achieved good results.

Effects of cold rolling and heat treatment on microstructure and mechanical properties of AA 5052 aluminum alloy

The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electron microscope, X-ray diffractometer, micro-hardness and tensile tests. The results show that with increasing rolling reduction, the equiaxed grains are elongated along the rolling direction obviously, and accumulation of rolling reduction increases the work hardening effect, which results in the enhanced strength and degraded plasticity. When rolling reduction is 87%, the ultimate tensile strength reaches 325 MPa but elongation is only 2.5%. There are much more secondary phase precipitates after annealing treatment. With an increase of annealing temperature, the amount of precipitates increases and work hardening diminishes continuously. The elongation is improved to ~23% but the tensile strength is decreased to 212 MPa after annealing at 300 °C for 4 h, which are comparable to those of as-homogenized alloy.

Multilayered Ti-Al intermetallic sheets fabricated by cold rolling and annealing of titanium and aluminum foils

Multilayered Ti-Al based intermetallic sheets were fabricated by sintering alternately layered titanium and aluminum foils.The microstructure and phase formation of the obtained sheets under different sintering conditions were evaluated by various techniques.The results reveal that when the sintering temperature is above the melting point of aluminum,the self-propagating high-temperature synthesis reaction occurs between Ti and Al,and forms various phases of Ti-based solid solutions including α-Ti Ti3Al,TiAl,TiAl2 and α-Ti including TiAl3,etc.When the sintering time increased,Ti-based solid solution,TiAl2 and TiAl3 disappeared gradually,and the sheet containing Ti3Al and TiAl phases in a multilayered structure formed finally.A lot of voids were also observed in the sintered structures,which were caused by the melting Al,Kirkendall effect and the difference of molar volumes between reactants and products.The voids were eliminated and a dense sample was obtained by the following hot press.

Shear deformation and plate shape control of hot-rolled aluminium alloy thick plate prepared by asymmetric rolling process

Asymmetric rolling （ASR）, as one of severe plastic deformation （SPD） methods to make ultra-fine materials with enhanced performance is mainly used to prepare foil and thin strip. The asymmetrical rolling was achieved by adjusting the diameters of the upper roll and the bottom roll and was used to prepare hot-rolled thick plate of 5182 aluminium alloy. The shear deformation and plate shape control were experimentally studied. The experimental results show that asymmetrical rolling has a significant effect on metal deformation stream and can somehow refine microstructure and improve the uniformity of microstructure and properties. The asymmetrical rolling process can also reduce the rolling force. However, bending of rolling plate often happens during asymmetrical rolling process. The factors affecting the bending were discussed.