Effects Of Rolling Parameters Research Articles

Development and perspectives of rolling of rib stiffened plate

Thin-wide aluminium rib stiffened plate structure reduces the weight and provides high stiffness, which makes it in high demand in transportation vehicles, marine, and structural applications for energy saving and CO2 emission reduction. In this study, the applicability of rolling in manufacturing an integral rib stiffened plate is reviewed through analysis of different rolling processes. The effect of rolling parameters and rib geometry on the formation and quality of ribs are analysed. The analysis provides an important basis to advance the understanding of metal flow, viscoplastic deformation and roll shape design during rolling, significantly helping the design of an innovative rolling process for rib stiffened plate. In addition, geometry and rolling parameters, plate curvature, and roll pass design (RPD), that highly affect the rolling process design are discussed. This paper presents the limitations and improvements of specific shape rolling processes and preliminarily concludes that rolling could be a potential method to produce high quality thin-wide panels with high stiffeners.

Preparation, structure and properties of Mg/Al laminated metal composites fabricated by roll-bonding, a review

Laminated metal composites (LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft, and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are expected to combine the advantages of both Mg and Al alloys to broaden their application prospects. Roll-bonding is the most popular process for the fabrication of Mg/Al LMCs due to high production efficiency and good product quality stability. The roll-bonding process involves the deformation of the substrates and the formation of the interfacial diffusion layer. The latter will directly determine the interface bonding strength of Mg/Al LMCs. Bonding strength is very sensitive to the thickness of the reaction layer in the diffusion layer. When the thickness of the reaction layer exceeds 5 µm, the bonding strength decreases sharply. Therefore, controlling the thickness of the reaction layer is very important for the design of rolling parameters. The latest research also showed that the addition of intermediate layer metal and the construction of three-dimensional interfaces can further improve the interface bonding strength. How to apply these methods to roll-bonding is the focus of future research. Recently, a new rolling technique, corrugated roll/plat roll rolling+flat roll/flat roll rolling has been developed to fabricate Mg/Al LMCs. It can effectively promote the deformation of the hard layer and generate a wavy interface, resulting in the enhancement of the bonding quality and rolling quality. In the current review, the effects of rolling parameters and subsequent annealing on the interface structure of Mg/Al LMCs were elaborated in detail. The application of some special rolling techniques in the preparation of Mg/Al LMCs was also summarized. The latest research results on the relationship between interface structure and mechanical properties of Mg/Al LMCs were reviewed. Finally, further research directions in this field were proposed.

Effect of Rolling Parameters on Microstructure, Texture, and Mechanical Properties of Al/Mg/Al Laminated Composites

Effect of Rolling Parameters on Microstructure, Texture, and Mechanical Properties of Al/Mg/Al Laminated Composites

Rolling deformation behaviour and interface evaluation of Cu-Al bimetallic composite plates fabricated by horizontal continuous composite casting

Cu-Al bimetallic composite plates with a thickness of 2 mm were prepared by a horizontal continuous composite casting-rolling process. The effects of rolling parameters on the forming performance of Cu-Al composite plates and the interface evolution mechanisms were investigated. The results reveal that a suitable deformation temperature and an increase in first-pass deformation are both conducive to enhancing bimetallic deformation coordination. For cold rolling, the first-pass reduction should exceed 60 % to avoid delamination cracking. When the rolling temperature rises to 200–300 °C, the first-pass reduction can be decreased to 55 % due to the better deformation coordination of bimetallic. However, an excessive rolling temperature results in the formation of a continuous layer of intermetallic compounds at the new interface, and the formability of the plates is decreased significantly. In the rolling process of Cu-Al composite plates, the original Cu-Al interface is first shattered, and then the matrix metal flows into the gaps of the broken interface. Finally, a new oxidation-free interface at the atomic scale is developed, which is beneficial to the bonding strength of the composite plates. The Cu-Al composite sheets prepared by the above reasonable parameters exhibit a tensile strength of 180–191 MPa, an elongation of 8%–12 %, and an excellent interfacial bonding strength of 66–89 MPa.

Research on Mechanical Properties of 210Cr12 Shaft Surface Processed with Rolling

The rolling process is one of the most effective ways for strengthening a part’s surface. As the press force exerted on specimen in rolling process, material in the surface layer will deform plastically if the press force is sufficient. That might result in grain refinement, dislocation configuration change, or phase change in specimen surface layer material. Consequently, the surface material mechanical properties can be changed. The effects of rolling parameters on surface residual stress, micro-hardness, and surface roughness for a 210Cr12 shaft have been investigated. After the rolling process, the surface residual stress of the specimen changes from tensile stress to compressive stress, and a stable residual compressive stress layer is formed. The maximum absolute value of compressive stress can be up to 216MPa. With the increase of the value of contact stress exerted on shaft surface and the number of rolling cycles, the absolute value of residual compressive stress increases firstly and then becomes stable. With the increase of depth from shaft surface to interior, the absolute value of residual compressive stress increases initially, then decreases and disappears finally. The maximum absolute value of residual compressive stress exists at the position beneath specimen surface about 0.025mm. The depth of residual stress layer is about 0.2 mm. Research results indicate that shaft surface microhardness can be improved within small range, surface roughness can be reduced up to 67%.

Effect of Rolling Processing on Mechanical Properties of Material Cr12

The rolling process changes the mechanical properties of the specimen’s surface material, and it also directly affect the fatigue strength and service life of the workpiece. The effects of rolling parameters on surface residual stress, microhardness, surface roughness and surface microstructure are studied by rolling test of Cr12 specimens. After rolling, the residual stress on the surface of Cr12 specimens changes from tensile stress to compressive stress, and the maximum compressive stress is -216MPa. With the increase of contact stress and rolling passes, the residual compressive stress increases at first and then remains stable. Rolling processing can effectively improve the surface hardness of specimens up to 30%, and the surface roughness can be reduced by 25%-67%. The fine grains aligned with the rolling direction, and the 50-60 μm grain refinement layers were observed, which resulted in the changes in the surface mechanical properties of the specimens.

Rolling tuning microstructure and tensile properties of nano/microcrystalline 304 stainless steel

The effect of rolling parameters on microstructure and tensile properties of nanocrystalline/microcrystalline 304 stainless steel (SS) casted by the aluminothermic reaction was investigated in this work. It was found that majority of the nanocrystalline austenite of the 304 SS rolled at 700[Formula: see text]C and 900[Formula: see text]C grew up and transformed to sub-microcrystalline. While the nanocrystalline/microcrystalline structure still retained rolled at 900[Formula: see text]C with 40% deformation followed 600[Formula: see text]C with 70% thickness reduction, and microcrystalline austenite grains distributed evenly. The strength and ductility of the various rolled 304 SS were improved compared with the as-casted 304 SS steel. The steel rolled at 900[Formula: see text]C with 80% deformation exhibited a uniform elongation as large as 31.3%, which is almost the same ductility level of counterpart coarse-grained steel. The rolled steel at 700[Formula: see text]C with 80% deformation achieved the maximum tensile strength but the smallest elongation. The sample, two-step rolled at 900[Formula: see text]C with 40% thickness reduction and then 600[Formula: see text]C with 70% thickness reduction, yielded the satisfactory combination of strength and ductility. The yield strength and elongation were appropriate 767 MPa and 22.8%, respectively, which resulted from the optimized nanocrystalline/microcrystalline structure and distribution.

Numerical Investigation of the Effect of Rolling on the Localized Stress and Strain Induction for Wire\u2009+\u2009Arc Additive Manufactured Structures

Cold rolling can be used in-process or post-process to improve microstructure, mechanical properties and residual stress in directed-energy-deposition techniques, such as the high deposition rate wire + arc additive manufacturing (WAAM) process. Finite element simulations of the rolling process are employed to investigate the effect of rolling parameters, in particular rolling load and roller profile radius on the residual stress field as well as plastic strain distribution for the profiled roller. The results show the response to rolling of commonly used structural metals in WAAM, i.e., AA2319, S335JR steel and Ti-6Al-4V, taking into account the presence of residual stresses. The rolling load leads to changes in the location and the maximum value of the compressive residual stresses, as well as the depth of the compressive residual stresses. However, the roller profile radius only changes the maximum value of these compressive residual stresses. Changing the rolling load influences the equivalent plastic strain close to the top surface of the wall as well as in deeper areas, whereas the influence of the roller profile radius is negligible. The plastic strain distribution is virtually unaffected by the initial residual stresses prior to rolling. Finally, design curves were generated from the simulations for different materials, suggesting ideal rolling load and roller profile combinations for microstructural improvement requiring certain plastic strains at a specific depth of the additive structure.

An Integrated Model for Rolling Schedule Design of Microalloyed Steels

Processing parameters have direct impacts on the quality of the steels produced. This is particularly true for microalloyed steels, the production of which involves a thermomechanical controlled rolling process, which combines multi-pass hot rolling with accelerated cooling. On one hand, hot rolling may finish below A3 temperature when austenite starts to transform to ferrite. On the other hand, controlled cooling is applied to obtain the desired microstructure from austenite decomposition. To optimise the TMCP parameters of such alloys, not only a clear understanding of each metallurgical phenomenon involved is required, but also the interactions among them. This paper reports our recent work on modelling of microstructural evolution and deformation resistance during multi-pass hot rolling of steels. The model considers the following metallurgical phenomena as well as their interactions: - Precipitation of MX type carbides, nitrides or carbonitrides. - Interactions between precipitation and recrystallisation and their effects on grain refinement. - Effect of grain size and cooling path on transformations from austenite to ferrite, pearlite, bainite and martensite. - Effect of rolling parameters, recrystallisation and microstructure on the deformation resistance of the alloy. The model predicts the evolution of microstructural features such as precipitate size and amount, recrystallisation fraction and effective strain, grain size, and austenite decomposition, as well as the alloy’s deformation resistance during hot rolling. It has been applied to a wide range of steels and demonstrated good agreement with experimental observations. Therefore, it has the great potential to be implemented in a production line to help optimise the rolling schedule for both C-Mn and microalloyed steels.

Numerical study on the shell-side flow and heat transfer of superheated vapor flow in spiral wound heat exchanger under rolling working conditions

In order to explore the shell-side flow and heat transfer characteristics for spiral wound heat exchanger (SWHE) in floating liquefied natural gas (FLNG), a model was established to simulate the flow and heat transfer of shell-side superheated vapor flow under rolling working conditions. The effects of rolling parameters and working parameters were investigated. By comparing, the deviations between simulation results and experimental data were generally within ±10%. Under static working conditions, both frictional pressure drop gradient and heat transfer coefficient increased with the increasing mass flux, which were consistent with the predictions of calculation correlations. After that, an improved heat transfer correlation was proposed with an error of ±5%. Meanwhile, rolling motions can affect the shell-side flow and heat transfer characteristics of superheated vapor flow and lead them to show obvious periodicity. The influence of rolling period was smaller than that of rolling amplitude, and 90% of the working conditions in FLNG SWHE can lead to the enhancement of heat transfer from −0.5% to 2.6%. These results can provide some instructions in the design and efficient running for FLNG SWHE.

Fabrication and Analysis of Accumulative Roll Bonding Process between Magnesium and Aluminum Multi-Layers

In the present study commercially pure magnesium and aluminum strips were fabricated using the process of accumulative roll bonding. It is a prominent solid state joining process to manufacture similar and dissimilar materials for various applications. Three layers of stack was used for bonding of multilayered composite and preheated at 250 °C for 20 min. The effects of rolling parameters on bond strength and deformation of the strips were analyzed. The interface between aluminum and magnesium were characterized to identify the formation of diffusion compounds, and are found to be the presence of Al12Mg17 intermetallic compounds. Tensile strength of the bonds was increased with the decreasing of thickness of the strips. The interface characteristics were analyzed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDAX) to reveal the intermetallic compounds, micro cracks and bonding properties. The strength of the composites is varying with width of the intermediate strip and maximum strength values were obtained after three passes of the roll bonding.

Effect of Al2O3 Particles on Bond Strength in the Roll Bonding Process of Al-1050 Bi-Layers

Aluminum alloy 1050 strips are roll-bonded with interlayer Al2O3 particles. The effect of rolling parameters on the bond strength, such as the content of Al2O3 particles, plastic deformation, and rolling temperature are investigated by peel test. It is established that higher bond strength can be obtained by increasing the rolling temperature, reducing the thickness, and decreasing the alumina content. The peeling surface of samples versus alumina content is characterized by scanning electron microscopy.

Analytical approach of asymmetrical thermomechanical rolling by slab method

In this paper, based on the slab method and focusing on the rate-dependent flow condition, asymmetrical thermomechanical rolling (ATMR) is investigated to establish a new model for calculation of the rolling force. Unlike the former models where the rate-dependent condition of the yield shear stress has not been considered, in this study, a visco-plastic flow stress formulation of material is used for applying the rate and temperature sensitivity parameters and kinetic of work hardening and softening of the material. Comparison of the present analytical model with experimental data and other models reveals the precision of calculation. An asymmetrical rolling index (ARI) is introduced to evaluate the effects of rolling parameters on asymmetrical conditions of the rolling process. Using the response surface methodology (RSM), the interaction effects and contribution of rolling parameters are studied. Investigations indicate that the speed rate plays a role as an intensifier of the parameters’ effect on the ARI. Furthermore, the occurrence of high value of speed rate with a low percent of thickness reduction leads to the restricted rise of the ARI levels. The verification of the statistical models indicates an acceptable competency of results.

The improved plasticity of NiTi alloy via electropulsing in rolling

NiTi alloys were cold-rolled and electroplastic-rolled (EP-rolled) respectively, and the effect of rolling parameters on working plasticity was studied. NiTi alloy is easy to be embrittled and cracked in cold rolling, and the number of edge cracks is increased with higher thickness reduction. Electropulsing can enhance the ductility of NiTi alloy in rolling. In rolling, the resistance of deformation can be decreased, and deformation degree at the same roll gap increases because NiTi alloy develops recrystallisation and the hardness is decreased.

Analysis of Thin Strip Shape and Profile in Cold Rolling: A Way to Improve Strip Profile and Mechanical Properties

Optimisation of the physical and mechanical properties of cold rolled thin strips is achieved by controlling the rolling parameters. In this paper, the factors affecting the low carbon steel thin strip profile of asymmetrical cold rolling have been studied at a speed ratio of 1.3 without lubricant applied. The effect of rolling parameters on the resulting microstructure was also investigated. It was found that under dry condition, work roll shifting and work roll cross angle can improve the strip profile, and the improvement is more significant with an increase of work roll cross angle rather than that of work roll shifting. A slight change in microstructure was evident with increasing work roll shifting values. In addition, effects of rolling parameters on the strip profile and microstructure have also been discussed.

Application of hyperbolic sine velocity field for the analysis of tandem cold rolling

Automatic control systems for tandem cold rolling are constantly being applied due to consumers’ requirements: good flatness and surface finish, accurate strip thickness, and consistent metallurgical properties. And those requirements are related to accurate prediction of the roll force directly. A novel analytical approach to predict roll force in tandem cold rolling is proposed based on elastic and plastic mechanics. A hyperbolic sine velocity field is firstly proposed to get the required minimum roll force in plastic deformation zone in this paper. The field, Inscribed Dodecagon (ID) yield criterion and the co-line vector inner product method are applied to integrate the analytical expression of total deformation power functional. The values of roll torque, roll force and stress effective factor are obtained considering the effect of roll flattening on the roll force. A good agreement between theoretical predictions of roll force and other researchers’ models, especially on-line measured roll force in a tandem cold rolling plant, verifies that the proposed mathematical model is efficient and stable, and the model can be considered to be applied in cold rolling. Besides, the effects of rolling parameters on location of neutral point and stress effective factor are discussed respectively.

Effects of forming parameters on coupled thermomechanical behaviours in combined ring rolling

Combined ring rolling (CRR) is a new method for manufacturing rings which feature thick walls, deep grooves and small bores. Compared with general ring rolling, two driven rolls with fixed axes are added to control the circumferential metal flow and form the deep groove. Rolling force and energy, strain distribution uniformity, and temperature distribution uniformity are very important to the process design and forming quality of rings, which are sensitive to rolling parameters, such as motions of the driving roll, temperature and friction. In this paper, the reasonable ranges of feed parameters were determined based on stable rolling conditions. A reliable 3D coupled thermomechanical finite element model was then established using the dynamic explicit code ABAQUS/Explicit and the effects of rolling parameters investigated, including rotational velocity of driving roll n, the feed velocity of the driving roll v, initial temperature of workpiece and friction among the rolls and the ring. The research results are significant for process design and forming optimisation of CRR production.

Influence of rolling parameters on dynamically recrystallized microstructures in AZ31 magnesium alloy sheets

Abstract Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates, starting rolling temperatures, and rolling speeds, and the effects of rolling parameters (i.e., temperature, equivalent strain, and rolling time) on dynamically recrystallized (DRX) microstructures of AZ31 alloy during hot rolling were studied quantitatively. The temperature-strain dependence of the high-angle grain boundary fraction (HAGB%) was examined through electron backscattered diffraction. Results showed that as-rolled microstructures with high HAGB% may be obtained under average rolling temperatures of 270–320 °C, equivalent strains higher than 0.8, and a rolling speed of 246 mm/s. These results may be related to the DRX kinetics and dynamic recovery which are controlled by deformation temperature and strain. HAGB% decreased with increasing rolling time (decreasing rolling speed), which is attributed to dynamic recovery, and the recrystallized grain size decreased as rolling time increased. However, further increases in rolling time increased average grain sizes but decreased mean subgrain sizes; these results are attributed to increases in the low-angle grain boundary (LAGB) length per unit area with rolling time. LAGB formation was controlled by dynamic recovery, which consistently follows polygonization or formation of new subgrains inside larger grains; hence, average subgrain sizes decreased with the rolling time. The effect of dynamic recovery on HAGB and LAGB formation and their related mechanisms over a wide range of strains and temperatures were discussed in detail.

A Study on Subsequent Static Aging and Mechanical Properties of Hot-Rolled AA2017

In this work, the effects of rolling parameters, cooling media, and deformation path on mechanical properties and aging behavior of hot-rolled AA2017 were studied. First, hot-rolling experiments were conducted under different working conditions, and the rolled strips were then aged at room temperature for up to 57 days during which hardness and tensile tests were carried out to record the changes in the mechanical properties of the alloy. Furthermore, due to the importance of static recrystallization on subsequent aging behavior, the rate of recrystallization was also computed. To this end, a mathematical model was developed to predict thermomechanical responses during hot rolling using the finite element software, Abaqus/Explicit. Then, a physically-based model was employed for the determination of the kinetics of static recrystallization using the predicted thermomechanical parameters. Finally, the effects of rolling schedule on the mechanical properties and the aging behavior of rolled alloy were evaluated by means of the experimental results and the predictions. The results indicate that natural aging occurs in the hot-rolled alloy, while its influence on the mechanical properties is highly affected by the static recrystallization occurring in the interpass region and/or after rolling on the run-out table.

Effects of Rolling Parameters on Texture and Formability of High Strength Ultra-Low Carbon BH Steel

The effects of hot rolling and cold rolling parameters on texture and r (plastic strain ratio) value of high strength ultra low carbon bake hardening (ULC-BH) steels are studied with orientation distribution function (ODF) structural analysis method. After hot rolling, the high strength ULC-BH steel sheet has weak γ-fiber with uniform orientation distributions, and weak γ-fiber, of which {445}>110< component forms a high intensity peak at coiling temperature of 750 °C. After cold rolling, both {111}>110<−{111}>112< intensity on the γ-fiber and {111}−{112} >110< intensity on the α-fiber enhanced. As a result of substitutional solute elements Mn and P being added to the steel, strong {112}>110< deformation texture component is observed on γ-fiber, especially at 80% cold rolling reduction, and this leads to the strong {111}>112< recrystallization texture after annealing. The increase of cold rolling reduction shifts the maximum intensity on the γ-fiber from {111}>112< to {111}>113<. After annealing, a very strong γ-fiber is obtained, with intensity peak at {111}>112< component when cold rolling reduction reaches 80%. Increasing coiling temperature and cold rolling reduction improve γ-fiber intensity and r value, resulting in good deep drawability.