Increase In Rolling Temperature Research Articles

Effect of caliber rolling temperature on the deformation behavior and mechanical properties of dual-phase medium Mn steel

Dual-phase medium manganese steel (MMS) was caliber rolled at 800, 900 and 1000 °C, respectively, in order to clarify the deformation behavior and mechanical properties of warm deformed MMS. Herein, the microstructure evolution, tensile behavior and fracture characteristics exhibit obvious dependence on the caliber rolling temperature. The warm rolled steel contains martensite and austenite phases with heterogeneous grains including coarse fiber grains (CFG) and ultrafine equiaxed grains (UFG), which shows different microstructural stability. With the increase of rolling temperature, dynamic recrystallization (DRX) is more obvious, corresponding with the increasing percent of UFG, as well as the decreasing percent of CFG and martensite volume fraction. Meanwhile, high deformation temperature also leads to high austenite stability and the decreasing Transformation Induced Plasticity (TRIP) effect. The strength, strain hardening behavior and total elongation are gradually increased with the decrease of rolling temperature, which is attributed to severe strain partitioning and unique laminated structure in the caliber rolled MMS with low rolling temperature. Moreover, the warm rolled MMS reveals obvious ductile-ductile transition behavior in the temperature range from 25 °C to −60 °C. In addition, the low caliber rolling temperature also results into high impact energy, which is attributed to the high volume fraction of CFG.

Interfacial reaction behavior of titanium/steel composite plate formed by cold-hot rolling

Titanium/steel composite plate was prepared by cold-hot rolling method. The influence of temperature on the interfacial reaction behavior of titanium/steel composite plate was studied by double beam focused ion beam system and spherical aberration correction transmission electron microscopy. The results show that the interfacial reaction of the cold-rolled titanium/steel composite plate mainly occurs in the heating stage, and the continuous intermetallic compounds layer formed at the interface during heating fractures during hot rolling. An interfacial layer composed of submicron TiC layer and α-Ti/α-Fe is formed when the hot rolling temperature is not higher than 850 °C, and the interfacial bonding strength increases with the increase of rolling temperature. An interface layer composed of micro (FeTi+TiC)/Fe2Ti layer, nano FeTi/Fe2Ti layer and micro pores is formed when the hot rolling temperature exceeds 900 °C. The interfacial micro (FeTi+TiC)/Fe2Ti layer and micro pores will seriously damage the interfacial bonding quality.

Effect of Rolling Temperature on Microstructure and Properties of Al-Mg-Li Alloy.

In this study, the effects of hot-rolled processes at different temperatures (420 °C, 450 °C, and 480 °C) and subsequent solid solution and aging treatments on the microstructure, mechanical properties, and corrosion properties of Al-Mg-Li alloys with trace Sc and Zr addition were investigated. The aging treatment of rolled sheets after solid solution treatment could obtain Al3Li particles and Al3(Sc, Zr)/Al3Li core-shell particles to improve the mechanical properties of Al-Mg-Li alloy products effectively. The results showed that, as the rolling temperatures increased from 420 °C to 480 °C, the alloy's ultimate tensile strengths and yield strengths increased, while the corrosion resistance decreased. The increase in rolling temperature increased the precipitation-free zone (PFZ) width of the alloy, which undermined the corrosion resistance of the alloy. Moreover, elevating the hot rolling temperature changes the texture strength of the alloy. Particularly in the 480 °C hot-rolled sample, the decrease in the Brass texture strength and the increase in the S texture and Copper texture strength led to an increase in the Taylor factor (M). The increase in rolling temperature also raised the number density of the Al3(Sc, Zr)/Al3Li core-shell particles. The presence of such particles not only inhibits grain growth but also changes the strength mechanism from dislocation cutting to Orowan bypassing. Due to the combination effect of grain morphology, texture evolution, and precipitation behavior, the 480 °C hot-rolled sample had the highest properties.

Effect of rolling temperature on microstructure evolution and mechanical properties of high carbon high manganese steel

The effects of rolling temperature ranging from −55 to 300 °C on dislocation density, twinning behavior and correlative tensile properties of a high carbon high manganese steel were investigated. Results showed that the twinning behavior was enhanced at −55 °C but suppressed at 300 °C. The twin thickness and spacing increase with the rolling temperature. At low rolling reduction of 10%, the dislocation multiplication rate decreased with the increase in rolling temperature. However, the dislocation multiplication rate maintained high level when rolled at high rolling reduction and high temperature. At a given rolling reduction, the samples rolled at −55 °C possessed higher work hardening rate. Especially, the strength of −55°C-rolled-20% sample was higher than that of 300°C-rolled-30% sample and was equivalent to room temperature (RT)-rolled-30% sample. Concurrently, the elongation of the −55°C-rolled-20% sample was higher than the other two. The contributions of dislocation strengthening and twin strengthening to the yield strength of high carbon high manganese steel after rolling at different conditions were calculated by the parameter model. The dislocation strengthening effect played a dominant role under various deformation conditions. Twin strengthening effect showed a temperature sensitivity in the temperature range selected in the present study. Lower rolling temperature showed greater contribution of twin strengthening, whereas the dislocation strengthening effect was insensitive to temperature.

Effect of Rolling Treatment on Microstructure, Mechanical Properties, and Corrosion Properties of WE43 Alloy.

Magnesium alloys show broad application prospects as biodegradable implanting materials due to their good biocompatibility, mechanical compatibility, and degradability. However, the influence mechanism of microstructure evolution during forming on the mechanical properties and corrosion resistance of the magnesium alloy process is not clear. Here, the effects of rolling deformation, such as cold rolling, warm rolling, and hot rolling, on the microstructure, mechanical properties, and corrosion resistance of the WE43 magnesium alloy were systematically studied. After rolling treatment, the grains of the alloy were significantly refined. Moreover, the crystal plane texture strength and basal plane density decreased first and then increased with the increase in rolling temperature. Compared with the as-cast alloy, the strength of the alloy after rolling was significantly improved. Among them, the warm-rolled alloy exhibited the best mechanical properties, with a tensile strength of 346.7 MPa and an elongation of 8.9%. The electrochemical experiments and immersion test showed that the hot working process can greatly improve the corrosion resistance of the WE43 alloy. The hot-rolled alloy had the best corrosion resistance, and its corrosion resistance rate was 0.1556 ± 0.18 mm/year.

Effect of Caliber Rolling Temperatures on Microstructure Evolution and Mechanical Properties of High‐Mn Steels

Three kinds of high‐Mn steels are successfully fabricated by caliber rolling at different rolling temperatures, ranging from 773 to 1373 K. The effects of rolling temperature on the microstructure and mechanical properties of steels with different stacking fault energies (SFEs) are studied. With the increase in rolling temperature, the fibrous grains of the high‐Mn steels transform into equiaxed grains, and the microstructure evolution mechanism changes from discontinuous dynamic recrystallization to continuous dynamic recrystallization. The yield strength and microhardness of the experimental samples increase significantly with decreasing caliber rolling (CR) temperature, while the samples sacrifice various degrees of plasticity. Fe–30Mn–4Si–2Al steel with low SFE value fabricated by warm CR has the best microhardness (512 HV) and yield strength (1078.82 MPa), as well as a notable fracture elongation (11.10%) among three experimental steels. This is mainly attributed to the stability of dislocations and the dislocations and twin/ε‐martensite competitive mechanisms.

Microstructure characteristics and enhanced properties of network-structured TiB/(TA15-Si) composites via rolling deformation at different temperatures

Discontinuously reinforced titanium matrix composites (DRTMCs) with network structure have attracted much attention in recent years due to their superior strengthening effect and ductility. To figure out their microstructure characteristics of the as-rolled network-structured composites under different rolling temperatures, hot rolling deformation processes at α+β region, upper α+β region, β region were performed on a series of TiB whiskers reinforced Ti–6.5Al–2Zr–1Mo–1V–0.3Si (TA15) composites (TiB/TA15–Si). The results showed that with the increase of rolling temperature, primary α (αp) phases and silicides gradually decreased, while transformed β (βT) phases, secondary α (αs) phases and TiB aspect ratio gradually increased, which is attributed to the phase transformation, Si dissolution and lower deformation resistance. And the silicides were fractured into several parts at 900 °C due to the low solid solubility and excessive growth. Besides, the composite rolled at α+β region exhibited dominant dynamic recrystallization (DRX) of α phase, while the composite rolled at β region presented an elongated deformation of prior β phase inside the network and DRX behavior near the network. With the increasing rolling temperature, the composites showed an increasing trend in strength and a decreasing trend in ductility. The composite rolled at 1100 °C can obtain better overall ultimate tensile strengths of 1260 MPa (at RT), 843 MPa (at 600 °C), 729 MPa (at 650 °C) and 595 MPa (at 700 °C), which increased by 13.4%, 38.2%, 36.3%, 21.9% compared with those of the as-sintered composite, respectively. The superior strengthening mechanism of the as-rolled composites can be mainly attributed to grain refining of the matrix and load transfer of TiB.

Preparation of Ti/Al composite plates by differential temperature rolling with induction heating

In the current study, we proposed a method of differential temperature rolling with electromagnetic induction heating to prepare Ti/Al composite plates in a protective atmosphere to realize the homogeneous deformation of Ti/Al bonding rolling and improve the interfacial bonding strength of the composite plates. The temperature field required for homogeneous deformation rolling of titanium and aluminum was constructed using finite element simulation by adjusting the parameters of electromagnetic induction heating, which made a temperature difference of about 632 °C between titanium and aluminum, and the temperature of each plate was relatively uniform. The induction heating experiment was designed based on the finite element simulation, and the experiment verified the accuracy of the simulation results. The effects of rolling temperature and reduction rate of homogeneous deformation and bonding strength of Ti/Al composite plates were evaluated by rolling experiments. With the increase of rolling temperature and reduction rate of titanium, when the heating temperature of the Ti plate is 750–850 °C, and the reduction rate is 30%–48%, the reduction rate of Ti plate and Al plate gradually tend to be the same. When the titanium plate and aluminum plate temperature is 850 °C and 188 °C, respectively, with a rolling reduction rate of 48%, the deformation rate of Ti plate and Al plate is 46.8% and 48.6%, respectively. Moreover, the bonding strength of the composite plate reaches 77MPa.

Microstructural evolution and mechanical properties of hot-rolled Ti-30Zr-5Al-2.5Sn alloy with mixed α and α′ phases

Ti-30Zr-5Al-2.5Sn (TZAS, wt. %) is a novel α-type Ti-Zr based alloy. Herein, the effect of phase and microstructure evolution on mechanical properties of hot-rolled TZAS alloy with mixed α and α′ martensite phase were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and statistical analysis. The content of primary α phase decreased as the hot-rolling temperature increased from α to α+β region. When the rolling temperature increased to 875 °C, the predominant phase transformed from α phase to α′ martensite phase. The spheroidization degree of TZAS alloys increased with rolling temperature until 850 °C. As the rolling temperature increased from 775 °C to 825 °C, the yield strength gradually enhanced, attributing to the synergistic effect of grain-boundary strengthening, dislocation strengthening and second-phase strengthening from martensite. While, as further increase of rolling temperature, the coarsen primary α grains led to the decrease of yield strength. A peak yield strength of 1038 ± 26 MPa and total elongation of 14 ± 0.6% were obtained after rolling at 825 °C. One should note that work hardening was also a key factor for the alloys strengthening. Furthermore, the fracture mechanisms of studied alloys were also discussed in depth.

Effect of Warm Rolling Temperature on the Microstructure and Texture of Microcarbon Dual-Phase (DP) Steel

The effect of warm rolling temperature on microstructure and texture of microcarbon dual-phase (DP) steel was investigated through scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that with the increase of rolling temperature, the density and thickness of the deformation band first increased and then decreased. Ferrite and fine martensite were observed in the annealed sheet, and the ferrite had a much more homogeneous distribution in the sample rolled at 450 °C. During warm rolling, the ferrite developed a dominant γ-fiber and a weak α-texture. During the annealing of the rolled sheet, the intensity of the γ-fiber was increased and a weak {001}<100> texture developed in the sample rolled at room temperature. An increase in the rolling temperature generated an initial decrease and subsequent increase in the strength of the unfavorable {001}<110> texture in the annealed sheet. In addition, the strength reached a maximum at 550 °C due to an increase in the dissolved carbon in the matrix, which was result of carbide dissolution. By contrast, the intensity of the γ-fiber remained relatively higher and was deemed the weaker {001}<110> component in the annealed sheet rolled at 450 °C. Therefore, a larger texture factor (fγ-fiber/f(α-fiber+λ-fiber)) can be produced under this process.

The dependence of fatigue crack growth on hydrogen in warm-rolled 316 austenitic stainless steel

The fatigue crack growth rate of warm-rolled AISI 316 austenitic stainless steel was investigated by controlling rolling strain and temperature in argon and hydrogen gas atmospheres. The fatigue crack growth rates of warm-rolled 316 specimens tested in hydrogen decreased with increasing rolling temperature, especially 400 °C. By controlling the deformation temperature and strain, the influences of microstructure (including dislocation structure, deformation twins and α′ martensite) and its evolution on hydrogen-induced degradation of mechanical properties were separately discussed. Deformation twins deceased and dislocations became more uniform with the increase in rolling temperature, inhibiting the formation of dynamic α′ martensite during the crack propagation. In the cold-rolled 316 specimens, deformation twins accelerated hydrogen-induced crack growth due to the α′ martensitic transformation at the crack tip. In the warm-rolled specimens, the formation of α′ martensite around the crack tip was completely inhibited, which greatly reduced the fatigue crack growth rate in hydrogen atmosphere.

Effect of warm rolling process on microstructures and tensile properties of 10 Mn steel

The influence of warm rolling processes on the microstructures and tensile properties of 10 Mn steel was studied. Strength appeared to increase with the rolling temperature but strengthening mechanisms varied. The increase of warm rolling temperature from 250 °C to 600 °C leads to enhanced recrystallization in martensite during the intercritical annealing (IA) at 620 °C for 5 h. As a result, both ultimate tensile strength (UTS) and total elongation (TE) increase. However, the size of relatively coarse recrystallized austenite grains and the resultant yield strength (YS) remain almost constant in this temperature range. The further increase of rolling temperature to 700–800 °C causes a considerable amount of pearlite to be formed during the IA, and then martensite is formed after the IA, resulting in dramatical increases in both YS and UTS but at the great loss of ductility. The warm rolling at 600 °C with 63% thickness reduction can produce the steel with the best mechanical combination of 1.2 GPa UTS and 35% TE, due to the formation of many ultrafine austenite grains and strain-induced cementite precipitates. This demonstrates that the mechanical combination of non-V-alloyed medium Mn steel can be improved to an equivalent level of 0.7% V alloyed 10 Mn steel just via the economic strain-induced cementite precipitation.

Influence of cold rolling deformation mechanisms on the grain refinement of Fe–15Mn–10Cr–8Ni–4Si austenitic alloy

The efficiency of rolling deformation mechanisms on grain refinement during recrystallization annealing was studied in Fe–15Mn–10Cr–8Ni–4Si austenitic alloy samples rolled to different strains at 0, 25, 100 and 200 °C. Two deformation routes were examined: rolling to a fixed strain (r) of 48% and rolling to strains of 55, 67, 88 and 93%, which were identified as the maximum allowable strains achieved in the alloy at 0, 25, 100 and 200 °C, respectively. The increase in rolling temperature changed the major deformation mechanism from deformation-induced ε-martensitic transformation (ε-MT) at 0 < T ≤ 25 °C, which provided the formation of multi-phase austenite/ε-martensite microstructure, to mechanical twinning of austenite at 100 < T < 200 °C; both of these deformation mechanisms were accompanied by dislocation slip. Moderate rolling strains of 48–67% were sufficient to produce multi-phase microstructures with a sufficiently high driving force for the formation of truly recrystallized grains (approximately 2 μm in size) during annealing at 700 °C for 30 min. The change in the deformation mechanism from deformation-induced ε-MT to mechanical twinning reduced the recrystallization driving force due to a decrease in stored dislocation density and an increase in microstructure homogeneity. In a single-phase microstructure, rolling strains above 88% were required to provide a sufficiently large driving force for the formation of fully recrystallized fine-grained microstructures during annealing.

Theoretical Analysis and Experimental Research into the Mechanical Properties of Al‐Ti‐Al Symmetrical Laminated Plate

In order to have both the surface corrosion resistance of aluminum alloy and the high specific strength characteristics of titanium alloy, titanium alloy TC4, and aluminum alloy 6061 can be used to make aluminum‐titanium‐aluminum (Al‐Ti‐Al) three‐layer laminated plate by hot rolling. In this paper, the classical laminated plate theory was used to calculate the stiffness, specific stiffness, strength, and specific strength of the laminated plate. The results showed that when the coating rate of titanium alloy TC4 was 0.5, bending specific stiffness and bending specific strength were the minimum, but all other parameters increased with the increase of the coating rate of titanium alloy TC4. Therefore, in actual production, the coating rate of titanium alloy should be avoided being 0.5. Then, the rolling experiments of the Al‐Ti‐Al laminated plate were carried out with different temperatures, reduction rates, and thickness ratios. Finally, the tensile test and energy spectrum analysis of the laminated plate were carried out. The results showed that, with the increase of rolling temperature, the tensile strength, the extensibility, and the thickness of the diffusion layer increased; if the coating rate of titanium alloy TC4 was between 0.2 and 0.33, the mechanical properties, the bonding strength, and the thickness of the diffusion layer increased with the increase of the coating rate of titanium alloy TC4.

Effect of hot rolling temperature on microstructure evolution, deformation texture and nanoindentation properties of an intermetallic Ti-43Al-9V-0.2Y alloy

In this paper, microstructure evolution, deformation texture and nanoindentation properties of an intermetallic Ti-43Al-9V-0.2Y (at. %) alloy have been investigated after hot rolled in α+β+γ (R#1) and β (R#2) phase field regions. The primary components of sample R#1 are (β+γ) mixture and (α2+γ) lamellar structure. With the temperature increases to 1250 °C, the microstructure of R#2 shows a new characteristic of martensitic α2 and acicular γ phase. And γ phase has different precipitation mechanisms by hot rolling at 1200 °C and 1250 °C. In R#1, γ phase is obtained through three provenances, which are the precipitating from β to form (β+γ) mixture, the precipitating from α phase to form (α2+γ) lamellar structure, and the remnant γ phase during cooling from α+β+γ phase field. However, for R#2, γ phase always nucleates and grows within β matrix. Meanwhile, microstructure evolution of R#2 is discussed. In addition, the increase in rolling temperature also results in a significant change of the fiber texture. Comparing with γ phase, β phase has the stronger texture, which is due to the formation of γ grain along the K-S orientation relationship in β phase. In R#1 state, β phase exhibits a typical {121} <1–11> texture, while γ phase shows {031} <−5-13> and {112} <1–10> texture. Aiming at R#2, β phase displays {010} <100> cube texture, and γ phase has {-215} <5–53> and Goss {110} <001> texture. The hardness (H) and reduced elastic modulus (Er) are investigated by nanoindentation. The (β+γ) mixture structure in R#2 has the highest H (12.63 GPa), whereas the Er is related to the microstructure composition.

Increasing cold workability of Ti-6Al-4V alloy via thermo-mechanical processing: simulation and experiment

AbstractRolling temperature is thought to have a significant effect on the cold workability of Ti-6Al-4V alloy. To investigate the extent of this effect, four Ti-6Al-4V strips were hot rolled at different rolling temperatures in the range of 650–950 °C while other process parameters were invariant. The specimens revealed an increase in work hardening capacity with increase in rolling temperature, based on tensile and plane strain compression testing. After 10 % cold rolling, the same annealed samples exhibited propagation of edge cracks in specimens that had been hot rolled at 650, 750 and 850 °C while no cold rolling defect was found in the specimen hot rolled at 950 °C. The results of finite element method reveal that during cold rolling, the von Mises stress field is decreased as a result of increasing previous hot rolling temperature. In accordance with X-ray diffraction results, increasing previous hot rolling temperature is associated with lower lattice strain storage during subsequent cold rolling.

Influence of rolling temperature on the interfaces and mechanical performance of graphene-reinforced aluminum-matrix composites

To study the influence of rolling on the interfaces and mechanical performance of graphene-reinforced Al-matrix composites, a rolling method was used to process them. Using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and tensile testing, this study analyzed the micromorphology, interfaces, and mechanical performance of the composites before and after rolling. The experimental results demonstrates that the composites after hot rolling has uniform structures with strong interfacial bonding. With an increase in rolling temperature, the tensile strength and elastic modulus of the composites gradually increase. However, when the rolling temperature is higher than 500°C, granular and rod-like Al4C3 phases are observed at the interfaces and the mechanical performance of the composites is degraded. When the rolling temperature is 480°C, the composites show the optimal comprehensive mechanical performance, with a tensile strength and elastic modulus of 403.3 MPa and 77.6 GPa, respectively, which represent increases of 31.6% and 36.9%, respectively, compared with the corresponding values prior to rolling.

Effect of interlayer material and rolling temperature on microstructures and mechanical properties of titanium/steel clad plates

Titanium (Ti)/steel clad plates with interlayer material of interstitial free (IF) steel, vanadium (V) and IF steel + V were successfully fabricated by hot roll bonding method at temperature of 850, 900 and 950 °C. Tensile shear test and tensile test were performed to evaluate the mechanical properties of the Ti/steel clad plates. The interfaces and the fracture surfaces of Ti/steel clad plates were carefully characterized by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The results reveal that the interlayer materials have influence on the compounds at the Ti/steel interfaces. Carbides are detected at the interfaces of Ti/steel with single IF steel or V interlayer. The formation of carbides impairs the shear strength of clad plates. σ phases instead of carbides are observed at the interface of Ti/steel clad plate with IF steel + V interlayer, which is beneficial for the tensile shear strength. Rolling temperature also has significant influence on mechanical properties of Ti/steel clad plates. The thickness of σ phase increases with the increase of rolling temperature. Thick σ phases impair the mechanical properties of the Ti/steel clad plate.

Study on Al/Mg/Al sheet fabricated by combination of porthole die co-extrusion and subsequent hot rolling

Al/Mg/Al sheet was fabricated by the proposed porthole die co-extrusion and subsequent hot rolling (PCE-R) method. The intermetallic compounds of β-Al3Mg2 and γ-Mg17Al12 were formed in transition layer after PCE-R process, and the thicknesses of β and γ layers became larger at higher rolling temperature or higher reduction ratio. Partial dynamic recrystallization (DRX) occurred in Al layer, and Al layer mainly consisted of shear-typed {111} fiber textures. However, if the rolling reduction is as high as 75%, Al layer exhibited quite different texture components. Mg layer consisted of fine equiaxed grains and several elongated grains, implying the occurrence of near complete DRX. With the increase of rolling temperature or reduction ratio, the number of Mg17Al12 particles in Mg layer was reduced, resulting into larger grain size. Mg layer had strong basal plane texture with c-axis parallel to transverse direction. Al/Mg/Al sheet rolled at 300 °C with 65% reduction exhibited two stress-drop fracture mechanism during tensile test, and it showed excellent tensile strength of 149 MPa, and elongation of 0.13. However, Al/Mg/Al sheet rolled with 75% reduction had inferior tensile properties due to the existence of some cracks after rolling.

Effect of Rolling Reduction and Temperature on the Oxide Scale of Hot Rolled Mild Steel Strip

Hot rolling experiments were designed to investigate the effect of rolling temperature and rolling deformation on microstructure, thickness and surface red scale of hot rolled mild steel oxide scale by spectrometer, SEM and pickling experiment. The research results show that in the same other experiment conditions, the greater the rolling deformation, the thinner the oxide scale extend; with the increase of rolling temperature, the plasticity of oxide scale is enhanced, the oxide scale can be compacted under a larger rolling reduction, which increase the adhesion of oxide scale to substrate and reduce the oxide scale falling off. The higher rolling temperature is, the greater the allowable critical deformation to inhibit red scale is, and the thicker tolerable thickness of the initial oxide scale is. In the process of hot strip rolling, improving rolling load distribution of the front frame and reducing the rolling deformation of the tail frame is helpful to control strip red scale and make oxide scale deform uniformly.