Increase In Cold Rolling Reduction Research Articles

Effect of Cold Rolling on Microstructure and Mechanical Properties of AISI 304N Stainless Steel

Effect of cold rolling at room temperature on microstructure and mechanical properties of a nitrogen-bearing austenitic stainless steel AISI 304N was studied in this paper. The cold rolling reductions from 5% to 90% were adopted for the cold rolling test. Microstructures were observed by an optical microscopy, volume fractions of strain induced α’-martensite were measured by a ferritescope, and deformation induced transformation was investigated by X-ray diffraction. Hardness and tensile tests were carried out to determine the mechanical properties. The results showed that with increase of cold rolling reduction, the volume fraction of strain induced α’-martensite increased while grains were elongated along the rolling direction. The formation of α’-martensite and the lamellar grains resulted in the significant strengthening of the steel and substantial decrease of elongation.

Effect of Cold Rolling on the Fretting Wear Behavior and Mechanism in Inconel 690 Alloy

The influence of cold rolling on the fretting wear behavior and mechanism of Inconel 690 alloy at 320 °C in air was studied. The wear volume and worn surface were obtained and analyzed using laser scanning confocal microscopy, electron back-scattering diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The grinding surface and strain distribution were also studied by electron back-scattering diffraction to analyze the mechanism of fretting damage. The results indicated that with an increase in cold rolling reduction, the microhardness was increased. However, the friction coefficient and wear volume first increased and then decreased. The characteristics of fretting areas changed from a gross slip regime to a partial slip regime. Accordingly, the damage mechanism in the gross slip regime was a combination of oxidative wear, abrasive wear, and delamination, whereas the damage mechanism in the partial slip regime was mainly adhesive wear.

The significant impact of cold deformation on structure-property relationship in phase reversion-induced stainless steels

The present study aims to investigate the impact of cold deformation on structure-property relationship in phase reversion-induced stainless steels. The commercial 18Cr-8Ni stainless steel was cold rolled at room temperature to 30%, 60% and 90% thickness reduction, respectively and subsequently annealed at 900 °C for 1–100 min. Evolution of phases in selected samples was identified and quantified by X-ray diffraction together with the corresponding microstructural characterization through optical, scanning and transmission electron microscopy, and electron backscatter diffraction. Mechanical properties of selected samples were determined by the tensile test. The results indicated that parts of metastable austenite transformed into strain-induced martensite during cold rolling process, and the volume fraction of martensite increased with increase in cold rolling reduction. The kinetics of reversion transformation from martensite to austenite was fastest in 90% cold-rolled sample during annealing treatment. The austenite grain size for the 90% cold-rolled sample after annealing was smallest and most uniform, which induced highest yield strength and elongation combination.

{411}<148> Texture in Thin-Gauge Grain-Oriented Silicon Steel

The significant occupancy of {411}<148> texture exists in the thin-gauge grain-oriented silicon steel (TG-CRGO is defined that thickness of the sheet is <0.25 mm and the reduction in cold rolling is more than 90%) which has been considered to have obviously effects on the abnormal growth of Goss-oriented grains during the secondary recrystallization process. The microstructures of the TG-CRGO were investigated by X-ray diffraction and electron back-scattered diffraction in this study. It was found that {411}<148> texture mainly exists in the center layer of hot-rolled as well as normalized plates. With the increase in cold rolling reduction, {411}<148> orientation gradually rotates to α-fiber texture (<110>//RD). Finally, few {411}<148> would retain at the boundaries of deformed α-fiber grains (<110>//RD) as the reduction in cold rolling reaches 90%. After annealing treatment, a small amount of γ-fiber textures (<111>//ND) preferably nucleates and recrystallizes between the DBs (deformation bands) at first; then, the {411}<148> recrystallization texture occurs and mainly nucleates at the grains boundaries of the deformed α-fiber grains, and also quite a few {411}<148> orientation grains nucleate in the inner of {112}<110> grains. But this phenomenon was not observed in the {100}<011> deformation grains. With respect to the occurrence of {411}<148> recrystallization texture, it is mainly induced by strong α-fiber as well as weak γ-fiber textures formed during cold rolling other than originating from {411}<148> regions in hot bands.

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.

Effect of mode of deformation by rolling on texture evolution and yield locus anisotropy in a multifunctional β titanium alloy

Present work describes the evolution of texture during different modes of deformation by cold rolling of a Gum metal or multifunctional β titanium alloy. The cold rolled materials exhibit the presence of β and small amount of stress induced martensitic (α″) phases. The development of texture has been explained in terms of α and γ fibres. The effect of different modes of rolling results in different patterns of changes in the intensities of texture components in the α fibre. The overall intensity of γ fibre reduces with increase in cold rolling reduction in TCR, MCR and CR specimens although distribution of intensities is different in each case. Texture hardening occurs with increase in rolling reductions in all the modes of rolling. The extent of anisotropy is maximum in MCR while it is minimum in CR specimens.

Texture and Planar Anisotropy of &lt;I&gt;r&lt;/I&gt;-Value in Duplex Stainless Steel Sheet

The effect of cold-rolling reduction on texture and planar anisotropy of the r-value was investigated in type 329J4L duplex stainless steel (DSS) sheet, which has a two-phase ferrite (α) and austenite (γ) microstructure. In addition, the possibility of predicting the planar anisotropy of the r-value on the basis of the Taylor theory was investigated in consideration of the texture gradient through the thickness. An increase in cold-rolling reduction resulted in the improved average r-value and the strong directionality with a maximum value at the diagonal direction. The α phase had an extremely strong αbcc-fiber texture and the γ phase had β- and αfcc-fiber textures. The texture gradient in the thickness direction was more remarkable in the α phase than in the γ phase. The r-values calculated from the overall texture of the α phase using the relaxed constraints model with two relaxed shear strain constraints e13, e23 and a CRSS ratio of 1.1 for {112} and {011}〈111〉 glide systems were in quite good agreement with the experimental r-values. This suggested that slip deformation in the α matrix was dominant for type 329J4L DSS sheet. However, the difference between the experimental and calculated results was remarkable in the vicinity of the diagonal direction.

The Study on the Microstructure Characters of Pure Iron during Cold Rolling by High Energy X-Ray Diffraction

The microstructure characters of pure Iron during cold rolling were studied by HEXD (high-energy x-ray diffraction). The experimental result shows that the Debby ring of HEXD before cold rolling is discrete and very strong, the discrete diffraction points become continue and smooth with the increase of cold rolling reduction. The {001}&lt;110&gt; textures transform to the {001}&lt;uvw&gt; texture after cold rolling, in this process the grains divisional are analyzed by the HEXD result.

Magnetic Properties and Recrystallization Texture Evolutions of Phosphorus-bearing Non-oriented Electrical Steel Sheets

The effect of phosphorus (P) on magnetic properties and also on recrystallization texture of non-oriented electrical steel sheets has been investigated to develop core materials with low core loss and high permeability. Specimens containing different amounts of P were cold-rolled to various thicknesses, i.e. with various cold-rolling reductions, and annealed for recrystallization and grain growth. Magnetic induction of the steel with a large amount of P was higher than that of the steel with a small amount of P. Moreover, magnetic induction of the steel with a large amount of P slightly decreased with reduction of sheet thickness, i.e. with an increase in cold-rolling reduction, whereas magnetic induction of the steel with a small amount of P dramatically decreased. The most effective way to reduce core loss was to reduce thickness of electrical steel sheets. Therefore, P-bearing thin gauge non-oriented electrical steel sheets achieved low core loss and high permeability. The typical magnetic properties of P-bearing non-oriented electrical steel sheets with a thickness of 0.27 mm were 16.6 W/kg in W10/400 and 1.73 T in B50. These excellent magnetic properties were provided by the recrystallization texture control by P. {111}‹112› component in recrystallization texture, which deteriorates magnetic properties of electrical steel sheets, was suppressed during recrystallization. Furthermore, {φ1, Φ, φ2} = {25°, 10–15°, 45°} component significantly developed at the expense of {111}‹112› component during grain growth. P segregation at initial grain boundaries would be responsible for this texture evolution. Accordingly, P would greatly contribute to the improvement of magnetic properties of non-oriented electrical steel sheets through the recrystallization texture control.

高炭素冷延鋼板の延性におよぼすミクロ組織の影響

The effect of void initiation due to microstructural factors, including the size and distribution of spheroidized cementite and ferrite grain size, on elongation in JIS S35C and JIS S65C high carbon cold-rolled steel sheets were investigated.Among mechanical properties after 2nd annealing, yield strength (YS) and tensile strength (TS) both increased as cold-rolling reduction increased, and total elongation (T.EI.) also increased simultaneously. This resulted in large improvement in the TS-T.EL. Balance. As mirostructural changes in this case, with the increase in cold-rolling reduction, the ferrite grain diameter decreased and cementite on the ferrite grain boundary increase.According to the results of a detailed study of S35C, when the microstructure was composed of fine ferrite and cementite on the ferrite grain boundary, elongation was high. In the tensile deformation process, destruction of the grain boundary cementitie was frequently observed. Voids were initiated from these points of origin, and fracture then occurred rapidly. On the other hand, when the microstructure was composed of coarse ferrite grains and fine cementite existed within the ferrite grain, elongation was low. In particular, uniform elongation was markedly decreased. In this deformation process, voids were initiated from cementite on deformation bands, then joined to form cracks, resulting in fracture.

Mechanical properties and deformation behavior of Al–4Mg–0.4Sc–1.5Mm alloy at room temperature

Tensile test at room temperature has been performed on the Al–4Mg–0.4Sc–1.5Mm (Misch metal) alloy sheet with different reduction rate at crosshead speed of 0.036 mm min −1. The experimental results show that the fracture strain is strongly sensitive to cold rolling reduction rate, and the fracture strain increases with an increase of cold rolling reduction. The Portevin–LeChatellier (P–L) effect with a significantly serrate oscillation of stress–strain curves has been shown to be very regular for Al–4Mg–0.4Sc–1.5Mm alloy during tensile deformation. The onset strain decreases with an increase of cold rolling reduction rate. The average interval and the amplitude of stress–strain oscillation can be described by an exponential function with the strain.

Change in Earing of Low-carbon Aluminum-killed Steel Sheets with Hot- and Cold-rolling Conditions.

Experiments have been conducted to investigate the effect of hot-and cold-rolling conditions on earing. It was shown that the earing of cold-rolled and annealed sheets increases with an increase in cold-rolling reduction. On the other hand, the earing decreases with a finishing temperature below Ar3 temperature in hot rolling, the effect of the finishing temperature below Ar3 being minimal in connection with a hot-rolling reduction. The earing increases as the hot-rolling reduction increases and a finishing temperature below Ar3 decreases. With a lower coiling temperature, a deformed structure remains in hot-rolled band and the earing is increased. These increases or decreases in earing depend on the growth or suppression of 45° earing arising from the texture of RD//<110>±20°. The texture development is affected by the initial texture and initial grain size before cold-rolling, and the earing is controlled by the effect of a balance between the same.