单向轧制70/30黄铜的形变织构及形成模型

对70/30黄铜进行不同形变量的单向轧制,用三维取向分布函数分析这种有宏观统计不对称的形变织构。根据单向轧制的受力状态描述其形成模型。结果表明:单向轧制黄铜形变织构的主织构与换向轧制的主织构相同,但其{110}〈112〉中各组分的强度和漫散程度不同,且强点偏移理想位置;有宏观统计不对称织构是由轧件所受的剪力而致,非正常滑移和剪切带的作用对其形成起着关键作用。     

退火时间对单向异步轧制70—30黄铜再结晶织构的影响

借助三维取向分布函数探讨了退火时间对单向异步轧制７０－３０黄铜再结晶结构及其宏观统计不对称性的影响，结果表明，各层再结晶织构存在明显的宏观统计不对称性，是由形变织构的不对称所致；随着退火时间的不断延长，宏观统计不对称性逐渐增强，待再结晶结束后趋于稳定。     

Texture Characteristics of Thin Grain Oriented Silicon Steel Sheet Produced by Cross Shear Rolling

1. IntroductionSilicon steel is widely used as core materials oflarge transformers and large rotating machines. AfterWalter et al.11] reported that a difference in surface en. ?ergy induced tertiary recrystallization, very thin (lessthan 100 pm) grain oriented silicon steels producedby using tertiary recrystallization phenomena in vacuum have excellellt soft magnetic properties[2]. Nevertheless, since starting material using grain orientedsilicon steel sheet after secondary recrystallization i…     

Textures and Magnetic Properties of Grain Oriented ElectricalSteel Produced by Cross Shear Rolling

Commercial grain oriented electrical steels were made by cross shear rolling (CSR) with a chosen mismatch speed ratio 1.1. Original sheets of 0.75 mm thick, which had been produced by conventional cold rolling and intermediate annealing were rolled to thickness from 0.35 mm to 0.15 mm, and followed by industry annealing. The deformation texture and the magnetic properties were measured. Results indicate that: in the condition of the CSR, the deformation texture of rolled sheet is generally similar to that of conventional rolled sheet; for sheets with the thicknesses from 0.35 mm to 0.25 mm, favorable deformation textures, mainly consisting of {111} <112>, are also found at subsudece layers, which may help produce sharp Goss texture, and after the final annealing, the magnetic properties of sheets are not lower than that of conventional rolled sheets     

Formation of textures and microstructures in asymmetrically cold rolled and subsequently annealed aluminum alloy 1100 sheets

The formation of textures and microstructures in asymmetrically cold rolled and subsequently annealed AA 1100 sheets was investigated. The asymmetrical rolling procedure in this experiment was performed in a rolling mill with different roll velocities (roll velocity ratio of 1.5/1.0). In order to enhance the shear deformation, asymmetrical rolling was performed by a large reduction per pass and without lubrication. Asymmetrical rolling led to the formation of strong shear textures. The evolution of asymmetrically cold rolled textures was analyzed by FEM simulations. After recrystallization annealing, pronounced {111}//ND orientations prevailed in all thickness layers. Intensified shear deformations by asymmetrical rolling also led to the formation of ultra-fine grains after recrystallization annealing.     

Effects of changes in strain path on the anisotropy of yield stresses of low-carbon steel and 70-30 brass sheets

Uniaxial tensile tests in various directions following uniaxial extension, equibiaxial stretching or plane strain rolling have been performed to study the effects of changes in strain path on the anisotropy of yield stresses of aluminium-killed low-carbon steel and 70-30 brass sheets. The anisotropy could be predicted from the specimen textures, if dislocation structure were equiaxed, as in the case of equibiaxial stretching. However, elongated dislocation cell structures, developed in the steel specimens prestrained in uniaxial tension or plane strain rolling, gave rise to the second-stage yield stresses higher than predicted from textures in the directions different from the maximum prestrain direction. Planar dislocation structures in the brass specimens prestrained in uniaxial tension or plane strain rolling gave the second-stage yield stresses lower than predicted from the textures in the directions different from the maximum prestrain direction. The phenomena are discussed based on textures and dislocation structures.     

Through Thickness Variation of Cross Shear Rolling Texture in Grain Oriented Silicon Steel

The texture inhomogeneity in cross shear rolled grain oriented Si steel was investigated by means of the through thickness texture analysis. For the chosen rolling reductions (55%, 66.5%) and mismatch speed ratios (1.0, 1.1, 1.3), the deformation textures in various thickness layers consist of three major components, i.e. strong γ-fiber, medium α-fiber and weak η-fiber, and they show an asymmetrical distribution throughout the thickness. The effect of reduction on the texture gradient is found to be more significant at and near the center layer; however, the effect of mismatch speed ratio is less important. In most cases, a strong {111}<112> texture component appears in the subsurface layers, that may favour the formation of a sharp Goss texture during the subsequent annealing.     

异步轧制对硅钢极薄带三次再结晶的影响

分别采用同步和异步轧制将成品工业取向硅钢板冷轧到0.045～0.10mm,然后在纯氢气热处理炉中进行三次再结晶高温退火,研究轧制工艺参数对取向硅钢极薄带织构和磁性能的影响,探索异步轧制对硅钢极薄带三次再结晶行为影响机理.结果表明,采用异步轧制取向硅钢极薄带的磁性能优于同步轧制的;硅钢极薄带厚度愈薄,磁性能愈好,三次再结晶发展得越完善.     

3%Si电工钢铸坯中柱状晶的形变、再结晶行为及织构演变规律

利用电子背散射衍射(EBSD)技术和X射线衍射仪(XRD)研究3%(质量分数)Si电工钢铸坯中柱状晶的形变、再结晶行为及织构演变规律。结果表明:柱状晶长轴分别沿轧向、横向和法向放置,具有不同的初始织构。热轧后,表层形成的3种剪切取向中高斯取向较容易形成。中心区,RD样品中的α和γ线轧制取向,TD样品中的强γ线取向,ND样品中的强{100}取向以及各样品中的立方取向,均表现出明显的初始取向依赖性。冷轧后,RD,TD样品中的强{111}〈112〉取向来自热轧板中的高斯取向,ND样品中的强旋转立方取向遗传自初始{100}取向。受初始取向偏差及大晶粒尺寸影响,ND样品中的旋转立方取向晶粒内取向梯度较大。退火后,样品中心大尺寸的{100}取向晶粒是柱状晶初始取向遗传性的表现。     

Primary Recrystallization of Grain Oriented Silicon Steel Strip Rolled by CSR and Annealed in Magnetic Field

The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling (CSR) of different mismatched speed ratio (MSR) and annealed in magnetic field under hydrogen were presented. Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.     

冷轧形变量对异步轧制高纯铝箔织构的影响

应用取向分布函数(ODF)研究和分析了异步轧制高纯铝箔的形变织构和再结晶织构.结果表明:异步轧制高纯铝箔的形变织构除了C{112}<111>、B{110}<112>和S{123}<634>织构组分外,还有较强的CubeND{001}<110>和{102}织构.异步轧制高纯铝箔的再结晶织构由强的立方织构{001}<100>和弱的R{124}<211>织构组成.随着形变量的增加,异步轧制高纯铝箔的形变织构和再结晶织构呈现规律性的变化,{102}织构减少,S织构先增后减,速比较小时C织构近线性减少,速比较大时C织构则先增后减.异步轧制高纯铝箔的退火样品中有很强的立方织构,这与异步轧制提高高纯铝箔的形变储能有关,形变量过大时,立方织构随形变量的增加急剧减少.{102}织构有利于再结晶立方织构的加强.     

Mechanical properties and anisotropy of ME20 magnesium sheet produced by unidirectional and cross rolling

The microstructures and textures of 90% unidirectionally (UR) and cross rolled (CR) RE-containing magnesium alloy ME20 were investigated for different reductions per rolling pass (r.p.p). During cross rolling the strain path was changed between the rolling passes which led to a weaker texture development and a finer recrystallized grain size compared to conventional unidirectional rolling. The presence of Ce-containing second phase particles with micrometric sizes is suggested to facilitate recrystallization by particle stimulated nucleation (PSN). The tensile mechanical properties in terms of strength and ductility, and also the sheet anisotropy of the UR and CR rolled materials were investigated at room temperature. CR specimens showed enhanced ductility of 26% elongation-to-fracture and an average r-value close to 1, which was attributed to the soft sheet texture prior to tension.     

The characterization of shape memory effect for low elastic modulus biomedical β-type titanium alloy

This work investigates the textures of biomedical TiNbTaZr alloy rolled by 99% cold reduction ratios in thickness. The relationship between textures and superelasticity of the specimens treated at 873 K and 1223 K for 1.2 ks is studied. The microstructure of tensile specimen is investigated by transmission electron microscopy. Textures of cold-rolled and heat-treated specimens are studied. During unloading, the anisotropy of superelastic strain and pure elastic strain in the heat-treated specimens is observed. Superelastic strain along rolling direction and transverse direction is larger than those along 45° from rolling direction while pure elastic strain shows the highest value along 45° from rolling direction in the specimen treated at 873 K. For the specimen treated at 1223 K, higher pure elastic strain is obtained along rolling direction. The maximum recovered strain around 2.11% is obtained along rolling direction.     

Effect of thermo-mechanical processing on texture evolution in austenitic stainless steel 316L

In this study we implemented two rolling modes to investigate the strain path effect on deformation and annealing textures of austenitic stainless steel 316L. We applied unidirectional rolling and cross-rolling to achieve up to a 90% reduction in thickness. Results show that for deformed austenite, Brass, Goss and γ-fibre were the main texture components in the unidirectional rolled sample, while Brass was the dominant texture in the cross-rolled sample. In addition, rotated Copper and rotated Cube were the main textures of martensite after 90% reduction for unidirectional rolled and cross-rolled samples, respectively. Results also show that recrystallization texture has a direct correlation to that of deformed austenite since transformed martensite reversion was athermal. After recrystallization, Brass and a combination of Brass and Goss were the dominant textures for cross-rolled and unidirectional rolled samples, respectively.     

GH4169合金楔横轧加工过程中动态再结晶及织构演变

为研究GH4169合金楔横轧加工过程中动态再结晶及织构演变规律,采用金相显微镜(OM)和电子背散射衍射(EBSD)对30%,50%两种断面收缩率下GH4169合金楔横轧件表层与心部的微观组织、晶体取向及织构进行分析。结果表明:GH4169合金楔横轧加工过程中,随着动态再结晶的发生,晶体取向逐渐变得随机化分布;轧制表层大角度晶界数量较轧件心部多,轧件表层织构强度变化不大,心部织构强度明显增强;经过楔横轧变形后织构发生转动,原始态织构类型为{001}〈110〉,{111}〈110〉,{111}〈011〉,轧制后主要织构类型为{001}〈010〉,{112}〈110〉,{110}〈111〉,{110}〈112〉;GH4169合金楔横轧件动态再结晶及织构演变规律是由楔横轧特殊变形特点决定的。     

Calculation of yield stresses and plastic strain ratios

Yield stresses and plastic strain ratios of aluminium, copper, brass and steel sheets having various textures, which are characterized by the orientation distribution functions, have been calculated as a function of angle to the rolling direction using the Bunge method based on Taylor's minimum energy theory and another method suggested by the present authors. The calculated results are compared with the measured ones. For steels, the two methods yield almost identical yield stress results. The Bunge method yields higher average plastic strain ratios than the measured data, while their variation with the angle to the rolling direction agrees very well with the measured values. The plastic strain ratios calculated by the second method are in very good agreement with the measured data in their average values but show smaller variations with the angle to the rolling direction than the measureD. Therefore, combination of the two methods can yield very good agreement between calculated and measured plastic strain ratios. For the f c c metals, the calculated yield stresses and plastic strain ratios are in good agreement with measured data, regardless of the calculation method.     

Microstructure and texture of rolled and annealed β titanium alloy Ti–10V–4.5Fe–1.5Al

This work describes the evolution of texture during cold rolling and annealing of a hot rolled and solution treated sheet of a low cost β titanium alloy Ti–10V–4.5Fe–1.5Al. The alloy was cold rolled up to 60% reductions and then annealed in β phase field at different temperatures to study the re-crystallisation textures. The rolling and re-crystallisation textures obtained in this study are compared with those of other β titanium alloys and bcc metals and alloys such as tantalum and low carbon steel.     

Magnetic properties of grain oriented ultra-thin silicon steel sheets processed by conventional rolling and cross shear rolling

A new procedure consisting of the cross shear rolling (CSR) and the subsequent tertiary recrystallization annealing under dry hydrogen atmosphere was developed to produce the grain oriented ultra-thin silicon sheets less than 0.1 mm with high magnetic property performance. For comparison, the conventional rolling (CR) was also used to process the grain oriented ultra-thin silicon steel sheets. The effect of processing parameters on magnetic properties of the grain oriented ultra-thin silicon steel sheets was investigated. With the increase of annealing temperature and holding time, magnetic properties of the sheets processed by both rolling methods reach saturation as the result of the proceeding of the tertiary recrystallization. The thin sheets rolled by CSR did achieve better magnetic properties than those rolled by CR.     

Effect of asymmetrical rolling and annealing the mechanical response of an 1050-o sheet

The asymmetrical rolling process has been studied as a way to promote intense shear deformations across the sheet thickness. These shear deformations may lead, given the proper conditions, to the development of shear texture components ({001}<110>, {111}<110> and {111}<112>) and also grain refinement. In this work, a 1050-O sheet is asymmetrically rolled and annealed. Conventional rolling is also performed, for comparison purposes. Shear texture components are obtained for the asymmetrically rolled specimens, and seem to be retained after annealing. Differences in mechanical response between asymmetrical and conventionally rolled specimens, as well as texture evolution after heat treatment processing are inferred based on experimental tensile and shear tests. Numerical simulations are used to help explain the differences found on experimental tests. It is proven that it is difficult to spread shear texture through the entire sheet thickness from a general asymmetric rolling process. Based on the fact, future research is discussed at closure.     

Evolution of strain states and textures during roll-cladding in STS/Al/STS sheets

The evolution of strain states and textures during roll-cladding of three plies of sheets comprising ferritic stainless steel (STS), aluminum (Al) and ferritic stainless steel was investigated by measurements of crystallographic textures and by simulations with the finite element method (FEM). Because the deformation mainly occurs in the Al layer during roll-cladding, the present investigation was focused on the Al layer located at the middle of clad samples. Roll-cladding of STS/Al/STS sheets led to the development of a strong through thickness texture gradient in the Al sheet which was characterized by shear textures at the surface layer and rolling textures at the center layer. The temperature of the cladding operation played an important role in the evolution of textures.