蛇形轧制复合成形镁/铝板材的弯曲曲率研究

针对镁/铝板材轧制复合在轧后容易出现弯曲问题，提出了蛇形轧制复合工艺，以达到降低轧后弯曲曲率并提高界面结合强度的目的。利用ANSYS LS-DYNA有限元软件，研究了蛇形轧制复合过程中不同错位量、异速比、压下量、层厚比及轧制温度对轧后复合板的弯曲曲率的影响规律，并开展轧制复合实验，验证了有限元计算结果的准确性。结果表明，与异步轧制相比，蛇形轧制可有效降低轧后复合板弯曲曲率。相同轧制条件下，异步轧制轧后弯曲曲率随着异速比的增大而增大，随着压下量及层厚比的增大而减小。蛇形轧制错位量可对轧后弯曲抑制产生明显的效果，在一定范围内，复合板的弯曲曲率随错位量的增大而减小。当初始板厚为50 mm、层厚比为2:3、压下量为30 mm、轧制温度为400℃、异速比为1.05和错位量为30 mm时，轧后复合板接近平直。     

Texture Evolution of the Mg/Al Laminated Composite by Accumulative Roll Bonding at Ambient Temperature

以商业纯Mg、纯Al板材为初始材料,采用累积叠轧法(ARB)在室温下成功制备出Mg/Al多层复合板材。在累积叠轧过程中,复合板材中Mg层和Al组织随着循环次数的提高而细化。通过中子衍射技术对复合板材的织构进行测试后表明:在初始复合后的Al/Mg/Al三明治复合板材中,Mg层和Al层主要织构类型均为剪切织构。而在后续的累积叠轧过程当中,由于其工艺特点,导致Mg层和Al层中轧制织构组分出现,最终Mg层主要呈现出典型轧制织构而Al层则表现出以轧制织构组分为主并伴有剪切织构的混合织构类型。     

碳钢/不锈钢同速异径蛇形轧制复合变形规律

为提高碳钢/不锈钢板材轧制复合界面结合强度并降低轧后弯曲，采用ANSYS LS-DYNA有限元软件模拟了碳钢/不锈钢在1200℃开轧温度下的同速异径蛇形轧制复合过程，分析了不同压下率、辊径比、错位量与初始板厚等对轧后板材变形行为的影响规律，并进行了轧制复合实验，验证了有限元模拟的准确性。结果表明，与同步轧制和异步轧制相比，同速异径蛇形复合轧制能提高轧后板材界面结合强度并降低轧后弯曲。增大压下率可提高轧后板材界面的结合强度和轧后层厚比，且随压下率和辊径比的增大，轧后板材均出现反向弯曲，表明存在合适工况使轧后板材平直，如当初始板厚为20 mm,压下率为40%,错位量为5 mm,辊径比为1.15～1.20,初始层厚比为0.25～0.33时，轧后板材接近平直。     

累积叠轧Mg/Al多层复合板材的织构演变及力学性能

以商业纯Mg和AA1050 Al板材为初始材料,采用累积叠轧技术在室温下进行不同轧制道次变形制备了Mg/Al多层复合板材料,并对3 cyc轧制的Mg/Al多层复合板材料在200℃分别进行不同时间退火处理.利用OM,SEM和中子衍射技术对微观组织和宏观织构进行了研究.结果表明,复合板材中Mg和Al层组织均随着循环次数的提高而细化;在200℃时随着退火时间的增加,晶粒逐渐均匀但没有明显长大.累积叠轧过程中Mg层主要呈现出典型的轧制织构类型,Al层则表现出以轧制织构组分为主,同时伴有剪切织构组分的混合织构类型.对于3 cyc轧制的Mg/Al多层复合板材,在200℃经不同时间退火后,Mg层依然为轧制织构类型,Al层为轧制织构与剪切织构组分混合.随着累积叠轧循环道次的增加,屈服强度和抗拉强度都逐渐上升.     

轧制参数对钛/铝轧制复合板的结合强度和剥离面SEM形貌的影响

研究了钛/铝的轧制复合工艺对轧后结合强度和剥离面形貌的影响。试验结果表明,钛的变形程度是控制结合强度和剥离面形貌的主要因素;轧制时铝的温度对结合也有重要的影响。在钛和铝的热轧复合中并存着3种结合机制。     

室温累积叠轧Mg/Al多层复合板材织构演变(英文)

以商业纯Mg、纯Al板材为初始材料,采用累积叠轧法(ARB)在室温下成功制备出Mg/Al多层复合板材。在累积叠轧过程中,复合板材中Mg层和Al组织随着循环次数的提高而细化。通过中子衍射技术对复合板材的织构进行测试后表明:在初始复合后的Al/Mg/Al三明治复合板材中,Mg层和Al层主要织构类型均为剪切织构。而在后续的累积叠轧过程当中,由于其工艺特点,导致Mg层和Al层中轧制织构组分出现,最终Mg层主要呈现出典型轧制织构而Al层则表现出以轧制织构组分为主并伴有剪切织构的混合织构类型。     

脱溶析出对累积复合轧制Al/Zn层状复合材料组织及性能的影响

在400 ℃条件下采用累积复合轧制(ARB)工艺制备Al/Zn层状复合材料。采用SEM,TEM等设备对第二轧制周期试样及第三轧制周期的试样进行显微组织观察,结果表明：在轧制过程中,Al/Zn层间界面不同成分发生相互扩散,形成扩散层;随着轧制周期的结束,扩散层中过饱和的Zn原子随温度的降低而脱溶析出,在消除晶粒边界及内部位错的同时细化晶粒。在试样内部,因为扩散层中Zn原子存在浓度梯度,过饱和的Al基体中析出的富Zn相存在不同典型的组织形态。采用万能拉伸试验机对第一、第二、第三轧制周期试样进行力学性能测试,结果显示,随着轧制周期的增加,Al/Zn层状复合材料的抗拉强度和伸长率均有大幅度提升,抗拉强度由第一轧制周期的128.81MPa增加至第三轧制周期的351.54MPa,提升了173%,同时伸长率由6.66%提升至11.08%。采用SEM对试样断口进行观察后发现,断口表现出明显的复合材料强界面裂纹偏转现象。采用累积复合轧制（ARB）工艺制备Al/Zn层状复合材料,因为存在复合材料强界面裂纹偏转作用以及晶粒的细化作用,表现出良好的综合力学性能。     

Fe基非晶合金增强1060铝基多层复合材料的组织与性能

采用累积叠轧焊+中间退火法复合轧制1060Al/Fe基非晶多层铝合金复合板材。利用光学显微镜、扫描电镜、X-衍射分析仪以及拉伸试验机分析Al基复合材料的微观组织结构变化、断口形貌、物相组成以及力学性能。结果表明:Fe基非晶复合材料的增强体在300 ℃中间退火过程中发生部分晶化,在累积变形轧制过程中发生破碎,并随着变形道次的增加,破碎程度随之增大;复合板前6道次的累积轧制变形出现了明显的加工软化现象,并且随着变形道次的增加,其加工软化的效果愈明显;随着累积轧制变形道次增加,Al基复合材料的力学性能发生了明显的变化,第2道次轧制变形后屈服强度与抗拉强度达到了最大值为140 MPa和156 MPa,伸长率为5.53%,达到最佳综合性能。     

离心铸造半钢复合轧辊

采用卧式离心机经两次复合铸造生产出半钢复合轧辊。文中介绍了三层结构的设计、半钢的冶炼、浇注及热处理工艺。该轧辊的性能热轧机精轧前段工作辊的要求，毫米轧制量为３８００吨。     

累积叠轧制备Ti/Ni多层复合材料的组织演变与力学性能研究

本文以工业纯Ti、纯Ni板材为初始材料,采用累积叠轧法(ARB)制备出Ti/Ni多层复合板材料。利用扫描电镜、透射电镜、万能试验机、显微硬度仪对复合材料的组织、界面结构和力学性能进行观察和测试分析。结果表明：随着轧制道次的增加,复合材料中Ti层和Ni层显微组织细化明显,均匀程度提高,ARB5道次后,Ti、Ni层的平均晶粒尺寸分别为200 nm和300 nm;复合材料的抗拉强度、显微硬度和界面结合强度显著提高,ARB5道次后抗拉强度达到810 MPa,延伸率为24.4%,Ti、Ni层平均显微硬度分别为233 HV和229 HV。在ARB1-5道次轧制变形过程中,界面处无明显的原子扩散现象发生。     

热轧带钢边部翘皮缺陷成因分析

为了探明低碳钢在带钢轧制过程中出现边部翘皮缺陷的形成原因,取样分析了翘皮缺陷形貌及夹杂物成分,并采用ø750 mm×550 mm高刚度二辊热轧机组进行实验室模拟轧制分析翘皮缺陷演化过程。通过建立不同轧制方案,探明了热轧带钢翘皮缺陷形成于精轧道次,缺陷的产生与坯表面质量和边部原始凝固组织无关,轧材在轧制过程中由于边部不均匀变形形成侧面凹陷,凹陷在后续轧制中被轧制压缩闭合,并翻转到表面成为翘皮缺陷。最后,工业生产试验表明,倒角铸坯可提高轧材边部在轧制过程中的温度和均匀性,抑制轧材边部不均匀变形,有效降低翘皮缺陷的发生率。     

中厚板平面形状变形规律及其测定的研究

论述了中厚板在轧制过程中的平面形状变形行为，阐述了用合成照相法定量确定中厚板平面形状的原理和测定方法。并用铅试样进行了模拟实验，采用合成照相法定量测定轧制过程中轧件的平面形状，探索了其变化规律，为中厚板平面形状控制建立数学模型提供了实用的方法。     

Influence of roll radius on contact condition and material deformation in skin-pass rolling of steel strip

Skin-pass rolling (or temper rolling) is the final forming step in the production of cold rolled steel sheets. Although a large roll radius compared to the contact length is one of the characteristics of skin-pass rolling conditions, numerous studies have been conducted thus far using laboratory mills with small radius rolls. In this paper, the influence of roll radius on the contact condition and material deformation in skin-pass rolling is examined and clarified by numerical analysis by an elastic–plastic FEM analysis as well as experimental rolling tests, which were performed to verify the result of the analysis. Some characteristics of skin-pass rolling related to pressure distribution, contact condition and material deformation are not properly simulated using small radius rolls. Considering characteristic skin-pass rolling conditions, two cases using simplified models, i.e., vertical compression and rolling with a circular, rigid roll, were analyzed.     

The influence of heat treatment and deep rolling on the mechanical properties and integrity of AISI 1060 steel

This work addresses the influence of distinct microstructures and deep rolling parameters on the behaviour of AISI 1060 steel. For this purpose, the work material was initially subjected to subcritical and full annealing as well as to hardening through quenching and tempering. The specimens were subsequently deep rolled under different rolling pressures and numbers of passes. The findings indicate that plastic deformation increases with rolling pressure and number of passes due to more intense cold working and that under identical deep rolling conditions the fully annealed material presents more severe deformation than the subcritically annealed samples. Moreover, the ability of deep rolling to increase surface hardness decreases with the elevation of the hardness of the original material. The values of the yield and ultimate tensile strength were affected in different manners by deep rolling depending on work material condition and the tensile residual stresses observed after turning were converted into compressive values by deep rolling. Finally, the elevation of rolling pressure and number of passes presented distinct effects on the microhardness distribution beneath the surface depending on the work material condition.     

Rolling Textures in Compacts of Copper and Steel

This study was undertaken to determine whether differences exist in the rolling textures of materials rolled with and without cladding and whether such differences are affected by bonding the clad and core by hot isostatic pressing (HIP’ing) prior to rolling/ Both steel-clad copper and copper-clad steel were studied, using compacts having nominal volume fractions of core equal to.33 and.50. Unclad core material having the same initial thicnkess as the cores was rolled to similar reductions for comparison with material rolled with cladding. No significant difference in the deformation textures, compared to unclad material, were observed for steel-clad copper. However, for copper-clad steel, a pronounced deformation texture developed in the core at lower total reductions than those required to developed the same degree of texture in unclad material. In these cases, the cladding showed evidence of a shear texture. Prebonding of the compacts by HIP’ing intensified this effect.     

20CrMnTi热轧带钢带状组织的控制

20CrMnTi热轧带钢直接作为适宜规格齿轮原料在可加工性和使用性能上具有显著优势,但带钢中的带状组织缺陷是影响其使用性能的关键因素。通过板坯加热均质化控制试验、精轧变形量及变形速率控制试验及轧后控制冷却试验,对20CrMnTi热轧带钢带状组织进行了分析。结果表明,20CrMnTi板坯加热时应保证心部温度大于1 000 ℃,保温时间在150 min以上;采用奥氏体再结晶轧制工艺,终轧温度控制为930 ℃,卷取温度控制为670 ℃,可有效控制成品带钢带状组织级别在3级以内。     

基于ANSYS/LS-DYNA的楔横轧应力应变分析

通过ANSYS/ LS-DYNA有限元分析软件,对楔横轧轴类件的成型过程进行数值模拟,分析楔横轧轴类件轧制过程的应力应变规律,并对各轴向应力应变进行比较,阐明楔横轧轴类件的变形特征,得到轴类零件轧制过程中轧件内部的应变场、轧件表面变形形状等信息,可为其他零件轧制成形机理及变形规律的研究提供理论依据和参考.     

Effect of thermo-mechanical processing on filiform corrosion of aluminium alloy AA3005

The effect of laboratory scale thermo-mechanical processing of aluminium alloy AA3005, supplied as 2.9 mm sheet at the hot roll transfer gauge, on filiform corrosion (FFC) susceptibility, electrochemical properties and near surface microstructure was investigated. Corrosion testing showed that the as hot rolled material exhibited poor FFC resistance and that heat treatment of both the as hot rolled and subsequently cold rolled samples resulted in a drastic loss of corrosion resistance. Microstructural characterisation showed that both hot and cold rolling resulted in enhanced surface shear deformation and the formation of a thin layer of metal in the surface with different properties and microstructural characteristics than the underlying bulk material. Enhanced surface deformation resulted in a redistribution of intermetallic particles in this region. Poor FFC properties were correlated with the presence of a higher density of fine intermetallic precipitates in the surface layers than in the underlying bulk. It is suggested that enhanced secondary precipitation of intermetallic particles in the deformed surface layers during high temperature exposure, e.g., during hot rolling or annealing steps, is the main contributing factor to the observed poor FFC resistance.     

方形轧件在椭圆孔的塑性失稳分析

针对35CrMo合金冷锻钢粗轧过程出现的表面褶皱，采用非线性有限元分析方法， 分析不同鼓形率轧件在椭圆孔中的轧制过程，从变形的角度分析了轧件表面由于塑性失稳产生褶皱的原因及位置。结果表明，方形轧件在椭圆孔中轧制时，轧件角部区域塑性变形剧烈，塑性应变能密度分布出现峰值，最易产生塑性失稳而形成褶皱。增大方形轧件的鼓形率，可减小塑性应变能密度分布峰值，降低轧件表面发生褶皱缺陷的概率。     

润滑对3104铝合金板变形织构的影响

在无润滑(WOL)和润滑(WL)2种轧制条件下,分别对2.3 mm厚的热轧3104铝合金板进行不同压下量的冷轧.应用取向分布函数(ODF)定量计算和分析在不同轧制压下量下润滑对3104铝合金板材沿板厚方向织构演变的影响.结果表明:随着轧制压下量的增加,样品各层的织构组分强度均逐渐增加;无润滑轧制时样品表面层主要织构组分取向密度普遍高于相同压下量下润滑轧制时的取向密度.导致表面层织构组分增强的原因是摩擦引起应变状态改变的结果.