Recrystallization Texture and Microstructure of Metal Substrate for Y123 Coated Superconductor

Thesecondgenerationofhigh temperaturesuper conductingtapesusingYBCO 12 3superconductorhavebeenanattractivesubjectinrecentyears .IncomparisonwithBibasedsuperconductors ,YBCOshowsbetterirreversibility ,lowAClosscapabilityandhighcriticalcurrentdensityJC inhighmagneticfields[1] .However ,owingtoitspropertyofphysicalmetallurgy ,YBCOtapescannotbeproducedbyOPIT(OxidePowderinTube)technique ,whichhasbeenusedinBibasedsuperconductorsuccessfully[2 ] .Fur thermore ,poorintergrainbondinginpolycrys…     

Influence of deformation and annealing conditions on the recrystallization cube texture in the three-layer NiW/NiCr/NiW substrate tapes

The formation of a sharp cube texture in a three-layer composite tape with the outer (working) layers made of an Ni–4.8 at % W alloy and the inner layer made of an Ni–11 at % Cr alloy is studied after cold deformation by rolling at a reduction of 98.4–99.5% and subsequent recrystallization annealing at a temperature of 1000–1150°C. An analysis of the sharpness of the cube texture and the magnetic properties of the three-layer composite material shows that such tapes can be used as substrates to create second-generation HTSC. At a temperature of 80 K, the specific magnetization of the composite three-layer tape is lower than that of a widely used tape made of an Ni–5 at % W alloy.     

Microtexture Evolution and Grain Boundary Character Distribution of Interstitial-Free Steels With Moderate Levels of Cold Rolling Reductions

High-strength interstitial-free steel sheets have very good deep drawability when processed to have {111} recrystallization texture. The microtexture evolution and grain boundary character distribution of interstitial-free steels as a function of moderate levels of cold rolling reductions were investigated by the metallographic microscopy and electron backscatter diffraction technique. The results showed that there was a close relationship between microtexture and grain boundary character distribution for interstitial-free steel, especially the distribution and features of some specific types of coincident-site lattice boundaries. In addition, α-fiber texture was weakened to vanish while γ-fiber texture strengthened gradually as cold rolling reduction was increased from 20% to 75% for cold rolled and annealed samples. Accordingly, increasing the rolling reduction from 20% to 75% would lead to a significant increase in the proportion of Σ3 boundaries. Also, it was found that the microtexture of 20% cold rolled sample would induce a high frequency of Σ11 grain boundaries, but the microtexture of 75% cold rolled sample would produce more Σ7 and Σ17 grain boundaries. It was suggested that texture played a significant role in the formation of grain boundary character distribution.     

取向硅钢板坯加热温度对热轧及冷轧板织构的影响

 采用取向分布函数及取向线分析方法对取向硅钢高温和低温板坯加热工艺的热轧及冷轧钢板织构进行了研究。结果表明：低温与高温板坯加热工艺的热轧板及冷轧板织构组分有明显不同。低温板坯加热热轧板中{100}<001>及{110}<110>织构较强,但经冷轧后{001}<110>织构最强。     

DP590双相钢不同工艺下组织与微观织构的EBSD研究

借助场发射扫描电镜（FESEM）和电子背散射衍射（EBSD）等测试手段研究了DP590双相钢不同工艺下的显微组织与微观织构。结果表明,从热轧、冷轧到连退过程组织发生了明显的变化,由热轧态的块状铁素体和少量珠光体组织转变为退火态的铁素体和少量的马氏体,晶粒尺寸由8μm细化至6μm。从热轧、冷轧到连退过程织构同样发生了显著的变化,随着工艺过程的进行,旋转立方织构逐渐减弱,但减弱幅度不大,相应的（001）<110>晶粒逐步减少;不利于深冲性能的α织构先增强后减弱,其最强组分（112）<110>的取向密度在冷轧阶段达到最大值,相应的（112）<110>晶粒先增加后减少;有利的γ织构逐渐增强,其最强组分（111）<112>的取向密度在连退阶段达到最大值,相应的（111）<110>晶粒和（111）<112>晶粒均逐步增加,但（111）<112>晶粒要多于（111）<110>晶粒。     

薄板坯连铸连轧工艺下Hi-B钢的组织及织构

采用金相显微镜和扫描电镜研究实验室模拟薄板坯连铸连轧（TSCR）工艺试制的高磁感取向硅钢（Hi-B钢）组织、织构的演变特征.研究发现实验室模拟薄板坯连铸连轧工艺试制的Hi-B钢热轧板显微组织及织构在厚度方向上存在不均匀性.常化板表面脱碳层铁素体晶粒明显粗化,常化板织构基本继承了热轧板相应的织构类型,仅织构强度不同.一次大压下率冷轧后,晶粒及其晶界沿轧向被拉长形成鲜明的纤维组织,织构主要为α纤维织构和γ纤维织构,脱碳退火后试样发生回复和再结晶现象并形成初次晶粒组织,脱碳退火后织构分布较为集中.温度升高至1000℃时二次再结晶开始,1010℃时钢中晶粒发生异常长大,高斯织构强度达到61.779.成品磁感为1.915 T,铁损为1.067 W·kg-1.      

高性能取向硅钢的工业化生产研究

采用光学显微镜、X射线衍射仪等分析了宁波钢铁有限公司生产的取向硅钢不同工序下的组织及织构演变规律.结果 表明:铸坯经过热轧后,沿着厚度方向组织不均匀;一次冷轧并经脱碳退火后,组织由条状纤维状变成等轴状的初次再结晶晶粒,初次再结晶平均晶粒尺寸为18.17 μm,织构主要以α织构和γ织构为主;在二次冷轧后,晶粒再次被压缩,转变为纤维状,织构主要为γ织构;经过高温退火后,发生二次再结晶,晶粒异常长大,晶粒尺寸达到厘米级,织构成分为单一且锋锐的Goss织构.     

50W1300无取向硅钢的显微组织和织构演变

运用金相观察和电子背散射衍射技术,研究了实际生产条件下50W1300无取向硅钢在热连轧—冷轧—退火过程中显微组织和织构的演变。结果表明,在热塑性加工过程中,热轧板表层均为等轴晶,芯部为变形压扁组织。经冷轧后,热轧组织转变为扁平的带状组织,芯部呈现纤维组织特征。退火组织为晶界清晰且较规整的等轴铁素体晶粒。沿厚度方向,热轧板织构类型不同。冷轧板织构类型基本不变,主要为α织构、γ织构和旋转立方织构{100}<110>;在板厚1/4处,α织构和旋转立方织构强度达到最高,γ织构显著减弱。退火板中γ织构强度有所降低。     

Fiber texture and substructural features in the caliber-rolled low-carbon steels

Caliber rolling at the recrystallization temperatures of ferrite is a new process that was developed to fabricate an ultrafine-grained microstructure for low-carbon steels. In the present investigation, the electron backscattered diffraction (EBSD) measurement was carried out to characterize thoroughly the texture and substructural features in two caliber-rolled low-carbon steels, with special attention on the effects of a phosphorus addition to the steel and the annealing treatment after rolling. Finer ferrite grains appeared in the phosphorus-added steel under the same rolling condition. The phosphorus addition caused also the stronger <110>//rolling direction (RD) fiber texture in the caliber-rolled steel bars and, hence, showed a larger average Taylor factor than the steel without phosphorus. Microband features within the ultrafine ferrite grains were characterized with both transmission electron microscopy (TEM) observation and orientation-imaging micrograph (OIM) analysis. Nearly half of the low-angle boundaries, whose kernel average misorientation was larger than 0.8 deg, were found to have the planar character and were specifically parallel to the {110} or {112} planes. In the as-rolled condition, the total volume fraction of the low-angle boundaries was 0.3 and 0.23 in the steels with and without a phosphorus addition, respectively. More {112}-type planar boundaries were observed than the {110} type boundaries in both steels. Annealing treatment increased the volume fraction and changed the type of the low-angle boundaries in both steels. Using the model proposed by Peeters et al., the critical resolved shear stress (CRSS) of the 110 and 112 slip systems was calculated by considering the contributions of both the randomly distributed dislocations and the oriented planar boundaries. We concluded that the contribution of the planar low-angle boundaries to the total CRSS was less than 2 pct. The texture features and dislocation structure in the ultrafine-grained steels influenced the mechanical behavior to some extent, in addition to the refined ferrite grains. Phosphorus added to the steels showed a larger influence on the formation of texture and the retained dislocation structure, than that on the grain refinement in the caliber-rolling process.     

CSP流程试制50W270高牌号无取向硅钢织构的演变

研究了CSP流程试制50W270高牌号无取向硅钢热轧→常化→冷轧→退火过程中织构的演变.利用电子背散射衍射技术对全流程织构进行测量和分析.发现热轧板织构在厚度方向上存在较大差异,表层主要为铜型、黄铜和高斯织构,1/4层存在微弱的高斯织构和旋转立方织构,中心层以γ纤维织构和旋转立方织构为主,还含有较弱的α纤维织构.与热轧板相比,常化板表层和1/4层织构变化不大,中心层旋转立方织构和α纤维织构增强.冷轧板各层均具有α纤维织构和γ纤维织构.与冷轧板相比,成品板各层中α纤维织构基本消失,还出现了立方织构和高斯织构.      

Evolution of Through-Thickness Texture in Ultra Purified 17%Cr Ferritic Stainless Steels

 Texture inhomogeneity usually takes place in ferritic stainless steels due to the lack of phase transformation and recrystallization during hot strip rolling, which can deteriorate the formability of final sheets. In order to work out the way of weakening texture inhomogeneity, conventional hot rolling and warm rolling processes have been carried out with an ultra purified ferritic stainless steel. The results showed that the evolution of through-thickness texture is closely dependent on rolling process, especially for the texture in the center layer. For both conventional and warm rolling processes, shear texture components were formed in the surface layers after hot rolling and annealing; sharp α-fiber and weak γ-fiber with the major component at {111}<110> were developed in both cold rolled sheet surfaces, leading to the formation of inhomogeneous γ-fiber dominated by {111}<112> after recrystallization annealing. In the center layer of conventional rolled and annealed bands, strong α-fiber and weak γ-fiber textures were formed; the cold rolled textures were comprised of sharp α-fiber and weak γ-fiber with the major component at {111}<110>, and inhomogeneous γ-fiber dominated by {111}<112> was formed after recrystallization annealing. By contrast, in the centre layer of warm rolled bands, the texture was comprised of weak α-fiber and sharp γ-fiber, and γ-fiber became the only component after annealing. The cold rolled texture displayed a sharp γ-fiber with the major component at {111}<112> and the intensity of γ-fiber close to that of α-fiber, resulting in the formation of a nearly homogeneous γ-fiber recrystallization texture in the center layer of the final sheet.     

低温加热取向硅钢组织与织构演变研究

采用OM、EBSD、XRD分析研究了含Cu低温加热取向硅钢组织、织构的演变特征,研究结果表明：热轧板中存在铁素体层和珠光体层彼此交替的带状组织,且显微组织在厚度方向上分布不均匀,热轧板中{001}〈110〉、{112}〈110〉织构以及{110}〈001〉织构在板厚方向上分布不均匀;经过冷轧后,铁素体晶粒被严重拉长,形成了沿轧向伸长的纤维状组织,冷轧板织构类型主要是α织构和γ织构;脱碳时基体发生回复再结晶,显微组织为单一的铁素体等轴晶粒,织构主要为γ织构;二次冷轧板经渗氮后织构仅从强度上有所降低,其织构类型变化不明显。成品二次再结晶组织发展比较完善,晶粒尺寸约为10~20 mm。织构类型为锋锐的Goss织构。成品磁感B800达到了1.926 T,铁损P1.7/50为1.047 W/kg。     

Effect of Concurrent Precipitation on Recrystallization and Evolution of the P-Texture Component in a Commercial Al-Mn Alloy

The recrystallization behavior of a cold-rolled Al-Mn alloy was investigated, focusing on the effect of concurrent precipitation on nucleation and growth of recrystallization and the formation of the P- ( { 011 } á 111 ñ ) \left( {\left\{ {011} \right\}\left\langle {111} \right\rangle } \right) and ND-rotated cube ( { 001 } á 310 ñ ) \left( {\left\{ {001} \right\}\left\langle {310} \right\rangle } \right) texture components. It was observed that if precipitation took place prior to or simultaneously with recovery and recrystallization processes, i.e., by concurrent precipitation, this resulted in a delayed recrystallization, a coarse and elongated grain structure, and an unusually sharp P-texture component. The P-texture component sharpened with increasing initial cold rolling reduction, increasing initial supersaturation of Mn, and decreasing annealing temperature. The P- and ND-rotated cube nucleation sites have an initial growth advantage compared to the particle-stimulated nucleation (PSN) sites due to their 40 deg á 111 ñ \left\langle {111} \right\rangle -rotation relationship to the Cu component of the deformation texture. The boundaries between such sites and the surrounding matrix will be of the Σ7 type, and it is assumed that such highly perfect boundaries will be less affected by solute segregation and precipitation, resulting in early growth advantage. It was further observed that dispersoids present prior to cold rolling and annealing had a weaker effect on the recrystallized grain size and texture compared to concurrent precipitation, even though the average dispersoid density was higher in the pre-precipitation cases. The finer grain size was explained by the wider dispersoid free zones surrounding the large constituent particles compared to the concurrent precipitation cases. Subsequent growth of the nucleated grains, however, was more hindered due to the Zener drag, consistent with the higher dispersoid densities.     

薄板坯连铸连轧流程Fe-3％Si钢冷轧板织构

在实验室按照薄板坯连铸连轧工艺流程试制了Fe-3％Si硅钢热轧板,按照四种冷轧变形制度将热轧板冷轧后采用X射线衍射方法观察了织构分布,分析了14／16层、H／8层、H／4层、H／2层的取向密度变化,研究了热轧和冷轧过程的织构演变规律。试验研究结果为开发薄板坯连铸连轧短流程生产电工钢技术提供理论依据和参考数据。     

Influence of Controlled Rolling and Cooling Process on the Mechanical Properties of Low Carbon Cold Forging Steel

In the present paper,controlled rolling and cooling processing was conducted by using a laboratory hot rolling mill.The influence of different processing parameters on the mechanical properties of low carbon cold forging steel was investigated.The results show that the faster cooling after the deformation (especially in low temperature rolling conditions) leads to the refinement of the ferrite grain.The specimen exhibits very good mechanical properties owing to the finer ferrite grains.The pearlite morphologies can also affect the mechanical properties of low carbon cold forging steel.The mechanical properties increase with decreasing final cooling temperature within the range from 650℃ to 570 ℃ due to the finer interlamellar spacing of pearlite colony.The mechanical properties of the specimens with fast cooling after the conventional rolling are not only better than those of the specimens with slow cooling after low temperature rolling,but also almost similar to those of the specimens with fast cooling after low temperature rolling.It is suggested that fast cooling after high temperature rolling (the conventional rolling) process would be of important industrial value.     

Effect of Rolling and Subsequent Annealing on Microstructure,Microtexture, and Properties of an Experimental Duplex Stainless Steel

A lean duplex stainless steel (LDSS) has been prepared with low-N content and processed by different thermo-mechanical schedules, similar to the industrial processing that comprised hot-rolling, cold-rolling, and annealing treatments. The microstructure developed in the present study on low-N LDSS has been compared to that of high-N LDSS as reported in the literature. As N is an austenite stabilizer, lower-N content reduced the stability of austenite and the austenite content in low-N LDSS with respect to the conventional LDSS. Due to low stability of austenite in low-N LDSS, cold rolling resulted in strain-induced martensitic transformation and the reversion of martensite to austenite during subsequent annealing contributed to significant grain refinement within the austenite regions. δ-ferrite grains in low-N LDSS, on the other hand, are refined by extended recovery mechanism. Initial solidification texture (mainly cube texture) within the δ-ferrite region finally converted into gamma-fiber texture after cold rolling and annealing. Although MS-brass component dominated the austenite texture in low-N LDSS after hot rolling and cold rolling, that even transformed into alpha-fiber texture after the final annealing. Due to the significant grain refinement and formation of beneficial texture within both austenite and ferrite, good combination of strength and ductility has been achieved in cold-rolled and annealed sample of low-N LDSS steel.     

Effect of Through‐Thickness Macro and Micro‐Texture Gradients on Ridging of 17%Cr Ferritic Stainless Steel Sheet

In order to study the formation of ridging in ferritic stainless steel (FSS) sheets, the evolution of the crystallographic texture was investigated by macro and micro‐texture measurements throughout the thickness of the sheets. The as‐received hot band material displayed a pronounced through‐thickness texture gradient with a strong rotated cube orientation in the sheet center layer. The initial texture of the hot band had a high impact on the formation of the cold rolling texture and on the final recrystallization texture. Modification of the cold rolling texture by means of cross‐rolling led to an improvement of the macro and micro‐textures after final recrystallization annealing, which gave rise to an enhanced sheet formability in FSS. Tensile tests of specimens with half thickness revealed that ridging formed in the sheet center was much stronger than that in the surface. This observation was attributed to the more frequent formation of orientation colonies in the sheet center when compared to the sheet surface.     

Effect of intermediate heat treatment on microstructure and texture evolution of continuous cast Al-Mn-Mg alloy sheet

The microstructure and crystallographic texture evolution of continuous-cast, hot-rolled Al-Mn-Mg alloy sheet during cold rolling and subsequent annealing was investigated. All specimens cut from the as-received sheet were cold rolled and subsequently annealed, with some of these specimens receiving an intermediate heat treatment (IHT) prior to cold rolling. It was found that the degree of deformation and temperature of the annealing had a significant effect on the final grain size and texture of the sheet specimens, respectively. Furthermore, the IHT altered the development of the microstructure and texture of the final sheet specimens when compared to similarly produced specimens without it. For the sheet specimens without the IHT, a severely elongated grain structure was found in which the texture was dominated by a strong P orientation {011}<566>, despite the fact that the specimen was completely recrystallized. In contrast, specimens receiving the same cold rolling and annealing conditions but with the IHT had an equiaxed grain structure with a sharp Cube orientation {001}<100>. Counterbalancing the deformation textures from rolling with a sharp Cube orientation from annealing may lead to reduced earing behavior of CC Al-Mn-Mg alloy sheet products during deep drawing applications.     

Texture Evolution of Columnar Grains in Electrical Steel During Hot Rolling

Columnar grains in cast slabs of electrical steel show strong anisotropy in grain orientation and morphology and thus influence the subsequent microstructure and texture after hot rolling significantly. The texture evolution of hot rolled sheets containing initial columnar grains with their <100> directions approximately parallel to the rolling direction (RD), transverse direction (TD) and normal direction (ND) of the hot rolled sheets was investigated by using EBSD technique. The results indicated that, whatever the initial texture of the columnar grains was, typical Goss, brass-type and copper-type shear texture component could develop in shear-deformed surface region. The copper-type texture formed under the maximum shearing force with the fine, sheared or dynamically recrystallized grains, and Goss grains were mainly elongated and deformed grains, while brass grains behaved between them. Additionally, the rotating relationship of the three types of shear textures was different due to the restriction of grain boundaries. In homogenously deformed center region, the RD sample contained more {112} <110> grains, and TD sample was covered by {100} textures such as {100}<011> and {100}<021> with coarse grains, while the ND sample developed many {100}<011> grains which were attributed to more {100} grains in the initial sample. Remarkable texture transition occurred on both sides of grain boundaries when {110} grains were adjacent to α-fiber texture grains. It was found that significant texture gradient and preferred distribution of rotating axis existed in the soft orientation grains on the α-fiber when the grains neighbored hard grains on γ-fiber.     

Effect of Hot Band Annealing Processes on Microstructure,Texture and r-Value of Ferritic Stainless Steel

The effect of hot band annealing processes,namely simulating batch annealing and continuous annealing,on microstructure,texture,grain boundary character and r-value of ferritic stainless steel was investigated.The hot band displayed a highly elongated ribbon-like structure and a pronounced deformation texture.The fully recrystallized grains were observed after continuous annealing while the "typical" hot rolled structure was remained after batch annealing.Also,the α-fibre texture formed during hot rolling almost disappeared after continuous annealing and a weak γ-fibre texture was obtained.By contract,the α-fibre texture remained very stable after batch annealing.After cold rolling and recrystallization annealing,the favorable γ-fibre texture was achieved in the continuous annealed steel.Instead of forming the γ-fibre texture,the recrystallization texture was notably shifted toward {223}582 in the batch annealed steel.Finally,the improvement in drawability with high r-value and low Δr-value were also displayed in sheet through the initial continuous annealing process.