成品厚度对高牌号无取向电工钢组织、织构和磁性能的影响

文中采用某企业高牌号无取向电工钢常化板，经过不同冷轧压下率一次性冷轧后高温退火，获得了不同厚度的成品板。利用EBSD等手段研究了成品厚度对组织、织构和磁性能的影响。研究结果表明，随着成品厚度减薄，总铁损不断降低，尤其在高频下降低更为明显，这是因为高频下涡流损耗占主导，同时涡流损耗占总铁损的比重也随着成品厚度减薄而不断降低。平均晶粒尺寸随着成品厚度减薄略有减小，组织均匀性变差，但厚度减薄导致的涡流损耗降低仍占据着主导作用，因此总的铁芯损耗出现下降。随着冷轧压下率的增加，γ织构和α*织构不断增强，λ织构呈减弱的趋势；有利织构与有害织构体积分数的比值不断下降，导致磁感应强度B₅₀也随之降低。      

Hot direct rolling in ferrite region in extra low-carbon steel

For the first time, hot direct rolling was applied in ferrite region in the mill and the resulting quality of the cold rolled and annealed sheet steel was as good as that hot direct rolled in austenite region with respect to microstructure and mechanical properties. In case of ferrite phase rolling, microstructure of the hot strip reveals abnormal grains and deformation bands in the grains, and elongation and r value are not so good as those rolled in the austenite phase. However, these abnormal grains left no traces and appeared to be equiaxed grains like the austenite phase rolled microstructure after 75 % cold rolling and continuous annealing at 830°C. This is attributed to the deformation bands which provide nucleation sites for recrystallization during annealing so that recrystallization occurs uniformly in the matrix. (111) texture was well developed and r value thus appeared high.     

0.20 mm薄规格取向硅钢的开发及关键工艺探讨

为开发磁性能优良的0.20 mm薄规格取向硅钢,对该取向硅钢的组织特征,不同冷轧压下率和高温退火气氛对磁性能的影响进行了研究。结果表明：所获得的0.20 mm薄规格取向硅钢成品组织二次再结晶完全,铁损（P1.7/50）为0.89 W/kg,磁感（J800）为1.906 T;热轧和常化1/8层的主要织构组分为Goss织构,冷轧织构为较强的{001}〈110〉,退火织构主要为{411}〈148〉,脱碳晶粒尺寸约为21.17 μm,Goss晶粒极少;0.20 mm薄规格取向硅钢合适的冷轧压下率为91.3 %;高温退火升温段合适的气氛为75% N2。     

终轧温度对超纯铁素体不锈钢组织、织构及成形性能的影响

研究了终轧温度对铌、钛双稳定化超纯Cr17铁素体不锈钢的组织演变、织构演变及成形性能的影响。研究结果表明,降低终轧温度能有效细化、均匀化热轧及退火组织。降低终轧温度能增强冷轧退火板的γ纤维再结晶织构、减轻偏离{111}121组分的程度。降低终轧温度是提高r值、降低Δr值、改善冷轧退火板成形性能的有效手段。     

Structure and Texture Formation During Single and Double Cold Rolling and Annealing Processes for Nb+Ti Added Interstitial-Free Steels

 The structure and texture formation for single cold rolling (SCR) with annealing and double cold rolling (DCR) with annealing were investigated based on optical microscope and X-ray diffraction (XRD) with a Nb+Ti bearing interstitial free (IF) steel. The results indicated that DCR recrystallization grain was smaller than that of SCR sample and double cold rolling process resulted in better mechanical properties than those resulted from single cold rolling process with the same total reduction conducted. The plastic strain ratio increases from 2. 23 for single cold rolling process to 3. 2 for double rolling process. The fish-bone structure was observed in all SCR and DCR samples. DCR annealed sample is made up of equiaxed grains of almost uniform size, whereas SCR annealed sample shows a duplex grain structure, consisting of both large and small-sized grains. (Ti+Nb)C and Fe(Ti+Nb)P type precipitates were very rarely observed in SCR annealed and DCR annealed steels. The intensity of {111}∥ND for the DCR annealing was higher than that for SCR annealing.     

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Effect of double cold rolling on magnetic properties and microstructure of 3.98%Si-0.71%Al non-oriented silicon Steel Sheets cast by twin-roll thin strip casting process were investigated. The results show that the structure of the thin strip is equiaxed crystal, the recrystallization is complete and normalizing has lesser effect on microstructure. Using both cold rolled and double cold rolled process, the microstructure is equiaxed grain after final annealing. The average grain size of annealed sheet in double cold rolled specimen was smaller than single stage cold rolled sheet. Double cold rolling process is helpful for iron loss and magnetic flux density.     

热轧工艺对无取向硅钢组织结构和磁性能的影响

研究了热轧加热温度、终轧温度、卷取温度对w(Si)=1.50%无取向硅钢晶粒组织、织构演变、铁损和磁感的影响.结果表明,随着铸坯加热温度的提高,冷轧无取向硅钢成品晶粒尺寸减小,有利织构组分增加,铁损增加,磁感提高.提高终轧温度可以促进热轧板的再结晶,增加成品中有利织构组分,降低铁损,提高磁感.卷取温度对成品的晶粒大小没有显著的影响,但提高卷取温度能增加成品中有利织构组分,降低铁损,提高磁感.     

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.     

一种高Nb-IF冷轧薄板钢的组织性能及织构

 采用拉伸试验、金相、ODF织构分析及电子背散射衍射(EBSD)技术研究了一种冷轧高Nb-IF钢和传统Nb+Ti-IF钢在不同退火温度下的组织性能、织构及晶界特征。结果表明：与传统Nb+Ti-IF钢相比,该新型高Nb-IF钢由于添加了质量分数为60×10-6的碳和010%的铌,其再结晶温度和再结晶完成温度均大幅度提高;新型高Nb-IF钢具有晶粒细小、组织均匀性良好的组织和γ取向织构发展充分且强点密度高的织构,能够获得强度高、伸长率高和r值高的优异的综合性能。EBSD分析结果表明,该新型高Nb-IF钢中小角度晶界和低指数重位点阵(ΣCSL)晶界含量较多,这也是试验钢获得优良成形性能的原因之一。     

Effect of Rolling Reduction on the P$$ \left\{ {011} \right\}\left\langle {455} \right\rangle $$ Recrystallization Texture in a Supersaturated Al-Mn-Mg Alloy

The hot band of a continuous cast (CC) Al-Mn-Mg alloy was cold rolled to different reductions ranging from 0 to 90 pct and then annealed at 482 °C for 3 hours. The effect of rolling reduction on the P recrystallization texture was investigated by X-ray diffraction. The results show that the recrystallization texture of the hot band is characterized by weak P orientation and 22.5 deg normal direction (ND) rotated cube orientation. The strength of the P texture increases with increasing rolling reduction. After 90 pct cold rolling, the recrystallization texture of the cold-rolled sheet is dominated by a strong P component.     

Recrystallization kinetics of an austenitic high-manganese steel subjected to severe plastic deformation

The evolution of the microstructure and the properties of an austenitic high-manganese steel subjected to severe deformation by cold rolling and subsequent recrystallization annealing is investigated. Cold rolling is accompanied by mechanical structural twinning and shear banding. The microhardness and microstructural analysis of annealed samples are used to study the recrystallization kinetics of the high-manganese steel. It is shown that large plastic deformation and subsequent annealing result in rapid development of recrystallization processes and the formation of an ultrafine-grained structure. A completely recrystallized structure with an average grain size of 0.64 μm forms after 30-min annealing at a temperature of 550°C. No significant structural changes are observed when the annealing time increases to 18 h, which indicates stability of the recrystallized microstructure. The steel cold rolled to 90% and annealed at 550°C for 30 min demonstrates very high strength properties: the yield strength and the tensile strength achieve 650 and 850MPa, respectively. The dependence of the strength properties of the steel on the grain size formed after rolling and recrystallization annealing is described by the Hall–Petch relation.     

Effect of Cold Rolling Reduction Ratio on Microstructure and Magnetic Properties of Secondary Cold-Rolled High-Grade Nonoriented Silicon Steel

Trial production of 0.25 mm-thick thin-gauge high-grade nonoriented silicon steel with a Si content of 3.5% by the secondary cold rolling process is studied. The recrystallization microstructure and magnetic properties are systematically studied by the microstructure, texture evolution, and the effect of two-stage cold rolling reduction ratios (37.5–70.5%) during the whole process. The results show that the magnetic induction intensity B₅₀₀₀ first increases and then decreases; the iron loss first decreases and then increases at the frequencies of 50 and 400 Hz with the reduction of the cold rolling reduction rate in the second stage. The cubic and Goss texture of the finished annealed sheet has the highest strength when the reduction ratio of the second stage cold rolling is 58.3%. The highest magnetic induction intensity, B₅₀₀₀ = 1.671 T. Lowest iron loss, P_1.0/50 = 0.83 W kg⁻¹, P_1.5/50 = 1.98 W kg⁻¹, and P_1.0/400 = 11.94 W kg⁻¹, respectively.     

Effect of thermomechanical treatment on the evolution of rolling and recrystallization textures in twin-belt cast AA5754 aluminum alloy

The relative importance of shear banding, particles, and grain size in determining the rolling and recrystallization textures of a twin-belt strip cast AA5754 aluminum alloy has been investigated. Various thermomechanical processing schedules have been employed that incorporate homogenization, warm and cold rolling, and intermediate anneals in various combinations prior to a final recrystallization treatment. Despite its inherent susceptibility, the alloy undergoes limited shear banding during rolling and displays a large random component of the deformation texture. The effect is most pronounced in the as-cast alloy subjected to cold rolling without any prior or intermediate heat treatments. This can be attributed to the denser distribution of particles, a greater scattering of the initial texture, and a relatively small grain size. Homogenizing prior to cold rolling promotes more extensive shear banding and accelerates the development of a strong rolling texture. A grain shape effect results in a prominent S component in the rolling texture at higher reductions, irrespective of the processing history of the material. In the heavily rolled as-cast alloy, the recrystallization texture is dominated by Cube and R components indicating the prevalence of oriented growth processes. However, homogenizing the as-cast alloy prior to cold rolling imparts a characteristic recrystallization texture with strong CH component, which is most likely due to selected growth of grains following particle-stimulated nucleation.     

在动态热处理条件下对取向电工钢二次再结晶的研究

对应用动态加热进行短时温度退火的取向电工钢进行了二次再结晶研究。所进行研究的实验用取向电工钢是经过终冷轧和后续罩式退火后的一条工业化生产线生产的。研究结果表明,运用短时热处理条件可引起研究钢完全的异常晶粒长大。在实验室处理的材料的织构和金相组织与工业化生产的经过终退火而获得的相同的取向电工钢类似。但是,在实验室处理的取向电工钢的二次再结晶的矩阵中可观测到"寄生"晶粒。从磁性观点看,这些"寄生"晶粒含有不理想的{111}取向织构。     

热带退火对00Cr17Ti薄板成形性能的影响

 通过对00Cr17Ti经热带退火、不经热带退火两种工艺的对比试验,在分析显微组织、织构、值和ΔR值的基础上,研究了热带退火对00Cr17Ti薄板成形性能的影响。研究结果表明：与不经热带退火相比,经热带退火能使00Cr17Ti薄板的值提高约0.2,但是,ΔR值会增大约0.7。这是由两种工艺的成品薄板在显微组织、织构上的差异造成的。与不经热带退火相比,经热带退火的成品薄板具有更大的晶粒尺寸、更加均匀的组织以及更强的{111}再结晶织构,这使值提高,但是,其{111} γ取向线上各织构组分强度的非常不一致却导致ΔR值明显偏大。     

Effect of two step cold rolling — continuous annealing on micro-structures,textures and mechanical properties in IF and IF-HS steel sheets

In the present work, the objectives were to investigate the type of microstructure and texture that developed after two step cold rolling — continuous annealing. Further, an attempt has been made to correlate the microstructure and texture with mechanical properties. Interstitial free (IF) and interstitial free — high strength (IF-HS) steel sheets which contain almost γ-fiber textures, were subjected to two step cold rolling for different percentage of reduction and further continuously annealed. It was observed that cold rolling strengthened the region of (223)[1$ \bar 1 $ \bar 1 0] and 335[1$ \bar 1 $ \bar 1 0] orientations of α-fiber as well as γ-fiber. After continuous annealing, cold rolled γ-fiber as well as (223)[1$ \bar 1 $ \bar 1 0] and 335[1$ \bar 1 $ \bar 1 0] orientations transformed to extremely strong new γ-fiber. It was found that at two steps 80% cold rolling -continuous annealing, drawability of IF steel sheet was exceptionally high i.e. around 3.15, whereas for IF-HS steel sheets, it was around 2.7. Although, two steps cold rolling -continuous annealing enhanced percentage elongation and stretchability exceptionally, but it reduced the yield strength substantially. However, ultimate tensile strength was hardly affected. In addition, it is also observed that two steps cold rolling — continuous annealing developed uniform grain size in both the grades of steel sheets.     

Fe-6.5%Si钢极薄带的试制

 为了研究Fe-6.5%Si钢极薄带的制备工艺,并获得良好的产品磁性能,以薄带铸轧试验机制备的6.5%Si钢铸带为原料,分别采用一次温轧法、二次温轧法和基于应变诱导无序(DID)原理的高硅钢室温冷轧3种工艺制备出厚度为0.1 mm的Fe-6.5%Si钢。分析结果显示,一次温轧法退火后以高强度γ织构为主,由于压下率达到90%,形变储能高,晶粒尺寸最大,铁损最低,同时磁感也最低;二次温轧的退火板除了γ织构外,还有较强的η织构,故其磁感值高于一次温轧法,该方法得到的6.5%Si钢薄带综合磁性能最优,但生产成本高,效率低;基于DID原理,对6.5%Si钢热轧板在温度为300～450 ℃、压下率为45%～65%的条件下进行温轧,实现了6.5%Si钢软化,随后可将6.5%Si钢室温冷轧至0.1 mm,此时温轧板和冷轧板内部有序相消失,基体变成无序态;室温冷轧板退火后晶粒更细,铁损略有升高。此外,室温冷轧可促进{111}<112>形变晶粒在冷轧剪切带中形核形成有利织构,因此磁感值得到更大提升;采用DID原理进行室温冷轧,效率较高,后续可通过优化退火工艺使其进一步降低铁损,该方法为薄带铸轧工艺批量生产磁性能优异的6.5%Si钢极薄带提供技术参考。     

高硅钢近柱状晶初始组织的形变、再结晶行为及磁性能

采用电子背散射衍射技术对高硅钢近柱状晶初始组织直接热轧、温轧、冷轧和退火组织及织构演变进行分析,并测定相应退火板的磁性能.该实验条件下组织与织构演变规律体现了表层剪切细小组织和中心层粗大组织的竞争关系,其中中心层组织与原始立方取向相关或表现为α线取向.柱状晶的影响在最终退火组织中仍存在,少量立方取向区域可遗传到最终退火板中,虽然没有大量出现,仍有效削弱了{111}织构.形变退火过程中与原始立方取向线有关的晶粒尺寸普遍较大,有利于磁性.样品最终的磁感应强度低于文献报导的强{120}〈001〉或{100}〈021〉织构样品,但高于普通无取向高硅钢,且轧向和横向磁感应强度值差异小,所以柱状晶组织有利于无取向高硅钢的制备.     

Influence of transverse rolling on the

The influence of transverse rolling passes on the recrystallization texture was investigated in an effort to strengthen the {111} 〈uvw〉 type components and reduce the intensity of the {100} 〈0vw〉 components, improve the uniformity of the microstructure, and refine the grain size in high-purity tantalum plate. Tantalum, from three different ingot breakdown processes, received an additional 80 pct reduction in the transverse direction (perpendicular to the ingot centerline) in the processing schedule prior to final annealing. This work investigated the influence of the additional transverse rolling passes on the development of texture in the as-rolled tantalum and also in rolled plus annealed tantalum. After annealing, the tantalum plates had significantly strengthened {111} 〈uvw〉 crystallographic orientations, not only for the side forged process, but also for the upset and side forged tantalum. For tantalum processed by extrusion, the transverse rolling did not improve the final recrystallized texture.     

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.