冷轧微碳深冲钢板的非{111}织构及其形成原因和对策

结合实际生产和实验室实验,介绍了试制的冷轧微碳深冲钢板中出现的远离常规的非{111}织构的情况。分析了这种非{111}织构的特征及其对钢板塑性应变比的影响,并研究了非{111}织构的工序演变过程及冷轧织构的形成特点,在此基础上进一步分析了非{111}织构的热轧原因,并研究了冷轧压下率和罩式退火升温速度对非{111}织构的影响。最后,依据非{111}织构的形成特点和{111}织构的产生条件提出了控制冷轧微碳深冲钢板织构的对策。     

热轧钢板固溶元素析出对冷轧织构的影响

将热轧钢板在不同温度保温处理析出固溶元素后,在实验室四辊冷轧机上进行轧制,通过透射电镜观察（TEM）和三维取向分析（ODF）,研究了热轧钢板中固溶元素的析出对冷轧织构的影响。结果表明：热轧钢板经700℃和1000℃保温处理后,其冷轧织构仍保持了非{111}织构特征;热轧板中固溶元素析出为二相粒子,有利于冷轧织构中{111}组分的增强,进而具有抑制非{111}织构组分的作用。     

冷轧压下率和罩式退火升温速度对微碳深冲钢板织构的影响

在四辊冷轧试验机和Gleeble-1500试验机上进行了热轧微碳钢板的冷轧和退火试验。用D/max-RC衍射仪测量了试样的1／4层织构，并用Roe软件进行了ODF分析。研究表明，所研究的热轧微碳深冲板压下率约为75％，退火升温速度为20－40℃/h时，试样为{111}织构特征；压下率较大（80％）时，退火织构为较弱的{111}组分。无论{111}织构还是非{111}织构都是在形核阶段开始形成，在晶粒长大优先长大，受到定向形核和选择生长双重机制的作用。     

冷轧压下率对连续退火Ti-IF钢组织和织构的影响

以工业生产的Ti-IF钢热轧板为研究材料,结合连续热镀锌线的工艺特点,采用实验室冷轧、盐浴退火方法和金相、X射线织构测试等分析手段,研究了冷轧压下率对组织和织构的影响规律。试验结果表明,随着冷轧压下率从60%提高到90%,冷轧态α取向线上的取向密度不断增强,而且主要形成了{223}110和{114}110织构,γ线上的{111}110和{111}112织构亦有所增强;退火后铁素体晶粒尺寸从9.0级细化到10.5级;试验钢退火后仍具有较强的{223}110和{114}110织构,且随着冷轧压下率的提高,{111}织构有增强的趋势。要获得强的{111}织构,冷轧压下率需在80%以上。     

冷轧过程中IF钢的织构演变

以铁素体区热轧低温卷取的Ti-IF钢为研究对象,选择13%~75%的冷轧压下率,观察在冷轧过程中织构的演变。研究表明,压下率为46%是一个转折点,冷轧压下率较小(13%~35%)时,表面上取向变化为{110}001→{554}225→{111}112→{111}110→{223}110,{114}110转向{001}110;压下率达到46%时,{111}织构消失;继续增加压下率,{111}织构再次出现,并随压下率增加而增强。随着冷轧压下率的增加,中心面上的{111}织构强度先增加,压下率达到46%后又降低,最强组分先由{001}110向{223}110转动;压下率达46%时,又向反方向转动。     

冷轧压下率对IF钢织构的影响

采用CSP工艺生产厚度为3.5 mm的IF热轧钢板,分析了冷轧压下率对冷轧织构、退火织构、各组分含量、{111}/{100}比值的影响。结果表明,采用71.4%的冷轧压下率生产的IF钢{111}织构占比最大,最有利于冲压性能的提高。     

冷轧压下率对无抑制剂取向硅钢初次再结晶退火的影响

对无抑制剂取向硅钢不同压下率下初次再结晶退火后的显微组织、宏观织构和微观织构进行了研究.结果表明,冷轧板织构主要为α取向线{001}＜110＞、{112}＜110＞和{111}＜110＞织构以及γ取向线{111}＜110＞织构.初次再结晶退火后,α取向线织构减弱,织构主要为γ取向线{111}＜112＞织构.随冷轧压下率的增加,冷轧和初次再结晶织构强度增加.当压下率为88％时,初次再结晶退火后 Goss 织构和{111}＜112＞织构强度最高,最有利于发生二次再结晶.EBSD 分析显示,Goss 取向晶粒大多与{111}＜112＞取向晶粒相邻.提高冷轧压下率,Goss取向晶粒和{111}＜112＞取向晶粒都增加,Goss 取向晶粒偏离理想取向角度减少.     

冷轧压下率对IF钢组织织构和性能的影响

以工业生产的热轧板为原料,研究了冷轧压下率对罩式退火后的Ti-IF钢和Ti＋Nb-IF钢组织织构和性能的影响。研究结果表明,经罩式退火后,两种IF钢再结晶基本完成,晶粒呈饼状;随着压下率的增加,晶粒尺寸变小;应变硬化指数n90°值逐渐降低。Ti＋Nb-IF钢塑性应变比r90°值在碳含量较高、压下率为70%,或碳含量较低、压下率为80%时,达到最大值;Ti-IF钢塑性应变比r90°值在压下率70%时,达到最大值。随着冷轧压下率的加大,IF钢的织构也越强,并且织构从较低冷轧压下率时的{223}〈110〉、{114}〈110〉和{111}织构变为较高压下率时的{223}〈110〉、{111}〈110〉和{114}〈110〉织构,织构类型有向{111}织构靠拢的趋势。     

冷轧压下率对薄规格取向硅钢冷轧和退火织构的影响

实验采用不同厚度的低温取向硅钢热轧板冷轧至0.18 mm。通过XRD分析冷轧板表面和中心层的织构,通过EBSD分析了脱碳板截面的织构。结果表明,冷轧样品表层和中心层,随着压下率增大,{111}面织构总含量有所减少,{100}面织构总含量有所增多;脱碳样品中{111}面织构明显增多,尤其是{111}〈112〉织构组分,{100}面织构明显减少,尤其是{100}〈011〉织构组分,{411}〈148〉织构组分也明显增多;脱碳样品中,随着压下率增大,晶粒尺寸逐渐减小。不利于二次再结晶发展的织构随着压下率的增大明显增加,同时有利的CSL晶界随着压下率的增加会稍有减少。     

Ti-IF钢析出物行为与织构研究

研究了Ti-IF无间隙原子钢热轧、冷轧、退火(700、800℃)过程的析出行为与织构.该钢在700℃退火过程中形成的FeTiP析出颗粒降低了{111}织构强度,导致r值降低;而800℃退火过程中形成的析出颗粒提高{111}织构强度,强的{111}织构强度增加r值.700℃退火析出物主要为FeTiP,800℃退火析出物主要为Ti4C2S2;由于形成Ti4C2S2析出物,使C在再结晶退火过程中很容易从固溶体中析出而形成{111}织构,促使800 ℃退火时获得良好的成型性.     

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.     

退火工艺及压下率对超低碳CSP冷轧薄板织构的影响

在实验室用电阻炉模拟了包钢CSP工艺生产的以62.0%和71.4%压下率冷轧的1.9 mm和1.0 mmCD01钢(0.047%C)和SPCC钢(0.041%C)冷轧板的700℃罩式退火工艺。结果表明,冷轧板退火后主要以{111}〈110〉和{111}〈112〉织构为主;71.4%压下率冷轧板快速升温退火后{112}〈110〉取向密度最大,且大角度晶界所占比例较大,织构密度较大,织构主要集中在γ取向线附近。     

Influence of hot-rolling conditions on texture development in deep-drawing steels

As the textures of deep-drawing sheet steels are important for certain material properties the purpose of this paper was to take a closer look at the hot-rolling, cold-rolling and annealing textures of different deep-drawing steel grades. Several Al-killed mild steels and vacuum-degassed Ti-IF steels have been hot rolled in the mill varying the finishing temperature (FT). After coiling, cold rolling and short-time annealing the textures at different thickness levels have been measured by means of (110)-pole figures and orientation distribution functions (ODFs). For both steel groups the textures at the surface of the hot strip exhibit a more or less pronounced shear type character. Towards the mid-thickness level (with lower FT more clearly) typical (cold-) rolling textures exist characterized by a strong {001}<110> orientation and in the Ti-IF steels additionally by a significant {112}<110> orientation density. In the case of high FT cold rolling and annealing lead to favourable {111}-textures where deep-drawing application is concerned. For the Al-killed steels lowering FT results in diffuse recrystallization textures whereas in the Ti-IF steels a sharp texture with near {223}<582> orientations can be observed which have not been known for these steels before. The results prove that the hot strip textures can be of great importance for the resulting annealing textures and the according material properties.     

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 α-fiber, of which {445}<110> component forms a high intensity peak at coiling temperature of 750 ℃. 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 α-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.     

微碳深冲钢板非{111}织构的定量化表征

对生产试制的一批微碳深冲钢板制成织构试样,在D/max-RC衍射仪上采集测试面的不完整极图,然后由Roe系统ODF织构分析软件绘制ODF图。分析发现,这批钢板的织构均不是典型的{111}织构特征,而是独特的非{111}织构特征。该非{111}织构在ODF图中主要体现为两条螺旋取向线和3条直取向线,对此织构特征进行了分析和定量化表征。     

B对含P高强度无间隙原子钢{111}面织构的影响

借助光学显微镜(OM)、X射线衍射(XRD)技术及电子背散射衍射(EBSD)技术,分析了2种含P高强度无间隙原子(IF)钢的热轧组织和热轧、冷轧及退火织构,结果表明:不含B与含B的高强IF钢热轧后,均得到多边形铁素体,但不含B热轧板晶粒尺寸较大。2种钢热轧板织构均比较散漫,γ纤维织构强度较弱,而不含B的IF钢经过80%大变形量冷轧以后,获得强的γ纤维织构,{111}面织构的体积分数达到41.41%,而含B的IF钢冷轧后{111}面织构的体积分数为33.83%。含B的IF钢冷轧后{112}110织构组分的体积分数比不含B的IF钢要高。2种实验钢在810℃退火60~180s以后,{111}面织构强度进一步增强,不含B的IF钢退火120s后{111}面织构的体积分数最大达到72.8%,而含B的IF钢退火120s后{111}面织构的体积分数最大达到66.6%。     

Development of recrystallization textures in 0.08%C steel

The present work investigates the effect of cold deformation on the evolution of microstructure and textures during recrystallization in 0.08%C steel. The cold rolling texture consists of partial α-fiber (RD//〈110〉) and complete γ-fiber (ND//〈111〉) along with Goss ({110}〈001〉) and cube ({100}〈100〉}) texture components. The sharpness of α-fiber, γ-fiber and cube component increases with the increase in rolling reduction from 70 to 85% while that of Goss component decreases. After recrystallization (750 and 800°C), the textures were composed of α and γ-fiber along with significant Goss components. The strength of γ-fiber decreases after annealing. The presence of Goss component in recrystallization textures is attributed to preferential nucleation in {111}〈112〉 type deformed grains.