Crystallite orientation distribution analysis of the cold rolled and recrystallization textures in low-carbon steels

The development of the cold rolled and recrystallization textures in low-carbon rimmed and killed steels was investigated using the crystallite orientation distribution analyses. With increasing cold reduction low-carbon steels exhibit the simultaneous development of a partial <110> fiber axis parallel to the rolling direction and a <111> fiber axis parallel to the normal direction. The strongest individual texture component rotates from a {111} <110> at 60 pct cold reduction towards a {112} <110> at 80 pct. During the early stages of recrystallization the (110) and <111> fiber textures decrease in both the rimmed and killed steels. However, the decrease in the <111> fiber texture is greater in the rimmed than in the killed steel. With further recrystallization and grain growth this <111> fiber texture increases in both steels but to a greater extent in the killed steel. The strongest individual texture component after complete recrystallization is the {111} <110>, being ∼5.5 and ∼3.0 times random in the killed and rimmed steel, respectively.     

Textures induced by tension and deep drawing in low carbon and extra low carbon steel sheets

The texture evolution induced by tensile deformation and by deep drawing was investigated. For this purpose, the textures of 3 types of steel (rimmed, Al-killed drawing quality, and interstitial free) were measured and analyzed using the series expansion method. The results indicate that the initial texture changes drastically after a few percent of plastic strain and evolves towards a single orientation for which the <110> direction is aligned with the tensile or drawing axis. The distinct earing behaviors of the AKDQ and IF steels (i.e. 4-eared for the Al-killed and 6-eared for the interstitial free) are interpreted in terms of differences in the sharpness and homogeneity of their ND-fibres and in the influence of the {332} <110> and the partial {223} fibre.     

普通取向硅钢轧制过程中组织和织构的演变

借助电子背散射衍射(EBSD)及ZEISS-200MAT金相显微镜对某钢厂普通取向硅钢(CGO)进行研究,研究结果表明:热轧板组织、织构沿板厚方向存在明显的不均匀性,在热轧板表层及次表层发生再结晶,同时存在强度较高的Goss织构,中心层存在较强的{001}110变形织构。冷轧组织均呈纤维状条带组织,一次冷轧后,热轧板中的Goss织构消失,织构主要为α、γ织构,经中间脱碳退火后,α、γ织构强度减弱,并出现一定强度的Goss织构和利于Goss织构发展的{554}225、{332}113等织构,经二次冷轧后,二次冷轧织构类型与一次冷轧织构一致,但织构强度不同。     

CSP工艺0.04C钢热轧板冷轧-退火织构的演变

通过实验室4辊轧机和保护气氛管式退火炉，对0．04C钢CSP工艺生产的3姗热轧板进行冷轧（至0．8mm）和退火试验，并用蚀坑法对退火试样进行织构分析；同时对包钢薄板厂CSP3mm热轧板冷轧的1．2姗板卷退火试样进行了X-射线检测。结果表明，1．2mm SPCC冷轧板退火织构表层有较弱的{111}织构组分，中心层没有发现有利于提高钢的深冲性能的{111}织构。1．2mm板卷退火试样{111}／{100}取向密度比为2．0～3．0，与实验室蚀坑法的试验结果一致。     

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.     

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.     

Textures and Properties of Hot Rolled High Strength Ti-IF Steels

The texture evolution in a high strength Ti-IF steel during the processing of hot rolling, cold rolling, and annealing is studied. For comparison, both ferrite rolling and austenite rolling are employed. It is found that the texture type is the. same after ferrite rolling and austenite rolling, but the texture intensity is much higher in the ferrite rolled sample. Furthermore, texture characteristics at the surface are absolutely different from those at the mid sec tion in both ferrite rolled and austenite rolled samples, as well as under the cold rolled and annealed conditions. The shear texture { 110 } 〈001 〉 disappears and orientation rotates along { 110 } 〈001 〉→ { 554 } 〈 225 〉→ { 111 } 〈 112 〉→{111}〈110〉→{223}〈110〉 during cold rolling. Compared to the austenite rolled sample, the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher.     

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%。     

冷轧压下率和再结晶退火温度对Ti-IF钢织构和成型性能的影响

采用背散射衍射技术(EBSD)研究了3.13 mm热轧板的冷轧压下量(65%~80%)和再结晶退火温度(660~780℃)对0.64~1.10 mm Ti-IF钢冷轧板(/%:0.02C、0.01Si、0.10Mn、0.013P、0.011S、0.064 Ti、0.028Al、0.002 0N)的织构和成型性能应变硬化指数(n)、塑性应变比(r)的影响。结果表明,Ti-IF钢冷轧板在冷轧压下率为75%时{111}织构含量最大,成型性能最佳;在740℃以下再结晶退火时材料{111}<110>织构含量高,高于740℃时材料{111}<112>织构含量高;在660~780℃再结晶退火随温度增高,材料{111}织构含量增加,成型性能提高。     

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。     

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.     

冷轧压下率对DQ级深冲带钢组织和性能的影响

研究了60%～80%冷轧压下率对3.5 mm CSP热轧板轧制的1.4～0.7 mm冷轧深冲带钢力学性能、组织和织构的影响。结果表明,随冷轧压下率由60%提高至80%,冷轧带钢的再结晶开始温度由560℃降至520℃,成品带钢组织细化;当冷轧压下率为74.3%时,成品DQ级带钢的深冲性能最佳。随冷轧压下率提高,成品深冲带钢△r值逐渐减小,这与成品带钢中{112}〈110〉织构取向函数值f(g)升高有关。     

Precipitation Behavior and Textural Evolution of Cold-Rolled High Strength Deep Drawing Dual-Phase Steels

Low-carbon Cr-Mo micro-alloyed deep drawing dual-phase steels were designed in laboratory. As the microstructure and texture evolution in hot-rolled strips and annealed sheets were investigated using SEM, TEM and XRD technologies, the attribution of solute Mo and MoC particles to DP sheets' drawing capacity was investigated. The precipitation thermodynamics were also calculated by Thermo-calc software. Results show that the precipitates in hot-rolled strips mainly are MoC, AlN and MnS, and with the increase of Mo-addition, finer and denser MoC particles precipitated in matrix and along grain boundaries of ferrite more easily. Weak textures are shown in the hot-rolled strips, and {112}<110> and {223}<110> components tend to be stable in subsequent cold rolling process. During annealing, on one hand, the development of <111> // ND texture is suppressed because finer MoC particles prevent the grain boundary migration. On the other hand, unfavorable texture {001}<110> significantly reduces with Mo increasing, which is attributed to that part of solution C in matrix has been fixed during recrystallization. In addition, the addition of Mo can enhance hardenability strongly and MoC easily re-dissolve at high temperature, which is favor to form martensite in dual-phase steel.     

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。     

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.     

Microstructural Evolution and Crystallographic Texture Formation of Cold Rolled Austenitic Fe‐30Mn‐3Al‐3Si TWIP‐Steel

The microstructural and texture evolution of cold rolled low stacking fault energy fcc Fe‐30Mn‐3Al‐3Si alloy was investigated as a function of the cold rolling strain. The alloy was melted and cast in a vacuum induction furnace, hot rolled and annealed before being cold rolled at three different strains: ε = 0.035, e = 0.2 and ε = 1.2. During the cold rolling process different deformation mechanisms became active depending on the strain. At low strain levels, ε = 0.035 and ε = 0.2, slip traces were observed whereas at higher strains shear bands appeared. The brass orientation {110}<112> spreading towards the Goss orientation {110}<001> was dominant at every strain level. The intensity of these texture components increased with increasing rolling strain. The increase of the brass component was more pronounced when e varied from 0.035 to 0.2, whereas the increase of the Goss component was more pronounced when ε varied from 0.2 to 1.2. Additional texture components developed: the E orientation {111}<110> lying on the γ‐fibre and the S orientation {123}<634> lying on the ß‐fibre. This evolution is comparable to other low SFE fcc materials exhibiting the brass‐type texture.     

铁素体不锈钢铸轧薄带凝固组织对冷轧退火带晶粒簇的影响

 研究了Cr17铁素体不锈钢铸轧薄带凝固组织对其冷轧退火带晶粒簇、成形性和皱折特性的影响。利用电子背散射衍射技术对Cr17铁素体不锈钢铸轧薄带及相应的冷轧退火带进行了显微织构分析。结果表明：①Cr17铁素体不锈钢铸轧薄带冷轧退火带的晶粒簇依赖于初始铸轧薄带的凝固组织类型;②柱状晶组织的铸轧薄带具有显著的{001}∥ND晶体取向特征,而等轴晶组织的铸轧薄带晶体取向随机、分散;③等轴晶组织铸轧薄带比柱状晶组织铸轧薄带的冷轧退火带具有更少的{001}<110>晶粒簇和更多的{111}<112>、{111}<110>晶粒簇;④铸轧薄带的等轴晶组织比柱状晶组织有利于提高冷轧退火带的成形和抗皱性能。     

摩擦对IF钢铁素体区热轧和退火织构的影响

采用X射线衍射仪分析IF钢铁素体区热轧织构以及退火织构的演化,在实验室热轧机上进行了IF钢的铁素体区热轧,研究了摩擦对IF钢铁素体区热轧、退火织构的影响。结果表明：无润滑轧制时,钢板表层形成强高斯织构组分{110}〈001〉,弱γ纤维织构,导致再结晶织构中高斯组分强度高,γ纤维织构强度低;润滑轧制时,钢板表层高斯织构组分强度降低,{100}〈011〉、γ纤维织构强度提高,退火后γ纤维织构强度提高。钢板中心受摩擦作用影响较小,轧制过程中发展为较强的α和γ纤维织构,退火后γ纤维织构成为主要织构组分。