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。     

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。     

常化温度对无取向电工钢组织和性能的影响

研究了常化温度对无取向电工钢组织及性能的影响。结果表明：常化板织构特征呈现织构梯度分布,中心层分布的主要是{100}〈021〉、{114}〈481〉、{112}〈421〉等α*取向晶粒,Goss和黄铜等取向晶粒则主要分布于表层及次表层区域。经5 min常化处理,常化温度由840 ℃提升到920 ℃,常化板晶粒尺寸增加,成品板晶粒尺寸增加,铁损值P1.5/50降低约0.106 W/kg,成品板中心层{100}取向晶粒体积分数增加,{111}和{112}取向晶粒体积分数降低,织构得以改善,磁感B5000升高约0.016 7 T。     

Deformation banding and copper-type rolling textures

It is shown by a crystallographic etching technique applicable to copper that deformation banding is an important deformation mode in f.c.c. metals and alloys. In a cold rolled coarse grain copper, deformation banding forms in a three dimensional manner dividing the grain on average into over 600 regions of different orientations. The influence of this important, but long ignored deformation mode, is studied by incorporating it into the Taylor model. The predicted textures from the new model are better than those from other existing models in mainly two respects. Firstly, the DB model predicts the co-existence of the three major f.c.c. rolling texture components, namely {123}〈634〉 or S component, >112>〈111〉 or C and >110>〈112〉 or {f}B{/f}. The existing models are deficient in that they predict either C and S or B, but not their co-existence. The second point is that textures predicted by the existing models are always too sharp compared to the experimental textures. The DB model predicts texture peaks with larger spread and hence more realistic texture sharpness. Another feature of the model is that only two independent slip systems, instead of five, are required to accomodate the imposed shape change, which agrees with experimental observation.     

Prediction of transformation textures in steels

Both discrete and continuous mathematical formalisms are employed to simulate texture evolution during the γ-to-α transformation in steels. Five f.c.c. NiCo alloys with different stacking fault energies (SFE's) were previously cold rolled to four reductions (40, 70, 90 and 95%) and their textures characterized by the orientation distribution function (ODF) method. The corresponding b.c.c. transformation textures are calculated from these experimental textures according to three different orientation relationships. The ODF's derived from the Bain relation are much sharper than the ones deduced from the Kurdjumov-Sachs (KS) or the Nishiyama-Wassermann (NW) relations, although the general trends of the three families of textures are similar. Ferrite textures determined on controlled rolled steels, heavily deformed in the unrecrystallized γ region, agree reasonably well with the b.c.c. textures calculated, according to the KS relationship, from the NiCo alloy with similar SFE. The two major ferrite components, namely the {332} 〈113〉 and {113} 〈110〉, are shown to originate from the three main orientations of cold rolled f.c.c. material, i.e. the {112} 〈111〉 (Cu), {110} 〈112〉 (Bs) and {123} 〈634〉 (S). Such ferrite formation from heavily deformed austenite follows the KS relationship without any variant selection. By contrast, the texture of martensite produced from deformed austenite involves significant amounts of selection.     

TC4钛合金轧板的织构对动态力学性能影响

利用分离式Hopkinson压杆试验装置,对具有不同织构特征的TC4合金试样进行动态压缩试验,分析织构特征对钛合金轧板各方向动态力学性能的影响。结果表明,900℃轧制板材的主织构为{1219}<12391>±30°RD,织构强度为10.557,在φ1=15°时出现峰值,有一定的织构分散,其中晶面{1219}平行板材的轧面,与基面{0001}夹角26.6°,晶向由〈1010〉向〈6 331〉方向漫散;950℃轧板的主织构为{1219}〈5321〉±20°RD,织构类型与900℃轧板相似,但织构强度为6.387,相对900℃轧板较弱,晶向由〈7341〉向〈4311〉方向漫散,在φ1=35°出现峰值;1050℃轧制板材的主织构为{12 19}〈1010〉,织构比较集中,织构强度为15.333,晶向〈101-0〉平行板材的轧向,与c轴为90°夹角。950℃轧制的TC4板材,织构强度较弱,其轧向(RD)、横向(TD)、法向(ND)的动态流变应力和动态均匀塑性应变差别不明显。900℃和1050℃轧制的TC4板材,由于织构强度较高,轧板存在明显的各向异性:TD方向的动态流变应力最高,ND次之,RD最低;RD方向的动态均匀塑性应变最大,ND次之,TD最小。     

Texture Development in the Ni47Ti44Nb9 Shape Memory Alloy During Successive Thermomechanical Processing and Its Effect on Shape Memory and Mechanical Properties

For improving the shape memory performance and mechanical properties of shape memory alloys (SMAs), crystallographic texture and second phase are generally induced in SMAs by suitable thermomechanical processing. For this purpose, the development of texture in the Ni₄₇Ti₄₄Nb₉ SMA during successive processing (e.g., hot forging, hot rolling, cold rolling, and heat treatment) and the effects of texture, grain size, and β-Nb particle precipitation on recoverable strains and tensile properties were studied. In the hot-forged and hot-rolled Ni₄₇Ti₄₄Nb₉ alloy rods, intense 〈111〉 fibers are formed, and water quenching from 873 K and 1123 K (600 °C and 850 °C) leads to the decrease in intensity of 〈111〉 fiber in the hot-rolled rod. When the hot-forged rod is hot-rolled into sheet, intense {001} and weak {123} fibers appear, but grain growth leads to the disappearance of {001} fiber and {110}〈001〉 becomes the strongest component. Cold-rolling deformation of the hot-rolled sheet promotes the development of γ-fiber and the convergence of {332} and {123} fibers to {233}〈110〉 and {123}〈121〉 components, respectively, and the intense component is turned into {111}〈110〉; in this case, the recoverable strain (ε _SRS) and tensile yield strength (σ _YS ) exhibit an anisotropy. When the quenching temperature is 1123 K (850 °C), some weaker components appear, the anisotropy of ε _SRS disappears, and the difference level in σ _YS along the rolling direction (RD) and transverse direction (TD) becomes smaller. Therefore, an appropriate heat-treatment temperature should be selected to maintain the deformation texture and also to obtain fine grains for different thermomechanical processing.     

Textures and plastic anisotropy in γ-TiAl

A polycrystalline alloy of composition Ti-36 wt % Al consisting mainly (about 95 vol. %) of γ-TiAl has been deformed in compression at 450°C as well as in rolling at 1040°C. The textures of the deformed specimens were measured and analyzed in terms of orientation distribution functions (ODFs). The textures after hot rolling show a cube-like component (100) [010] with an alignment of the c-axis with the transverse direction. A comparison of measured compression textures with those simulated on the basis of the Taylor theory of polycrystal deformation leads to the following conclusions. Both the “easy” {111} 〈110〉 and “hard” {111} 〈101〉-slip modes of deformation occur in γ-TiAl at 450°C. The critical resolved shear stresses (CRSSs) for these two slip modes differ by a factor of less than 2, the CRSS for {111}〈110〉-slip being higher than that for {111}〈101〉-slip. The rolled specimens show a pronounced plastic anisotropy, which can only be explained on the basis of microstructural considerations.     

Comparison between simulated and experimental transformation textures in a Nb microalloyed steel

Samples of a Nb microalloyed steel were control rolled and finished (i) at 1020°C (in the γ recrystallization range) and (ii) at 870°C (in the γ no-recrystallization range). The textures of these materials were compared with b.c.c. transformation textures derived analytically from (i) annealed and (ii) cold rolled samples of an f.c.c. Ni30Co alloy. For this purpose, the Kurdjumov-Sachs relationship was assumed, together with the absence of variant selection. The ferrite texture of the experimental steel finish rolled in the γ recrystallization range is sharper than the corresponding simulated texture, the major components of both being {100}〈011〉 and {110}〈110〉. The texture of the experimental steel finish rolled in the γ no-recrystallization range is again sharper than the corresponding simulated texture, both containing {113}〈110〉, {332}〈113〉 and {100}〈011〉 as the major components. The detailed textural features of the steel finished at 1020°C can be explained by allowing for some variant selection, together with selective growth of the {100}〈011〉 oriented α grains during transformation. A combination of selective α grain growth and variant selection is again required to explain the detailed texture of the steel sample finished at 870°C.     

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。     

稀土Y对6.5%Si高硅钢热轧和温轧组织织构演变的影响

摘要：以无稀土与含质量分数为0.03%的Y的6.5%（质量分数）Si高硅钢为研究对象,经过热轧、常化、温轧及退火工艺制备出0.5mm高硅钢薄板,采用EBSD、SEM和EDS测试技术,研究了稀土Y对高硅钢热、温轧组织织构演变的影响。结果表明,热轧板中以{001}〈110〉和{110}〈001〉织构为主,常化板织构类型遗传了热轧板,添加稀土Y削弱了热轧、常化板中整体织构强度。含Y高硅钢较无稀土高硅钢温轧剪切带增多,位错密度增加,α织构减弱且γ织构增强。随着退火温度升高,温轧板以{001}〈140〉为主的λ织构和{114}〈481〉为主的α*织构强度不断增强。添加稀土Y削弱了相同退火温度下温轧板的λ织构与α*织构的强度,然而η织构却有所增强,这与稀土Y促进剪切带形核有关。添加质量分数为0.03%的Y具有细化晶粒的作用,细小弥散的稀土Y氧化物阻碍晶界迁移是导致高硅钢温轧板再结晶晶粒细化的重要原因。     

Ti-26Nb-4Zr合金冷轧板材的织构和力学性能

采用X射线衍射和室温拉伸方法研究了冷轧变形和固溶处理对Ti-26Nb-4Zr合金板材的织构和力学性能的影响.研究发现,50%冷轧时形成了{001}〈uvw〉织构,随着冷变形量的增加,逐渐形成了{121}〈111〉和{001}〈110〉混合织构,〈110〉方向由与轧制方向垂直转到与轧制方向平行.800℃固溶处理后,随着变形量的增加,{111}〈110〉再结晶织构形成并逐渐增强,但〈110〉方向始终保持与轧制方向平行.由于加工硬化及晶粒细化的作用,导致随着变形量增加,冷轧板材的强度逐渐提高,塑性降低.固溶处理后,由于发生再结晶,使得板材的塑性相比冷轧态明显提高.      

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%。     

Effect of Austenite Pancaking on the Microstructure,Texture, and Bendability of an Ultrahigh-Strength Strip Steel

The effect of austenite pancaking in the non-recrystallization regime on microstructure and texture evolution and thereby on bendability was investigated in an ultrahigh-strength strip steel with a martensitic-bainitic microstructure. The results indicate that an increase in rolling reduction (R _tot) below the non-recrystallization temperature, which improves the strength and toughness properties, increases the intensities of the ~{554}〈225〉 _α and ~{112}〈110〉 _α texture components along the strip centerline and of the ~{112}〈111〉 _α component at the surface region. Even with the highest R _tot of 79 pct, the bendability along the rolling direction was good, but the preferred alignment of rod-shaped MA constituents along the rolling direction led to a dramatic decrease in the bendability transverse to the rolling direction, with severe cracking occurring even at small bending angles. The early cracking is attributed to localization of the strain in narrow shear bands. It is concluded that the R_tot value has to be limited to guarantee successful bendability.     

薄板坯连铸连轧流程Fe-3%Si钢热轧板和常化板织构

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,采用EBSD和X射线衍射方法观察了A钢和B钢热轧板和常化板的织构组织,分析了α、ε和γ取向线上织构取向密度变化规律。A和B钢热轧板具有相似的{110}〈112〉和、{001}〈110〉和{001}〈010〉和高斯织构组织,A试样表层的晶粒均匀性较差,B试样具有较强的γ织构取向。采用EBSD观察比较了A钢和B钢热轧板和常化板的垂直TD面的EBSD微观织构组织,A钢和B钢常化退火后基本保留了热轧时形成的中心部位的组织,而次表层和表层晶粒发生了再结晶长大,晶粒组织和织构梯度减小,织构主要集中在{001}〈^-1^-10〉和{001}〈0^10〉和之间以及高斯织构上。常化后织构的总体强度下降,高斯强度减弱。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。     

Texture distribution through-the-thickness after cold-rolling of 3% silicon steel

A simple laboratory technique was used to produce cold-rolled specimens with various reductions from 40 to 80% at a 10% interval starting with commercial hot band of 3% silicon steel. The quantitative and sensitive Orientation Distribution Function (ODF) method was applied to analyze the evolution of texture from hot-rolled to cold-rolled through-thickness. The results indicated that there are two different types of texture in hot sheet which are called recrystallization type texture and deformation type texture. The developed texture at each level of cold sheet specimens was inherited from the texture at respective level of hot sheet. The Goss texture memory effect at subsurface level was discussed. The conclusions indicated that it is important to get suitable hot band which has strong recrystallization type texture at its surface level and use appropriate cold rolling reduction for producing cold band which has a texture distribution of strong {111}〈112〉, weak {001}〈110ång; and some {110}〈001〉 components at its subsurface level and is beneficial to forming sharp Goss texture during recrystallization. The appropriate reduction is about 70%.     

Mechanisms of phase and structural transformations and texture formation in titanium alloy sheet semiproducts

Inverse pole figures are used to analyze texture formation in sheet semiproducts made from titanium alloys of various classes. The role of the mechanisms of phase and structural transformations in texture formation has been revealed. A VT6 alloy is used as an example to study the texture formation during hot, warm, and cold rolling of high-alloy α + β titanium alloys. Hot rolling followed by cooling is shown to form the β → α transformation texture. Warm or cold rolling of α + β titanium alloys leads to the (0001)〈hkio〉 deformation texture of the α phase, and subsequent annealing in the two-phase field results in the transformation texture with a strictly determined orientation distribution of α-phase crystallites due to the shear mechanism of α-phase nucleation. Specifically, the 〈10\(\overline 1 \)0〉 orientation is parallel to the rolling direction, the [0001] direction is parallel to the transverse direction, and the {11\(\overline 2 \)0} planes are parallel to the rolling plane. Thermohydrogen treatment in combination with rolling is shown to form nano-and submicrocrystalline structures with a virtually textureless α phase in VT6 sheet semiproducts. As a result, the anisotropy of the mechanical properties of the sheet semiproducts produced by this new combined hydrogen technology decreases sixfold.     

Formation of crystallographic texture in titanium nickelide single crystals during rolling

The texture formation in the single crystals of the Ti-48 at % Ni-2 at % Fe alloy rolled at a temperature of 350°C up to a strain of 80% in eleven different initial orientations is examined. There are three stable initial orientations that remain unchanged in rolling: {011}〈011〉, {111}〈011〉, and {111}〈112〉. The TiNi single crystals are shown to be deformed by means of a combined action of slip in systems {011}〈001〉 and twinning in systems {114}〈221〉 and {118}〈441〉. The types of formed rolling texture in the single crystals depend on their initial orientation and strain.     

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。     

Crystallographic Reconstruction Study of the Effects of Finish Rolling Temperature on the Variant Selection During Bainite Transformation in C-Mn High-Strength Steels

The effect of finish rolling temperature on the austenite-(γ) to-bainite (α) phase transformation is quantitatively investigated in high-strength C-Mn steels using an alternative crystallographic γ reconstruction procedure, which can be directly applied to experimental electron backscatter diffraction mappings. In particular, the current study aims to clarify the respective contributions of the γ conditioning during the hot rolling and the variant selection during the phase transformation to the inherited texture. The results confirm that the sample finish rolled at the lowest temperature [1102 K (829 °C)] exhibits the sharpest transformation texture. It is shown that this sharp texture is exclusively due to a strong variant selection from parent brass {110} \( \left\langle {1\bar{1}2} \right\rangle \) , S {213} \( \left\langle {\bar{3}\bar{6}4} \right\rangle \) and Goss {110}〈001〉 grains, whereas the variant selection from the copper {112} \( \left\langle {\bar{1}\bar{1}1} \right\rangle \) grains is insensitive to the finish rolling temperature. In addition, a statistical variant selection analysis proves that the habit planes of the selected variants do not systematically correspond to the predicted active γ slip planes using the Taylor model. In contrast, a correlation between the Bain group to which the selected variants belong and the finish rolling temperature is clearly revealed, regardless of the parent orientation. These results are discussed in terms of polygranular accommodation mechanisms, especially in view of the observed development in the hot-rolled samples of high-angle grain boundaries with misorientation axes between 〈111〉γ and 〈110〉γ.