罩式退火工艺的升温速率对无取向硅钢织构及性能的影响

研究了罩式退火工艺的升温速率对0.8%Si无取向硅钢组织、织构及磁性能的影响。结果表明,经过不同升温速率退火后,无取向硅钢的再结晶织构主要为{111}织构,伴随有{110}、{100}织构。随着退火升温速率的提高,晶粒尺寸逐渐增大,{111}织构明显减弱,{110}织构明显增强,{100}织构没有明显变化,铁损P_1.5/50逐渐降低,磁感应强度B₅₀₀₀逐渐增强。但当升温速率由80 ℃/h升高至100 ℃/h时,{111}织构出现一定程度的增强,{110}织构出现减弱,{100}织构没有明显变化,铁损P_1.5/50增大,磁感应强度B₅₀₀₀减小。在退火升温速率为80 ℃/h时,无取向硅钢可获得最优的磁性能:P_1.5/50=4.249 W/kg,B₅₀₀₀=1.715 T。     

退火过程中无取向电工钢的晶粒长大行为及磁性能演变

对Fe-3%Si无取向电工钢冷轧板进行不同时间的退火处理,利用光学显微镜、EBSD等研究了退火过程的晶粒长大行为及其对磁性能的影响。结果表明,随着退火时间的增加,退火板中Goss以及γ织构晶粒占比降低,{114}<841>以及{001}<120>织构晶粒占比增大。在退火时间低于20 s时,退火织构以强γ和Goss织构为主。退火时间为60 s时,{001}<120>织构晶粒长大速率急剧增大,平均晶粒尺寸达到约105 μm。退火时间达到240 s时,退火织构以强{001}<120>以及{114}<841>织构为主。退火时间为30～60 s时轧向及横向磁感值迅速增大,60 s时轧向磁感达到最大值1.74 T,120 s时横向磁感达到最大值1.67 T,之后随着退火时间增加而轻微降低,并分别稳定在1.72 T和1.66 T左右。退火板45°方向磁感值先升高后降低,20 s时达到最大值1.67 T。各方向的铁损值均随退火时间的增加而降低,且磁各向异性逐渐减小。     

退火温度对CSP生产薄规格无取向电工钢性能的影响

以CSP流程生产的35W440无取向电工钢热轧板为研究对象,研究了不同退火温度对无取向电工钢磁性能的影响规律.研究的结果表明,在实验参数的范围内,随着退火温度的升高,最终成品的晶粒尺寸增大.利用X射线测量了不同退火温度的成品板的宏观织构,结果表明,退火温度的提高有利于减弱{111}面织构,从而有利于改善产品磁性能的α纤维织构和{100}〈0vw〉有利织构组分得到了增强.因此随着退火温度的提高,成品板试样的铁损降低,磁感增加.     

热轧组织对冷轧无取向硅钢退火织构及组织的影响

对不同加热温度处理的热轧低硅钢带进行了冷轧及退火实验,分析了热轧钢带的组织对冷轧无取向硅钢再结晶退火过程中的组织及织构的影响。结果表明:热轧组织对冷轧无取向电工钢冷轧板再结晶组织及织构演变有重要影响;等轴晶粒组织的热轧钢带比混晶组织的热轧钢带冷轧后再结晶退火快,且退火后晶粒尺寸均匀;随着等轴晶粒尺寸增加,冷轧退火后形成的冷轧硅钢{110}类型的织构增强,{100}类型的织构减弱;表明热轧组织为等轴晶粒时,不利于冷轧无取向硅钢磁性能的改善。     

退火工艺对平整轧制后50W800无取向硅钢磁性能的影响

为提高50W800无取向硅钢的板形,需要对再结晶退火后的硅钢进行平整轧制,在平整后会出现硅钢片磁性能下降现象。对平整轧制后的50W800无取向硅钢进行400~800 ℃的去应力退火,利用单片测量法测量其铁损和磁感应强度,并用EBSD技术对组织织构进行分析。结果表明,经过平整轧制后,50W800无取向硅钢小角度晶界增加,但晶粒不均匀性会导致磁性能下降;采用700 ℃×2 min去应力退火后,50W800无取向硅钢磁性能得到较好的改善。EBSD技术分析发现,去应力退火能消耗大量小角度晶界,使晶界含量降低,晶粒均匀性增加,不利形变织构{111}<112>强度降低,这是50W800无取向硅钢磁性能改善的主要原因。     

Texture Optimization for Intermediate Si-Containing Non-oriented Electrical Steel

Columnar grains can be obtained by decarburization annealing in the two-phase region of Si-containing non-oriented electrical steel under wet-mixed atmosphere. However, iron oxidation or oxidation of alloying elements on the surface hinders the decarburization process and, consequently, the preferred microstructure and texture evolution. This study aims to optimize the texture and obtain excellent magnetic properties in intermediate Si-containing non-oriented electrical steel by process adjustments, such as final annealing under pure hydrogen atmosphere and coarsening initial microstructure by hot-band annealing. First, pure hydrogen atmosphere is used to weaken the surface oxidation layer and to promote the effect of anisotropic strain energy. Driven by anisotropic strain energy during phase transformation, a number of {100}-nearly oriented columnar grains are obtained. Second, high amounts of non-gamma fiber-oriented recrystallized grains, which strongly influence the final transformation texture, are observed during the rapid heating process in the final annealing because of the coarse initial microstructure. Non-gamma fiber-oriented grains grow from the surface into the center layer along the normal direction and form poor columnar grains by carbon diffusion during slow austenite to ferrite (γ → α) transformation in final annealing under pure hydrogen atmosphere. A notable increase in magnetic properties is observed, with magnetic induction at 5000/Am (B ₅₀) above 1.76 T and core loss at 1.5 T by 50 Hz (P _15/50) below 2.6 W/kg.     

低硅无取向电工钢退火过程中晶粒组织变化对磁性的影响

最终退火温度的设计是无取向电工钢实现最终磁性十分重要的工艺参数,本文着重研究了0．25％Si无取向电工钢退火过程中晶粒组织的变化对磁性的影响。研究表明其磁感最高点出现在纤维组织完全消失,{111}（112）、{554}（225）织构组分较弱的组织状态。铁损的降低主要依赖于磁滞损耗的降低,织构的影响不大。     

轧制工艺对薄带铸轧无取向硅钢组织性能的影响

利用光学显微镜、XRD、EBSD等研究了轧制工艺对薄带铸轧无取向硅钢组织、织构和磁性能的影响。研究表明,随热轧压下率增大,冷轧组织变形储能及剪切带的比例逐渐降低,冷轧板中α织构减弱,γ织构增强。退火板晶粒尺寸随热轧压下率增大而增加。热轧压下率为17%及40%时,退火织构以强的Goss织构及相对弱的{100}织构为主,热轧压下率达到55%后,退火织构为强的{115}<110>和{114}<371>织构,Goss织构和{100}组分明显减弱。随热轧压下率增大,退火板磁感值先升高后降低,铁损值先减小后增加。热轧压下率为40%时,退火板综合磁性能最优。     

Effect of copper content, initial structure, and scheme of treatment on magnetic properties of ultra-thin grain oriented electrical steel

The effect of the copper content, initial structure, and scheme of treatment on the magnetic properties of an ultra-thin grain oriented electrical steel has been investigated. In the material with copper and an initial sharp texture, the nucleation of new grains upon primary recrystallization is connected with deformation twins; in the samples without copper and with copper and diffuse texture, it is connected predominantly with shear bands and transition bands. Upon heating at a rate of ～0.004 K/s, the temperature of primary recrystallization in the copper-bearing samples is considerably higher than in the copper-free material. Upon heating at a rate of ～4 K/s the appearance of new grains occurs almost simultaneously for all of the studied samples. In the samples with copper and initial sharp texture after annealing at 1050°C, a significant part of the volume is occupied by grains that had undergone normal grain growth; in the samples without copper and with copper and diffuse texture, anomalous growth is hardly observed at all. To obtain high final magnetic properties of the ultra-thin grain oriented electrical steel produced by the Littmann method, it has been suggested to use an grain oriented electrical steel with 0.5% Cu that exhibits the diffuse orientation of grains as the workpiece.     

卷取工艺对新型冷轧无取向电工钢

研究了卷取工艺对一种新型含铜无取向电工钢晶粒尺寸、织构演变、铁损和磁感应强度的影响。结果表明，试样织构组分主要为{111}、{112}、{100}和高斯织构，在550℃卷取、保温2～3h，{100}织构有增强趋势，磁感应强度较高，铁损较低。     

Final thickness reduction and development of Goss texture in C- and Al-free Fe-3%Si-0.1%Mn-0.012%S electrical steel

The correlation between final thickness reduction and development of Goss texture has been investigated in a C- and Al-free Fe-3%Si electrical steel. During final annealing, the annealing texture is transited from {110}⊥ND to {100}⊥ND texture with increasing final thickness reduction. This is due to the decrease in primary grain size after pre-annealing with increasing final thickness reduction which accelerates the selective growth rate of the {100} grains at the expense of the other {hkl} grains. At an optimal final thickness reduction of 75.8%, the high magnetic induction of 1.95 Tesla, which arises from the sharp {110}<001> Goss texture and is comparable to that of conventional grain-oriented electrical steels, is obtained from the C- and Al-free Fe-3%Si-0.1%Mn electrical steel. Such a high magnetic property is produced through the surface-energy-induced selective grain growth of the Goss grains under the lower surface-segregated condition of sulfur which makes the surface energy of the {110} plane lowest among the {hkl} planes.     

退火温度对新能源汽车用含Ce无取向电工钢组织和织构的影响

采用SEM、EBSD和XRD等分析手段研究了退火温度对含Ce新能源无取向电工钢组织及织构的影响。结果表明:800 ℃退火后,试验钢边部和中心部位均能观察到再结晶组织及亚晶组织,α线织构中的{112}<110>取向密度最高,γ线织构中的{111}<112>取向密度较弱,退火板存在少量η织构;830～920 ℃退火后,温度越高,再结晶越充分,α线织构取向密度下降,γ线织构取向密度增加,η织构基本消失;试验钢在950 ℃退火后发生了完全再结晶,平均晶粒尺寸为48.29 μm,γ线织构中的{111}<112>取向密度最高,为11.36。     

The effect of magnetic field annealing on the texture of 2nd recrystallization for a deformed Fe−3.2% Si steel sheet

The effects of deformation on 2nd recrystallization behavior with or without magnetic field for a 1st recrystallized electrical steel sheet have been investigated. Annealing temperatures (800, 1000 °C) and cold-rolling rates (50, 70 %) were experimental parameters. A magnetic field of 5 T using a superconducting magnet at a heating rate of 15 °C/min was applied in a direction parallel to the rolling direction. The intensity of α-fiber was increased due to the deformation and, in particular, the formation of {100}<110> component was tremendous. Considerable formation of {001}<100> component was also found. At 800 °C, α-fiber was developed rapidly due to deformation, and η-fiber was also formed in the components {100}<100> and {110}<100> The effect of magnetic field annealing was more significant at 800 °C, while the effect at 1000 °C was negligible. These results are discussed in a phenomenological context considering the atomic fluctuation and magnetic induction depending on annealing temperature and magnetic field.     

Effect of Annealing Treatments on the Microstructure and Texture Development in API 5L X60 Microalloyed Pipeline Steel

Effect of annealing treatments at 600, 800, 1000 and 1200 °C on the microstructure, texture, grain boundary characteristic and recrystallization fraction of Nb-microalloyed X60 steel is evaluated by using x-ray diffraction and EBSD techniques. The results indicate that bimodal as-received microstructure is changed to a homogeneous equiaxed grain structure above annealing at 1000 °C. Macro-texture investigations depict that increasing annealing temperature results in considerable variation of texture intensity, especially at 1200 °C. Maximum intensity corresponds to {001}〈310〉, Goss, copper texture components as well as near γ-fiber at 1200 °C. Recrystallization analysis shows that volume fraction of recrystallization noticeably is increased by annealing temperature at 1200 °C. Recrystallized grains are mainly oriented along γ-fiber, especially close to {111}〈112〉 texture component. Moreover, coincidence site lattice (CSL) analysis shows that the effect of annealing temperature on the volume fraction of Σ3 boundary is negligible.     

Effect of annealing temperature on microstructure,texture and properties of molybdenum foil

The microstructure, texture and mechanical properties of 0.06 mm thick molybdenum foil after annealing at different temperatures were studied by micrograph and EBSD analysis. The results show that the grains of the cold-rolled molybdenum foil along the rolling direction are fibrous. As the annealing temperature increasing from 750 °C to 1000 °C, the average layer thickness of these fibrous grains gradually grows. And the relative frequency of low-angle grain boundaries increases, while the relative frequency of high-angle grain boundaries decreases. Also, the main texture of the unidirectional-rolled and annealed molybdenum foils is {112}〈110〉 which content continuously increase to 62% till 1000 °C. Therefore, the strength of RD, TD and 45°RD direction decreases but the elongation increases. During these processes, the mechanism includes classical nucleation and coarsening of subgrain and with annealing temperature rising, the latter dominates the recrystallization process. After annealing at 1050 °C, the molybdenum foil undergoes secondary recrystallization. The grain boundary distribution becomes diffused and the main texture changes into {001}〈110〉, which the fraction is as high as 96%, thus, the mechanical properties of RD, TD and 45°RD exhibit sharp decrease simultaneously.     

磁场预退火对取向硅钢二次再结晶组织及织构的影响

对二次冷轧后高温退火前3.2%Si取向硅钢在实验室自主设计研发的脉冲磁场预退火管式炉内进行不同温度的预退火处理,通过光学显微镜与XRD对其组织织构进行分析,利用硅钢片磁性能测试系统对高温退火后的试样进行磁性能分析。结果表明,经脉冲磁场预退火处理后,整体上取向硅钢平均晶粒尺寸随预退火温度升高略微减小,晶粒尺寸主要集中在10~25 μm范围内;通过ODF图及{200}极图分析可知,经脉冲磁场预退火后,最强织构随预退火温度的升高从{112}<110>织构变化到{223}<110>织构和{111}<110>织构;随着预退火温度的升高,高温退火后试样的磁性能反而降低。     

Characterization of Microstructure and Texture in Grain-Oriented High Silicon Steel by Strip Casting

Grain-oriented 4.5 wt% Si and 6.5 wt% Si steels were produced by strip casting, warm rolling, cold rolling, primary annealing, and secondary annealing. Goss grains were sufficiently developed and covered the entire surface of the secondary recrystallized sheets. The microstructure and texture was characterized by OM, EBSD, TEM, and XRD. It was observed that after rolling at 700 °C, the 6.5 wt% Si steel exhibited a considerable degree of shear bands, whereas the 4.5 wt% Si steel indicated their rare presence. After primary annealing, completely equiaxed grains showing strong γ-fiber texture were presented in both alloys. By comparison, the 6.5 wt% Si steel showed smaller grain size and few favorable Goss grains. Additionally, a higher density of fine precipitates were exhibited in the 6.5 wt% Si steel, leading to a ~30-s delay in primary recrystallization. During secondary annealing, abnormal grain growth of the 6.5 wt% Si steel occurred at higher temperature compared to the 4.5 wt% Si steel, and the final grain size of the 6.5 wt% Si steel was greater. The magnetic induction B ₈ of the 4.5 wt% Si and the 6.5 wt% Si steels was 1.75 and 1.76 T, respectively, and the high-frequency core losses were significantly improved in comparison with the non-oriented high silicon steel.     

The effect of cold rolling parameters on the recrystallization texture of non-oriented electrical steel

The effect of cold rolling condition on magnetic properties of non-oriented electrical steel was investigated. For evaluation of cold roiling condition, utilizing rolling shape factor (RSF) was proposed. In the case of small RSF, magnetic induction was improved. Development of ND ∥ <111< components was suppressed in the recrystallized texture near the surface, and the vicinity of the {100}<001> component was developed after grain growth. The relation between RSF and cold-rolling condition was examined by computer simulation; such results were attributed to the increment of shear strain in the surface texture. Magnetic properties would be improved by adequate control of cold-rolling condition.     

退火时间对异步轧制无取向硅钢再结晶织构与磁性的影响

对高牌号无取向硅钢进行异步轧制,然后在不同时间下进行再结晶退火,研究异步轧制条件下高牌号无取向硅钢再结晶织构随退火时间的演变过程,探讨高牌号无取向硅钢再结晶织构的形成及再结晶织构组分与磁性的关系。结果表明:在750℃再结晶退火过程中,随着退火时间的延长,α织构强度减弱,织构组分逐渐向{111}〈112〉附近聚集,铁损逐渐下降。快慢辊侧再结晶织构类型基本相同,但慢辊侧强度高于快辊侧。     

Microstructure Evolution and Hardness of an Ultra-High Strength Cu-Ni-Si Alloy During Thermo-mechanical Processing

Microstructure evolution and hardness changes of an ultra-high strength Cu-Ni-Si alloy during thermo-mechanical processing have been investigated. For hot-compressive deformation specimens, dynamic recrystallization preferentially appeared on deformation bands. As deformation temperature increased from 750 to 900 °C, elongated grains with the Cubic texture {001} 〈100〉 were substituted by recrystallized grains with Copper texture {112} 〈111〉. For the samples having undergone cold rolling followed by annealing, static recrystallization preferentially occurred in the deformation bands, and then complete recrystallization occurred. Goss, Cubic, and Brass textures remained after annealing at 600 and 700 °C for 1 h; R texture {111} 〈211〉 and recrystallization texture {001} 〈100〉 were formed in samples annealed at 800 and 900 °C for 1 h, respectively. For samples processed under multi-directional forging at cryogenic temperature, the hardness was increased as a result of work hardening and grain refinement strengthening. These were attributed to the formation of equiaxed sub-grain structures and a high dislocation density.