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本文介绍了利用电解铝液直接生产铸轧带坯的常见质量缺陷,分析了这些质量缺陷的产生原因,提出了改善铸轧带坯冶金质量的有效措施。采取这些措施后,铸轧带坯的冶金质量显著提高,氢含量降低至0.10~0.14mL/100gAI,晶粒度达到二级以上。 相似文献
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《钢铁》2018,(12)
为了探究双辊薄带铸轧技术中施加的机械振动对铸轧带坯微观组织及力学性能的影响,设计并制造了?500 mm×350 mm微振幅双辊薄带铸轧机。以该铸轧机为试验平台进行了多次工艺探索试验,最终确定了能够实现振动铸轧稳定生产的合理工艺参数。分别对振动与无振动两种工艺条件下所得20CrMn合金钢铸轧带坯的显微组织和力学性能进行了检测与分析,结果表明,与传统铸轧带坯相比,振动铸轧带坯法向面的平均晶粒尺寸由70减小至35μm,带坯纵截面振动侧和非振动侧晶粒也得到不同程度的细化;振动铸轧较传统铸轧所得带坯沿垂直轧制方向屈服强度、抗拉强度和伸长率分别提高了21.36%、27.35%和42.86%。以上研究结果证明,机械振动能有效改善带坯微观组织,细化晶粒,并提高其力学性能。 相似文献
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分析了电解铝液温度高、含渣量大、易吸气等特点,详细介绍了电解铝液降温增核、超纯净化、微观组织控制等关键技术。通过这些技术处理后的电解铝液完全可以达到铸轧双零铝箔用坯料的要求。铸轧带坯晶粒度达1级;铝箔针孔度不大于70个/m^2。 相似文献
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磁场处理对微合金钢由奥氏体向铁素体的转变过程产生影响,主要体现在铁素体的形核率和晶粒长大速度两个方面.磁场处理增加了铁素体的形核率,同时也提高了晶粒的长大速度.由于磁场对铁素体形核率的影响效果显著,缩短了相变时间,最终得到细晶组织. 相似文献
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《有色金属材料与工程》2017,(2)
对Al-Mn-Si-X合金进行不同温度和不同时间的退火,采用金相显微镜(OM)、扫描电子显微(SEM)和电导率仪对不同状态的合金组织进行观察、能谱(EDS)分析和电导率测试,研究AlMn-Si-X合金的再结晶行为.结果表明:随着退火温度的升高,再结晶晶粒尺寸越来越小.Al-MnSi-X合金的再结晶晶粒大小主要受再结晶形核数量的影响,再结晶后期的晶粒长大现象不明显.Al-Mn-Si-X合金存在着大量细小弥散的AlMnSi/AlMnSiFe析出相,这些析出相强烈抑制了再结晶形核和再结晶后期的晶粒长大.当退火温度低时,形核激活能较大,形核率低,再结晶晶粒粗大;当退火温度高时,形核激活能较小,形核率增加,再结晶晶粒细小. 相似文献
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通过50 kg真空感应炉冶炼,用常规流程和薄带铸轧两种工艺分别在实验室制备了含稀土钇的3%Si取向硅钢。薄带铸轧浇注温度1530℃,轧制速率0.3 m/s,铸带厚度2.5 mm。常规流程为80 mm铸坯加热温度1150℃,热轧板厚度2.4 mm,终轧温度935℃。采用扫描电镜(SEM)和电子探针(EPMA)研究了钢中夹杂物成分、形貌、数量、尺寸和分布;利用光学显微镜(OM)和电子背散射衍射(EBSD)分析了硅钢铸带、热轧板、0.3 mm冷轧板、870℃7 min和1100℃10 min再结晶退火板组织和织构。实验结果表明:与常规流程相比,薄带铸轧硅钢一次再结晶后晶粒较细小,且γ织构强度达到17,但是二次再结晶后晶粒尺寸不均匀,平均晶粒尺寸为61μm,部分Goss取向晶粒尺寸达到1 mm以上。原因为细小的含钇夹杂物数量过多,且分布不均匀,夹杂物聚集的区域晶粒长大受到明显抑制。常规流程生产的含钇硅钢二次再结晶热处理后晶粒均匀长大,平均晶粒尺寸为102μm,没有形成明显的Goss织构。 相似文献
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最初形成的喷射沉积Al-Zn-Mg-Cu铝合金的显微组织分析 总被引:1,自引:1,他引:0
用喷射成形工艺制备了Al-Zn-Mg-Cu高强铝合金。通过对最初形成的沉积坯的显微组织的观察,分析液滴在飞行和沉积过程中的形核、长大过程,分析均匀化和热挤压后最初形成的沉积材料的显微组织变化。由实验结果,经雾化沉积制备的Al-Zn-Mg-Cu合金。最初沉积坯的沉积态由于经历了两次形核,形成了大小不一的近似等轴晶;均匀化晶粒无明显长大,晶粒进一步球化。同常规的工艺相比,雾化沉积制备的材料可以省略均匀化过程;沉积态组织直接经过热挤压形成均匀致密的组织。 相似文献
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采用金相显微镜和力学拉伸机对工艺改进前后的3102空调箔组织进行分析,研究了不同工艺条件下铸轧带坯和空调箔成品的组织和性能。结果表明:采用大铸轧区铸轧工艺后,3102空调箔铸轧坯料晶粒得到了显著细化,延伸率提高,使用组织细化铸轧坯料生产的空调箔产品延伸率有着显著的优势,并可以在此基础上实现减薄。 相似文献
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《Acta Metallurgica》1986,34(7):1377-1385
A method for estimating the grain size of a newly formed phase is presented for isothermal and continuous cooling transformations in which the new phase nucleates homogeneously, on the parent grain boundary surface or grain edges. In the isothermal transformation it is demonstrated that the grain size of the new phase depends only on the ratio of the nucleation rate to the growth rate and not on the individual values of nucleation or growth rates. It is also demonstrated that the grain size of the new phase is proportional to one half and two thirds the power of the parent grain size for grain surface and grain edge nucleations, respectively. In continuous cooling transformation, the grain size of the new phase depends on both nucleation and growth rates. When the ratio of the nucleation rate to the growth rate is independent of temperature, the grain size of new phase does not depend on the cooling rate. The grain size of the new phase in the process of transforming, or when more than two types of sites are active is also discussed. The results obtained in the present study are applicable to reactions where a parent phase transforms completely to a new phase, such as solidification, recrystallization, massive and discontinuous transformations. 相似文献
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摘要:为了探究冷却速率对薄带连铸低碳钢微观组织的影响,采用相变仪设备对铸带重新加热并进行不同冷却速率冷却,采用光学显微镜、场发射电子探针和电子背散射衍射等手段对微观组织和针状铁素体形核所利用的夹杂物进行了分析。结果表明,铸带经1200℃保温3min后,原奥氏体晶粒尺寸约为150~650μm,可以满足晶内针状铁素体形核对原奥氏体晶粒尺寸的需要。在2~5℃/s的冷却速率范围内,试样中得到了大量的针状铁素体组织,冷却速率为2℃/s的试样中大角度晶界所占比例约为60%;当冷却速率大于20℃/s,针状铁素体的形成受到抑制。铸带中针状铁素体形核所利用的夹杂物是Ti-Al-Si-Mn-O+MnS复合夹杂物。 相似文献
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The microstructures of strip-cast low-carbon steels and their response to thermal processing 总被引:2,自引:0,他引:2
The as-cast microstructure and its modification when subjected to heat treatment is examined for strip-cast low carbon steels. The local solidification rate in the twin-roll strip casting process is estimated to. be 590 to 850 °C/s, and the primary and secondary dendrite arm spacings are approximately 17 to 25 and 10 μm, respectively. The as-cast structure is predominantly Widmanstätten ferrite and, thereby, differs from the conventional hot-rolled sheet. It is suggested that the as-cast morphology is a result of the large initial austenite grain size and the cooling rate and is not a unique characteristic of rapid solidification of strip casting. By restricting the austenite grain size and cooling rate, polygonal ferrite morphology probably can be produced during strip casting. The response to heat treatment depends on the presence of aluminum; with a moderate amount of aluminum, the A1N precipitates in the as-cast structure inhibit the subsequent grain boundary movement and may affect the subsequent recrystallization behavior. 相似文献
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晶粒的大小、均匀性及取向决定着带材深冲性能,其受到加工率、退火温度、原始晶粒大小等因素的影响。可采用多轧程轧制和退火的方法生产制锁用H65黄铜带材,均匀分配加工率,采用中轧加工率55%、中间退火工艺460℃~520℃×8h,有利于带材深冲性能的良性遗传;采用精轧加工率50%、成品退火温度680℃,晶粒度控制在20~25μm,充分均匀晶粒和优化结晶取向,可提高带材深冲性能避免深冲破裂。 相似文献
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2试验方案和退火工艺
2.1试验方案
根据前节分析,H68合金属单相α高锌合金,第一再结晶温度低,第二晶粒易长大。结晶理论指出,原始晶粒粗大,加工退火后再结晶晶粒亦大,H68合金在成品冷轧前需经两次中间退火(6.5mm热轧卷坯退火,2.3mm冷轧卷坯退火), 相似文献
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This work was carried out in context with the development of strip casting with the single‐belt process. In this new process the hot rolling is performed in‐line with considerably lower velocity than in conventional hot rolling. It is of interest to study the effect of low rolling speed on the material properties. Based on a finite element model used to predict the thermomechanical behaviour of the strip in tandem mills, the microstructural evolution of austenite was computed. In order to take account of the non‐isothermal conditions in industrial hot rolling, the material equations for recrystallization and grain growth are modified. The parameter studies were carried out over a wide range of volumetric flow rate extending from that in thin slab casting to that in conventional finishing rolling. They demonstrate that the “slow hot rolling” can produce a fine grain of austenite. Austenite grain evolution was computed for conventional rolling with a seven stand mill and for in‐line hot rolling of strip produced by the single‐belt process. It is found that the final grain size of austenite is about the same for the two processes under the condition that strip thickness behind the last stand is the same. 相似文献