板坯连铸工艺参数对取向硅钢铸坯中心等轴晶率的影响

通过对取向硅钢铸坯的低倍检验,研究了中间包钢水过热度、电磁搅拌电流、二冷水强度、拉速及断面尺寸对铸坯中心等轴晶率的影响。结果表明,试验条件下,中间包钢水过热度控制在14~18 ℃范围内时,因过热度不同引起的中心等轴晶率的变化较小,变化范围仅为0%~3%;电磁搅拌电流和铸坯断面尺寸对中心等轴晶率的影响较为明显,随搅拌电流的增大,中心等轴晶率呈增加的趋势,而当铸坯断面尺寸增加时其呈减小的趋势;二冷水强度和拉速对中心等轴晶率的影响相对较小,随着二冷水强度的增大,中心等轴晶率呈减小的趋势,而当拉速提高时其呈增加的趋势。     

对连铸结晶器钢液施加电脉冲提高铸坯等轴晶率的研究

从结晶器施加电脉冲的输入能量、电脉冲频率、钢液过热度角度,探讨电脉冲技术提高铸坯等轴晶率的效果.在攀钢1     

430不锈钢连续浇铸过程连铸坯等轴晶率的变化规律

430不锈钢是铁素体不锈钢中应用最广泛的钢种之一。在工业试验条件下,为了提高430不锈钢连铸坯等轴晶率,以430不锈钢在连续浇铸过程中连铸坯等轴晶率变化为研究对象,通过测定不同浇铸长度的连铸坯等轴晶率,找出其变化规律,并对炉次之间仅有的化学成分和过热度的变化对连铸坯等轴晶率的影响进行了分析。试验结果表明:在相同连铸工艺下,430不锈钢在连浇过程中不同炉次之间连铸坯等轴晶率的变化不显著,但浇次头坯和尾坯等轴晶率纵向却呈现出不均匀特性,另外提高钢中[C]+[N]%含量和降低浇铸过程中的过热度对430铁素体不锈钢连铸坯等轴晶区域的扩展是有益的。     

不同冷却工艺对冷墩钢小方坯等轴晶率的影响

通过改变现场连铸冷却制度,发现一冷、二冷工艺对连铸坯的等轴晶比例具有较大的影响。当结晶器冷却水流量下调后,结晶器内冷却水温差提高,冷却水带走的热量增加,结晶器与铸坯的接触情况及结晶前沿的温度分布得到改善,从而控制了柱状晶的生长,扩大了铸坯中心等轴晶区;二冷水量的改变,更进一步有利等轴晶的生成。采用合理的一冷、二冷工艺可...     

复式结晶器传热特征及其对铸坯凝固组织的影响

为了验证复式结晶器在提高铸坯等轴晶率方面的作用,分析比较了复式结晶器和传统结晶器的传热特征,并检测了两种结晶器所浇注铸坯的宏观组织。结果表明：复式结晶器能够降低钢液凝固前沿的温度梯度,从而使铸坯的等轴晶率超过80％。     

电磁搅拌对包钢板坯等轴晶率的影响

文章主要对包钢宽厚板坯连铸机采用二冷区电磁搅拌后,不同电磁搅拌参数对板坯中心等轴晶率的影响进行了分析。生产实践表明:当连铸工艺相同时,随着搅拌电流、搅拌频率的增大,板坯的中心等轴晶率平均增加了20%。     

两对二冷电磁搅拌对无取向硅钢铸坯等轴晶率和热轧板组织的影响

通过电磁搅拌力计算及工业试验,研究了两对二冷电磁搅拌器在不同搅拌参数及组合方式下50W800无取向硅钢的铸坯等轴晶率及热轧板组织。结果表明,两对搅拌辊搅拌参数一致时,搅拌参数均为380A/6Hz的铸坯等轴晶率最高,为23.48%;两对搅拌辊搅拌参数不一致时,第一对搅拌参数为380A/6Hz和第二对搅拌参数为350A/3Hz的铸坯等轴晶率最高,为25.42%。随着铸坯等轴晶率的增加,热轧板表层的再结晶晶粒尺寸逐渐增加,1/4厚度处和心部的纤维组织明显减少,且1/4厚度处再结晶晶粒的数量增加、尺寸增大。综合考虑增加铸坯等轴晶率和热轧板晶粒尺寸、减少热轧板带状组织以及降低电能消耗,第一对搅拌辊的搅拌参数为380A/6Hz和第二对搅拌辊的搅拌参数为350A/3Hz为最优搅拌参数组合方式。     

连铸坯枝晶凝固的重要微观结构特征参数的研究进展

连铸钢水凝固时结晶方式包括柱状晶和等轴晶对铸坯质量有显著影响。连铸过程合金成分、铸坯过热度、尺寸，冷却速度和温度梯度等技术参数均影响一次、二次枝晶臂间距、柱状晶至等轴晶转变边界位置和糊状区渗透率等结构特征参数。在已有研究的基础上总结了微观结构特征参数的半解析计算公式，在对连铸时宏观流场、温度场和浓度场分布的微观．宏观耦合数值模拟时可采用合适的半解析计算公式计算这些特征参数。     

各种因素对铝合金超声波铸锭等轴晶占有率的影响

以超声波探针顶上导入方式为例,讨论了金属熔体、超声波参数、探针和铸型等一系列因素对铝合金铸锭等轴晶占有率的影响,并对超声细晶机理进行了探讨。结果表明:金属超声铸锭的细化能力与自身的化学成分有关;随着超声波功率和处理时间的增加,等轴晶占有率提高,但是增加到一定峰值后开始下降;超声波探针应置于液面对称中心的位置,且浸入较小深度为宜;对于不同体积的铸型,存在一个最佳的径高比。     

连铸结晶器振动喂钢带对铸坯组织影响

以低碳钢种Q235B、250 mm×1 600 mm铸坯为研究对象,在某钢厂采用连铸结晶器振动喂钢带技术,往连铸结晶器钢水中喂送低碳钢带。研究了连铸结晶器振动喂钢带对铸坯的组织结构以及性能的影响,结果表明,采用连铸结晶器振动喂钢带技术,连铸坯中心疏松与宏观偏析分散且有所减轻,可改善其宏观组织结构质量,降低轴向区域化学非均质性,以及提高厚轧板的可塑性。     

The effect of Ti addition on equiaxed grain formation in ferritic stainless steel welds

This study examines mechanisms for providing nuclei to equiaxed grains in the welds of pure ferritic stainless steel(FSS).The addition of the alloy element Ti to pure FSS 439 causes the precipitation of TiN,which can benefit the columnar-to-equiaxed transition(CET) of gas tungsten arc welding(GTAW).Meanwhile,the initial morphology of the precipitates,the concentration multiplications of Ti,N,etc.of FSS 439 should be controlled to induce the formation of CET during the short welding process.     

硫含量对KR脱硫渣中硫赋存状态的影响

KR脱硫渣中的CaO是转炉冶炼工艺中重要的造渣原料,将其回用于钢铁冶炼工艺可降低冶金企业的CaO原料消耗,减少企业KR脱硫渣堆积量,节约企业冶炼的经济成本.KR脱硫渣中的2CaO·SiO2 (C2S)在转炉脱磷冶炼过程中可与炉渣中的磷形成稳定的2CaO· SiO2-3CaO· P2O5固溶体,提高磷在渣中的稳定性.将K...     

超低硫管线钢硫含量控制实践

结合唐山钢铁集团公司超低硫管线钢试验生产实践,介绍了全流程硫含量控制技术,指出了超低硫冶炼的关键控制点在铁水预处理和精炼.抗氢致裂纹的关键在于钢中央杂物的控制.得出了通过全过程硫含量控制能够牛产超低硫管线钢的结论.     

硫含量对重轨钢中非金属夹杂物的影响

摘要：实际生产过程中由于原料和操作控制不精确,钢中硫含量和非金属夹杂物波动较大,严重影响钢的洁净度。为了准确控制重轨钢中硫化锰等非金属夹杂物的尺寸、形态和数量,在实验室开展了硫含量对重轨钢中非金属夹杂物的影响研究。钢中硫质量分数增至70×10-6、110×10-6、140×10-6后随炉冷却,采用全自动夹杂物分析仪对钢中非金属夹杂物进行统计,获得了硫含量与钢中非金属夹杂物成分、尺寸、形态和数量的关系。结果表明,钢中夹杂物大部分为以氧化物为形核核心的复合型MnS;随着硫含量的升高,复合型MnS、MnO-SiO2和MgO-Al2O3-SiO2-CaO型夹杂增多,CaO-SiO2和MgO-CaO-SiO2夹杂减少;夹杂物平均尺寸随硫含量的升高而增大,且不同尺寸的夹杂物均有所增加,尺寸为2~10μm增多最明显;硫质量分数为(70~140)×10-6的钢液凝固过程液相中都能单独析出MnS,且硫含量越高,MnS析出越早,含量越多。     

Effect of sulfur content on non metallic inclusions of heavy rail steel

Due to the inaccurate control of raw materials and operation in the actual production process, the sulfur content and non-metallic inclusions in the steel fluctuate greatly, which seriously affects the cleanliness of steel. To accurately control the size, shape and quantity of non-metallic inclusions such as manganese sulfide in heavy rail steel, the effect of sulfur content on non-metallic inclusions in heavy rail steel was studied in the laboratory. To investigate the changes of the number and morphology of non-metallic inclusions in steel under different sulfur contents, the sulfur content of test steel was increased to 70×10-6, 110×10-6 and 140×10-6, respectively. During the experiment, the test steel was heated and melted in a tubular furnace according to a certain heating rule, and then cooled naturally in the furnace. Subsequently, the non metallic inclusions in steel were scanned by automatic inclusions analyzer, and the relationship between sulfur content and the composition, size, form and quantity of non-metallic inclusions in steel was obtained. The results indicate that most of the inclusions in the steel are composite MnS with oxides as nucleating cores. With the increase of sulfur content, the quantity density of composite MnS, MnO-SiO2 and MgO-Al2O3-SiO2-CaO inclusions increase, while the CaO-SiO2 and MgO-CaO-SiO2 inclusions decrease. The average size of inclusions increases with the increase of sulfur content, and the number of inclusions with different sizes also increases, especially for inclusions with sizes of 2-10μm which increase obviously. During solidification, MnS can be separated from molten steel with sulfur content of (70-140)×10-6. In addition, the higher the sulfur content is, the earlier MnS inclusions precipitate and the more the MnS content is.     

振动激发金属液形核对锌凝固组织的影响

为提高铸坯的等轴晶率和凝固组织的均匀性,以金属锌为研究对象进行了大量的振动激发金属液形核实验。结果表明,当一种带有冷却结构且进行高频振动的晶核发射器插入锌液内时,锌液在晶核发射器表面迅速形核且长大,在高频振动作用下表面形成的晶粒将被折断剥离,从而连续不断地弹射到锌液中,成为凝固过程中形成大量等轴晶的晶核来源;采用带有水冷和气冷结构的晶核发射器对锌液进行振动激发形核处理后,锌凝固组织中的等轴晶率可分别提高到65%和80%。     

Effect of acid soluble aluminum and niobium content on inclusion characteristics of grain oriented silicon steel

In order to elucidate the effect of Als (acid soluble aluminum) and Nb content on the characteristics of inclusions in grain oriented silicon steel, the type, quantity, size and size distribution of inclusions were studied by the field emission scanning electron microscope (FE SEM) equipped with an energy dispersive X ray spectroscopy (EDS) and image analysis software. Combined with the micro segregation model of solute elements during solidification, the precipitation mechanism of AlN and NbN inclusions was analyzed specially. The results indicate that the inclusions are mainly NbN, AlN and AlN-NbN, and the size distribution of the inclusions is affected by Als and Nb simultaneously. With the increase of Als content added in the steel, the content of Al2O3 in the oxide composite inclusions increases, while that of SiO2 decreases. The increase of Als content promotes the removal of silicate inclusions in the steels, but the segregation precipitation of AlN and AlN NbN inclusions increases. With the increase of Nb content added in the steel, the average size of inclusions reduces. The increase of Nb content promotes the earlier precipitation of NbN at the solidification front and its precipitation with oxides as the core. Als mainly affects the precipitation characteristics of oxide and nitride inclusions in the steel, and Nb also affects the oxides and nitrides precipitation characteristics via affecting the activity of oxygen and nitrogen combined with Als.     

酸溶铝和铌含量对取向硅钢夹杂物特征的影响

摘 要：为了掌握Als（酸溶铝）和Nb含量对取向硅钢中夹杂物特征的影响,借助场发射扫描电镜(FE-SEM)结合能谱仪(EDS)和图像分析软件研究了钢中夹杂物类型、数量、尺寸及尺寸分布,结合钢液凝固过程中溶质元素的微观偏析模型,重点分析了Als和Nb含量影响钢中AlN和NbN析出的机制。结果表明,钢中的夹杂物以NbN、AlN和AlN-NbN为主,夹杂物尺寸分布由Als和Nb含量综合影响。Als含量的增加使含氧复合夹杂物中Al2O3含量增加,SiO2含量降低,促进了钢中硅酸盐类氧化物夹杂的去除,但大大增加了AlN和AlN-NbN夹杂的偏析析出。Nb含量的增加使夹杂物的平均尺寸变小,促进了钢中NbN在凝固前沿的提前析出和以氧化物为核心析出。Als主要影响钢中的氧化物和氮化物夹杂,Nb通过影响与Als结合的O和N的活度影响钢中氧化物和氮化物夹杂的析出特性。