高纯Cr17钢板厚方向织构演变、成形性能及表面皱折

以高纯Cr17铁素体不锈钢为实验材料,对比研究了热轧不退火、退火两种工艺对其板厚方向织构演变、成形性及表面皱折的影响。采用金相显微镜、X射线衍射技术及背散射电子衍射技术观察两种工艺条件下的组织和织构演变。结果表明:成品板各层织构特征存在显著差异,这是由于低温轧制过程中沿板厚方向不同应变状态导致的热轧织构梯度遗传所致。与热轧不退火相比,热轧退火有利于成品板各层γ纤维再结晶织构增强,偏离{111}<112>组分的程度减弱,α纤维织构弱化;有利于弱化成品板的带状晶粒簇,促使晶粒簇分布均匀分散。     

齿轮钢20CrNiMo轧材表面裂纹缺陷原因分析

针对规格不小于?80 mm的齿轮钢20CrNiMo轧材探伤合格率低,轧材表面存在裂纹缺陷问题,对轧材裂纹缺陷进行分析,可知这可能是铸坯裂纹缺陷造成的。为了验证这一观点及查找出确切原因,便于提供解决方法,首先对铸坯表面进行抛丸检查,未发现裂纹缺陷;其次将存在裂纹的铸坯轧制成材的缺陷与轧材表面裂纹缺陷通过金相显微镜进行对比分析,发现裂纹形貌及周围脱碳程度存在差异,分析认为轧材裂纹不是由铸坯缺陷导致的;最后将铸坯开坯后方坯直接挑出缓冷后抛丸检查,发现表面存在严重划伤和凹坑缺陷,划伤缺陷形貌和周围脱碳程度与轧材裂纹相似。结果表明:轧材裂纹及翘皮缺陷是由铸坯开坯过程中产生的划伤和凹坑缺陷导致的,不是由铸坯裂纹缺陷导致的。     

采用Φ210mm连铸坯的轧坯生产冷拔高压锅炉钢管

介绍了天津市无缝钢管厂采用２０ＧΦ２１０ｍｍ连铸坯（先经６５０轧机轧制成Φ７５ｍｍ实心圆管坯）生产冷拔高压锅炉钢管的管坯生产工艺、冷拔工艺和产品质量，讨论了生产中应采取的主要技术措施。生产实践表明，这种管坯可以生产出符合标准要求的高压锅炉钢管。     

冷轧带肋钢筋专用母材技术开发

冷轧带肋钢筋母材的选用是影响冷轧带肋钢筋性能的关键因素,介绍了冷轧带肋钢筋专用母材的技术开发。     

冷轧高强度低合金钢HC420LA的连续退火工艺

根据冷轧高强度低合金钢HC420LA的产品要求对其冷轧连续退火工艺进行了研究。HC420LA钢产品成分采用Nb、Ti微合金化成分体系、生产工艺选择热连轧+冷轧连续退火的工艺路线。通过实验室再结晶温度试验测定了HC420LA钢产品的再结晶温度,在工业化试生产阶段对连续退火工艺进行了试验研究,得出冷轧低合金高强钢 HC420LA 的再结晶温度为700 ℃,工业化生产时最佳加热均热温度为760 ℃。     

������Ʒ����������ȱ�ݳ���Ԥ����ʩ

 冷轧板最主要的质量问题就是表面缺陷,亮带缺陷是目前首钢冷轧板最为常见的表面问题。通过研究不同亮带表面缺陷形貌及亮带处缺陷形貌、发生规律、元素构成、以及全流程缺陷的遗传性,分析了首钢冷轧亮带缺陷的主要原因,包括连铸坯皮下夹渣、皮下气泡、氧化铁皮压入以及辊印等因素。     

铸坯轧后拉伸试样断口分层原因分析及预防措施

结合邯钢生产实践,对板坯连铸机铸坯轧后拉伸试样分层缺陷原因进行分析并提出了预防措施,有效减轻了铸坯中心偏析及疏松,提高了铸坯实物质量,减少了铸坯轧后分层缺陷。     

Use of Taguchi method to study a robust design for the sectioned beams curvature during rolling

Finite element DEFORM™ 3D software is employed to examine the plastic deformation behavior of V-sectioned and T-sectioned porous beams at the roll gap under various rolling conditions. The finite element code is based on a rigid–plastic model in which it is assumed that the rolls are rigid bodies and that the temperature change induced in the beams during rolling is sufficiently small that it can be ignored. The analytical model is used to systematically examine the effect of the inclination angle of the roll profile, the friction factors between the rolls and the beam, the roll radii and the angular speed of the upper and lower rolls on the curvature of the rolled beam, the rolling torque, the effective strain, the effective stress and the variation of density of the rolled product at the exit. The Taguchi method is employed to design the rolling parameters to optimize the curvature of the beams. The analytic results have shown that: (1) the inclination angle of the inner part (i.e. vacancy) of the upper roll, the friction factor of the lower roll, the angular velocity of the lower roll and the roll radii, respectively, all have a significant influence upon the curvature of the rolled V-sectioned product, κ = 1/r_a; (2) the reduction ratio of the porous beam, the friction factor of the lower roll, the angular velocity of the lower roll, and the roll radii, respectively, all have a significant influence upon the curvature of the rolled T-sectioned product, κ = 1/r_a.     

Some fundamental considerations for the control of residual flatness in tension levelling

Tension levelling is a process used in the steel industry in order to remove any shape defects present in temper rolled strip. It is generally the final process before the cold rolled product is despatched to the customer, and therefore plays an important rôle in delivering the desired material properties and the product standards required.

In this paper a designed factorial analysis has been employed in order to study the effect that tension levelling process parameters have on the shape characteristics of the levelled product. These characteristics include residual flatness (longitudinal curvature or longbow), centreline elongation and residual (or internal) stress imbalances; criteria which determine whether the customer accepts the material or not. It has been identified that in a basic five-roll leveller the final, adjustable roll wrap angle, has the most significant influence on these characteristics in over 70% of cases. It has also been determined that final flatness is dictated by many second-order process interactions.     

典型半工艺电工钢产品M660-50K5生产及应用技术解析

对欧盟市场汽车压缩机专用产品进行技术解析,对比分析了其电磁性能、退火和发蓝处理、物理性能、化学成分、应用特点等参数。探讨国内外电工钢产品应用方式的不同特点,并结合鞍钢自身工艺装备和炼钢、热轧、冷轧工艺参数介绍了其生产可行性。提供了冶金工艺流程下,后工序电工钢专业生产线及传统冷轧系统生产线两种生产方式,均能满足用户最终使用要求。     

半固态60Si2Mn直接轧制成形技术的研究

利用自行研制的高熔点半固态金属材料的轧制设备，对60Si2Mn弹簧钢进行半固态直接轧制成形，并研究流变行为和规律，探索出适合于半固态钢铁材料直接轧制成形的生产工艺。研究结果表明：固－液两相的塑性变形行为是不同的，从而导致了轧制产品的心部和边部在组织及性能上的差异。在变形过程中，大多数的固相集中在试样的心部，而液相则流向轧件的边部。随着固相率的提高，固相颗粒发生塑性变形的程度亦提高。若半固态浆料中液相含量过少或变形速率过大，轧辊表面与轧件的温差过大，则轧件的表面会产生微小的裂纹。     

我国400MPa热轧带肋钢筋应用现状和发展建议

介绍了近年来我国 40 0MPa热轧带肋钢筋推广应用的进展情况 ,典型应用实例 ,其有关标准的修订及与国外同类产品的性能比较。并对今后 40 0MPa热轧带肋钢筋的推广应用工作提出了建议。     

The improved control for an aluminium hot reversing mill using the combination of adaptive process models and an expert system

Of major concern to the producers of aluminium sheet is the quality and consistency of the rolled product. The metallurgical and dimensional properties of rolled strip must be carefully controlled if the product is to be of prime quality. Mill control systems have been introduced to automate many tasks normally performed by the mill operator. This paper details the development of a prototype mill set-up and control system that runs under the supervision of an expert system. The system has been developed around an expert system shell and tested in simulation.     

������ǿ�ȴ��ֽ�ֱǰ�����Ӧ���ֲ����о�

 本文针对热轧钢板产品常出现的旁弯、翘曲等板形质量问题,通过盲孔法测量钢办矫直前以及粗矫、精矫后的残余应力分布来分析矫直工艺对带钢残余应力分布的影响,以便改善热轧钢板产品的质量。实测结果表明：矫直前钢板板宽方向残余应力很不均匀,并且在钢板边部存在残余压应力使钢板出现边浪等板形不良的情况;经过粗矫后应力值分布不均减小;在精矫后应力值进一步减小并且分布趋于均匀。而同一矫直工序中钢板长度方向不同位置残余应力分布也不同,其中钢卷中部的残余应力值为最小。     

AN INVESTIGATION OF FINE GRAINS IN THE PRODUCT OF ORIENTED-GRAIN SILICON STEEL SHEET WITH HIGH INDUCTION

本文采用金相蚀坑法对高磁感取向硅钢成品中细晶进行了研究,证明板坯加热温度过高,热轧板产生粗大的形变组织,促使初次再结晶{100}<011>-<001>组分增强,该区域晶粒也较粗大,高温退火后,成品中出现线晶。热轧板坯加热温度太低,热轧前的MnS和AlN不能完全固溶,成品中出现混晶。另外,指出提高钢中碳含量,增加热轧的压下率,采用二次冷轧法都可减少或消除成品中的线晶。     

An Analytical Modified Model of Clad Sheet Bonding by Cold Rolling Using Upper Bond Theorem

In this paper, clad sheet bonding by cold rolling was investigated using the upper bond theorem. Plastic deformation behavior of the strip at the roll gap was investigated, unlike previous methods; distinctive angular velocities are used for different zones in roll gap in present model and absolute minimum of rolling power function is achieved. Rolling power, rolling force, and thickness ratio of the rolled product affected by various rolling condition such as flow stress of sheets, initial thickness ratio, roller radius, total thickness reduction, coefficient of friction between rollers and metals and between components layer, roll speed, etc., are discussed. It was found that the theoretical prediction of the thickness ratio of the rolled product, rolling force, and rolling power are in good agreement with the experimental measurement.     

基于铁素体轧制工艺低碳铝镇静钢板r值降低原因分析

某钢厂试开发基于铁素体轧制工艺的SPCC板,经热轧-冷轧-罩式退火工序后对样品进行性能检测,发现与传统奥氏体轧制工艺相比,该工艺路径下的产品各项力学性能指标均有不同程度下降,且r值有明显降低。对两种工艺路径的热轧板和冷轧退火成品板进行了组织和织构的对比分析,且提出了改进措施。结果表明:铁素体轧制工艺中热轧精轧温度过高,形成两相区轧制,得到粗大F+纤维状F的不均匀室温组织,从而导致冷轧退火板中存在较高强度{001}<110>织构组分,是导致最终产品r值降低的主要原因。     

冷轧纵切机组产品表面缺陷产生原因及其控制

针对攀枝花钢铁有限责任公司冷轧厂纵切机组产品表面存在擦伤、划伤等缺陷问题,从生产工艺和设备两方面对缺陷产生原因进行了分析,并相应进行了工艺、设备和管理制度的优化。改进后不仅产品实物质量明显提高,而且进一步提高了机组生产效率。     

国产汽车钢板材料性能波动特性的统计学分析

汽车钢板材料性能波动特性是影响汽车制造质量的重要因素之一。运用统计学方法系统分析、比较了应用广泛的国产软钢系列的性能波动特性,通过正态检验得知,并非所有性能的概率分布满足正态并对不符合正态的分布提供了Box-Cox转换模型;由软钢系列的分析、比较得知,强度级别越高(断裂延伸率越低),波动越明显,镀层钢板的力学性能均值基本没有变化,而性能的波动有所减少。     

铁素体轧制对普通用冷轧钢板组织和性能的影响

采用光学显微镜和扫描电镜对比研究了铁素体区热轧工艺及奥氏体区热轧工艺对普通用冷轧钢板(SPCC)产品热轧组织、冷轧组织及性能的影响。结果表明,与奥氏体区轧制工艺相比,采用铁素体区热轧工艺生产的SPCC热轧板晶粒尺寸会增大约17 μm,{111}面织构数量减少了8.74%,强度略微降低,而{001}<110>织构数量增加了12.40%,强度提高了19.81。此外,采用铁素体区热轧工艺生产的SPCC成品晶粒呈近似等轴状,与奥氏体区热轧工艺相比平均晶粒尺寸增大了4.5 μm。SPCC铁素体区轧制热轧板中更大的晶粒尺寸、更少的{111}面织构及更强的{001}<110>取向织构导致了冷轧成品更低的屈服强度和塑性应变比r值,较奥氏体区热轧工艺而言平均屈服强度降低了19 MPa,平均r值下降了1.1。