Inversion Solidification Cladding of H90Steel

The variation law of cladding thickness as well as the structures and properties of H90steel clad strip produced by inversion solidification was studied. The interface bonding mechanisms were approached. It is found that the thickness of H90 cladding goes sequentially through the solidification growth stage, holding stage, and remelting stage, with an increase in immersion time. The higher the preheating temperature of the steel coil, the thicker is the maximum cladding thickness. Observation by using optical microscopy (OM) and the electron probe microanalyzer (EPMA) shows that the microstructure of H90 cladding is composed of equiaxed grains, and that interdiffusion between Cu and Fe at interface occurs but obvious diffusion of Zn and the intermetallic layer are not observed. The diffusion layer is thin and about 4 μm. Multipass small reduction cold rolling and repeated bending tests show that the interface is firmly bonded. Tensile test shows that the mechanical properties of the asclad strips can meet the requirements of GB52132001 for the Fgrade deepdrawing steel plate though there is a slight difference in the mechanical properties among the clad strips with different cladding thickness.     

反向凝固连铸碳素钢带中复合层的凝固生长规律

在实验室条件下,用市售碳素钢板作为母带,用08Al低碳钢作为复合层材料,对反向凝固连铸薄带生产过程中复合层在母带表面的凝固生长规律进行了研究,研究结果表明,母带在钢水中的浸渍时间、母带厚度和钢水过热度对复合层厚度有显影响,而且这些工艺参数之间存在交互作的浸渍时间、母带厚度和钢水过热度对复合层厚度有显影响,而且这些工艺参数之存在交互作用;复合层的变化经历了“快速生长”、“平衡相持”和“迅速回熔”三个阶段,这三个阶段在复合层厚度－浸渍时间图上共同组成具有较长平台 的反向凝固“∩”形特征曲线;较低的钢水温度和较厚的母带有利于增加复合层厚度。     

定向凝固过程中固液界面稳定性的研究现状

界面稳定性是金属定向凝固过程中一个很重要的问题,关于它的研究也层出不穷。综述了这一领域的主要进展,着重讨论了基于MS理论研究的各种界面稳定性理论,并指出电磁场对界面稳定性的影响,同时分析了需进一步研究的主要方向。     

Interface-correlated Characteristics of Stainless Steel/Carbon Steel Plate Fabricated by AAWIV and Hot Rolling

Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy （OM）, scanning electron mi- croscopy （SEM） and transmission electron microscopy （TEM）. The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/ CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interracial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.     

热轧不锈钢复合板复合率和复合强度的研究

结合热轧复合工艺原理,分析了不锈钢复合板热轧复合过程中表面洁净度、复合坯压缩比、真空度、复合坯加热、轧制等工序对复合率和复合强度的影响,通过工艺参数的优化和应用,在实际生产中大幅度提高了不锈钢复合板的复合率和复合强度,并稳定了热轧复合工艺.     

Effect of Co on Microstructure and Interfacial Properties of Fe-Based Laser Cladding

The coatings consisting of Fe0.64 Ni0.36 dendrites as matrix and (Fe,Cr)7 (C,B)3 interdendritic compounds as reinforcement were fabricated on the medium steel substrate by laser cladding using the Fe-based powders with different Co content, and Co is uniformly dissolved in the coatings. Compared with the coatings containing 10% and 5% Co, the coating containing 3% Co increases in the area fraction of the interdendritic region by about 5%, in the microhardness nearby the interface by about HV 55 and in the interracial bond strength by about 30 MPa. The interface fracture morphology exhibits the tear appearance, which can be characterized as the ductile fracture.     

利用相区场模型模拟凝固过程枝晶的生长--各向异性相区场模型的推导

凝固组织枝晶生长过程的机理和数值模拟一直是材料领域的研究热点。扩散界面模型中的相区场方法近来得到了广泛应用，文章给出了纯物质凝固过程相区场模型的数学推导过程，并结合变分方法将各向异性引入到模型中来。     

快速凝固过程分析

从快速凝固的基本原理着手,详细总结了快速凝固技术的冷却方式判定方法,从物质的导热原理出发讨论了单辊熔体急冷法、双辊熔体急冷法的冷却方式,分别概括了它们的界面导热系数的计算,分析了冷却速度的计算方法。对快速凝固的过程分析具有参考价值。     

反向凝固钢带母带与凝固层间焊合的研究

研究了反向凝固钢带母带与凝固层之间的焊合,分析了反向凝固钢带的组成,焊合的条件及影响焊合的因素。结果表明:母带与凝固层可以实现良好的焊合,焊合的条件是母带表面产生部分熔化;钢难过热度对焊合有一定影响。     

垃圾焚烧飞灰预处理后水泥固化实验研究

为实现焚烧飞灰的无害化和资源化，采用对飞灰进行预处理后再与水泥混合固化的方法来处理飞灰，并比较了不同方式的处理效果：（1）用去离子水润湿飞灰再厌氧堆放24h后用水泥固化；（2）用绿矾溶液处理后再用水泥固化；（3）飞灰直接与水泥混合固化。研究3种方式所得水泥固化砌块试件强度的发展和控制重金属浸出的效果与直接固化物的对比，研究结果表明：在飞灰与水泥的质量比相同的条件下，采用先用绿矾处理飞灰再进行固化的处理方式，不但稳定重金属的效果好，而且试件强度最高，有望加以应用。     

垃圾焚烧飞灰预处理后水泥固化实验研究

为实现焚烧飞灰的无害化和资源化,采用对飞灰进行预处理后再与水泥混合固化的方法来处理飞灰,并比较了不同方式的处理效果:(1)用去离子水润湿飞灰再厌氧堆放24h后用水泥固化;(2)用绿矾溶液处理后再用水泥固化;(3)飞灰直接与水泥混合固化。研究3种方式所得水泥固化砌块试件强度的发展和控制重金属浸出的效果与直接固化物的对比,研究结果表明:在飞灰与水泥的质量比相同的条件下,采用先用绿矾处理飞灰再进行固化的处理方式,不但稳定重金属的效果好,而且试件强度最高,有望加以应用。     

反向凝固复合不锈钢带厚度数值计算

通过建立一维变物性参数凝固传热模型计算了用反向凝固工艺生产复合不锈钢带时钢带的厚度变化,计算结果与实验结果吻合较好,且很好地说明了钢带厚度的变化规律。     

复合轧制SM45钢板的组织性能

 连铸坯直接轧制生产特厚钢板时,由于压缩比的限制,很难生产出厚度超过100 mm的高质量钢板。采用复合轧制工艺可生产出厚度为260 mm的SM45复合钢板。对钢板进行探伤、冷弯、拉伸、冲击及硬度等试验检验其结合度和力学性能。结果表明,复合轧制生产的SM45钢板结合度良好,未发现明显的缺陷存在。钢板复合界面与基体的强度均在600 MPa以上;[Z]向试样的强度也达到600 MPa以上,断面收缩率在30%以上;冲击功在37 J以上。钢板不同位置处的基本组织都为铁素体与珠光体,但晶粒尺寸不同。复合界面处的组织为一条铁素体为主的带状组织,该组织的产生是由先共析铁素体导致的。     

Heat Transfer Analysis During "One-Step" Directional Solidification Process for Giant Magnetostrictive Materials

By theoretical analysis of heat transfer during the "one-step" directional solidification process, the functional relation between the temperature in solid-liquid interface and its effect factor was studied. The thermal gradient in solid liquid interface and heat transfer coefficient between the samples and surroundings were also calculated. On the basis of the above analysis, some suggestions for improving the thermal gradient in solid-liquid interface were put forward. It will provide a theoretical instruction for preparing high performance giant magnetostrictive materials (GMM).     

金刚石镀膜对金刚石强度以及与胎体结合性能的影响

采用真空镀膜的方法在金刚石表面镀覆金属Ｔｉ，测定了单粒抗压强度和金刚石样品的抗弯强度，用扫描电镜观察了金刚石样品的断口形貌；讨论了金刚石镀膜后对其单粒抗压强度和抗弯强度的影响，与未镀膜比较，金刚石镀膜后能够提高金刚石工具的磨削能力和使用寿命。     

电脉冲对细化金属凝固组织的影响现状

综合论述了电脉冲在细化金属凝固组织方面的应用和研究状况，从不遇角度对其作用机理做了分析探讨。同时指出电脉冲这一新技术应用前景广阔，但仍需克服多方面的困难，进行更系统和深入的研究。     

亚快速凝固技术的研究进展

介绍了实现亚快速凝固的两种方法：激冷法和深过冷法,并概述了亚快速凝固理论的最新研究进展.亚快速凝固的冷却速度介于快速凝固和近平衡凝固之间,为10^0～10^3 K/s,其凝固过程比较复杂,兼有快速凝固和近平衡凝固的优点.与传统工艺生产的材料相比,亚快速凝固材料的组织和性能更加优异.尽管亚快速凝固的理论研究还刚刚起步,但随着薄带连铸技术的快速发展,该技术在工业生产中的应用前景十分广阔.     

定向凝固大型铸锭研究

为满足高质量，大单重用厚钢板的急需，舞钢研制开发了，定向凝固技术经过２ｔ，１０ｔ铸坯的质量检验证明定向凝固工艺是成本低质量好的工艺路线，定向凝固改变了传统模注凝固模式，改善了结晶组织结构，气体夹杂成分偏析也与模注不同，有希望在低速大压下的轧制工艺下得到高质量的厚钢板。     

反向凝固复合不锈钢带的轧制工艺及界面结合

针对用反向凝固法生产不锈钢复合带的工艺,研究了轧制温度、轧制速度及轧制变形率对母带与凝固层间结合的影响。结果表明：轧制温度为１２５０℃、两道次的轧制变形率为５０％时,界面结合较好,轧制速度对界面结合的影响不明显。经分析得知 喧与凝固层的界面结合是靠元素相互扩散形成过渡区实现的。