Kinetics of hydrogen reduction and the influence of gas composition on hot-rolled steel scale after temper rolling

For replacing the presently employed pickling method with a more environmentally friendly descaling method,hydrogen reduction of oxide scale formed during hot rolling was studied at 800 ℃ under a varied atmosphere.The hydrogen level and water vapor content in the reducing atmosphere were found to influence the reduction rate wherein increasing hydrogen level as well as decreasing water vapor content resulted in faster oxide reduction. The reduction reaction substantially obeyed a parabolic rate law. Oxide scale of a usual thickness( approximately 7micrometer) could be reduced almost completely in an atmosphere of 20 vol. % hydrogen with a water vapor content corresponding to a- 40 ℃ dew point at 800 ℃. When lowering the hydrogen level to 10% and increasing the water vapor content to a 10 ℃ dew point,quite a large extent of the oxide scale was retained,which might be attributable to the formation of an outermost dense layer of pure iron at the early stage of reduction.     

Effects of Al contents on microstructure and properties of hot-dip Zn-Al alloy coatings on hydrogen reduced hot-rolled steel without acid pickling

A new hot-dip galvanizing method was employed on hot-rolled low carbon steel. The effects of Al contents on microstructure, micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigated. Phase composition, microstructure and element distribution in Zn-Al alloy coatings were analyzed using X-ray diffraction (XRD) and electron probe micro analysis (EPMA), respectively. It is found that Al content (0. 6–6. 0 wt. %) in galvanizing zinc affects surface quality and adhesion between coatings and matrix in the newly developed method. In addition, with increasing Al content, micro-hardness significantly increased due to the increase in Zn-Al eutectoid phases. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) also revealed that increase in Al plays a noticeable role in improving the corrosion resistance of Zn-Al alloy coatings.     

硅钢氧化皮SXC-B酸洗促进剂的应用

研制出了一种硅钢氧化皮SXC -B酸洗促进剂。实验室和工业试验表明 ,硅钢酸洗工艺使用这种促进剂可收到显著的效果。SXC -B酸洗促进剂可以提高酸液对钢板氧化皮的去除能力 ,加快酸洗速度降低酸耗 ,改善酸洗环境 ,提高酸洗后硅钢板面质量。     

热轧奥氏体不锈钢带钢酸洗工艺机理分析

 详细分析了热轧奥氏体不锈钢带钢的表面氧化皮形成机理、退火对氧化皮特性的影响机理、酸洗工艺机理。结论是：热轧奥氏体不锈钢带钢表面氧化皮外层主要以铁氧化物为主,内层主要以交替分布的Cr2O3和FeCr2O4层为主;退火后,氧化皮结构变得疏松多孔,且易脱落,贫铬层厚度增加,带钢更加容易酸洗;酸洗时,带钢表面的氧化皮主要通过机械剥离作用去除。分析结果对热轧奥氏体不锈钢带钢酸洗技术的改进具有一定的理论指导意义。     

Study on transformation behavior of hot-rolled microalloyed trip steel北大核心CSCD

Effects of deformation mode, deformation temperature, deformation rate, cooling rate and slow-cooling stop temperature on the transformation behavior of hot-rolled microalloyed TRIP steel were studied by means of MMS-300 thermomechanical simulator. The results show that for the samples subjected to the single or double pass deformation, ferrite transformation area is expanded, pearlite transformation area appears, and martensite transformation area disappears in the continuous cooling transformation diagrams. Transformation temperatures of A,i, B. and B( decrease, diffusional transformation is prevented and intermediate temperature transformation is promoted with the increase of deformation temperature or cooling rate. When deformation temperature is 850 ∗C , transformation temperatures of A,i, B, and Bi increase, the amount of ferrite also increases, and the amount of bainite decreases in the microstructure with the increase of deformation rate. With the decrease of slow-cooling stop temperature, ferrite amount increases, ferrite grains grow and retained austenite amount first increases and then decreases. © 2018 Gangtie Yanjiu Xuebao. All rights reserved.     

热轧带钢氧化铁皮的酸洗行为

热轧过程中,不同的轧制工艺和卷取条件会获得不同的氧化铁皮结构。其中,FeO的晶粒是以三角锥型或金字塔型的方式生长,Fe3O4以柱状晶的形式生长,Fe2O3以金属须状方式生长。针对不同结构的氧化铁皮进行酸洗模拟试验,研究热轧带钢不同位置的氧化铁皮的酸洗行为,绘制了不同氧化铁皮结构的酸洗动力学曲线,分析由于供氧差异对氧化铁皮结构和酸洗行为造成的影响;并揭示了两种典型氧化铁皮结构的酸洗机制,以FeO为主的氧化铁皮结构其酸洗机制为“剥离”、化学溶解和相结合,以Fe3O4为主的氧化铁皮结构其酸洗机制以化学溶解为主。     

冷轧酸洗钢板表面黑斑缺陷分析

针对冷轧酸洗钢板黑斑缺陷问题,对Q195、ST13钢在不同试验温度下进行了氧化铁皮的生成、冷却、酸洗试验,对试验后的试样和生产现场钢板的表面进行了微观分析。结果表明：冷轧酸洗钢板黑斑实质上是未完全酸洗掉而残存的氧化铁皮,是由热轧工艺引起;冷轧酸洗钢板黑斑主要由Fe3O4和FeP组成;温度越高,表面氧化铁皮越厚,e3O4含量越高,冷轧酸洗钢板越易产生黑斑。     

高强IF钢冷轧边部条带缺陷机理分析与控制

通过光学显微镜、扫描电镜、能谱分析以及酸洗模拟等方法,研究了高强IF钢HC250IF表面条带缺陷的产生原因、结构特点和控制措施。结果表明,氧化铁皮沿带钢宽度方向的不均匀分布以及拉矫破碎效果不充分导致了带钢边部比中部更容易发生过酸洗。在磷元素表面富集和晶界偏聚作用下,基体晶界处优先发生选择性侵蚀,侵蚀裂纹沿晶界从表面向内部扩展,形成具有厚度差的多孔区和粗糙区结构。冷轧过程中,缺陷部位变形撕裂,产生了大量表面微裂纹,增大了局部粗糙度差异,进而在带钢边部形成条带缺陷。以优化匹配热轧和酸洗工艺参数、改善热轧带钢表面状态为基础,通过控制酸洗进程、提高酸洗质量均匀性等措施,能够有效减少这类缺陷的发生。     

酸洗条件对不同规格钢种酸洗效果的影响研究

影响冷轧酸洗钢板表面质量的要素有酸洗温度、酸液浓度和酸洗速度等酸洗条件,但是不同规格的钢种对酸洗条件的要求也有较大差异.本文就酸洗条件对不同规格钢种的酸洗效果进行试验研究,从而进一步优化酸洗生产工艺,实现企业节能降耗.     

热轧11×75弹簧扁钢的试制

本文介绍了11×75系列弹簧扁钢的标准要求、孔型设计及生产工艺。     

工业锅炉水垢的酸洗

介绍了工业锅炉水垢形成、危害;阐述了工业锅炉的酸洗条件、原理及工艺.     

不锈钢的轧制、退火、酸洗综合生产线

将轧制、退火和酸洗工段综合在一起的一体化的主要设想可追溯到1990年在瑞典的Avesta Nyby厂增加在线轧机。自此以后，通过在J＆L Midland，然后在Ugina Isbergue，最后在AvestaPolarit RAP5生产线上取得了进展。对不同阶段的综合生产线的工艺发展进行了比较，并且对Tornio的AvestaPolarit RAP5生产线的工艺流程和设备安装进行了总结。     

热轧带钢表面氧化铁皮成因及去除方法

通过对热轧带钢生产过程关键因素的研究,具体分析了氧化铁皮的性质、结构,并提出了控制氧化铁皮生成和有效清除氧化铁皮的方法。     

冷轧不锈钢表面氧化皮残留和麻点缺陷问题探讨

对导致退火酸洗机组降速的不锈钢表面黑点和麻点两种缺陷进行了分析,并通过实验对比,给出了两种缺陷的不同成因,提出了相应的改善方法。实践表明,在改善产品表面质量和降低缺陷率的前提下,达到了提高机组产量的目的。     

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情诗的写作手法和用喻特点,并探析了及时行乐主题及其产生的社会历史原因。From The Flea to To His Coy Mistress:On the seductio     

不锈钢带材退火酸洗技术及应用

以某厂新建不锈钢退火酸洗生产线为例，介绍不锈钢退火酸洗的生产工艺、设备及自动控制系统，并对该生产线的主要特点予以阐述。     

不锈钢酸洗污泥碳还原过程中的物相变化及元素迁移行为

不锈钢酸洗污泥是危险废弃物,但其中含有大量有价值重金属,因而如何对其资源化利用具有重要意义.研究不锈钢污泥在碳热还原反应过程中铁、铬、镍等元素在物相间的相互作用及转化,探究铁、铬、镍元素在污泥中分布的影响因素.利用XRD分析污泥在还原过程中的矿相变化,金相显微镜、SEM-EDS分析污泥还原过程中金属颗粒的形貌及其迁移行...