国内热轧焊接气瓶钢的质量现状

介绍了国内焊瓶制造业和钢材生产厂家对热轧焊瓶钢板的质量需求与生产供应状况，分析了国内焊瓶钢的采标、质量控制和质量改进的进展。     

改进冒口减少台车体端部缩孔

台车体是烧结机的主要部件，我厂在过去生产中采用瓶式冒口，台车体有６０％￣７０％端部产生缩孔，要进行焊补，既影响了台车体质量，又造成了浪费。为提高台车体质量，我们将瓶式顶冒口改为靠边耳冒口，消除了端部缩孔。     

HP 295加工月牙开裂原因分析及对策

结合生产实践及加工特点,针对焊瓶钢HP295封头拉伸过程中月牙开裂缺陷产生原因进行了细致分析。分析认为:铸坯中间裂纹、长条状MnS夹杂是造成焊瓶钢加工月牙开裂缺陷的根本原因,而成分偏析、合理的组织构成和规范的加工工序亦非常重要。     

HP295钢中夹杂物对钢瓶拉延性能的影响

通过对HP295焊瓶钢制作的钢瓶封头缺陷进行分析，找到了影响钢瓶封头拉延性能的原因。结果表明，拉延焊瓶封头出现开裂是由于钢中集中分布的稀土夹杂物所致。皱折缺陷与钢中存在带状组织、钢板厚度不均以及拉延工艺有关。     

典型焊接气瓶用钢的制瓶工艺与质量要求

以国内的某些钢瓶厂为例，介绍了典型焊接气瓶用钢HP295、HP325、HP345制瓶工艺，结合常见的制瓶工艺失效形式，提出对钢板的质量要求，并分析了满足这些质量要求应该采取的措施。     

柳钢焊瓶钢冲压缺陷分析与工艺改进

通过对柳钢焊瓶钢冲压过程常见的缩口开裂、压延开裂、"黑线"三种缺陷进行综合分析,确定夹杂物与偏析、厚度超厚、划伤是上述三种缺陷产生的主要原因。通过工艺优化,焊瓶钢冲压缺陷率降低至千分之五以内。     

冷轧带肋钢筋焊接网的应用

冷轧带肋钢筋是Ⅰ级钢筋的换代产品,其焊接网在国外已广泛用于建筑工程中,使用焊网不但能提高施工质量、加快进度,而且可节约钢材30％左右.目前国内焊网推广中所要解决的问题是加强质量管理和降低成品价格.在我国,焊网的原材料占成品价的55％左右,大大低于国外的75％.通过降低焊网的市场价格,从而降低工程造价,才能更进一步地促进焊网的推广使用.     

冷却工艺对HP295焊瓶钢板屈强比的影响

为探讨工业生产条件下降低铁素体／珠光体钢屈强比的有效办法，研究了前段冷却、后段冷却和两段式冷却3种工艺对HP295焊瓶钢板屈强比的影响规律，通过采用两段冷却方式并控制带钢卷取温度使攀钢HP295焊瓶钢板的屈强比低于0．8，屈强比合格率由此前的不足90％提高到100％，各项力学性能满足国家标准GB6653—1994要求。     

管端内衬不锈钢复合钢管环焊缝质量缺陷研究

在国内某长距离输水工程压力钢管设计中,采用了管端内衬不锈钢复合钢管。在最初的焊接工艺评定及试焊过程中,大部分试焊的环焊缝均出现不同程度的质量缺陷,导致生产焊接无法进行。本文根据焊接工艺评定,试焊过程及相关试验检测数据,就质量缺陷出现的原因进行深入分析,得出相关结论。     

通钢FTSR工艺降低HP345屈强比的试验

为解决HP345焊瓶钢屈强比超标问题,在通钢FTSR生产线上,对影响屈强比的主要因素控轧控冷工艺进行试验研究。试验结果表明,提高终轧温度和卷取温度,层流冷却模式采取后段冷却,能够使HP345焊瓶钢的屈强比由最初的0.81降低至0.76,且各项力学性能满足国标GB 6653—2008要求。     

Use of LNG‐Oxygen Gas Mixture in RH Degassing Unit

Mixed gas of liquefied natural gas (LNG) and oxygen was injected into the vacuum vessel during non‐decarburization period using a multifunctional lance. Tthis study reports the experimental results when applying this process in a 100‐ton piece of equipment and reports the changes in temperature of the refractory surface and molten steel. Using a multifunctional lance allowed heat supplementation by injecting LNG‐oxygen mixed gas into the vacuum vessel of a RH device and then burning the gas near the outlet of the injection nozzle. The following was found: The minimum surface temperature required so that the skull would not adhere to the RH vessel was calculated as about 1643K (1370°C). When the interior of the RH vacuum vessel was preheated with a multifunctional lance so that the temperature would be higher than this, skull adhesion to the vessel did not occur. Calculation of heat balance for burning under atmospheric pressure showed that about 70% of the heat quantity of burning was supplied to the refractory. When mixed gas was burned during the RH process, it was shown from the temperature change of molten steel that about 52% of the burning heat was transferred to the steel. Heat quantity removed through lance cooling water was proportional to the charge length of the lance, and emissivity ε was equivalent to heat transfer quantity of 0.38.     

Scaling estimations of thermal and flow field in gas-stirred ladles

To obtain a better understanding of the physical process involved in gas stirring of a steelmaking vessel, a scaling analysis approach is developed that accounts for the effects of natural convection and axisymmetric bottom gas injection in the vessel. The orders of magnitude of some important quantities such as the transient velocity scale, thermal boundary layer thickness, and the critical flow rate to homogenize the thermal stratification in the molten steel are predicted successfully.     

Optimization of the heat treatment of ingots of high-strength vessel steel modified by rare-earth metals

A process is developed for the production of high-strength vessel steel. It includes the application of a microcrystalline REM-containing modifier and an improved regime of preliminary heat treatment of ingots. This process ensures high hot deformability of ingots and a substantial decrease in the time of production of high-strength vessel steel. The quality of the produced steel meets the requirements of the existing technical forms and records.     

Behaviour of Argon Gas Bubbles in an Electromagnetic Driven Swirling Flow

An innovative steelmaking process is suggested using an electromagnetic driven swirling flow in the up‐leg of an RH vacuum degassing vessel. The effectiveness of this new process depends on the two‐phase flow behaviour of molten steel and argon gas. A physical and a mathematical model are developed to understand the effect of electromagnetic driven swirling flows on the behaviour of gas bubbles in the up‐leg of an RH vessel. Both water model experiments and numerical simulation show the distribution and trajectories of the gas bubbles. The gas bubbles’ trajectories are spiral and move towards the centre of the up‐leg in the swirling flow field. The accumulation of gas bubbles depends on the swirling number. At the same time, the swirling flow can prolong the residence time and trajectories of non‐metal inclusions in the vessel. The viscous drag force becomes important for small bubbles in the RH degassing vessel, and small bubbles have the trend to rotate with the swirling flow.     

中低温压力容器用A516GR70钢板的研制

本文介绍了济钢中低温压力容器用A516GR70钢板的特点和研制，通过结果分析，表明了济钢生产的中低温压力容器用A516GR70钢板质量稳定可靠，符合标准和制造压力容器的要求。     

太钢RH真空处理

太钢RH真空处理属于冷扎硅钢生产线的配套工程。主要包括：钢包运输及顶升系统、真空系统、吹氧和煤气加热系统、合金系统、真空室等。     

Mathematical Modelling of Molten Steel Flow Process in a Whole RH Degasser during the Vacuum Circulation Refining Process: Application of the Model and Results

A three‐dimensional mathematical model for the molten steel flow during the RH refining process has been applied to the circulatory flow processes in both a practical RH degasser and its water model unit. The model was presented earlier [1] and one of its characteristics is that ladle, snorkels and vacuum vessel are regarded as a whole. Using this model, the fluid flow field and the gas holdups of liquid phases and others have been computed respectively for a 90 t RH degasser and its water model unit with a 1/5 linear scale. The results show that the mathematical model can properly describe the flow pattern of molten steel during the refining process in an RH degasser. Except in the area close to the liquid's free surface and in the zone between the two snorkels in the ladle, a strong mixing of the molten steel occurs, especially in the vacuum vessel. However, there is a boundary layer between the descending liquid stream from the down‐snorkel and its surrounding liquid, which is a typical liquid‐liquid two‐phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is ascending mostly near the up‐snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and molten steel in the up‐snorkel is closer to an annular flow. The calculated circulation rates for the water model unit at different lifting gas rates are in good agreement with experimentally determined values.     

Al含量和Cr-Mo微合金化对37Mn钢Φ350 mm铸坯裂纹的影响

通过试验研究和理论分析等手段，明确了柱状晶界面结合力弱是37Mn气瓶钢连铸坯裂纹产生的主要原因。采用拉伸试验、扫描电镜、金属膨胀仪、金相显微镜等研究设备，分析了柱状晶结合力的影响因素。研究表明，当Al含量0.007%增加至0.033%时，使800℃时钢的热塑性显著降低，同时导致A-F/P相变过程体积效应增大，柱状晶晶界位置易形成微裂纹及孔洞；同时晶界位置Al、P、S元素偏析也是形成裂纹的原因之一。在此基础上，提出了降低钢中N含量由0.0080%降至(0.0040%～0.0060%),添加微量Cr (0.20%～0.25%)、Mo (0.05%～0.08%)以及使连铸坯在750～600℃缓冷等措施，有效减轻了晶界相变应力及热应力，避免了37Mn气瓶钢连铸坯裂纹萌发和扩展。     

Tundish Metallurgy: Towards Increased Productivity and Clean Steel

Tundish in the steelmaking circuitry, like BOF/EAF and ladles, plays a pivotal role in determining plant performance and steel quality. Thus, beyond its traditional role as a buffer vessel, a steelmaking tundish is currently designed and operated to ensure maximum yield, superior cleanliness, negligible energy and materials losses and longer life. Naturally therefore, modern day steelmakers are emphasizing tundish management and practice. Adequate understanding of the physical, chemical and thermal interactions among steel, slag, gas and refractory phases is a pre-requisite to fully exploit the potential of any given tundish system. In the present work, a brief account of the theory of tundish processing is first presented. Following such, phenomena such as, inclusion removal, temperature drop, skull losses, grade intermixing as well as slag emulsification and entrainment in different tundish systems are discussed. In such context, decade long association with half a dozen domestic steel industries namely, JSW-Ispat, JSPL, JSW, RINL, Hospet steel and MUSCO is highlighted and our approach and efforts towards tundish process performance enhancement demonstrated.     

保证二炼钢厂RH—KTB处理用汽的探讨

福钢二炼钢２台２７５ｔ转炉均停吹后,蒸汽量不能满足乖下的最后、包钢水进行ＲＨ－ＫＴＢ处理,针对此问题进行分析,并提出提高ＬＴ煤气冷却系统蒸汽蓄絷器的放汽压力是解决问题的有效措施。