浮动芯棒速度对钢管连轧力学参数影响的有限元分析

采用ABAQUS显式动力仿真平台,结合生产实际,对宝钢140mm全浮动芯棒钢管连轧过程进行仿真分析,研究连轧过程中芯棒与轧件的运动状态,并采用单机架限动芯棒模型研究芯棒速度对轧制力和轧制力矩的影响。结果表明:芯棒-轧辊速比对轧制力和轧制力矩有很大的影响。当芯棒-轧辊速比小于1时,轧制力随速比的增加而显著增加;当速比约为1时,轧制力具有峰值;当速比大于1时,轧制力随速比的增加而减小。轧制力矩随芯棒-轧辊速比的增加单调减小。当速比大于1.25后,轧制力和轧制力矩的变化都不再明显。毛管头部咬入第5,6机架时,芯棒-轧辊速比的增加导致轧制力的增加,使荒管形成前竹节;毛管抛出第1~4机架时,芯棒-轧辊速比的增加亦使5,6机架的轧制力增加,使荒管形成后竹节。     

穿孔机前后台设备选型分析及应用

穿孔机组中非常重要的辅助设备是穿孔机前后台设备,文章在分析国内外穿孔机前后台的技术特点的基础上,重点分析了设备选型问题,最后介绍了包钢Φ159 mm连轧管生产线工程应用,指出穿孔机前后台设备选型对于推动无缝钢管制造装备的国产化具有积极作用。     

无缝钢管生产用芯棒断裂失效分析

某无缝钢管生产用的芯棒在使用过程中频繁在尾部断裂,通过宏观检查、化学成分分析、金相检验、力学性能试验等方法对断裂原因进行了分析。结果表明:芯棒尾部异常受力引起疲劳弯曲是导致芯棒尾部断裂的外在因素;芯棒结构不合理使尾部受力时芯棒过渡锥面与尾杆交接处产生较大弯矩与应力集中,且芯棒断裂处显微组织带状偏析较严重、横向冲击吸收能量较低、韧性较差是导致芯棒断裂的内在因素。     

大口径坯管步进式工业炉故障分析及解决办法

我国大口径无缝钢管发展同比国外研究生产落后很长一段时间,从2008年起我国投建了第一套720口径无缝钢管生产线,添补了我国大口径无缝钢管产业的空白。本文研究目标是对工业炉加热坯料形式上从管坯基础上增加了对“坯管”的加热工艺中步进式工业炉设备中容易出现的故障分析以及解决办法。     

身管膛线精锻成形金属流动与变形分析

以某身管膛线精锻加工过程为研究对象,使用通用有限元商业软件Abaqus建立了三维轴对称有限元模型,对身管膛线的成形过程进行数值模拟,分析了膛线嵌入芯棒过程中的金属流动情况。此外,还分析了芯棒结构及断面减缩率对膛线成形的影响,为实际加工过程中工艺参数的选取提供依据。     

高性能结构材料

新钢钒H型钢试轧成功近日,中国西南地区首支H型钢在新钢钒轨梁万能生产线上诞生,通过检测,H型钢的各项参数均达到标准要求。H型钢是用于厂房、桥梁等大型建筑结构的专用钢材。新钢钒面对H型钢良好的市场前景,在轨梁万能生产线的建设中,把100m长尺钢轨和250×250H型钢作为重要品种进行调试、试轧,对H型钢的各项工艺参数进行优化和改进,于近日试轧成功,从此结束了西南地区没有H型钢的历史。我国最大口径无缝钢管在华菱落户我国最大口径的无缝连轧管生产机组在华菱管线股份公司下属企业试车成功。该机组可年产直径140～365.1m m系列大口径…     

Ф22mm螺纹钢筋二切分的工艺设计与开发

介绍了川威棒材连轧车间的主要工艺及设备,Ф22mm螺纹钢筋二线切分工艺设计以及开发效果。     

开缝衬套孔挤压残余应力场数值计算研究

本文基于有限元技术模拟了开缝衬套挤压和直接芯棒挤压两种孔挤压工艺,对比研究了两种不同工艺导致的孔壁材料轴向流动和孔壁残余应力场。结果表明：开缝衬套挤压可有效抑制材料向挤出端流动,这在飞机夹层孔结构挤压中可减小夹层间隙尺寸;衬套开缝对应孔壁区域残余应力有突变,但仍然是对抗疲劳有利的压应力,而非拉应力;开缝衬套挤压挤入端孔边是压应力,而直接芯棒挤压是拉应力;相同干涉量条件下两种工艺引入的残余压应力峰值近似,但开缝衬套挤压残余压应力场域较直接芯棒挤压增大了约1 mm.     

16Mn合金无缝钢管在山区高水头管引工程的应用

山区管引工程地形复杂,大都具有坡陡谷深、高水头、小流量的特点,对管材的选择和接头处理要求较高,16Mn合金无缝钢管屈服点σs=300-400N/mm2,[σ]可达到150-200N/mm2,屈服点和允许应力较普通钢管和PE管较高。通过永平县普棚下大沟改建工程倒虹吸的设计施工和运行效果看,16Mn合金无缝钢管可作为我们优化设计的一种方法,在山区高水头管引工程中应用的推广。     

一次石灰桩施工爆炸事故及其分析

今年初,在某厂厂房施工工地上发生了一起石灰桩施工爆炸事故。事故发生的情况是这样的:第一天下午震动打桩机进行打桩作业,桩管(内径305mm,厚10mm无缝钢管)打入地下约7m,隔13h后的第二天上午继续打桩作业,桩管打入地下8.4m,即桩管加料口(宽220mm,高410cm)下部齐平地面时,停止打桩,随即开始加料。先后在不到10     

Modern mill technology and centralised processing system,an alternative for improving performance of palm oil mills in Abia State,Nigeria

An assessment of palm fruit processing technologies in Abia State palm oil industry was carried out in this study. About 95% of the mills were in the small scale category with capacities in the range 0.2–3.0 t/hr. Majority (80–90%) of the mills still utilized local drums for sterilisation of fruit and clarification of oil. Palm fruit digestion and oil extraction operations have been mechanised to some extent with about 90% of the mills having one device or the other to handle the operations. Hand-operated screw press was predominant (80%) in most of the mill as a device for palm oil extraction. Fruit stripping was manually carried out. Nut/fibre separation by mechanical method is adopted by small group (40%) of the mills and 90% of the mills utilize nut cracker to crack their nuts. Most of the machines being utilized are sourced locally. Maintenance of the machines was being carried out mainly when they develop faults. More than 50% of the mills have abandoned one machine or the other with breakdown of machines being the predominant reason. Most of the mills sourced fruit by purchase or served as processing centre. The extraction rate of the mills was very low and was in the range of 7–13%. Cost of production was very high when compared with other West African palm oil producing countries. Introduction of a large scale mill utilising modern technology (and centralised processing system) in form of Public Private Partnership is being proposed. Such system will have to be backed up a palm oil act as well as adequate mobilization of the farmers in order to facilitate the adoption of the system by farmers. A modern mill of 5 t/hr capacity is being planned to serve a group of farmers in a catchment area as a model. This system will make available prompt returns to the farmers to strengthen their palm fruit production capacity and guarantee high quality oil that can be exported.     

Challenges in Procurement of HIC Resistant Steel Pipes

Welded pipes ordered for wet sour service are required to be manufactured from hydrogen-induced cracking (HIC) resistant steel plates. Pipe manufacturers procure steel plates with HIC testing, and other additional requirements with respect to chemistry, mechanical testing, and non-destructive testing (NDT) to meet client requirements. There have been several worldwide instances when the pipes ordered for wet sour service have failed HIC test at the pipe mill resulting in significant project delays. The causes of HIC test failures range from deliberate mistakes to improper testing practices. Also, subtle changes in steel making and rolling practices contributed to the HIC test failure following the pipe fabrication. Saudi Aramco has established several lines of defense to prevent recurrence of similar failures. Saudi Aramco reservation on mandatory HIC test requirement on seamless pipes as per the latest API 5L 44th edition, is discussed.     

芯轴螺纹升角对钛合金内螺纹管挤压变形均匀性的影响研究

目的 为了促进金属周向的流动、提高金属的流动均匀性以及钛合金内螺纹管的成形质量,确定合适的螺纹升角大小。方法 通过数值模拟技术对内螺纹芯轴的螺纹升角在10°～40°范围内进行适当调整,并用相对均差值衡量挤压稳态内螺纹管的流动均匀性,探究螺纹升角的变化对内螺纹管成形的影响。结果 适当增大螺纹升角至30°,可以促进金属周向的流动,提高金属流动均匀性。结论 当内螺纹芯轴螺纹升角为30°时,金属流动更为均匀。对优化后的内螺纹芯轴进行挤压试验,获得了成形质量良好的TA1钛合金内螺纹管。     

Computer-aided design of rolling mills

Computers have been used for design of rolling mills since 1960s. Easy access to high speed digital computers has facilitated use of more accurate rolling theories for design work and comprehensive computer simulations have been developed for all types of mills. These simulations include optimization of roll pass sequence, calculation of roll force, torque and temperature and detailed time studies for productivity calculations. These aspects of mill simulation are examined with specific examples. In the design of rolling mills equipment, computer-aided design has been widely used. The available software, which covers both steady state and dynamic analysis of items such as mill stands, drive systems, manipulators, cooling beds, roll cooling, and automatic gauge control systems, is reviewed with special reference to the nature of analysis and range of applications. Computer drafting is being increasingly used by rolling mills designers for both interactive and non-interactive applications. The integration of computer graphics with the design software holds promise for improving the productivity and creativity of designers and is an active area of development in rolling mills design organizations. A specific application where such integration has been achieved is discussed.     

无缝钢管直线度激光视觉在线测量

应用多个激光线结构光传感器对无缝钢管进行光切 ,求出各个光切面中心点的空间三维坐标 ,通过空间直线拟合和误差评定算法 ,由此确定钢管轴线的直线度。本文提出了无缝钢管直线度激光视觉在线测量方法 ,推导出数学模型 ,并进行实验研究 ,给出了实验结果。     

Towards cleaner technologies: emissions reduction, energy and waste minimisation, industrial implementation

This editorial introduces and provides an overview of a Special Issue dedicated to the jubilee 10th Conference of Process Integration, Modelling and Optimization for Energy Saving and Pollution Reduction—PRES’07. It contains thirteen selected papers covering various fields of cleaner technologies and environment policy problems. The technologies address recent developments in CO₂ capture in Combined Cycle power plants, CO₂ reduction in pulp and paper mills, process efficiency increases combined with energy savings at a mill, distillation separation enhancements and emissions control at gas plants, pre-combustion decarbonisation for polygenertion from fossil fuels, minimisation of CO₂ emissions in steam and power plants, a study of co-pyrolysis of biomass and plastic wastes, waste-to-energy system design (with a focus on incineration and gasification technologies), optimal design of wastewater treatment systems, and integrated production of sugar and biofuels from sugar beet. Among these topics, The Special Issue includes demonstration of the technologies in the form of Advanced Case studies.     

RESIDENCE TIME DISTRIBUTIONS IN BALL MILLS

ABSTRACT

A review is made of the methods and theory of measurements of residence time distributions (RTD's) in mills. Literature data on RTD's is assembled. The mean residence times indicate that some industrial mills are operated in the over–filled condition, leading to poor breakage conditions. Although all RTD's are somewhat similar on a dimensionless basis, there appears to be no consistent pattern to explain differences from one mill to another. The general form of measured RTD's Ms consistent with an axial convective–raixing model, but this model does not explain why the Peclet number is independent of mill length–to–diameter ratio and mass throughput. It is concluded that substantial work remains to be done before an adequate understanding of ball mill RTD's is obtained.     

空气压缩机余热回收技术在纺织厂的应用

针对某纺织厂空气压缩机大量余热被浪费的现状,对利用高效板式换热技术回收喷油型螺杆式空气压缩机余热的可行性和节能潜力进行分析,并对该工程进行改造设计.此改造方案投资约14万元,每年可以为企业节省39.3万元的生活热水费用,成本回收期不足5个月,具有很好的节能经济效益和社会效益.该方案可为空气压缩机余热回收利用技术在纺织厂的应用提供参考.     

RESIDENCE TIME DISTRIBUTIONS IN BALL MILLS

A review is made of the methods and theory of measurements of residence time distributions (RTD's) in mills. Literature data on RTD's is assembled. The mean residence times indicate that some industrial mills are operated in the over-filled condition, leading to poor breakage conditions. Although all RTD's are somewhat similar on a dimensionless basis, there appears to be no consistent pattern to explain differences from one mill to another. The general form of measured RTD's Ms consistent with an axial convective-raixing model, but this model does not explain why the Peclet number is independent of mill length-to-diameter ratio and mass throughput. It is concluded that substantial work remains to be done before an adequate understanding of ball mill RTD's is obtained.