非晶薄带厚度控制研究进展

从纵向厚度和横向厚度两个角度介绍了非晶薄带厚度控制研究情况。纵向厚度方面,喷嘴间隙、冷却辊转速、辊嘴间距等工艺参数是主要影响因素,对各种厚度控制的经验公式进行了比较;实际生产中,纵向厚度控制主要是对辊嘴间距的控制。相对于纵向厚度控制,横向厚度控制更为复杂,主要分析了喷嘴横向形状、熔潭稳定性、冷却辊辊型三个主要因素对横向厚度的影响。非晶薄带厚度控制还必须结合相关制带工艺的研究,与带材厚度检测相结合,实现非晶带材厚度的自动闭环控制,才能进一步提高厚度控制水平。     

热轧中间坯水印与成品精度关系分析

通过对热轧厂现场钢坯的在炉时间、坯料尺寸、轧制规格、水印温差和厚度精度差的数据统计与分析，找出坯料宽度对中间坯水印温差与成品厚度差的影响，轧制目标厚度与厚度精度的关系，目标厚度与厚度不合格率的关系。     

封头厚度设计的探讨

针对GB150中关于封头最小厚度的规定及材料力学性能随板厚范围变化而变化的问题,举例说明考虑在设计图样中中标注封头名义厚度和最小厚度的必要性,总结了当封头设计厚度处于相应材料厚度临界值时,设计应适当增加最小设计厚度、考虑尽量减小成形减薄量,以保证封头成形后的最小厚度仍能满足强度要求。     

钢种补偿在冷轧高强钢厚度控制中的应用

酸轧产线生产高强钢时,X射线测厚仪测出的带钢厚度和实际厚度有明显偏差,容易产生批量厚度不符的质量事故。分析了厚度偏差产生的原因,推导出了厚度离线钢种补偿的方法。该方法在产线应用后,X射线测厚仪测出的高强钢厚度偏差小于0.01 mm,满足了对高强钢厚度精度控制的要求。     

热连轧板带厚度控制的补偿研究

利用板带出口厚度的补偿控制、压下调节量的补偿控制、油膜厚度的补偿和辊缝零位实现对热连轧板带厚度控制的补偿,提高板带出口厚度精度。     

厚度自动控制在莱钢宽厚板轧制中的应用

以莱钢宽厚板厚度自动控制系统为例,详细论述了油膜厚度补偿控制、基于油膜厚度补偿的辊缝调节量计算、加减速厚度补偿控制、AGC和HGC的控制原理,为类似轧机的板材厚度的精确控制提供了借鉴的依据。     

中板轧机液压辊缝控制故障分析

中板轧机应用HAGC技术使钢板纵向厚差得到显著提高,钢板的出口厚度与很多因素有关,如来料的厚度、温度、压下响应速度和轧机刚度等.结合现场应用情况,对某2500中板轧机HAGC进行消化和分析,对偶尔发生出口厚度比目标厚度小0.4～0.5mm现象进行了研究,找出影响钢板出口厚度的主要因素,经过对HAGC的改进,消除了出口厚度比目标厚度小的现象,取得了良好的效果.     

冷轧硅钢板形与横向厚度控制的分析

带钢板形和横向厚度差是冷轧硅钢产品的关键质量指标。针对冷轧硅钢板形与横向厚度控制进行了研究分析,描述了冷轧硅钢板形和横向厚度存在的缺陷以及两者的相关性,指出了热轧原料断面厚度的不均匀性是硅钢板形与横向厚度控制存在的矛盾点,并表明了良好的热轧原料轮廓尺寸是保证冷轧硅钢板形与横向厚度协调控制的关键因素。     

中厚板轧机厚度自动控制系统研究及应用

某中厚板厂精轧机在调试后出现厚度自动控制不稳定的问题,主要表现在设定厚度与实际厚度差别较大、同板厚度差较大等。针对精轧机厚度控制不稳定的问题,通过优化L1控制程序的咬钢冲击补偿系数、EGC漂移补偿系数以及主平衡压力波动等,达到了精轧机高精度厚度自动控制和提高成材率的目的。     

宽厚板轧机变斜率头部厚度补偿模型及应用

宽厚板轧制时,钢板头部咬入冲击将对轧机弹跳产生影响,若不采取补偿措施,头部厚度将超差严重。邯郸钢铁集团有限责任公司3 500 mm轧机原来虽采用了三角形头部厚度补偿模型,但头部厚度超差仍达0.5 mm左右。通过对钢板头部厚度数据的分析,找出了头部厚度波动规律,提出了变斜率头部厚度补偿改进模型。采用该模型并严格执行咬入速度制度后,头部厚度超差减小到0.2 mm左右。     

无缝钢管三辊轧制荒管壁厚偏心分析

 三辊轧制荒管壁厚偏心控制是无缝钢管壁厚精度控制的重要环节。基于生产试验分析了荒管壁厚偏心的特征,运用解析方法建立了三辊轧制荒管壁厚偏心的理论计算模型,针对实际生产条件进行了预报计算与比较,分析了三辊轧管工艺因素对荒管壁厚偏心的影响特点,并进一步讨论了改善荒管壁厚偏心的方法。研究结果表明,荒管壁厚偏心的基本特征表现为“偏心螺旋型”,在荒管壁厚不均中的占比达80%以上;毛管壁厚偏心和温度偏心是影响三辊轧制荒管壁厚偏心的最重要因素;增大三辊轧制减壁量、降低毛管温度、提高轧辊台肩高度、增大轧辊转速有利于减小荒管壁厚偏心。     

X射线测厚仪测量压延铜箔厚度精度的影响因素及故障处理

东芝X射线测厚仪是X型铜箔轧机的关键检测设备及厚控系统(AGC)的重要组成部分,其精确的厚度测量功能是保证轧机厚度控制有效的基本条件。基于测厚仪的构成和测量原理,对满量程校准和精度验证的机理进行分析研究,对标样箱内部标准样板脱落、x射线发生器劣化等故障,采取切实有效的措施,提高了测厚仪运行稳定性和测量精度。     

厚度自动控制在莱钢宽厚板轧制中的应用

以莱钢宽厚板厚度自动控制系统为例,详细论述了油膜厚度补偿控制、基于油膜厚度补偿的辊缝调节量计算、加减速厚度补偿控制、AGC和HGC的控制原理,为类似轧机的板材厚度的精确控制提供了借鉴的依据。     

A Study of Thickness Effect on Fatigue in Thin Welded High Strength Steel Joints

It is well known that the fatigue strength of welded joints decreases when plate thickness increases. This decrease in fatigue strength is known as the thickness effect. In many standards for fatigue design the thickness effect is taken into account for joints with plate thickness typically greater than 25 mm. Previous work has mainly been focused on joints with plate thickness between 12‐200 mm. Less attention has been paid to thinner joints. Published investigations on joints with sheet thickness 2‐12 mm show an increase of fatigue strength with decreasing sheet thickness. In the present study results from constant amplitude fatigue testing of non‐load carrying welded joints in high strength steel of thickness 3‐12 mm are presented. The results show an increase in fatigue strength with decreasing sheet thickness down to 3 mm. Fracture mechanics calculations confirm the test results.     

Installed Geometry of Cast-in-Place Polymer Sewer Liners

Polymer liners cast within damaged sewer pipes are commonly used in rehabilitation without the disruption associated with conventional trench excavation and pipe replacement. Linear stability depends on both the thickness of the liner, and any out-of-roundness (ovality or other shape imperfections). Field trials of four cast-in-place liner systems permitted samples to be exhumed and inspected. Measurements of liner thickness and out-of-roundness are presented, for use by researchers and others seeking to establish the stability of these pipe repairs. Significant variations in thickness were observed. These took the form of wavelike increases in local thickness. For all four types of lining systems, the maximum thickness was more than double the average thickness, and up to three times thicker than the minimum thickness values. Higher frequency thickness variations were also superimposed on those wavelike changes in wall dimension. Liner ovality of up to 10% was also observed due to ovality in the clay sewer pipes being repaired, even though those pipes were not fractured longitudinally. Postconstruction inspection of liners ideally includes assessment of liner thickness. Wavelike increases in liner thickness might be estimated, where these lead to intrusions into the waterway. However, irregularities on the external surface of the liner or long wavelength thickness variations would be impossible to detect from video inspection alone, and new inspection techniques are likely need to be developed to ensure the installed liner performs successfully over its design life.     

无缝钢管张减过程壁厚前馈自适应控制

介绍了宝钢分公司钢管厂在无缝钢管张减过程壁厚控制中实现的前馈自适应控制技术。该技术利用准确料流跟踪所获得的对应来料荒管的管坯称重、连轧机后的测长数据,计算得到来料荒管的壁厚数据,然后根据张减机壁厚分布规律与钢管初始壁厚的关系,在轧制过程中在线计算和调整对应的各机架轧辊的轧制转速分布,实现张减机平均壁厚的前馈自适应控制,尽量减少由来料荒管壁厚偏差所造成的张减成品钢管壁厚偏差。