840D数控及西门子变频器在飞锯同步控制上的应用

本文介绍了利用西门子840D数控系统的HLA模块,由840D控制西门子6ES70矢量控制变频器驱动飞锯小车电机,实现飞锯与钢管的高精度同步控制,保证钢管切割精度。     

无涂层和带缺陷涂层X70钢焊接接头的腐蚀行为研究

为了有效延长海洋管道的使用寿命,分别采用自动焊和焊条电弧焊工艺进行了管道环焊缝焊接,并对无涂层和带缺陷涂层的管道环焊缝焊接接头的腐蚀行为进行了研究。研究结果表明,无涂层情况下,自动焊和焊条电弧焊两种工艺焊接接头的腐蚀速率几乎相同;焊接接头涂层破损时,自动焊工艺的抗腐蚀性能整体优于焊条电弧焊工艺,且自动焊工艺的腐蚀集中在涂层破损面边界,焊条电弧焊的腐蚀除涂层破损界面外,焊缝位置也出现点蚀坑。研究结果对海洋管道焊接工艺的制定有一定的指导意义。     

X70钢管道磁化及退磁特性试验研究

管道中的剩磁不仅会影响管道的检测精度,还会使管道内腐蚀速率加快.为了对X70钢管道的磁化及退磁特性进行研究,在X70钢材料特性分析的基础上,采用Maxwell软件建立了X70钢磁化模型,并基于响应面优化设计方法,研究了退磁率与磁感应强度和退磁速度的关系.研究结果表明:X70钢的磁感应强度在永磁铁垂直投影处最强,在垂直投...     

热矫直机与冷床交接辊道不同步故障的解决方案

本文主要介绍了某钢铁公司宽厚板生产线上,热矫直机输出辊道与冷床输入辊道之间因为以太网通讯存在滞后现象,导致两部分辊道存在速度不同步故障时,根据现场的实际情况提出的小投入,见大效的解决方案。     

IDT70V9289型高速同步双口SRAM的原理及应用

IDT70V9289是IDT公司新推出的一款高速同步双口静态存储器（SRAM），可实现不同传输方式的双路高速数据流的无损传输。文中详细介绍该电路的结构和原理．给出IDT70V9289的典型应用电路及设计时应注意的问题。     

感应热处理工艺在X70钢级 HFW焊管生产中的应用

为了优化HFW焊管的感应热处理工艺,进一步提高焊管质量,针对焊管感应加热热处理的应用优势和HFW焊管制管原理及工艺,分析了HFW焊管采用中频正火热处理的工作原理、工艺和作用。以规格为Φ323.9 mm×14.3 mm、钢级为X70的 HFW焊管焊缝采用在线中频正火热处理工艺为例,通过试验得出了热处理加热温度在930 ℃、传送速度12 m/min、经96 m空冷加喷淋冷却后,焊管能够获得良好的焊缝金相组织和综合力学性能。     

基于X70高级管线钢多道焊缝和单道焊缝组织EBSD研究

本文选用X70管线钢两种不同形式焊接接头为研究对象,使用EBSD技术对径向焊缝的横截面的Fe3C相分布、取向差角分布、晶粒有效尺寸、大角度晶界和小角度晶界的比率以及Taylor因子进行表征.结果发现,多道焊缝析出相分布很均匀、随机;各种颜色的晶粒取向均有分布且少量呈柱状存在;晶粒有效尺寸起伏较大,大小不一,但总是交替进行;大角度晶界比率较大,韧性较好;Taylor因子灰度图分布略有起伏,平均数值较大,抵抗塑形变形能力较差.单道焊缝则反之.     

精细控压压力平衡法固井技术的应用实践

精细控压钻井技术多用于解决同一裸眼油气井段存在多压力系统、窄安全密度窗口地层的安全钻进难题,其尾管固井作业若采用常规方法,在满足小间隙尾管固井顶替效率的前提下,施工过程中必然造成井漏;若采用"正注反打"工艺,固井质量又难以满足后期超深井试油工程的需要。为此,以四川盆地剑阁构造上所钻龙岗70井?114.3 mm尾管固井作业为例,探索精细控压压力平衡法固井技术在多储层、高低压互存、长裸眼段(859 m)中的固井应用。具体做法如下:①采取了确保水泥浆环空充填效率、固井施工全过程压力平衡等针对性的技术措施;②依靠精细控压钻井装置和中心管泵注加重钻井液的方式,精确控制环空压力平衡来降低钻井液密度,实现窄安全密度窗口地层的固井施工全过程井筒压力平稳。现场试验结果表明,该井?114.3 mm尾管固井质量良好,分阶段降密度期间喇叭口无窜流,试压合格。结论认为,该方法能够提高复杂超深气井尾管的固井质量,改善了后期高压气井试油安全作业的井筒条件。     

Part III: the influence of serial repitching of Saccharomyces pastorianus on the production dynamics of some important aroma compounds during the fermentation of barley and gluten‐free buckwheat and quinoa wort

The present paper is the last report of a comprehensive study regarding the influence of the serial repitching of Saccharomyces pastorianus TUM 34/70 on the composition of a barley, buckwheat or quinoa fermentation medium. In particular, it focuses on the production dynamics of important volatile compounds typically associated with the aroma of beer. Samples were taken every 24 h after 11 serial repitchings of a single starter culture, analysed for the particular aroma compound content by distillation followed by gas chromatography with flame ionization detection. The term ‘serial repitching factor’ is used for the first time to support the visual evaluation of the influence of serial repitching. Results showed that the levels of methanol in the quinoa wort fermentation were only slightly higher than in barley and in practical terms independent of successive fermentation. The behaviour of acetaldehyde in quinoa was similar to that in barley. However, there was a final 2‐fold lower production of some important aroma compounds compared with barley and buckwheat and for this reason quinoa cannot be recommended as a gluten‐free substitute to produce a bottom‐fermented beer. Regarding the buckwheat wort fermentation, a 2‐ to 3‐times lower final acetaldehyde content than in barley is desirable, whereas a relatively high methanol content is not desirable. Barley and buckwheat showed comparable sum concentrations and similar overall profiles of some important aroma compounds. From this perspective, buckwheat appears to be a promising substitute for barley as a brewing raw material. The overall conclusions of our comprehensive study (Parts I–III) are that buckwheat shows adequate brewing properties to substitute for barley in the commercial preparation of a bottom‐fermented gluten‐free beer‐like beverage, and yeast can be repitched at least 11 times. In contrast, quinoa in practical terms shows no substitutional potential for barley in beer; however, it has many nutritious advantages, thus the commercial preparation of a unique, bottom‐fermented gluten‐free ‘non‐beer‐like’ beverage – where the yeast could be repitched six times at most – appears feasible. Copyright © 2015 The Institute of Brewing & Distilling