埋弧自动焊导电嘴技术改造

埋弧自动焊导电嘴技术改造倪修智江苏省徐州市石油管道第二工程公司（２２１００８）目前国内所使用的埋弧自动焊机，其导电嘴结构基本上为分瓣形的，即焊机导电嘴由两瓣组成。通过长期的使用发现，这种导电嘴在焊接过程中在两瓣间隙容易集聚异物引起导电不良，同此引起的...     

新型埋弧自动角焊机的研制

研制的埋弧自动角焊机采用细丝埋弧焊,可以焊接角焊缝和对接焊缝,焊接小车可行走圆弧及直线轨迹。体积小、重量轻;控制系统中采用了微型计算机控制,可实现焊接参数动态调节和焊前预置、焊接参数数字显示等先进功能。该焊机已在实际生产中得到应用,效果良好。稍加改造即可用于自动气体保护焊。     

MZ-1000型埋弧焊机焊接过程中参数不稳的改进措施

MZ-1000型埋弧焊机在焊接过程中经常出现参数不稳现象,焊接电流和电弧电压波动剧烈,严重时电弧电压波动的幅度高达±10V,焊接电流的波动幅度也有±100A,使焊缝表面成形不好,甚至不能进行正常焊接。这一现象在使用φ4mm的焊丝(I>700A)时或φ5mm的焊丝(I>850A)时更为严重。经检查,电源、送丝系统均正常,导电嘴接触良好,焊接电流、电弧电压和焊接速度都在合适的范围内,焊剂的覆盖厚度和颗粒度也与所用的焊接电流相适应。经初步分析认为,问题出在焊机的参数自动调节系统上。 MZ-1000型埋弧焊机属于带电弧电压调     

MZ-1000埋弧焊机导电嘴的改进

MZ-1000埋弧焊机的导电嘴,在使用中感到更换很不方便,而且其制造也较麻烦,它是由两个半圆件构成的导电衬套(图1),根据不同焊丝直径和磨损情况进行更换。     

某核电厂钢衬里埋弧焊焊缝气孔分析及改进措施

针对某核电厂安全壳钢衬里(钢衬里)埋弧焊一次合格率较低的原因进行了分析,分析表明,埋弧焊焊接缺陷产生的原因主要为焊机接电瞬间不稳定、组对后长时间放置增加浮锈及粉尘、焊机行走过程焊丝对中控制不好等.通过采取设置焊接专用接线、组对前后待焊表面除锈除湿、组对完成后及时施焊、焊前增设焊丝对中确认等质量改进措施,某核电厂钢衬里板...     

螺旋缝埋弧焊管内外自动焊焊枪结构设计

介绍传统焊枪和新设计埋弧焊管内外自动焊焊枪的结构,分析新型埋弧焊枪的工作原理,对比两种焊枪在生产中的应用情况。分析认为:与传统焊枪相比,新设计的埋弧焊枪能始终保证焊丝与导电嘴一侧接触,保证焊接时焊丝的位置稳定,通过风冷可以有效降低焊丝温度,同样工况下提高了焊缝形貌及理化性能结果。新设计的焊枪结构仍存在短板,无法针对多丝焊进行调节;焊接内径较大的焊管时,利用传导机构调节内焊丝位置较容易,管径小时则不易操作。建议与自动化测量技术相结合,根据导电嘴损耗自动调节焊丝位置,避免因忘记手动操作或位置局限难操作等引起的焊丝位置偏离而造成的产品质量问题。     

SAW高速焊接焊丝和焊剂国产化替代的开发研究

卧式埋弧焊机高速焊接使用的焊丝和焊剂进行国产化替代,并在此基础上使用气保焊焊丝代替埋弧焊焊丝进行焊接,获得了成功。通过实践、理化试验相关金相证明,该焊接新工艺是可靠的。探索出的一条适合该卧式高速焊接的焊接工艺即ER50-6+SJ101的焊接新工艺,与旧工艺相比,新工艺应用广泛、取材广,应用价值和经济性更好。新工艺已经成熟,焊接质量稳定,焊接速度满足生产要求,焊接成本也大幅度下降,经济效益可观。     

埋弧焊接用导电成套装置的设计

我厂引进购置的林肯NA-3S埋弧自动焊机原焊丝操作系统适用于细丝焊接，配备的K231导电成套装置系管状结构，仅适用于φ2．0mm～φ2．4mm的焊丝。许用焊接电流一般为600A以下。根据国内生产习惯，锅炉用锅筒埋弧自动焊均使用φ4．0mm～φ5．0mm的焊丝进行生产，焊接电流在750A左右。由于匹配不合理，导致该导电成套装置使用寿命短，常常被烧坏。影响生产正常进行。为此对导电成套装置进行了重新设计，由管状结构改成夹瓦式，提高了载流量，经8年多的生产实践，使用效果良好，使用寿命提高了6倍。     

1000A IGBT逆变埋弧自动焊机及其控制系统的研究

研制开发了一套额定容量为1000A的新型IGBT逆变埋弧自动焊机,并已投入批量生产,文中对该焊机主电源的设计、高性能开关式小车行走电路及送丝电路的设计、埋弧焊自动调节系统和焊接过程控制与程序控制系统的设计等方面做了较详细的介绍和分析讨论。     

自动埋弧焊接过程的电弧控制方程与热学分析

埋弧焊系统由恒流特性逆变焊接电源、送丝机、行走小车和控制器组成.控制器的输入是电弧电压Uarc和设置电压Uset,控制器的输出是PWM方式调节DC电源,驱动并调节送丝速度.用一阶微分方程建立了埋弧焊接过程中焊丝送进速度与焊接电弧之间的数学模型,模型描述了埋弧焊接过程中焊丝一边在电弧中燃烧,一边由送丝机不断送到燃弧区的平衡关系.通过电源、熔池、焊丝的热平衡分析,得到焊接系统的焊丝选取方法,该方法是焊丝直径与焊接电流的平方根成正比,文中还给出了焊丝直径与焊接电流的定量选取公式.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.