40 Cr锻件法兰叉型腔裂纹原因分析

对调质热处理后的40Cr锻件法兰叉进行磁粉探伤时在其型腔底部发现多条横向裂纹,采用光谱检测、显微组织检测、硬度检测、锻造及热处理工艺分析等方法,对不同热处理状态的法兰叉进行分析。结果表明,法兰叉的化学成分和硬度均符合要求,法兰叉型腔裂纹并非调质热处理过程中产生,产生裂纹的主要原因是由于锻造加热温度过高,锻造工艺参数不合理。     

浅析酸气管道焊缝横向裂纹的产生原因及检出方法

为了提高酸气管道焊缝横向裂纹的检出率,确保管道工程的安全可靠运行,针对普光气田主体开发地面集输工程集气末站汇管泄漏事件,分析汇管焊缝横向裂纹产生原因。通过射线、超声波、磁粉、渗透检测方法对焊缝横向裂纹检出情况的比较,证明超声波检测法是针对酸气管道焊缝横向裂纹最有效的检测方法,为检测人员在今后遇到类似情况时及时选择正确的检测方法提供参考。     

灯泡贯流式机组泄水锥焊缝磁粉检测方法

详细介绍了灯泡贯流式机组泄水锥焊缝磁粉检测操作步骤,分析了裂纹缺陷产生原因,并给出处理意见。证明磁粉检测对泄水锥焊缝裂纹缺陷有良好检出效果。     

曲面工件近表面缺陷的磁粉检测

介绍利用磁粉检测发现在用含碱性柴油精制管道近表面缺陷如何选择便捷式直流磁粉探伤机、磁轭调整和磁化方法,并分析了裂纹产生的原因。     

17-4PH钢涡轮轴端面缺陷检验诊断与工艺改进

17-4PH钢涡轮轴经固溶时效处理、机械加工成型和镀硬铬工艺后的磁粉探伤检测时发现其端面有荧光磁粉显示存在缺陷,采用化学成分分析、显微组织和断口形貌观察、硬度和残余应力测试、磁粉探伤检测等方法,结合工艺生产过程的排查结果,对缺陷性质及产生原因进行了诊断,通过工艺试验研究确定工艺改进方案。结果表明,17-4PH钢涡轮轴端面荧光磁粉显示的缺陷是微裂纹,该裂纹是在镀铬工序中产生的氢脆裂纹。涡轮轴硬度偏高,残余应力偏大是产生氢脆裂纹的主要原因。采用430 ℃保温1 h的欠时效处理工艺方案可以适当的降低17-4PH钢涡轮轴的硬度和残余应力,避免其端面氢脆裂纹的产生。     

换热器壳体与接管焊缝裂纹的原因分析及修复

根据活塞式压缩机换热器壳体焊缝破裂情况,通过着色检测、磁粉检测等,分析壳体与接管焊缝处产生裂纹的原因,并对换热器壳体的焊缝裂纹修复提供技术借鉴。     

影响表面缺陷磁粉探伤检测质量的研究

磁粉检测被认为是表面裂纹检测最灵敏的方法之一,尤其是在表面不平或表面不规则性与所需检测的裂纹相比大得多的情况下,磁粉探伤通常被考虑为表面裂纹检测最好的方法.介绍表面缺陷磁粉探伤原理,对磁粉探伤的磁痕特性,磁痕形成受到磁粉性能、磁化规范、磁悬液的浓度和黏度、零件表面状况、裂纹形状等因素的影响进行分析,为提高磁粉探伤检测质量,操作中需要综合考虑这些因素,以便于使工件的表面缺陷经磁化形成的磁痕能清晰地显示出来而且能被准确地予以判断,提高表面缺陷检测准确性.     

锻件磁粉探伤技术与磁化设备的应用

磁粉检测是利用磁现象来检测工件缺陷的,是漏磁检测方法中最常用的一种。由于不同缺陷产生的裂纹不同,在锻造过程中产品的缺陷也不同。本文主要针对锻件常见的缺陷及磁痕的特征研究裂纹产生的原因,分析并判定裂纹种类。指出了锻件磁粉探伤日常工作中应注意的问题,避免了在日后工作中错检和漏检现象的发生。     

金属波齿垫片的失效分析

某石化公司中压蒸汽管道上一对法兰间的不锈钢波齿垫片在检修后的开工初期,突然断裂并导致泄漏。经过宏观检测、力学性能测试、能谱分析、金相检验、电镜分析、应力分析后得出失效原因是由于不锈钢波齿垫材料自身有严重的密集冶金缺陷和微裂纹。据此并考虑工况情况提出了改进措施,实施后四年再无这类事故出现。     

石化成品油外输管道泄漏的无损检测

通过对某石化成品油外输管道取样后进行射线检测、超声检测、磁粉检测等方法检测,结合理化性能检测、泄漏处材料金相观察、腐蚀坑内腐蚀产物成分分析等其他方法,对取样管段进行了检测评价。结果表明,该管段发现4处泄漏穿孔及19处相对较明显的点状缺陷;结合管道运行情况进行现场调研以及腐蚀产物分析,确定了该管段失效泄漏产生的原因。     

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.     

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.     

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.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.