车轮轮辋周向裂纹原因分析

某型号成品车轮磁粉检测时发现,同批多个车轮外侧轮辋存在数处长短不一的周向缺陷磁痕。利用热酸浸装置和金相显微镜对缺陷的宏观和微观形貌进行了试验分析。结果表明,缺陷为锻造工序产生的折叠裂纹。为避免后续批量产生此类裂纹,结合车轮制造工艺,制定了有效的预防措施。     

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酒钢CSP连铸连轧生产线生产热轧卷板过程中,阶段性出现表面纵裂纹缺陷,导致大量废品。研究过程对缺陷在厚度规格、宽度规格的统计规律进行了分析,对成品板材缺陷与铸坯缺陷宏观形态与分布特征进行了对比,对成品板材裂纹缺陷进行了金相分析,并使用扫描电镜对缺陷进行了形貌与能谱分析。最终确定此种裂纹发源于结晶器弯月面处凝固前沿不均匀的热力学条件,在结晶器锥度不合适、二冷区冷却不均匀条件下进一步发展,导致铸坯表面裂纹达到足以产生成品表面裂纹的程度。按照分析结果,针对钢水成分、主要浇注工艺参数、保护渣、连铸设备等各个方面制定出控制措施,在实际应用中取得了显著效果。     

某结构搭接接头焊缝裂纹产生原因分析

分别从断口的宏观形貌、微观形貌、能谱分析、金相分析4个方面对某结构搭接接头焊缝裂纹的产生原因进行分析,观察与分析结果表明,该焊缝裂纹为受外力作用开裂裂纹,产生原因是由于存在大面积的焊接缺陷,而焊接工艺不合理和焊接面清理不干净是造成焊接缺陷的主要因素。     

7050铝合金环锻件超声波探伤缺陷分析

7050铝合金环锻件内部经超声波探伤发现大量缺陷,缺陷将影响锻件性能,极易在精加工过程中暴露在成品表面,危害性极大。为了分析原因,利用低倍检验、金相显微镜、扫描电镜对7050铝合金环锻件的探伤缺陷进行相关检测,确定缺陷形貌及分布特点,解剖的缺陷特征属于典型的Al Mg O的化合物夹杂。     

石油钻杆接头缺陷分析

SAE4137H材料制作石油钻杆接头,在最终成品超声波探伤时发现内部有缺陷,缺陷宏观观察为孔洞,将缺陷样制成金相试样后在扫描电镜下观察其组织及断口形貌,发现由于热加工温度偏高,造成局部过热以及试样存在有疏松,并且在疏松周围聚集了大量的非金属夹杂物及低熔点的共晶产物是导致缺陷产生的原因。     

1Cr12Ni3MoV合金盘类锻件超声波探伤缺陷分析

1Cr12Ni3MoV合金盘类锻件内部经超声波探伤发现有超标缺陷显示，缺陷影响锻件产品寿命，极易在精加工过程中暴露在成品表面，危害性极大。为了分析原因，利用金相显微镜、扫描电镜对1Cr12Ni3MoV合金盘类锻件的探伤缺陷进行相关检测，确定缺陷形貌及性质，解剖的缺陷特征属于典型的夹渣类缺陷。     

高强低合金钢H420LA表面条斑缺陷成因分析

针对高强低合金钢H420LA退火带钢表面存在的暗色条斑缺陷,采用SEM、EDX等手段对带钢表面正常区及条斑区进行了微观结构对比分析,并追溯了热轧态及模拟酸洗后带钢表面不同区域的宏观及微观形貌差别。结果表明：H420LA热轧带钢表面红锈缺陷可遗传演变为退火成品的表面条斑。通过对红锈缺陷的微观结构及其成因分析,提出了提高出炉温度、增加粗轧除鳞道次的工艺措施,有效地减少了H420LA热轧卷表面的红锈缺陷,冷轧成品表面质量因此得到改善。     

4130圆筒锻件缺陷原因分析

4130圆筒锻件大端面边缘区域存在大量缺陷,经超声波检测发现缺陷属于外圆面浅表层缺陷,极易在精加工过程中暴露在成品表面,危害性极大。为了分析缺陷原因,利用低倍检验、金相显微镜、扫描电镜对4130圆筒锻件的缺陷进行相关检测,缺陷形貌及分布特点、解剖的裂纹特征属于典型的钢锭冶金皮下夹杂物、气泡。     

ML08Al冷镦开裂原因分析及控制

2009年10月份,方大特钢(原南昌长力钢铁股份有限公司)接到多起有关ML08Al冷镦钢的质量异议,反馈当月生产的ML08Al冷镦钢在冷镦加工过程中,经常出现冷镦开裂现象,有的客户成品报废率甚至达到30%以上。方大特钢对2009年10月份生产的ML08Al冷镦钢冷镦加工过程中开裂原因进行仔细分析,并根据高线厂线材生产特点提出了相应的控制解决措施,有效提高了ML08Al等冷镦钢的冷镦合格率。     

球铁马氏体彩色金相的制备及研究

球铁铸态试样与热处理态试样的彩色金相制备工艺规范不同。分析了热处理态试样难于成色的原因,并试验得出热处理态彩色金相制备工艺规范。通过彩色金相图对马氏体球铁磨球的结晶形态和晶内缺陷进行了深入讨论。结果表明,彩色金相比黑白金相能揭示更多的马氏体结构特征信息,并为保证获得力学性能良好的球铁提供依据。     

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.     

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.     

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.