制氢转化炉集合管接管焊口开裂分析及措施

本文采用多种分析技术,对制氢转化炉出口集合管接管焊口开裂进行失效分析。结果表明接管开裂的原因主要是由于原始焊接缺陷及接管母材和焊缝发生σ相脆化,导致裂纹容易产生;停车期间形成的湿H2S-CO2-H2O酸性腐蚀环境、连多硫酸应力腐蚀环境导致裂纹进一步扩展,最后发生开裂。     

不锈钢波形补偿器开裂原因分析

运用金相分析、SEM显微观察及能谱分析方法,研究热力管道中波形补偿器在使用条件下发生开裂的原因。实验结果表明,由于出口端环与出口管存在间隙,污水污泥等沉积在波形补偿器内表面,当腐蚀物质发生浓缩,沉积在内表面的腐蚀性成分Clˉ浓度大大增加,使得1Cr18Ni9Ti不锈钢发生点蚀,以至波形补偿器发生应力腐蚀,从而导致开裂。     

压缩机仪表引压管泄漏原因分析

针对某炼油厂加氢裂化装置中的循环氢压缩机出口仪表引压管的氢泄漏事故，对该管的材料成分、金相组织、腐蚀状况、裂纹及断口等进行了分析.结果表明，该管的材质为316不锈钢；失效原因是由于在其管外壁的局部环境中氯化物的富集而发生点蚀，进而引发管子应力腐蚀开裂，最终造成管内氢气的泄漏.     

HAl77-2铝黄铜换热管应力腐蚀开裂

针对换热管腐蚀泄漏问题,采用金相、扫描电镜、能谱等技术对换热管的腐蚀形貌、腐蚀产物成分进行分析。结果表明:换热管内冷却介质中高含量的氨氮对换热管应力腐蚀开裂起主要作用;管子端部与管板的胀接,使其胀管与未胀过渡区留下了较大的残余应力;换热管选用的HAl77-2铝黄铜管也不适合在含有很高氨氮介质的环境中使用。因此,在腐蚀介质、残余应力、敏感材料三个条件都具备的情况下,换热管短期内发生应力腐蚀开裂而泄漏失效。     

仪表管端盖开裂失效分析

通过无损检测、化学成分分析、金相检验等手段对仪表管端盖的开裂原因进行了分析。结果表明:端盖开裂的主要原因是氯化物应力腐蚀开裂,端盖组织中析出的碳化物颗粒成为应力腐蚀开裂敏感部位,裂纹沿晶扩展,最终导致端盖开裂。     

钛制再沸器管板接头焊缝腐蚀开裂的原因及改进措施

钛制再沸器是维尼纶生产厂醋酸精馏系统中的重要设备，使用工况苛刻、复杂，投入使用2年后，发现管板与换热管接头连接处焊缝产生腐蚀开裂。从钛制再沸器的选材、设计、制造、运行状况、使用条件、应力状态等几方面人手，分析管板接头焊缝产生腐蚀开裂的原因是：①工作介质醋酸酐和甲酸含水量低，不能维持钛在沸腾醋酸中的钝态；②在环境介质中，钛制再沸器管板接头焊缝长期受交变应力的作用，导致管板焊缝开裂。提出了避免钛制再沸器管板接头腐蚀开裂的4项措施。     

不锈钢换热管泄漏失效的原因

某化工企业多台管壳式换热器在服役3～4 a后陆续发生泄漏,拆卸后检查发现换热器内部大量304不锈钢换热管存在开裂或穿孔现象。通过宏观形貌分析,扫描电镜及能谱分析,金相检测,化学成分分析、晶间腐蚀试验、残余应力测试等手段对不锈钢管失效原因进行分析。结果表明：换热管出现穿孔和开裂失效的主要原因是材料发生了晶间腐蚀及应力腐蚀。换热管材料304不锈钢具有晶间腐蚀敏感性,换热管内外壁都存在明显的残余拉应力,且介质中存在S、Cl等腐蚀性元素,换热管材料同时具备以上3种应力腐蚀开裂的必要条件而发生应力腐蚀开裂。     

奥氏体不锈钢管道应力腐蚀开裂检测技术对比

通过对比渗透检测技术、X射线数字成像检测技术和涡流阵列检测技术对三通-管帽对接接头试样内、外表面检测的检测速度、表面开口应力腐蚀开裂检测能力和近表面应力腐蚀开裂检测能力,得出如何有效检测在役奥氏体不锈钢压力管道应力腐蚀开裂的方法。以带有应力腐蚀开裂的三通-管帽试件为检测对象,采用溶剂去除型着色渗透检测技术、X射线数字成像检测技术和涡流阵列检测技术进行试验,并对试验结果进行比较。结果表明:应力腐蚀开裂的面积型缺陷的特有属性和数字平板探测器不能弯曲的特性,会影响X射线数字成像检测技术对管道应力腐蚀开裂的检测能力,但其对近表面应力腐蚀开裂或埋藏性应力腐蚀开裂的检测能力仍优于涡流阵列检测技术和渗透检测技术;涡流阵列检测技术对表面开口应力腐蚀开裂的检测能力与渗透检测技术相近,对近表面应力腐蚀开裂的检测能力远优于渗透检测技术,检测速度也远快于渗透检测技术,故可在满足检测条件的情况下用涡流阵列检测技术替代渗透检测技术。     

304不锈钢焊管应力腐蚀开裂原因

某公司不锈钢焊管使用过程中出现大面积开裂泄露。采用宏观检验、化学成分分析、金相检验、SEM、EDS能谱分析等方法,对该管道的开裂泄露进行失效分析。结果表明,该焊管的开裂主要为氯离子应力腐蚀开裂。焊管成型后未热处理造成的残余应力、管外面橡塑保温材料释放出的氯离子共同造成了该不锈钢焊管的应力腐蚀开裂。     

加氢车间二套空冷入口管开裂分析

本文是对一根奥氏体不锈钢管的开裂所做的分析。通过对断裂部位的金相、断口和应力等的试验分析表明,该管具有由氯离子引起的奥氏体不锈钢应力腐蚀开裂的特征和条件。证明该奥氏体不锈钢管是由氯离子引起的应力腐蚀并伴有腐蚀疲劳造成的开裂。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.