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1.
依据NACE标准研究了X80级管线钢的抗硫化物应力腐蚀开裂(SSCC)和氢致开裂(HIC)行为。研究表明该X80级管线钢具有较好的抗SSCC和HIC性能,其中临界名义应力Sc达到:1 265 MPa;裂纹敏感率、裂纹长度率和裂纹厚度率均为0;酸性环境下氢的扩散以及应力集中的交互作用导致材料的韧性损失,从而促使裂纹的形成和扩展,最终导致材料断裂。以均匀细小的针状铁素体为主的显微组织具有优良的抗SSCC&HIC性能。  相似文献   

2.
通过扫描电镜(SEM)、透射电镜(TEM)等方法,研究了X65~X70级别管线钢在饱和H2S溶液中的氢致开裂行为,及不同显微组织、位错与析出对氢致开裂(HIC)的作用.结果表明:组织均匀的珠光体/铁素体型X65管线钢和铁素体/针状铁素体型X70管线钢均具有良好的抗H2S腐蚀性能;带状组织是裂纹萌生和扩展的主要途径;合金元素的弥散析出作用可以提高管线钢的抗硫化氢腐蚀性能.  相似文献   

3.
介绍了某钢铁有限公司在超宽热轧生产线上研制开发出的抗HIC(氢致裂纹)X70管线钢级热轧板的情况。对生产的X70管线钢进行组织观察和抗HIC实验表明,其组织主要为针状铁素体和准多边形铁素体等复合而成,晶粒细小均匀,带状组织轻微,有很好的综合力学性能和抗HIC性能。  相似文献   

4.
依据NACE TM 0284-2011标准评估了不同显微组织X100管线钢的氢致开裂(HIC)敏感性,采用场发射扫描电镜、氢显等手段观察了钢中HIC裂纹的萌生和扩展以及H的聚集,借助于氢渗透动力学参数分析了X100管线钢不同显微组织试样的氢捕获效率与HIC敏感性的内在关联。结果表明,具有不同显微组织的X100管线钢HIC敏感性依次为:原始铁素体-贝氏体组织试样炉冷处理的块状铁素体组织试样风冷处理的针状铁素体组织试样;钢中组织对氢的捕获效率越高,钢材对HIC敏感性越大;H原子容易在夹杂物和基体之间的界面处聚集,钢中的MnS夹杂、Ca-Al-Si-O复合夹杂和MnO夹杂均为HIC裂纹萌生源。  相似文献   

5.
通过LIBS-OPA-100原位分析仪、扫描电镜(SEM)、透射电子显微镜(TEM)等方法,从显微组织、硬度、偏析元素3方面研究了X65管线钢中心偏析带马奥岛(M/A)组元对氢致裂纹性能的影响,偏析与硬度以及偏析与氢致裂纹(HIC)之间的关系。结果表明:X65管线钢中C、Mn、S、Si元素在中心偏析后形成硬度较高的带状组织是导致抗HIC性能不合格的主要原因;显著的中心偏析马奥岛、铁素体带状组织和大尺寸的相颗粒析出不利于抗HIC性能;带状的马奥岛组织是氢原子的聚集场所,是导致氢致裂纹萌生与扩展的源头。  相似文献   

6.
采用NACE标准对X60和X100两种管线钢进行氢致开裂(HIC)试验,并通过金相显微镜和扫描电镜观察显微组织及夹杂物对两种管线钢氢致开裂性能的影响。结果表明,与X60钢相比,X100钢对HIC更为敏感,其裂纹数量远多于X60钢。X60钢在珠光体/铁素体界面上形成细裂纹,在铁的碳化物和Al-O-Ti夹杂物处形成粗裂纹。X100钢在贝氏体组织上形成细裂纹,在贝氏体组织和夹杂物的共同作用下形成粗裂纹。由于X100钢晶粒尺寸小,由夹杂物作为氢陷阱形成的粗裂纹宽度远小于X60钢中的。除了铁的碳化物和钙化的Al-O-Ti夹杂物,X100钢裂纹中出现更加复杂的Mn-Ca-Mg-Si-O-S多元素复合夹杂,钼元素的富集物对裂纹的扩展影响不显著。  相似文献   

7.
通过金相分析、扫描电镜和硬度分析,研究了X80管线钢试样的抗HIC性能。结果表明:X80管线钢中裂纹不是由夹杂物引起的,而是由Mn、P偏析生成了对HIC特别敏感的硬显微带组织;HIC裂纹在准多边形铁素体形核,向外扩展,终止于板条状铁素体。准多边形铁素体的抗HIC性能劣于板条状铁素体,板条状铁素体对裂纹的扩展有明显的阻止作用。  相似文献   

8.
采用NACE standard TM 0284-2003氢致开裂标准实验方法,研究了鞍钢生产的X80级管线钢分别在两种溶液中的抗氢致开裂性能.研究结果表明:该管线钢在两种溶液中均具有较好的抗氧致开裂性能,试样内部没有发现裂纹:试样表面的微裂纹主要在点蚀坑处形核并沿多边形铁素体扩展,扩展模式多为穿品型,并终止于针状铁素体.  相似文献   

9.
通过调整Mo、Ti的含量,得到了3种M/A组元含量不同的高强度管线钢,运用LIBS-OPA-100原位分析仪、扫描电镜(SEM)等手段,研究了偏析及M/A组元对高强度管线钢抗氢致裂纹(HIC)性能的影响。结果表明,3种高强度管线钢M/A含量分别为1号钢(高Mo低Ti)17.4%、2号钢(中Mo中Ti)2.1%、3号钢(无Mo高Ti)0.75%,Mo促进了M/A组元形成,Ti微合金化可有效抑制M/A组元形成,M/A组元的含量、尺寸、形状及分布是影响高强度管线钢抗HIC性能的重要因素,尤其是大块状的M/A使抗HIC性能急剧下降;C、Mn、Si元素在1/4处和中心发生偏析和硬度较高的M/A组元是导致1号、2号试验钢氢致开裂的主要原因;使用原位分析仪测得Al的偏析度顺序为2号钢1号钢3号钢,氧化铝夹杂物是诱发氢致裂纹一个重要原因。  相似文献   

10.
管线钢在硫化氢水溶液中的台阶状氢致开裂分析   总被引:8,自引:1,他引:8  
周琦 《金属热处理》2004,29(3):52-57
对管线钢室温分别在H2S NACE溶液和H2S 人工海水溶液中的氢致开裂进行了研究。管线钢在NACE试验介质中发生了氢致开裂(HIC),沿夹杂物/基体界面及轧制方向的(珠光体 铁素体)带状组织导致了台阶状裂纹;而其在人工海水中则对HIC不敏感。为了提高管线钢的抗氢致开裂性能,应控制带状组织形态和级别。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
吴玉梅  熊晓云  靳蓉  孙敬民  杨林  罗晓星 《金属学报》2005,10(10):1100-1103
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。  相似文献   

20.
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.  相似文献   

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