ZG35Cr26Ni12WNRE奥氏体耐热钢的研制

在ZG35Cr26Ni8NRE炼镁还原罐用耐热钢的基础上,开发了ZG35Cr26Ni12WNRE奥氏体耐热钢,并研究了新研制耐热钢的组织结构和蠕变性能。结果表明,新研制耐热钢的奥氏体基体固溶有较多的碳元素,含有较少的大尺寸(几十微米)颗粒状和蠕虫状碳化物相,在高温条件下会析出较多的超细颗粒(1微米左右)碳化物相;新研制耐热钢在1 000℃、16 MPa条件下的蠕变第二阶段蠕变速率为0.000 2%·h~(-1),仅是ZG35Cr26Ni8NRE的1/7,高温蠕变性能大幅提高。     

Al含量对Fe-22Cr-25Ni含铝奥氏体耐热钢高温抗氧化性能的影响

以HR3C合金成分为基础,通过调控Cr、Ni含量和添加1.5%,2.5%和3.5% (质量分数) 的Al制备了Fe-22Cr-25Ni型含铝奥氏体耐热钢,并研究了合金的高温抗氧化性能。利用SEM、EDS和XRD对含铝奥氏体钢700、800和900 ℃氧化后的氧化膜组成、结构进行了表征。结果表明：22Cr-25Ni-2.5Al和22Cr-25Ni-3.5Al含铝奥氏体耐热钢在700和800 ℃下具有优异的抗高温氧化性能。氧化后表层形成了连续致密的Al₂O₃保护膜,提高了其高温抗氧化性能。3种耐热钢经900 ℃氧化时形成外层为Cr₂O₃和MnCr₂O₄的复合氧化层,且氧化层下存在Al₂O₃内氧化物和AlN析出相,不能对基体起到有效保护作用。     

高Cr铸铁高温耐磨性能研究

对比分析了所研制的高Cr铸铁风帽与耐热钢(ZG40Cr24Ni9Si2NRE)风帽的高温耐磨性能。高Cr铸铁的碳化物为黑色细条杆状并且呈点状分布,有利于高温耐磨性能的提高;而现用的耐热钢w(C)量低,合金碳化物少,不利于高温耐磨性。对比试验、理论分析和生产验证,所研制的高Cr铸铁风帽在生产成本和使用寿命方面均优于厂家现用的耐热钢风帽。     

Al_2O_(3p)/20Cr25Ni20复合材料的高温磨损性能

研究了挤压铸造法制备的Al2O3陶瓷颗粒增强20Cr25Ni20耐热钢基复合材料在500℃下的高温磨损性能,并和基体材料20Cr25Ni20及其他几种常用的辊环材料进行对比。结果表明,在比压为7.95MPa时,Al2O3p/20Cr25Ni20复合材料高温耐磨性是基体材料20Cr25Ni20的3.4倍,比Cr16高铬铸铁提高了46%,YG10硬质合金耐磨性最好,是复合材料的6.5倍。基体材料高温磨损后发生塑性流动,切削严重,复合材料中氧化铝陶瓷颗粒作为高温耐磨相发挥出良好的耐磨作用。     

微合金化对40Cr25Ni20Si2耐热钢性能影响的研究

研究了Al、Ti、N、Nb等复合微合金化对ZG40Cr25Ni20Si2耐热钢组织和性能等的影响。结果表明,不同组合的复合微合金化ZG40Cr25Ni20Si2耐热钢均达到完全抗氧化级别;0.3%左右的Nb与Ti、Al等复合微合金化对耐热钢的抗高温氧化性能和高温变形抗力均有提升,继续增加Nb含量至0.7%以上,组织中出现大量Nb的碳氮化物析出,变形抗力继续增加,但抗高温氧化稳定性下降;Al、Ti复合微合金化抗高温氧化的稳定性最好,Cr₂O₃-Al₂O₃复合氧化层均匀、连续、致密且与钢基结合紧密,但高温变形抗力低于含Nb的试样。在N含量增加的情况下,适当降低Ni含量,结合微合金化,耐热钢总体性能保持稳定。     

Al对1Cr9Al(1-3)Ni(1-7)WVNbB合金相变与性能的影响规律

为了研究Al对铁素体耐热钢相变与性能的影响规律,通过在已有合金T92的成分基础上进行Al元素的添加及改性添加剂Ni的调整制备出了新型高铝铁素体耐热钢,研究了不同含量Al元素的加入及热处理工艺下铁素体耐热钢相变温度与淬火组织晶粒尺寸、硬度及抗氧化性的关系。结果表明,实验钢的平衡相变点随着Al元素含量的增加而升高,且实验钢的奥氏体晶粒尺寸越大,Ac1和Ac3温度越高;钢中添加的Al、Ni元素总量在2.4 wt %时,淬火后的奥氏体晶粒尺寸最小,且硬度最大;在650 ℃环境下,钢中添加3 wt %Al比添加1 wt %Al的抗高温氧化性能强;在750 ℃环境下,钢中所含改性添加剂Ni起到了一定的作用,Al-Ni比越大,钢便表现出了较强的抗氧化性。     

Al、Ni对1Cr9Al(1-3)Ni(1-7)WVNbB合金相变与性能的影响

为了研究Al对铁素体耐热钢相变与性能的影响规律,通过在已有合金T92的成分基础上进行Al元素的添加及改性添加剂Ni的调整制备出了新型高铝铁素体耐热钢,研究了不同Al元素含量的加入及热处理工艺下铁素体耐热钢相变温度与淬火组织晶粒尺寸、硬度及抗氧化性的关系。结果表明,实验钢的平衡相变点随着Al元素含量的增加而升高,且实验钢的奥氏体晶粒尺寸越大,起始温度(A_(c1))和终止温度(A_(c3))越高;钢中添加的Al、Ni元素总量在2.4%(质量分数)时,淬火后的奥氏体晶粒尺寸最小,且硬度最大;在650℃环境下,钢中添加3%Al比添加1%Al的抗高温氧化性能强;在750℃环境下,钢中所含改性添加剂Ni起到了一定的作用,Al-Ni比越大,钢便表现出了较强的抗氧化性。     

高镍铬含氮奥氏体耐热钢在高温渗碳环境中的蜕变

应用SEM，EDS及X射线衍射等方法分析研究了高镍铬含氮奥氏体型耐热钢Cr30Ni20NRE在长期高温渗碳环境运行中的蜕变。试验结果表明，长期在高温条件下服役，铸态Cr30Ni20NRE耐热钢中沿奥氏体晶界的珠光体首先融入奥氏体；长期高温单边渗碳形成大量富铬碳化物，促使镍富集并起泡形成瘤状物，催化含碳气体的分解；表层瘤状物使辐射管表层疏松，表面积扩张，加快了碳向基体的渗入，提供了碳化物持续长大的条件，并引起沿碳化物周边开裂和奥氏体基体严重萎缩；合金元素的重新分布造成主合金元素铬和镍产生两极分化，镍和硅的富集促使石墨化，与侵入的氧形成内部氧化空洞和膨胀疏松，最终导致构件穿孔失效。因此，对高温渗碳环境中长期使用的高合金耐热钢，迎渗碳面的抗渗碳性能和其内壁面的抗氧化性能十分重要。     

晶粒尺寸对耐热钢在高温水蒸汽中的氧化行为的影响

从氧化动力学、氧化膜相组成及微观结构方面,研究了晶粒尺寸对18Cr-8Ni耐热钢在700 ℃下的高温水蒸汽中氧化行为的影响。结果表明：晶粒细化提高了耐热钢的抗水蒸汽氧化性能,降低了其氧化增重,推迟了失稳氧化的发生;晶粒细化改变了耐热钢氧化膜的微观结构,减小了“弹坑”区的尺寸且促进了“弹坑”区与合金界面上富Cr氧化物层的形成;晶粒细化对耐热钢抗水蒸汽氧化性能的改善主要归因于其对氧化物的形核和Cr向氧化膜/合金界面扩散的促进作用。     

稀土钇对FeCrNi耐热钢循环氧化行为的影响

采用增重法在1100℃、1150℃和1200℃条件下对Fe-21Cr-11Ni试验钢进行循环氧化试验,结合X射线衍射、扫描电镜及能谱等方法研究了钇元素在耐热钢抗高温氧化中的作用机理。结果显示,添加微量稀土钇元素能显著提高耐热钢的抗高温氧化性能。在氧化过程中,钇元素能促进铬元素向氧化层的扩散,在含钇耐热钢表面,形成了致密的粘附性好的Cr2O3层和FeCr2O4尖晶石外氧化物层,起到了很好的保护作用,在内氧化层中,钇元素不仅加强了SiO2钉扎,而且直接参与和强化了钉扎作用。     

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。     

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.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

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.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

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.     

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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