耐候钢焊接接头锈层稳定化大气曝晒加速试验

利用锈层稳定化处理的耐候钢焊接接头,进行了大气曝晒(喷淋)加速试验,结果证明:经表面复合处理剂处理后的Q450NQR1耐候钢,腐蚀率显著降低,不仅提高了耐蚀性,而且也提高了抗局部腐蚀能力。经表面复合处理剂处理的焊接接头与非焊接样的腐蚀试验结果没有差别,说明表面复合处理剂适用于焊接接头的锈层稳定化处理。     

Microstructure,mechanical property and corrosion resistance property of Cr26Mo3.5 super ferritic stainless joints by P-TIG and laser welding

The characteristics of microstructure, mechanical property and corrosion behavior of Cr26Mo3.5 super stainless steel joints by pulse tungsten inert gas(P-TIG)welding and laser welding were investigated. The results indicate that the widths of the center equiaxed grain zone(EGZ)and the columnar grain zone(CGZ)increase with the increase of heat input in both welding processes. The precipitates of Nb and Ti carbides and nitrides are formed in the weld metal(WM)and the heat affected zone(HAZ). The joints by laser welding show better tensile and corrosion resistance properties than those by P-TIG welding due to the heat concentration and lower heat input. The tensile strength and elongation increase with the decrease of heat input, and the fracture mode of the joints turns into ductile-brittle mixed fracture from ductile fracture when the welding method turns into P-TIG welding from laser welding. Moreover, the corrosion resistance of all joints declines slightly with the increase of heat input. Hence, laser welding is more suitable for welding Cr26Mo3.5 super stainless steel in engineering applications.     

High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy ( SEM ), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAl coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings. It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.     

稀土和球化热处理对M42高速钢碳化物尺寸的细化作用(英文)

采用OM,SEM,EDS,TEM,EBSD,XRD等分析手段,研究了稀土和热处理对M42高速钢组织和性能的影响规律.结果表明,M2C是M42高速钢主要的共晶碳化物类型.稀土处理后,M2C共晶碳化物形貌由规则层片状变为不规则环状.尽管二者形貌差异明显,但具有相同的微观结构和晶体取向特征.与层片状碳化物相比,环状M2C共晶碳化物热稳定性较差,高温加热时更易发生分解和球化,使碳化物尺寸明显细化.小尺寸碳化物在淬火加热时易于溶解,提高了淬火后基体中合金元素的固溶度,使M42高速钢硬度增加了1.5 HRC.     

高铬铸铁的研究应用与发展

介绍了高铬铸铁的组织及碳化物的细化,高铬铸铁的耐磨性及应用,指明了下一步开展高铬铸铁研究的方向。     

MICROSTRUCTURE AND MECHANISM OF A NEW TYPE OF Ni－Fe－W－P－S WEAR－RESISTANT BRUSH PLATING LAYER

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＳＭＯＦＡＮＥＷＴＹＰＥＯＦＮｉ－Ｆｅ－Ｗ－Ｐ－ＳＷＥＡＲ－ＲＥＳＩＳＴＡＮＴＢＲＵＳＨＰＬＡＴＩＮＧＬＡＹＥＲＨｕｉＷｅｎｈｕａ（惠文华）ＺｈａｎｇＪｉｎｐｉｎｇ（张瑾平）ＳｈａｏＬｉｗｅｉ（邵力为）...     

Corrosion process detection of tinplate in deaerated functional beverage by EIS

The corrosion process of tinplate in deaerated functional beverage was investigated by using electrochemical impedance spectroscopy (EIS) combined with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The results reveal that the uncoated tinplate shows a poor corrosion resistance and the corrosion type is detinning. During the initial stage of immersion, EIS spectrum consisted of two capacitance arcs with obvious time-constant dispersion effect, which was attributed to the two-dimensional and three-dimensional inhomogeneous distribution of the electrode surface. With the increase of immersion time, the capacitance arc of high frequency shrunk and degenerated, due to the corrosion of tin coating. The pore resistance of tin coating and the charger transfer resistance of substrate, which are determined from the electrochemical equivalent circuit, can be used as the indicators of tinplate corrosion process. The decrease of the pore resistance of tin coating indicates that the corrosion degree of tin layer becomes more severe, whereas the decrease of the charger transfer resistance of substrate implies that the corrosion degree of steel substrate also becomes more severe as the immersion time prolongs.     

Microstructure and corrosion mechanism of as-cast Mg-Zn-Mn-Ca in Hank’s solution

An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting. The as-cast microstructure was investigated using XRD, SEM and EDS. It was shown that the alloy was composed of α-Mg, strip-like Ca2Mg6Zn3 and a few Mn- containing phases. Most of the Ca2Mg6Zn3 phase was distributed at grain boundaries while Mn-containing particles were deposited within grains. The as-cast samples were immersed in a Hank＇s balanced salt solution （HBSS） up to 24 h. The corroded surface morphology and cross-section microstructure were analyzed after different time of immersion so as to understand the corrosion behavior of the alloy. During immersion in the HBSS, the alloy corroded homogeneously at the very beginning and then localized corrosion occurred. The secondary phases protruded on the surface due to the dissolution of α-Mg, suggesting micro- galvanic corrosion occurred with secondary phases acting as the cathode and ct-Mg as the anode. Micro-cracks were formed at the interfaces between Ca2Mg6Zn3 and α-Mg, indicating an undermining tendency of the secondary phases.     

熔覆处理高铬高锰耐磨钢板的微观组织分析

文章选取对基材45#钢进行粉末电弧熔覆处理后获得耐磨钢板,研究其成分和微观组织特点,分析结合层的特性。结果表明:熔覆区为细小的树枝晶,组织均匀致密,并有硬质点弥散分布。冶金结合使得表面层具有高硬度和耐磨性,同时内部具有良好的耐冲击性能。     

不同Co含量对超音速火焰喷涂WC-xCo-3Cr涂层组织和性能的影响

通过超音速火焰喷涂工艺在Cr12模具钢表面上喷涂制备了WC-x Co-3Cr(x=8,10,12,14)涂层,并采用金相显微镜、扫描电镜、显微硬度仪和摩擦磨损试验机表征分析涂层的微观结构、显微硬度、耐磨损性能和耐腐蚀性,考察了不同Co含量对涂层组织和性能的影响。结果表明,Cr12模具钢超音速火焰喷涂后表面的耐磨损性能比喷涂前的基体耐磨损性能有较大的提高;表面硬度在不同程度上都得到提高,界面结合良好,其中WC-10Co-3Cr涂层的组织致密性最好、显微硬度最高、耐磨损及耐腐蚀性能最好。     

用激光表面处理改善碳素钢耐蚀性的研究

本文研究用激光表面处理使碳素钢表面合金化,从而提高普通碳素钢的耐蚀性,且研究表明随着焊缝中铬含量的增加,耐蚀性提高。研究还表明用较高的扫描速度和较大的激光功率可获得稳定的焊逢形状。     

2-巯基苯并噻唑三元复合缓蚀剂对碳钢的缓蚀作用

首先研究了2-巯基苯并噻唑（MBT）缓蚀率与其浓度的关系,选用碘化钾（KI）和硫脲（TU）与之进行了三元复配,并通过极化曲线和电化学阻抗研究了三元复合缓蚀剂的缓蚀机理,最后进行了热力学分析。实验结果表明,MBT,KI和TU三元复合缓蚀剂其浓度最佳配比为1：2：2;总浓度为250 mg/L时,在最佳配比下,缓蚀率可达97.7%;三元复合缓蚀剂是以抑制阳极溶解反应为主的混合型缓蚀剂,在碳钢表面的吸附符合Langmuir等温吸附模型。     

电弧喷涂技术及长效防腐涂层的应用

介绍了电弧喷涂技术的原理和技术特点，电弧喷涂锌，铝制备涂层，广泛用于钢铁构件耐大气，淡水，海水和土壤环境的长效附腐，中从工业及民用输水管道，普通钢结构，化工矿井和船舶钢结构四个方面普通防腐工艺进行了对比分析。     

镁合金上化学Ni-P-硬质氧化物复合镀层

结合溶胶-凝胶法和化学镀方法,于镁合金基材表面成功制备了均匀的复合Ni-P-SiO_2/TiO_2/Al_2O_3镀层,采用扫描电镜(SEM)、光学显微镜(OM)、摩擦磨损试验及电化学方法,对比研究了Mg基材、基础Ni-P镀层与3种复合镀层的显微组织结构、耐磨性及耐腐蚀性。结果表明,加入3种溶胶所制备的复合镀层较Mg基材大幅度提高耐磨性和耐腐蚀性;3种复合镀层较Ni-P镀层具有更加均匀、致密的显微形貌,减少了直接加入纳米粉末的团聚,同时耐磨和耐蚀性改善。其中Ni-P-SiO_2复合镀层具有较高的显微硬度(HV513)和最低的摩擦系数(0.34),最高的腐蚀电位(-1.18V)及较小的腐蚀电流密度(9.5×10~(-3)mA·cm~(-2))。综合制备最佳工艺,并考虑节能减排因素,Ni-P-SiO_2复合镀层可作为性能优良的Mg合金耐磨、耐腐蚀镀层使用,于实际工业生产大有裨益。     

La对电沉积纳米镍组织结构和耐蚀性的影响

添加不同含量的稀土氯化物LaCl3,制备了纳米晶体镍,采用透射电镜（TEM）和环境扫描电镜（ESEM）观察镀层的微观组织和结构．结果表明：添加LaCl3可以明显提高镀层表面光洁度、耐蚀性能,在加入1g／L LaCl3时,镀层具有最佳耐蚀性能．     

氮离子注入钛合金表面的耐点蚀性能研究

在Ti-6Al-4V合金表面分别注入3×1017、6×1017、9×1017和2×1018N+/cm2四种剂量的氮离子后,测定了基体材料和四种不同注入剂量下试样在3.5％NaCl溶液中的阳极极化曲线,并对它们的耐点蚀性能进行了比较.结果表明,在五种试样中,以3×1017注入剂量下具有最好的耐点蚀性能,但它的再钝化能力相对较低.     

电阻探针腐蚀监测仪的开发与应用

基于电阻探针腐蚀监测的原理,研制了适合气田环境的ER400电阻探针腐蚀监测仪,其仪器电阻分辨率可达到0.5(腐蚀速率灵敏度达到了0.1m/a)。用其所研制的电阻探针腐蚀监测设备与实验室的电化学极化测试和靖边气田现场磁阻探针、挂杆失重试验相比,发现其测量的腐蚀速率与室内和现场测试结果十分接近。说明ER400电阻探针腐蚀监测仪器的可靠性,达到了国内外同等仪器的先进水平。     

硫酸溶液中环丙沙星对低碳钢的缓蚀作用研究

采用失重法研究了环丙沙星在0.5 mol/L H2SO4溶液中对低碳钢的缓蚀性能以及温度对缓蚀效果的影响,通过量子化学计算和动电位极化曲线测试研究了缓蚀机理.结果表明:环丙沙星具有较好的缓蚀性能,在有效浓度为4mmol/L时对低碳钢的缓蚀效率可达到91.19%;它是以阳极抑制为主的混合抑制型缓蚀剂,通过苯环及O、N、F三种杂原子在碳钢表面形成的单分子层吸附达到缓蚀目的,并且随着温度的升高缓蚀效率降低.     

4Cr13不锈钢模具开裂原因分析及改进措施

捅善芒：采用化学分析、金相检验等分析方法,对4Cr13不锈钢模具在使用中发生开裂的原因进行了分析。模具的内壁离断裂面不远处有一条横裂纹,裂纹长40ram,裂纹中间有小孔洞存在。分析结果表明：4Cr13模具组织中有大量共晶碳化物是导致裂纹产生的主要原因。通过改进4Cr13钢的冶炼、浇注,锻造工艺,减少钢锭中碳化物量,可以消除4Cr13模具中共晶碳化物缺陷,使其裂纹发生率降低。关键词：4Cr13模具;共晶碳化物;裂纹中图分类号：TF764．1文献标识码：B文章编号：1672—9994（2013）03—0013一03     

Influence of Heat Treatment on Microstructure and Sliding Wear Behavior of Fe-Al/WC Composite Coatings

Researchershavebecomeincreasinglyinterestedinironaluminideintermetallics (includingFe3AlandFeAl)since 1970sinviewofthecombinationoflowcost,lowerdensity ,remarkableresistancetoerosion ,sulfidizingandoxidizingathightemperature .However ,industrialap plicationofthesealloyshasbeenverylimitedduetotheirpoorductilityandfracturetoughnessatroomtemperatureaswellastheirdifficultyinshaping[1] .Somestudieshaveindicatedthatcoatingstructuralmaterialswithironaluminidesbyusingthermalsprayingwillnotonlysolveth…