Incoloy800合金在含硫环境中的高温气体腐蚀

Incoloy800合金是一种铁基合金，含有大量Ni、Cr和少量Si、Mn、Cu、Al、Ti，具有较高的高温强度，同时具有良好的抗氧化性能、抗渗碳性能和抗渗硫性能。高含量的Cr、Ni保证腐蚀环境中的长期稳定性。Incoloy800合金裂化粗汽油炉管在氢加工厂使用150000h(17a)后，只受到轻微的腐蚀，仍然具有良好的机械性能。     

高温抗渗碳耐腐蚀红外辐射釉料的研制

高温抗渗碳红外釉料是一种非晶态结构的高温、抗渗碳、耐腐蚀的新型红外辐射材料。阐述了它的研制与制备工艺，试验了各种因素对其性能的影响。试验表明，红外釉层抗渗碳、耐腐蚀及机械强度等性能大大优于一般红外辐射涂层。     

碳对5Cr28Ni48W5钢焊缝金属抗裂性和高温力学性能的影响

本文就不同含碳量对5Cr28Ni48W5钢焊缝金属的抗裂性和高温力学性能的影响进行了研究,试验结果表明:使用碱性焊条,焊缝金属碳含量在0.3～0.75％时具有良好的抗裂纹性能,所焊接的接头焊缝金属具有与母材相等同的室温力学性能和高温力学性能,高温持久性能在30N应力时可达198 h48min。     

新的耐热钢——SANDVIK·253MA的制用

概要 253MA 在稀土金属和硅的配合作用下,即使到达1200℃也具有良好的抗氧化和抗渗碳性能。在氮和碳的配合作用下还具有较高的蠕变强度。它的组织性能稳定,高温下使用析出脆化σ相很少。由上所述,253MA性能俱优,实用范围广。可完全代替不锈铬钢、18Cr/8Ni和310S(25Cr/20Ni)钢等,就是     

回火温度对中碳合金钢4Cr5MoSiV1Nb组织和性能的影响

 为了优化合金性能，研究了回火温度对中碳合金钢4Cr5MoSiV1Nb组织和性能的影响。试验结果表明，4Cr5MoSiV1Nb合金钢的二次硬化温度区间为300～550 ℃，峰值出现在550 ℃，此时硬度值为56.3HRC，同时伴有冲击韧性的显著降低，冲击韧性降低的原因是合金钢回火时含铬铬的细短棒状合金渗碳体在晶界析出，可以推测减少淬火合金钢中铬的偏析将会减少晶界析出，提高冲击韧性。微量铌的加入形成了（V，Nb）C强化相颗粒。合金在250～350 ℃回火综合性能最佳，可以达到冲击韧性15 J/cm2、硬度55HRC以上。     

0Cr19Ni15Mn5Mo2NbN铸钢晶界高温相析出及对力学性能的影响

利用光学显微镜、扫描电镜及透射电镜,结合Thermo-Calc热力学分析,研究了铌稳定化0Cr19Ni15Mn5Mo2NbN奥氏体不锈钢铸钢晶界处高温相析出行为及其对力学性能的影响。结果表明,0Cr19Ni15Mn5Mo2NbN钢晶界处存在Nb Cr(CN)、Nb(CN)2种大尺寸高温析出相,均为凝固末期液析形成。在铌含量确定条件下,这2种大尺寸晶界析出相在凝固末期的竞争析出行为受碳含量的影响。碳含量存在临界成分,碳含量低于临界成分时,Nb Cr(CN)首先液析形成;碳含量高于临界成分时,Nb(CN)首先液析形成。液析形成的NbCr(CN)热稳定性较高,1 050℃固溶处理无法使之完全溶入奥氏体。沿晶界分布的大尺寸析出相,对0Cr19Ni15Mn5Mo2NbN铸钢固溶热处理后的塑性及冲击韧性损害较大。     

碳铬镍含量对高铬铸铁测温保护管性能的影响

通过高温氧化和高温磨损实验,研究了C、Cr、Ni 3个主要元素对高铬铸铁在高温条件下抗氧化和抗磨损性能的影响。结果表明:Cr含量越高,抗氧化性能和抗磨损性能越好;提高碳含量,明显提高高铬铸铁的高温抗磨性能;当w(Cr)=16％时,加入Ni能提高高铬铸铁的高温抗氧化性能;w(Cr)=30％时,Ni对高铬铸铁的抗氧化性能和抗磨损性能影响不明显.在1100℃以下,选用w(C)=2.8％,w(Cr)=30％、不加Ni的高铬铸铁铸造高温抗磨热电偶保护管,既有较好的使用寿命,又可降低成本.     

含碳量对Cr15—Ni25合金高温低周疲劳性能的影响

本文对含碳0.009、0.099、0.16Wt％的Cr15-Ni25合金高温低周疲劳性能进行了研究,疲劳波形为保持1min单向拉一拉疲劳。实验结果表明,材料的高温低周疲劳性能不仅与含碳量有关,而且同碳化物分布状态有关,材料的高温低周疲劳性能受晶界强度和晶内强度两部分控制,只有二者强度同时提高,才能提高材料的高温抗疲劳性能。     

新型Cu/Cr2Nb真空断路器触头材料的制备与性能研究

以Cu粉和Cr2Nb粉为原材料,分别采用真空烧结和真空热压工艺制备新型Cu/Cr2Nb触头材料.研究了制备工艺、材料成分对Cu/Cr2Nb触头材料的组织和性能的影响规律.结果表明,采用一般烧结工艺难以制备出致密度高的Cu/Cr2Nb材料,而采用热压工艺不仅可制备出致密度高的Cu/Cr2Nb材料,而且与CuCr50触头材料相比,在硬度相当的前提下,Cu/Cr2Nb材料的导电性能显著提高.     

Nb对铸态HP40合金抗氧化及高温强度的影响

通过Gleeble-1500热模拟机研究了Nb含量对10 kg真空感应炉熔炼的铸态HP40合金(%:0.40C、25Cr、35Ni、0.15Mo、0.05Ti、0.4～2.1Nb)1 150℃抗氧化性和抗拉强度的影响。结果表明,0.8%Nb时,HP40合金具有最佳的综合高温性能:在1 150℃合金氧化增重最低,为0.766 g/(m²·h),抗拉强度最高,为52 MPa。     

Electrochemical Behavior of Bulk Amorphous Steel Fe55M2Cr12Mo10B6C13Y2（M=Ni, Cu, Nb）

 Fe55Ni2Cr12Mo10B6C13Y2,Fe55Cu2Cr12Mo10B6C13Y2 and Fe55Nb2Cr12Mo10B6C13Y2 alloys with diameter of 4mm were produced by copper mold casting. The role of alloying additions (Ni, Cu or Nb) on corrosion resistance of Fe55Nb2Cr12Mo10B6C13Y2, Fe55Ni2Cr12Mo10B6C13Y2 and Fe55Cu2Cr12Mo10B6C13Y2 alloys were studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results show that Fe55Ni2Cr12Mo10B6C13Y2 and Fe55Cu2Cr12Mo10B6C13Y2 alloys can be cast into bulk metallic glasses. Fe55Ni2Cr12Mo10B6C13Y2 and     

Electrochemical Behavior of Bulk Amorphous Steel Fe55M2Cr12Mo10B5C13Y2(M=Ni,Cu,Nb)

Fe55Ni2Cr12Mo10B6C13Y2,Fe55Cu2Cr12Mo10B6C13Y2 and Fe55Nb2Cr12Mo10B6C13Y2 alloys with diameter of 4 mm were produced by copper mold casting. The effect of alloying additions (Ni,Cu or Nb) on corrosion resistance of Fe55 Ni2 Cr2Mo10 B6 C13 Y2,Fe55Ni2Cr12Mo10B6C13Y2 and Fe55 Cu2 Cr12 Mo10 B6 C13 Y2 alloys was studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results show that Fe55Ni2Cr12Mo10B6C13 Y2 and Fe55Cu2Cr12Mo10B6C13 Y2 alloys can be cast to form bulk metallic glasses. Fe55Ni2Cr12Mo10B6C13 Y2 and Fe55Cu2Cr12 Mo10B6C13Y2 amorphous alloys with passive potential about 1500 mV exhibit good corrosion resistance in NaCl solution of 5 % and 1 mol/L HC1 solution. The passive current density of the alloy with Ni addition is lower than that of other alloys. EIS results only show one impedance element. Amorphous alloy Fe55 Ni2 Cr12 Mo10 B6 C13 Y2 with larger charge transfer reaction resistance indicates good corrosion resistance.     

Cr35Ni45钢高温长期服役过程的氧化与渗碳机理

采用扫描电镜、电子探针和X射线衍射等手段对不同服役时间（原始态、1.5a和6a）Cr35Ni45乙烯裂解炉管内壁的氧化与渗碳机理进行了系统分析.结果表明:高温长时服役后炉管内壁出现了氧化层、碳化物贫化区和碳化物富集区三个区域,其氧化行为包括Cr₂O₃外氧化和SiO₂内氧化,且服役过程中外氧化膜发生反复破坏和重建;炉管服役过程的渗碳行为主要由内表面结焦引起,外氧化膜的反复破坏可以加重渗碳,但外氧化膜在破坏后能自动修复,所以服役态两个炉管的渗碳程度较轻;外氧化膜的反复破坏和重建使亚表层贫铬,导致形成碳化物的临界碳浓度增加,在内壁亚表层形成贫碳化物区,多余的碳原子在其内侧析出,形成碳化物富集区.      

Electrochemical Corrosion and Impedance Studies of Porous Ti–xNb–Ag Alloy in Physiological Solution

Porous titanium (Ti) and its alloys are promising materials for orthopedic applications due to their low elastic modulus, high strength, excellent corrosion resistance, and biocompatibility. In this study, the porous Ti–xNb–5Ag (x = 25, 30 and 35 wt%) alloys were synthesized using the powder metallurgy approach. The effects of Nb content on the porosity, mechanical properties, and electrochemical corrosion behavior of the alloys were investigated. XRD analysis revealed that the porous alloys mainly consist of α-Ti, β-Ti, intermetallic compound (Ti₄Nb), and oxides of TiO₂ and NbO phases. Porous alloys possess the porosity ranging from 57 to 65%, due to the addition of NH₄HCO₃ (45 wt%). Increase in Nb content lead to a reduction in the elastic modulus and compression strengths of the sintered porous Ti–xNb–5Ag alloys. All three developed porous Ti–xNb–5Ag alloys show the optimum combination of elastic modulus and compression strength, which is suitable for orthopedic applications. These porous alloys exhibit excellent electrochemical corrosion resistance in the simulated body fluids, and the samples having low porosity exhibit higher corrosion resistance than high-porosity samples.

     

Microstructure of Precipitation Hardenable Powder Metallurgical Ni Alloys Containing 35 to 45 pct Cr and 3.5 to 6 pct Nb

Ni-based alloys with high Cr contents are not only known for their excellent high temperature and hot corrosion resistance, but are also known for poor mechanical properties and difficult workability. Powder metallurgical (PM) manufacturing of alloys may overcome several of the shortcomings encountered in materials manufacturing involving solidification. In the present work, six PM Ni-based alloys containing 35 to 45 wt pct Cr and 3.5 to 6 wt pct Nb were produced and compacted via hot isostatic pressing. Samples were heat treated for up to 1656 hours at either 923 K or 973 K (650 °C or 700 °C), and the microstructures and mechanical properties were quantified and compared to thermodynamic calculations. For the majority of the investigated alloys, the high Cr and Nb contents caused development of primary populations of globular α-Cr and δ (Ni₃Nb). Transmission electron microscopy of selected alloys confirmed the additional presence of metastable γ″ (Ni₃Nb). A co-dependent growth morphology was found, where the preferred growth direction of γ″, the {001} planes of γ-Ni, caused precipitates of both α-Cr and δ to appear in the form of mutually perpendicular oriented disks or plates. Solution heat treatment at 1373 K (1100 °C) followed by aging at 973 K (700 °C) produced a significant strength increase for all alloys, and an aged yield strength of 990 MPa combined with an elongation of 21 pct is documented for Ni 40 wt pct Cr 3.5 wt pct Nb.     

新型准贝氏体渗碳钢及应用

研究了新型准贝氏体钢渗碳特性及渗层磨损性能。结果表明,准贝氏体钢具有良好的渗碳特性,特别是具有优越的空冷淬硬性,渗碳层的耐磨性达到１８Ｃｒ２Ｎｉ４ＷＡ钢的水平。磨料磨损机制为：二体磨损以微切削为主,三体磨损以应变疲劳为主。并阐述了准贝体钢在重型钎具方面的应用结果。     

稀土化合物对粉末冶金镍基合金摩擦磨损性能的影响

用粉末冶金热压方法制备了几种含不同稀土化合物（LaF3,CeO2,La2O3)的Ni基合金，将合金制备为块样，45^#钢为环样，在环－块摩擦试验机上考察了稀土化合物含量及其种类对Ni基合金摩擦磨损性能的影响，研究结果表明：添加稀土化合物可明显改善合金在高载高速下的耐磨性能，这与其摩擦表面形成摩擦保护性“釉质层”密切相关。     

Formation kinetics and rupture strain of Ni-Cr-Fe alloy corrosion films formed in high-temperature water

Nickel alloys such as Alloy 600 undergo stress corrosion cracking (SCC) in pure water at temperatures between about 260 °C and the critical point. Increasing the level of Cr in Ni-Fe-Cr alloys increases SCC resistance in aerated and deaerated water. The mechanism for Cr influence is not understood. The effect of Cr composition on the in-situ oxide rupture strain and corrosion kinetics of Ni-9Fe-Cr alloys was determined experimentally, to evaluate whether the rupture-dissolution model for SCC can account for the effect of Cr on SCC. The alloy corrosion rate and corrosion product oxide microstructure and mechanical properties are strongly influenced by Cr composition. As Cr concentration increases from 5 to 30 pct, oxide rupture strains measured in pressurized water at 288 °C increase from about 8×10⁻⁴ to 2×10⁻³ mm/mm. Corrosion kinetics are parabolic; the corrosion rate first increases and then decreases as Cr increases from 5 to 39 pct. These observations are qualitatively consistent with a rupture-dissolution SCC mechanism. However, parametric modeling of the SCC growth process, applying available creep, oxide rupture strain, and corrosion kinetics data, indicates that the rupture-dissolution mechanism accounts for only a fraction of the effect of Cr on SCC resistance.     

不同氧化条件下 Cr35 Ni45 Nb合金组织特征及其与持久寿命的关系

以Cr35Ni45Nb合金为研究对象,进行不同气氛条件下高温时效及高温持久试验,并结合扫描电镜及定量电子探针对样品表面及横截面的观察分析,系统研究不同氧化条件下Cr35Ni45Nb合金组织演变与持久寿命的关系.结果表明:随着处理时间的延长,管材边缘及内部组织均逐渐发生变化.氧化序列体现为先是在样品边界不同地点形成不连续的氧化膜,随后氧化膜连成一体形成连续氧化膜,同时贫化区也逐渐形成;由于温度波动,氧化膜破裂脱落,而在氧分压较高的时效环境中,氧化膜得不到及时修复,使得贫化区晶界中出现内氧化.此外,在空气中氧化与在真空充氩气石英管中持久试验结果表明,较薄的连续氧化膜有助于提高合金的蠕变性能,而随着高温时效时间的延长,边界贫化区逐渐形成,氧化膜破裂及内氧化的发生,使得合金的蠕变性能逐渐弱化.