国产108t矿山自卸车重载齿轮组织和硬化层研究

为了提高国产108 t矿用自卸车齿轮寿命,采用金相显微镜、硬度测试、扫描电镜等试验手段,对108 t矿用自卸车齿轮原热处理工艺进行了研究,分析了非金属夹杂物等级、硬度、淬硬层深度、渗碳层深度、碳化物等级。结果表明:108 t矿用自卸车齿轮原预先正火处理的试样晶粒粗大、夹杂物明显;使用HSFD-2型分级等温淬火油的渗碳淬火试样或者渗碳二次淬火热处理试样在渗碳层组织、淬硬层深度、夹杂物各方面优于使用N32机械油的渗碳淬火试样。     

磨削深度及原始组织对42CrMo磨削淬硬层的影响

在磨削深度为0.1～0.6 mm的条件下对调质态、正火态及退火态42CrMo钢进行了磨削淬火试验。结果表明:磨削淬火后,三种原始组织试样磨削淬火后的完全淬硬区显微硬度为510～878 HV。正火、调质及退火态试件的淬硬层厚度分别为1.75、1.5和1.25 mm。磨削淬火后,调质态的42CrMo钢完全淬硬层组织为略大的板条状马氏体组织,正火态的42CrMo钢完全淬硬层的马氏体组织最为细小,退火态的42CrMo钢完全淬硬层板条状马氏体尺寸居于二者之间。     

45钢超声波辅助油冷淬火工艺

针对小尺寸45钢零件在常规淬火时容易出现油冷淬不透而水淬开裂现象,对超声波辅助淬火工艺进行了研究,并对热处理后的试样进行显微组织观察和力学性能测试。结果表明:超声波辅助油淬能有效提高常规油淬的淬火效果;在超声波辅助油淬过程中,随着超声波功率的增大,马氏体含量逐渐提高且分布均匀,硬度和强度随之提高,而伸长率随之降低。     

淬火对汽车车身用6022铝合金烤漆硬化效应的影响

以6022铝合金冷轧板为研究对象,通过显微组织观察、硬度测试等方法研究了双级淬火工艺对6022铝合金组织及烤漆前后硬度的影响。结果表明:6022铝合金试样经过560℃×25 min固溶处理后,进行油淬+室温水淬双级淬火,油淬温度越高,6022铝合金硬度越高,对抑制自然停放效应不利影响的作用越明显。6022铝合金最佳的双级淬火工艺为110℃×50 min油淬+室温水淬。此淬火工艺下的试样烤漆前硬度为71 HV,利于冲压成形,烤漆后,硬度值达到108 HV,烤漆硬化效应值为37 HV,烤漆硬化效应明显。     

高压气淬后9Cr18钢的组织和性能

研究了真空高压气淬热处理工艺对9Cr18钢组织、性能及变形的影响。结果表明,两种状态淬回火工艺处理的试样组织基本一致,均由马氏体、一次碳化物、二次碳化物和残余奥氏体组成。淬透性能满足生产要求。经真空气淬的试样硬度仅比油淬的略有降低,但变形微小,便于产品的后续加工,可替代现有的真空油淬工艺。     

退火和调质处理的40Cr钢的性能研究

对尺寸为?15 mm×20 mm的40Cr钢试样分别进行了840℃保温40 min炉冷退火、840℃保温50 min水淬和油淬以及淬火后540℃回火40 min空冷。检测了交货态棒材和热处理后试样的显微组织和硬度。采用JMatPro软件对40Cr钢的奥氏体化、马氏体转变和CCT曲线及淬火和回火过程进行了模拟。结果表明：交货态40Cr钢棒材的表面硬度为61 HRA;840℃退火后试样的硬度为49 HRA,组织为铁素体和珠光体;840℃水淬后试样的硬度为73 HRA,油淬后为71 HRA,组织均为板条马氏体;水淬和油淬随后540℃回火后试样的硬度均为66 HRA,组织主要为回火索氏体。     

新型MQ-P-T技术在高铬铸球中的应用

利用水和空气作为淬火介质,对直径为80 mm的Fe-2.4C-12Cr高铬铸球进行多循环淬火-分配-回火(MQ-P-T)处理,并与常规正火和油淬处理后的同尺寸试样的力学性能和微观组织进行对比分析。通过微观表征技术,对MQ-P-T处理后高铬铸铁的强韧化机制进行了探讨。结果表明,经MQ-P-T处理后的高铬铸球径向硬度平均值约为60 HRC,比空冷铸球径向平均硬度约高出17 HRC,比油淬处理试样约提高5 HRC。经MQ-P-T处理后铸球冲击韧度平均值达到12.6 J/cm2,约为空冷冲击韧度的4倍,约为油淬冲击韧度的2倍。经MQ-P-T处理后铸球具有高的硬度和硬度均匀性,其冲击性能亦大大提高。经MQ-P-T处理后铸铁优异的力学性能主要归因于马氏体基体、相当数量的二次碳化物和稳定的残留奥氏体组织。     

MQ-P-T技术在高铬铸球中的应用

首次利用水和空气作为淬火介质,对直径为80 mm的Fe-2.4C-12Cr高铬铸球进行多循环淬火-分配-回火(MQ-P-T)处理,并与常规正火和油淬处理后的同尺寸试样进行力学性能和微观组织对比分析。通过微观表征技术,对MQ-P-T处理后高铬铸铁的强韧化机制进行了探讨。结果表明,经MQ-P-T处理后的高铬铸球径向硬度平均值约为60HRC,比空冷铸球径向平均硬度约高出17 HRC,比油淬处理试样约提高5 HRC。经MQ-P-T处理后铸球冲击韧度平均值达到12.6 J/cm2,约为空冷冲击韧度的4倍,约为油淬冲击韧度的2倍。经MQ-P-T处理后铸球具有高的硬度和硬度均匀性,其冲击性能亦大大提高。经MQ-P-T处理后铸铁优异的力学性能主要归因于马氏体基体、相当数量的二次碳化物和稳定的残留奥氏体组织。     

W18Cr4V钢真空气淬和普通油淬的组织与性能比较

采用真空气淬法和普通空气加热油淬法分别对W18Cr4V钢进行热处理。利用金相显微镜和洛氏硬度计对热处理后W18Cr4V高速钢的组织和硬度进行了比较观察和测试分析。结果表明,两种淬火工艺处理的试样组织基本一致,均为隐晶形的淬火马氏体基体组织、大颗粒状的共晶碳化物和细小点粒状的二次碳化物及残留奥氏体,气淬后的组织更均匀;回火后的组织也很相似,为回火马氏体及未溶解的共晶碳化物和二次碳化物。经真空气淬的试样硬度（65HRC）仅比普通空气加热油淬的（66HRC）略有降低,但能满足工模具的硬度要求,而且试样表面光洁,呈银灰色,变形微小,对于要求精度不太高的零件,无需进行后续加工,对环境也无污染。     

再结晶退火对高硅电工钢冷轧带材组织、有序结构和力学性能的影响

采用弯曲实验,拉伸实验,SEM,TEM和EBSD等手段,研究了再结晶退火对高硅电工钢冷轧带材组织、有序结构、力学性能和冷轧成形性能的影响.结果表明,冷轧试样经800~1200℃保温1 h再结晶退火随炉缓冷后,室温塑性大幅下降,可弯曲角度均由冷轧试样的150°下降至50°左右,且二次冷轧出现严重的边裂;提高再结晶退火后的空冷或油淬温度、冷却速率可显著提高试样的室温塑性,1000℃保温1 h再结晶退火后,900℃油淬试样的可弯曲角度增大至175°左右,拉伸断后伸长率由随炉缓冷试样的0.2%提高至5.2%,且二次冷轧基本不出现边裂;提高再结晶退火后的冷却温度和速率显著提高试样的室温塑性的原因是试样的有序相尺寸明显减小,例如,有序相畴尺寸可从600℃以下油淬试样的约5μm分别减小至700℃油淬试样的小于50 nm和900℃油淬试样的小于25 nm.     

Quick valence analysis method of vanadium toward accurate toxicity assessment of vanadium-containing hazardous wastes

In order to develop a quick, efficient and sensitive valence analysis method of vanadium(V), the high- performance liquid chromatography (HPLC) was utilized to separate and quantify EDTA-complexed V(III), V(IV) and V(V) ions. The influence of EDTA, TBAOH, solution pH and organic modifier on retention behavior of V−EDTA complexes was investigated. Complexed V(III), V(IV) and V(V) ions can be separated and quantified in 5 min, with detection limits of 0.04 mg/L V(III), 0.07 mg/L V(IV), and 0.06 mg/L V(V), respectively. The established method is applied to analyzing the hazardous waste of V−Cr-bearing reducing slag and results demonstrate 49.94% of its V element to be toxic V(V). This work opens a new avenue for quick and accurate toxicity assessment of hazardous wastes containing multivalent heavy metals.     

窄V带在锻压机床上的应用探讨

介绍了窄V带在锻压机床传动中的应用。通过对普通V带和窄V带的比较,阐述了窄V带的优点,窄V带的各种规格、制式,并探讨了窄V带的应用。     

Catalytic spectrophotometric determination of trace vanadium in fly ash and coal gangue by Triton X-100 enhancing effect

Trace V(V) catalyzes mightily the decolorization reaction of arsenazo Ⅲ(AsA Ⅲ) by oxidizing with H2O2 in a pH 4.0 HAc-NaAc buffer solution, and the addition of Triton X-100 can further increase the sensitivity of the reaction and its catalytic extent is linear with the content of V(V). A catalytic spectrophotometric procedure for determining trace V(V)was developed. The results show that the maximun absorption of the color solution is at 560 nm and the detection limit of the method for V(V) is 0.014 mg.L-1. Beer's law is obeyed for V(V) in the range of 0.00-0.20 mg.L-1. The recoveries are 99.0%-104.6%, and the relative standard deviations (RSD) are 2.7%-3.7%. Combined with ion-exchange resin, the method has been applied to the determination of trace vanadium in fly ash and coal gangue with satisfactory results.     

元素V对奥氏体焊缝金属晶间腐蚀敏感性的影响

采用透射电镜(TEM)分析技术研究了1Cr19Ni23N焊条熔敷金属中钒含量对组织及对熔敷金属抗晶间腐蚀性能的影响.结果表明,低钒含量焊条熔敷金属组织中沿奥氏体晶界析出M23C6型富铬碳化物,在晶界附近形成贫铬层,导致晶间腐蚀的发生;高钒含量焊条熔敷金属组织中,V优先于Cr与C形成细小弥散的碳化钒分布在晶粒内部,使得该焊条在保持原较高碳含量的基础上,通过改变碳化物形态和分布达到了保持高强度和改善晶间腐蚀敏感性的目的.     

Effects of vanadium carbides on hydrogen embrittlement of tempered martensitic steel

Precipitation of V carbides is known to suppress the hydrogen-embrittlement (HE) phenomenon as well as to increase material strength. Despite increasing attention to V carbides, there have been few systematic and quantitative investigations on their effects on HE resistance. This study reveals the role of V carbides on the HE behavior of tempered martensitic steel while eliminating other factors, such as chemical composition of other elements, mechanical strength, and dislocation density. The amount of trapped hydrogen increased with increasing V content, whereas the best HE resistance was attained at 0.2 wt% V and it decreased with further V addition. V carbide was considered as a non-diffusible hydrogen-trapping site in this study. However, excessive V content led to the formation of large undissolved carbides that gave rise to brittle fracture and decreased HE resistance. This study suggests that improved HE resistance can be achieved by minimizing the size and amount of undissolved V carbides.     

电压对铝合金微弧氧化陶瓷层形成的影响

研究了正向和负向电压对6063铝合金微弧氧化陶瓷层形成的影响,并结合微弧氧化过程中正向电流密度的变化,对影响机理进行了探讨.结果表明,提高正负向电压均有利于提高陶瓷层的厚度与均匀性当正负向电压从420V/120V提高到480V/200V时,陶瓷层厚增加了一倍;负向电压对陶瓷层形成的影响更加显著,当保持正向电压440V不变,负向电压从120V提高到200V时,层厚增加了约60%,均匀性明显提高.正负向电压提高时,通过试样的正向电量随之增大,而且与陶瓷层厚度之间有着较好的线性关系.正向和负向电压分别通过加快物质的迁移和强化膜层的击穿从而促进陶瓷层的形成.     

氢对Ti-6Al-4V合金微观组织的影响

采用累计流量法对供应态Ti-6Al-4V合金进行了固态置氢,运用OM、XRD、TEM分析等方法研究了Ti-6Al-4V合金固态置氢后的微观组织状态及演变过程。结果表明:供应态Ti-6Al-4V合金的置氢量低于0.30%(质量分数,下同)时,置氢使得Ti-6Al-4V合金中的α相减少、β相增加;置氢量达到0.30%时,置氢Ti-6Al-4V合金中有δ氢化物(TiH2相)形成;β-Ti(H)共析转变生成α-Ti和δ氢化物时主要以切变方式进行;置氢Ti-6Al-4V合金的相变温度最多下降了180°C,与Ti-6Al-4V合金在置氢过程中的相体积比变化和共析转变有密切关系。     

Thermal stability and creep behavior of Ti–V–Cr burn-resistant alloys

The thermal stability and creep behavior of Ti–35V–15Cr (35V alloy) and Ti–25V–15Cr (25V alloy) burn-resistant titanium alloys are researched. The results show that post-exposure tensile properties deteriorated with the increase in exposure temperature (450–600 °C). The decrease in tensile properties of the 35V alloy results from the combination of surface oxidation and microstructural changes and the decrease in tensile properties of the 25V alloy results from surface oxidation. The main change of the microstructure during thermal exposure is the heterogeneous precipitation of α phase on β grain boundaries. Increased vanadium content in the alloy shows an adverse effect on alloys’ thermal stability. The creep resistance of the 35V alloy is little better that that of the 25V alloy. During creep exposure at 540 °C for 100 h, the heterogeneous precipitation of α phase on β grain boundaries in 35V alloy strengthens the grain boundary, leading to increases in the creep resistance, while the heterogeneous precipitation of α phase in grains and grain boundaries in the 25V alloy is rod-like, leading to decreases in the creep resistance.     

吸热型金属合金化对钒基贮氢材料性能的影响

利用电荷自洽离散变分Xa（SCC—DV-Xa）方法计算了吸热型金属合金化对钒基贮氢材料性能的影响。结果表明：在V54H64中加入吸热型金属Cr，Mn，Fe，Co，Ni后，随着原子序数的增加，V51M2H64中H的净电荷逐渐增加，V的净电荷逐渐减小；氢化物V51M2H64中V-H之间的离子性相互作用逐渐减弱，共价性相互作用逐渐增强。材料放氢的平衡压力与其费米能有很好的一致关系，加入吸热型金属后，氢化物V51M12H64中费米能增加，氢化物更不稳定，从而改善材料的吸放氢性能。     

Removal of vanadium from ammonium molybdate solution by ion exchange

The separation techniques of vanadium and molybdenum were summarized, and a new method of removal V(Ⅴ) from Mo(Ⅵ) by adsorption with chelate resin was presented. Nine kinds of chelate resins were used to investigate the adsorbent capability of V(Ⅴ) in ammonium molybdate solution with static method. The test results show that DDAS, CUW and CW-2 resins can easily adsorb V(Ⅴ) in ammonium molybdate solution, but hardly adsorb Mo(Ⅵ). The dynamic experimental results show more than 99.5% of V(Ⅴ) can be adsorbed, and the adsorption rate of Mo(Ⅵ) is less than 0.27% at 294-296 K for 60 min at pH 7.42-8.02. The mass ratio of V to Mo decreases to l/5 0000 in the effluent from 1/255 in the initial solution. The loaded resin can be desorbed by 5% NH3·H2O solution, and the vanadium desorption rate can reach 99.6%. The max concentration of vanadium in desorbed solution can reach 20 g/L, while the concentration of molybdenum is less than 0.8 g/L.