电渣重熔连续定向凝固M2高速钢铸态组织的研究

研究了传统电渣重熔工艺(ESR)和电渣重熔连续定向凝固技术(ESR-CDS)所得到的M2高速钢铸态显微组织。结果表明:采用ESR工艺得到铸态组织边部为树枝晶且部分出现了三次枝晶,心部为粗大的等轴晶,晶粒之间有网状碳化物,铸锭的偏析较为严重,经深腐蚀凝固组织基体与碳化物过渡区较为疏松、粗糙,部分基体内部出现了细小的裂纹。而采用ESR-CDS工艺得到铸态组织边部和心部都以较为细小的树枝晶为主,组织中存在比较多的"不连续的复合规则型"的碳化物,组织较为均匀,经深腐蚀,碳化物与基体过渡区圆滑。     

铝、铬元素对热轧态Incoloy 800H合金耐碳酸熔盐腐蚀行为研究

金属合金在聚光太阳能热发电系统中会受到熔盐腐蚀,导致其寿命缩短。为了延长Incoloy 800H合金在碳酸熔盐腐蚀中的使用寿命,采用真空感应炉熔炼制备了不同Al、Cr含量的Incoloy 800H（800H）合金,通过XRD、SEM、TEM等分析测试手段,探究Al、Cr元素对800H合金耐碳酸熔盐腐蚀的作用机制。结果表明：在650℃的碳酸熔盐[32.1%（质量分数,下同）Li₂CO₃+33.4%Na₂CO₃+34.5%K₂CO₃]中浸泡240 h后,Al含量为3%的800H合金的腐蚀速率为1 071.00μm/a,当铬含量为2.75%时的800H合金的腐蚀速率为359.56μm/a,腐蚀产物主要为LiFeO₂和NiO。这是由于随着Al含量的增加,试验钢基体表面形成的Al的氧化物钝化膜更厚更致密,从而起到良好的保护作用。Cr含量的降低会减少可溶性Cr氧化物的生成,使其他保护性氧化层生成的含量增加,减少基体中Fe元素的析出,从而提高了合金的耐腐蚀性能。     

Incoloy 800H合金的开发

研制了一种Incoloy 80 0H合金并对其成分、力学性能、金相组织、晶粒度进行了检测 ,表明研制并生产出的板材、棒材 ,其质量达到了标准规定要求 ,满足了特定焊结构件用材的技术条件规定 ,并成功用于石油行业。     

铸态合金组织分析：第三讲 铸态合金的组织分析方法

前两讲介绍了组织组成物的特征及分布,这一讲将讨论如何根据组成物的特征和分布分析组织.1 组织组成物的观察分析合金组织,首先要在显微镜下对试样进行观察,观察的结果是分析组织的依据.所以观察很重要,必须认真、细心,使观察的结果真实.     

Incoloy 800H/20g复合板材料焊接技术探讨

研究Incoloy 800H/20g复合板焊接工艺,以解决以镍基合金复合板材为主体的设备在焊接过程中易产生裂纹、气孔及成分偏析等问题.焊接实验选择H1Cr16Ni21作为过渡填充金属,采用惰性气体保护焊和手工电弧焊2种形式焊接.实验结果表明,选择H1Cr16Ni21作为过渡填充金属,采用小电流、多道次焊接工艺,可得到质量良好的焊缝,焊缝宽度、焊缝余高、咬边及焊接错边均符合JB4730-94标准要求;力学性能优于20g耐热钢,焊缝成分与Incoloy800H接近.成功地解决了成分差异较大的2种材料焊接时易出现裂纹和气孔的问题.     

使用细长规格结晶器 推进电渣锭锭型细长化

通过粗、细结晶器规格／电渣锭锭型规格的对比,阐述细长锭型在产品质量、成本方面的优点,证明电渣锭锭型细长化更具合理性、适用性。     

铸态合金组织分析：第五讲 有色合金组织分析实例

1 ZHSi80-3合金组织分析ZHSi80-3是硅黄铜,成分是:79%～81%Cu,2.5%～4.5%Si,其余为Zn.图1是ZHSi80-3的两种组织.图1a中可观察到两种白亮物:一种是树枝状白亮物;另一种是带尖角的不规则块状或条状白亮物,这种白亮物数量较少.还可观察到分布于两种白亮物之间的黑色物.如果再仔细观察,可发现黑色物与树枝状白亮物之间的明暗度是逐渐变化的,而且没有明确的界线(如果放大倍数更高一些,这一特征更明显).而黑色物与带尖角的块状或条状白色物之间明暗度是突变的,界线明确.根据上述特征,可以认为树枝状白色物与黑色物是同一个相或者说是同一种组成物,之所以明暗度不同是枝晶偏析所致.带尖角的白色块状及条状物则是另一种组成物.综上所述,由观察可初步判断图1a的组织组成物有两种:一种是存在枝晶偏折的树枝晶;另一种是分布于树枝晶之间的白亮块状或条状物.而且由这两种组成物的分布可知其形成顺序是前一种组成物最先凝固形成,后一种组成物最后凝固形成.图1b的组织特征与图1a相近,其区别在于白色块状、条状物数量极少.仔细观察才可发现树枝晶之间存在极少的白亮细粒状组成物.现在需要分析确定图1中的两种组成物分别是什么合金相或组织.ZHSi80-3合金是在普通黄铜的基础上加入一定量的Si而成.加入Si对组织的影响     

钛氮合金的铸态组织与性能

采用熔铸工艺法制备了含氮量为0.045%～0.27%的原位自生氮化物增强钛基复合材料,分析并测试了合金的铸态组织和力学性能.研究结果表明:在Ti-N合金中,随着氮含量的增加,合金中氮化物的形态和相组成发生了明显的改变;当氮含量在0.045%～0.18%时,合金的基体为α-Ti,增强相为TiN0.3;氮含量增加到0.225%时,增强相转变为块状Ti2N;复合材料的硬度、抗压强度和弹性模量均高于纯钛基体且随着氮含量的增加而增加;当增强相由TiN0.3转变为Ti2N时,抗压强度显著增加;由压缩断口分析可知,基体为韧性断裂,随着氮含量增加合金由韧窝 解理断口向具有解理特征的脆性断裂转变.     

Incoloy 800波纹管膨胀节开裂失效分析

金属波纹管膨胀节具有热补偿功能,应用越来越广,同时其失效开裂问题也日益显现.为此,从宏观形貌、化学成分、金相显微组织、SEM微现形貌方面,对开裂的Incoloy 800波纹管膨胀节进行了分析.结果表明,波纹管膨胀节开裂的原因是高轴向拉应力条件下的材料失稳破裂,并提出了相应的改进措施.     

Experimental Investigation of the A-TIG Welding Process of Incoloy 800H

This work attempts to investigate the influence of different flux powders in the activated-TIG welding process of the Incoloy 800H super alloy. Three different fluxes (SiO₂, ZnO, and 50% ZnO +50% SiO₂) were used and welded under the same conditions and process parameters. The oxide fluxes used were in the form of nanoparticle powders. The metallurgical characteristics and mechanical properties were analyzed, and it was found that the SiO₂ flux could increase the depth of penetration whereas a ZnO flux was detrimental to this effect. Although a SiO₂ flux increased the depth of penetration, it led to a sensitization issue in the grain boundary. The combination of the fluxes 50% ZnO +50% SiO₂ produced a moderate increase in the depth of penetration compared to ZnO flux-coated weldments, but revealed a dendritic structure in the weld region.     

高温碳化环境对镍－铬－铁基耐蚀耐热合金的组织和性能的作用

研究了镍－铬－铁基耐蚀耐热合金ＩＮＣＯＬＯＹ８００Ｈ的高温抗碳化性能。该合金经７００℃、８００℃和９００℃城市煤气环境中长期保持后，其外观明显变化，８００℃及９００℃样品外表层严重剥落，剥落层主要由石墨、碳及氧化铬组成。而次表层则为碳化铬、氧化铬、氧化铁等混合物组成。经碳化后合金的高温机械性能有明显变化，屈服强度因表层化合物的强化作用而升高，抗拉强度及伸长率则下降，碳化温度越高则降低越显著。     

Heat treatment effect on CNC turning of Incoloy 800H superalloy

Nuclear power plant components, high-temperature furnace, and most of the nuclear reactors are in need of high creep rupture which can be attained by Incoloy 800H superalloy. Based on this, the present research work is aimed to relate the microstructure, mechanical, and machinability of Incoloy 800H in various conditions, namely, solution treated, heat-treated with air cooling, and heat-treated with furnace cooling. The samples were initially heated till 975°C after solution treated and then subjected to the aforesaid heat treatments. The optical microstructures revealed that the fine grains’ structure was obtained in the air-cooled sample, whereas coarse grain structure was obtained in a furnace-cooled sample. The heat-treated samples were machined using CNC dry turning process and the machining parameter effects on the machinability aspects were studied, investigated, and reported. Experimental investigations explained clearly that the machinability aspects were significantly influenced by the cooling medium. Furnace-cooled sample had shown improvement in mechanical and machinability performances.     

高温碳化环境对镍－铬－铁基耐蚀耐热合金的组织和性能的作用

研究了镍－铬－铁基耐蚀耐热合金ＩＮＣＯＬＯＹ８００Ｈ的高温抗碳化性能。该合金经７００℃、８００℃和９００℃城市煤气环境中长期保持后，其外观明显变化，８００℃及９００℃样品外表层严重剥落，剥落层主要由石墨、碳及氧化铬组成。而次表层则为碳化铬、氧化铬、氧化铁等混合物组成。经碳化后合金的高温机械性能有明显变化，屈服强度因表层化合物的强化作用而升高，抗拉强度及伸长率则下降，碳化温度越高则降低越显著。     

Carburization performance of Incoloy 800HT in CH4/H2 gas mixtures

Carburization performance of Incoloy 800HT has been studied after cyclic and isothermal exposures to CH₄/H₂ carburizing gas mixtures at high temperatures for 500 h. At 800 °C in 2% CH₄/H₂, Incoloy 800HT suffered external oxidation and carburization, the external continuous layer of reaction products consists primarily of Cr₇C₃, Mn_1.5Cr_1.5O₄, and FeCr₂O₄ with Fe(Cr, Al)₂O₄ as a minor phase. At 1100 °C in 10% CH₄/H₂, external carburization did not occur likely due to high carbon dissolution in the alloy substrate at this temperature. A thermodynamic analysis indicated that 1000 °C was an approximate critical temperature, below which the environment should result in mixed oxidizing/carburizing behavior, while above this temperature reducing carburizing behavior should occur. The experimental results approximately agree with the thermodynamic analysis. Metal dusting was not observed under highly carburizing conditions (a_C>1). The size and morphology of Cr-rich phases (or Cr-carbides) are both temperature- and time-dependent, while the external continuity is more temperature-dependent rather than time-dependent.     

Failure of a transfer line on an ethane cracking furnace due to sulfidation

An Incoloy 800H (UNS N08810) transfer line on the outlet of an ethane-cracking furnace failed during decoking of the furnace tubes after 9 years in service. A metallographic examination using optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS) revealed that the failure was due to sulfidation. The source of the sulfur in the furnace effluent was either dimethyl disulfide (DMDS), injected into the furnace feed to prevent coke formation and carburization of the furnace tubes, or contamination of the feed with sulfur bearing oil.     

铁镍基耐蚀合金凝固组织控制研究

采用固定式电渣重熔工艺、单电极导电结晶器抽锭电渣重熔工艺和双极串联抽锭电渣重熔工艺以不同的熔化速度生产出UNS N08825合金电渣锭,分析了电渣锭的结晶组织、热加工性能以及三种冶炼工艺的电极熔化速度、冷却条件和温度场差别。结果表明,当UNS N08825合金电渣锭凝固组织的柱状晶方向与纵轴方向夹角θ不大于54°时,钢锭具有良好的热加工塑性。     

超声波处理对镁合金铸态组织的影响

镁合金铸态组织的缺陷影响着其机械性能.在镁合金熔体中施加超声处理可以起到降低晶粒尺寸、均匀化组织的效果.总结了目前镁合金熔体中施加超声处理的研究现状,分析了超声波熔体处理的几种作用机理(空化作用理论、破碎理论、过冷形核理论、声流理论等),列举并分析了影响超声波作用效果的几种因素,展望了超声波处理在镁合金中的应用前景.     

退火温度对a-C:H膜结构及摩擦学性能的影响

为研究环境温度对含氢无定形碳(a-C:H)膜结构和性能的影响,将a-C:H膜在大气环境中进行高温退火处理,并借助红外光谱、拉曼光谱、X射线光电子能谱、3D表面分析仪和球盘摩擦试验机等手段对退火前后a-C:H膜的结构、组成和性能进行了系统地考察.研究发现,在较低的退火温度下(300℃),a-C:H膜结构无明显变化,而其内应力降低,摩擦学性能显著提高;在400℃和500℃下退火,膜结构发生明显变化并伴随严重氧化,同时摩擦学性能降低甚至完全失效.结果表明,退火温度的选择对a-C:H膜的结构、组成及性能具有重要影响.