九江大桥15MnVNq-C钢焊接过热区的低温韧性

１５ＭｎＶＮｑ－Ｃ钢为九江长江大桥主要用钢，其过热区低温韧性较优化前１５ＭｎＶＮｑ－Ａ钢有大幅度改善，为分析１５ＭｎＶＮｑ－Ｃ钢焊接过热区低温韧性改善的原因，本文采用热模拟技术对比研究了过热区组织及其对韧性的影响，过热区Ｖ（Ｃ，Ｎ），Ｔｉ（Ｃ，Ｎ）的析出行为及其析出相对组织和韧性的影响，结果指出，含微量Ｔｉ（０．０１２％）的１５ＭｎＶＮｑ－Ｃ钢过热区低温韧性的改善与难溶的ＴｉＮ析出相粒子有关。由于     

20MnVB钢碳氮化物析出相的研究

利用透射电镜和能谱分析仪对２０ＭｎＶＢ钢中的碳氮化物析出相进行了研究。结果表明，该钢中的碳氮化物析出相为面心立方结构的Ｖ－Ｔｉ复合碳氮化物（ＴｉｘＶ１－ｘ）ＣＮ，其中Ｖ和Ｔｉ的浓度比值随析出温度升高而降低。析出相的形貌为珠形或方形，随析出温度的升高，析出相的尺寸增大，数量减少。     

65Mn2SiVTi钢连续冷却转变的研究

用Ｆｏｒｍａｓｔｏｒ－Ｆ型全自动相变仪，金相显微镜和扫描电子显微镜研究了６５Ｍｎ２ＳｉＶＴｉ钢过冷奥氏体的转变动力学曲线及转变产物的组织，结果表明，６５Ｍｎ２ＳｉＶＴｉ钢不析出珠光体组织的临界冷却速度为１．３℃／ｓ，在０．１～０．５℃／ｓ冷却速度范围内可获得细片状珠光体。     

Fe0.85Mn0.15Ti0.9M0.1（M=Zr,V,Ca）合金的贮氢性能

系统地研究了Ｆｅ０．８５Ｍｎ０．１５Ｔｉ０．９Ｍ０．１（Ｍ＝Ｚｒ,Ｖ,Ｃａ）合金的贮氢性能。研究结果表明：Ｆｅ０．８５Ｍｎ０．１５Ｔｉ０．９Ｚｒ０．１合金在室温下经几分钟的孕育期就可吸氢,但合金在氢化过程中形成了氢含量很高的α相,导致合金的贮氢量降低,同时还使ｐ－ｃ－Ｔ曲线的平台特性变差;Ｆｅ０．８５Ｍｎ０１５Ｔｉ０．９Ｖ０．１合金的活化性能进上步得到改善,在室温下几乎不需要孕育期就可以吸氢,但同     

用中碳低合金双相耐磨钢铸造采煤机截齿

设计熔炼了ＺＧ４５Ｓｉ２Ｍｎ２ＭｏＶＲＥ双相耐磨钢。试验结果表明，该钢具有良好的２淬透性。通过热处理可得到马氏体＋下贝氏体复合组织；与原材料３５ＣｒＭｎＳｉ相比，具有较高的抗拉强度（１８８５－１９０５ＭＰａ）、硬度（５２－５４ＨＲＣ）、韧性（αｋ７２－１０６Ｊ／ｃｍ＾２）；并具有较好的耐磨性（相对耐磨性Δε＝１．２８）。     

Fe—Cr—Mn（W,V）合金焊接热影响区的辐照损伤及诱发的晶界元素偏析

采用电子束辐照研究裂变－聚变混合反应堆预选结构材料Ｆｅ－Ｃｒ－Ｍｎ（Ｗ,Ｖ）合金的焊接热影响区（ＨＡＺ）组织损伤,测定损伤组织和晶界处的合金元素浓度变化。实验结果表明：低温下剂达１０ｄｐａ,合金奥氏体组织稳定,未发现空洞形成和第二相析出;然而在高温下,剂量达４．８ｄｐａ就明显出现低密度微小空洞,并出现晶界移植现象。其次,在低温下,晶界附近大尺寸溶质原子Ｃｒ和Ｍｎ贫化,而小尺寸原子Ｓｉ,Ｖ,Ｎｉ,Ｗ     

高强韧铸造铝合金

本文探讨了Ｍｎ、Ｔｉ、Ｖ、Ｚｒ等合金元素对合金冲击韧性的影响规律,初步讨论了冲击韧性与强度、伸长率间的关系。以Ａｌ－Ｃｕ、ｍｎ合金为基,用Ｔｉ、Ｚｒ、Ｖ、Ｂ等微量合金化元素对其强化,并调整热处理制度,制成一种高强度、高韧性韧性的铸造铝合金。通过系统试验。确定该高强韧铸造铝合金的成分（质量分数,％）如下：４．６～～５．３Ｃｕ,０．３～０．５Ｍｎ,０．０５～０．２５Ｔｉ０．０５～０．２５Ｚｒ,０．、～     

马氏体与贝氏体组织GC—4超高强度钢的腐蚀疲劳裂纹扩展

本文研究了马氏体组织与贝氏体组织４０ＣｒＭｎＳｉＭｏＶＡ（ＧＣ－４）超高强度钢的腐蚀疲劳（ＣＦ）裂纹扩展特性及机理。结果表明，不显微组织状态下，ＧＣ－４钢在３．５ＮａＣｌ溶液中的ＣＦ裂纹扩展曲线上，都出现了类似于应力腐蚀的平台区，而且马氏体组织ＧＣ－４钢的平台区裂纹扩展速度远大于贝氏体组织。断口分析与理论研究表明，氢脆在ＧＣ－４钢的腐蚀疲劳中起重要作用。     

加Ti可有效改善Fe-Mn-C合金的减振性能

加Ｔｉ可有效改善Ｆｅ－Ｍｎ－Ｃ合金的减振性能研究了添加Ｔｉ（０．４３％～１．３１％）对于改善Ｆｅ－Ｍｎ－Ｃ减振合金性能的效果，合金由电炉生产，其成分含Ｍｎ１７．５６％～１７．８８％，Ｃ０．０２％～０．２１％，余为Ｆｅ。合金铸锭经１１００℃×２４ｈ均匀...     

Ni_3Al－Cr－Zr－B－Mg合金的高温晶界脆性SCIEI

应用电镜及Ｘ线衍射技术，研究了高温下Ｎｉ_（７５）Ａｌ_（１６．６）Ｃｒ_（７．８４）Ｚｒ_（０．４５）Ｂ_（０．１）Ｍｇ_（０．０１）合金晶界失效行为。经１１８０℃保温，由于偏聚晶界区Ｍｇ含量（ａｔ．－％）达１５－１９。同时Ｚｒ含量（ａｔ，－％）明显增大可达２８－３３；并观察到局部晶界共晶熔化现象。通过１０００℃固溶及变温热循环处理，合金中晶内出现ＣｒＮ相沉淀，沿晶界有Ｃｒ２（Ｃ，Ｎ）相析出。     

氮含量对含Ti-Nb的X70管线钢焊接热影响区组织及冲击韧性的影响

采用中频真空感应炉冶炼了两种不同N含量的X70管线钢。利用Gleeble-2000热模拟研究了两种钢焊接热影响区的组织及冲击性能。采用三丝埋弧焊对两种钢分别进行了焊接,随后采用光学显微镜和冲击试验研究了两种钢的焊接接头组织及冲击韧性。结果表明:在N含量高的钢中发现了尺寸为20~50 nm、弥散分布的(Ti,Nb)(C,N)粒子,而N含量低的钢中只存在少量尺寸为50~100 nm的(Ti,Nb)(C,N)粒子。细小、弥散的(Ti,Nb)(C,N)粒子抑制了晶粒的长大,细化了晶粒,对稳定试验钢的热影响区冲击韧性有利。     

铁路货车用TCS345不锈钢焊接热影响区韧性分析

利用 thermol-cal 软件获得一定成分体系下铁路货车用 12%Cr 铁素体不锈钢的相图,结合相图对 12%Cr 铁素体不锈钢的焊接过程进行分析.利用光学显微镜、扫描电镜分析 12%Cr 铁素体不锈钢的焊接热影响区为铁素体和马氏体以及碳、氮化物组成的粗晶区和细晶区两部分.结果表明,铁素体晶粒的尺寸与马氏体的含量是影响热影响粗晶区韧性的主要因素.当母材中的碳、氮化物颗粒尺寸在 2～5μm 时,具有最优的冲击性能;当母材中碳+氮含量为 0.02% 左右时,在文中试验条件下粗晶区的马氏体含量为 40%,焊接接头粗晶区具有 -22 ℃的最低韧脆转变温度.

Abstract：

The transformation temperature phase diagram of 12% chromium steel is obtained by using Thermal-cal software. Process of welding 12% chromium stainless steel is analysed with the phase transformation temperature scope. The heat-affected zone (HAZ) of the weld joints is observed with optic microscope and scanning electronic microscope, which the microstructure consists of ferrite, martensite, coarse grain heat-affected zone (CGHAZ), fine grain heat-affected zone (FGHAZ) and Ti(C/N). The key elements that affect toughness of CGHAZ are ferritic grain size and martensitic content. The base material has the best impact toughness when grain size of Ti(C/N) reaches 2-5μm. The lowest ductility-brittle transition temperature in CGHAZ is -22 ℃ when content of carbon plus nitrogen in base material is about 0.02% and martensitic content in CGHAZ is 40% under some certain welding procedure.     

00Cr25Ni6Mo3N双相不锈钢的力学性能

00Cr25Ni6Mo3N双相不锈钢可用于要求具有良好力学性能特别是低温冲击韧度的鼓风机叶轮等零件。某公司的00Cr25Ni6Mo3N双相不锈钢锻件低温冲击性能很不稳定。为此,对冲击性能不良的00Cr25Ni6Mo3N钢锻件进行了1050℃、1070℃、1100℃和1050℃保温1.5h水冷的固溶处理,随后测定了力学性能。结果表明:锻件的-40℃冲击吸收能量差异很大,有的达不到要求的27J。金相分析发现,00Cr25Ni6Mo3N钢锻件冲击韧度低的原因是锻造工艺不当析出了金属间相,而且热处理不能消除这种金属间相,严格控制锻造加热制度是解决该问题的唯一途径。     

Zr对高强度钢热影响区第二相粒子及韧性影响

研究了0.012 4%锆对低合金高强度钢焊接热影响区粗晶区第二相粒子和冲击韧性的影响.结果表明,模拟20 kJ/cm焊接线能量下无锆钢焊接热影响区粗晶区中第二相粒子为Al-Ti复合氧化物和（Ti,Nb） N析出物.而含锆钢则是Zr-Al-Ti复合氧化物及（Al,Ti,Nb） N和（Ti,Nb） N析出物.同时,定量数据分析表明含锆钢中氧化物和氮化物粒子密度更高且尺寸更加细小.这些高密度的细小的第二相粒子在焊接过程中能有效钉扎晶界移动,抑制奥氏体晶粒粗化,在焊接热影响区粗晶区中得到尺寸相对细小均匀的原奥氏体晶粒,使得含锆钢焊接热影响区粗晶区呈现韧性断裂和极好的低温冲击韧性.     

马氏体不锈钢堆焊层组织和耐冲蚀性能

采用2Cr13和经过V、Ti、Nb、N微合金化改性处理的1Cr13马氏体不锈钢进行埋弧堆焊试验,分析微合金元素和热处理工艺对马氏体不锈钢堆焊层显微组织和耐冲蚀性能的影响。研究结果表明:微合金元素V、Ti、Nb与C、N在奥氏体形核初期形成大量颗粒细小、弥散分布的稳定化合物,使堆焊层金属的晶粒得到细化;奥氏体晶粒稳定后,这些化合物又起到析出强化的作用;回火后,部分碳化合物在马氏体板条间析出,起到了二次强化的作用,同时降低马氏体中的碳含量,改善基体韧性。较好的基体强韧性配合最终提高了材料的耐冲蚀性。     

Microstructure and mechanical performances of CGHAZ for oil tank steel during high heat input welding

Microstructure and mechanical performances of the coarse grain heat-affected-zone (CGHAZ) for oil tank steel with different Ti content were investigated through Gleeble-3500, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometer. The results show that the strength and low-temperature toughness of base material are significantly improved for the high titanium content steel, but the impact toughness of CGHAZ is seriously deteriorated after the high heat input welding and declined sharply with the heat input increasing, while the effects of heat input on impact toughness are very weak for the low titanium content steel, impact toughness of which is gradually larger than that of high titanium content steel with the welding heat input increasing because of the granular bainite increasing, TiN particle coarsening, and (Ti, Nb) N composition evolution during the high input welding for high titanium content steel.     

HG50钢模拟焊接过热区组织与低温韧性研究

利用热模拟技术对国产HG50钢焊接过热区组织和低温韧性进行了试验研究,建立了焊接冷却时间t8/5与低温韧性的关系曲线,分析了HG50钢模拟焊接过热区组织转变特征及其对韧性的影响,为焊接工艺优化设计提供了重要的技术支持.     

Precipitation of carbonitrides and high-temperature strength in heat-affected zone of high-Nb containing fire-resistant steel

The morphology and structure of precipitates in the heat-affected zone (HAZ) of fire-resistant steel were studied by transmission electron microscopy, while the simulated elevated temperature strength studies were carried out to elucidate the effect of precipitation state on strength at high temperature. The precipitates were identified as (Nb,Ti)(C,N) with FCC structure. A high density of fine (Nb,Ti)(C,N) precipitated in subcritical HAZ. As the peak temperature of thermal cycle was increased, the density and size of particles were observed to decrease. During austenisation, precipitates were dissolved mostly in the coarse-grained heat-affected zone and dissolved totally in the fusion line. The higher strength at 600?°C was present in coarse-grained heat-affected zone and lower in intercritical heat-affected zone. The different precipitate condition in sub-HAZs led to the different evolution behaviour of carbonitrides on heating and thus high-temperature strength.     

Effect of submicron Ti(C,N) on the microstructure and the mechanical properties of Ti(C,N)-based cermets

There is an increased industry demand for Ti(C,N)-based cermets with improved material properties. One of the parameters which are supposed to influence these properties is the mean particle size of the Ti(C,N) powder used. In this study the effects of a newly developed submicron Ti(C,N) powder grade on the properties of Ti(C,N)-based cermets, including hardness, toughness and microstructure were investigated. The cermets showed only small differences with respect to outgassing upon sintering (investigated by MS-EGA) as well as shrinkage (dilatometry). Cermet formulations with submicron Ti(C,N) could be sintered under identical conditions as with fine Ti(C,N), yielding completely dense bodies of A00 porosity. From SEM and XRD investigations it was found that submicron Ti(C,N) powders cause accelerated diffusion and homogenisation of the microstructure leading to a substantially increased amount of outer rim phase, a higher amount of inverse grains and substantially finer and less Ti(C,N) cores. Upon using submicron Ti(C,N), hardness (HV10) is increased and in one grade the fracture toughness (Palmqvist–Shetty) is increased as well.