连续退火工艺对低碳铝镇静钢性能的影响

利用正交试验方案,在多功能连续退火模拟器(Multipas)平台上对低碳铝镇静钢板进行了连续退火工艺试验,结合方差分析方法研究了连续退火工艺对低碳铝镇静钢性能的影响.结果表明,在700～720℃之间退火低碳钢板的屈服强度随退火温度的升高而降低;在575～600℃缓冷对低碳钢力学性能有一定影响,过时效温度、快冷温度对力学性能影响不显著.     

退火方式对低碳冷轧搪瓷用钢组织性能的影响

研究了罩式退火及连续退火工艺对低碳冷轧搪瓷用钢组织性能的影响规律。结果表明,实验钢中的贮氢陷阱以MnS和Fe3C为主,且罩式退火及连续退火工艺均能使实验钢的成形性能及抗鳞爆性能满足要求。连续退火的退火温度较高,再结晶织构发展充分,得到更优的力学性能及成形性能;罩式退火保温时间长,更有利于析出物的析出,从而增加第二相粒子作为贮氢陷阱得到更优的抗鳞爆性能,对比得出了最优工艺流程,为实验钢的工业化生产提供了理论依据。     

退火工艺对含钛超低碳搪瓷钢板成型和贮氢性能的影响

就罩式退火和连续退火工艺对含钛超低碳搪瓷钢板成型性能和贮氢性能的影响进行了研究。结果表明，试验材料经连续退火后其成型性能较罩式退火好；经罩式退火后钢中析出相的密度(单位体积内颗粒数)较连续退火的大，钢板氢穿透时间延长，氢扩散系数减小。试验材料经罩式退火后其贮氢性能优于连续退火。     

连续退火工艺对440MPa级含La高强IF钢组织和性能的影响

通过用热模拟试验机对440MPa级含La高强IF钢经过不同连续退火工艺下的组织、析出物和性能进行研究,分析了连续退火工艺对组织和性能的影响。结果表明:440MPa级含La高强IF钢在连续退火过程中,在800℃,120m/min的退火工艺下能发生完全再结晶,并且提升退火板带的运行速度能有效的细化晶粒,减少FeTiP的析出并优化织构,从而提升板材的硬度和深冲性能,得到合格产品。     

退火对镍铝青铜合金组织和性能的影响

利用光学显微镜、X射线衍射仪和显微硬度测试等方法研究了退火工艺对镍铝青铜合金组织和性能的影响.结果表明:经1020℃×16h均匀化退火后,镍铝青铜铸态组织中的粗大枝晶消失;锻造后发生了显著的再结晶,并有NiAl和FeAl相析出,再经950℃×1h退火获得了细小均匀的显微组织,有利于合金的后续加工.     

退火温度对低碳铝镇静钢板组织及力学性能的影响

通过拉伸试验检测了单机架可逆轧制冷轧压下率为68％低碳铝镇静钢板力学性能,用金相显微镜观察试验钢板冷轧态与退火态的纤维组织,并用X射线衍射仪测量试验钢中不同类型织构的含量.结果表明,退火温度由660℃升高至720℃,低碳铝镇静钢的屈服强度为201 ～212 MPa,抗拉强度为278 ～311MPa,屈强比为0.68 ～0.72,总伸长率为38％ ～ 42％,加工硬化指数n值为0.21-0.24,而塑性应变比r值为1.25 ～1.58,|△r|值为0.39 ～0.78.退火温度的升高使得再结晶后晶粒尺寸增加和“饼型”程度加大,γ纤维织构强度增加.当退火温度升高至720℃时,再结晶晶粒尺寸不均匀,|△r|值较大,且抗拉强度明显降低.综合作用的结果是,退火温度在680 ～700℃范围时较为合适,深冲性能较好.     

不同酸溶铝含量低碳铝镇静钢的显微组织及粒子析出行为

通过单向拉伸试验测试酸溶铝质量分数分别为0.02%和0.10%两组低碳铝镇静钢退火试样的力学性能,利用背散射电子衍射仪(EBSD)观察其显微组织,以及透射电镜观察其二相粒子析出规律。结果表明,酸溶铝含量为0.02%和0.10%的退火试样塑性应变比r值分别为1.19和0.81,3°~10°范围的小角度晶界所占比例分别为3.2%和10.6%,重合位置点阵CSL特征晶界中Σ3点阵晶界频率分别为1.3%和5.3%,Σ9点阵晶界频率分别为0.5%和1.6%,前者析出相主要为50 nm左右的Mn S粒子,后者析出相数量较多,主要为50~100 nm的Mn S和Al2S3复合粒子及少量长方形的Al粒子,粒子的析出能够通过其析出热力学及动力学规律解释。从降低生产成本和减少不利粒子析出考虑,低碳铝镇静钢生产过程中可选用低酸溶铝含量(0.02%),而应避免高酸溶铝含量(0.10%)。     

超低碳铝镇静钢冷轧薄板再结晶温度及性能研究

采用模拟大生产的连续升温条件测定超低碳铝镇静钢的再结晶温度,研究了冷轧压下率对再结晶温度和各项性能的影响.分析比较发现,碳含量在0.003％(质量分数)的铝镇静钢冷轧薄板,当冷轧压下率为70％、75％、80％时,开始再结晶温度为560～570℃,T50分别在585、575、565℃左右,随冷轧压下率增大再结晶温度降低;对冷轧板经700℃模拟罩式退火后进行单向拉伸试验.结果表明,退火板具有良好的力学性能和成形性能,压下率为70％～80％时,r值随压下率增大而提高,最高可达到2.44.     

退火过程的过时效段对IF钢性能的影响

对某一生产条件下的Ti+Nb-IF钢冷轧后试样进行不同退火温度下的连续退火实验,检测其金相组织与力学性能,分析了连续退火过程中过时效段的有无对超低碳IF钢性能的影响.结果表明:在有过时效段和无过时效段两种连续退火过程中,超低碳IF钢的金相组织和力学性能指标均无大的变化与差异,IF钢的连续退火不需要发生过时效.     

汽车用冷轧超低碳烘烤硬化钢板的组织性能与析出

实验研究了汽车用冷轧超低碳烘烤硬化钢板的成分、热轧冷轧及退火工艺对钢组织性能的影响规律,并分析了冷轧后连续退火和罩式退火不同条件下钢中析出第2相粒子形态和钢板的织构变化。     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.     

Mechanism of Nucleation of Precipitates of Carbides of Refractory Metals Under Hot Rolling of Automotive Sheet Steel

Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory...