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1.
用TEM研究了新型钎钢40MnMoV的正火组织,发现它与Si-Mn-Mo系的另一种钎钢55SiMnMo相似,由无碳化物上,下贝氏体Bu、Bl、以孪晶马氏体为主的“块状组织”和约15%残余奥氏体Ar组成,但40MnMoV的Bu,Bl较多,Ar和L则较少;Bu板条较粗大,其间分布着不连续的A小片条;Bl片中有渗碳体与粤氏体A共存;L的尺寸较小,硬度较低,讨论了该钢正火时贝氏体(B)相变的原因及影响贝氏  相似文献   

2.
研究了热轧以相钢Fe-0.078C-1.44Mn-1.11Si-0.38Cr经不同温度回火后的显微组织变化。透射电镜观察表明:热轧双相钢的组织中不可避免地混有少量珠光林(<5%),它们对钢的基本力学性能并没有多大影响。本钢种200℃回火组织中,马氏体基本不变化,为板条态,双相钢仍保持屈服行为;300℃回火组织中,大量马氏体发生分解,形成碳化物,与少量珠光体交界处的马氏体首先发生分解。该温度回火完全  相似文献   

3.
王晓丹  沈宝莲 《材料工程》1995,(1):21-22,20
本文采用金相和透射电子显微镜对3CrMnMoVS塑料模具钢的微观组织进行了分析,实验结果表明,经正火处理的3CrMnMoVS钢的微观组织为形状不规则的铁基体上分布着许多粒状的组织,并有条状或纺锤状的硫化物存在。而粒状组织由上贝氏体、下贝氏体及马氏体组成,在部分铁素体中还存在部分尺寸在0.05~0.15μm 的Pe_3C相。  相似文献   

4.
观察和比较了油淬热处理和等温热处理40crNi2Si2MovA钢的显微组织。研究表明,两种热处理后钢均得到回火马氏体+贝氏体+残余奥氏体的混合组织,但贝氏体及残余奥氏体形态有所不同。等温热处理后钢的韧性相较多而对韧性有益,主要表现为裂纹起始功的提高。  相似文献   

5.
凌斌  钟炳文 《材料工程》1995,(7):31-32,10
观察分析了冷却速度对低合金超高强度钢(40CrMnSiMoVA)精细组织的影响。结果表明,在冷却、低温等温(或回火)过程中,钢显微组织中的马氏体或贝氏体存在时效阶段。其组织特征为呢纹花样。α和ε间的取向不满足Jack关系,它属一种新的取向关系。过渡型碳化物可直接从呢纹花样区析出。  相似文献   

6.
38Si2Mn2Mo钢等温下贝氏体中微量ε碳化物的TEM检测   总被引:1,自引:1,他引:0  
以38Si2Mn2Mo钢为例,阐述了利用透射电子显微镜准确而有效地检测中低碳钢贝氏体中析出的微量ε碳化物的方法,并测定了ε碳化物与贝氏体铁素体间的位向关系。  相似文献   

7.
65Si2MnWA钢下贝氏体碳原子调幅分解及有序化的TEM研究   总被引:2,自引:0,他引:2  
利用Si元素阻碍碳化物析出的作用,对65SiMnWA钢进行适当热处理,获得无碳化物析出的下贝氏体组织,通过透射电镜分析了贝氏体基体衍射花样特征,进而考察其碳含量,结果表明,该钢下贝氏体转变初期存在碳原子调幅分解及有序化过程,其碳原子行为与马氏体回火早期阶段碳原子行为相似,说明该钢下贝氏体基体含碳量是过饱和的。  相似文献   

8.
30CrMnSiA和30CrMnSiNi2A钢超高温淬火组织与性能的研究   总被引:3,自引:0,他引:3  
研究了30CrMnSiA、30CrMnSiNi2A钢超高温淬火组织与力学性能关系。试验结果表明,在该钢Ac3以上-200℃超高温淬火可获得组织细小均匀的板条马氏体加残余奥氏体。控制超高温淬火加热保温时间,毁唯奥氏体化又能获得细小奥氏体晶粒,从而显著提高了该钢的强韧性。  相似文献   

9.
运用OPM、TEM、X-Ray和静拉伸试验方法,研究了40MnMoV钢在正火和正火十回火状态时的拉伸性能。该钢经过900℃、0.5h奥氏体化后空冷,得到非典型上、下贝氏体和块状组织,各种组织中均存在残余奥氏体。将正火状态下的试验钢回火时,残余奥氏体发生分解,随着回火温度升高,残余奥氏体百分含量减少,而钢的屈服强度和屈强比提高,并在400℃达到极大值,同时延伸率下降,且于400℃降至极小值。  相似文献   

10.
主要研究了QRO90Supreme热作模具钢显生组织及其合金碳化物对钢的热稳定性的影响。结果表明:该和模具钢经淬,回火后,弥散分布在马氏体基体上的碳化物大多数是VC和(MnMo)2C,其余为少量的M3C合金渗本,因而其回生和热稳定性明显优于ESRH13钢。  相似文献   

11.
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.  相似文献   

12.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

13.
14.
A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.  相似文献   

15.
On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……  相似文献   

16.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.  相似文献   

17.
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill.  相似文献   

18.
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from  相似文献   

19.
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.  相似文献   

20.
新闻(英文)     
正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to  相似文献   

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