一种镍基单晶高温合金的热处理工艺研究

研究了一种镍基单晶高温合金的热处理工艺。采用差热分析法和金相测试法确定合金的初熔温度在1280℃左右;利用光学金相显微镜观察了合金在不同固溶处理后的微观组织,测试了合金的持久性能。结果表明,合金的最佳热处理工艺为1245℃/2h,AC+1275℃/4h,AC+1100℃/2h,AC+850℃/24h,AC。采用该工艺处理后的单晶高温合金具有优异的持久性能,在980℃、235MPa的条件下持久寿命达159.35h。     

热处理对Ni_3Al基单晶合金IC6SX组织和性能的影响EI北大核心

研究了热处理对Ni3Al基单晶合金IC6SX的微观组织和持久性能的影响。实验结果表明:IC6SX单晶合金的铸态组织具有典型的树枝晶结构,由γ′相、γ相和NiMo相组成。合金经过1280℃/10h,风冷固溶处理后,γ′相全部固溶,合金组织均匀,γ′相尺寸约为0.28μm。合金在1340℃固溶处理后发生了少量的初熔。对固溶后的合金进行了870℃/32h,空冷的时效处理,得到了尺寸约为0.5μm的立方状分布的γ′相。对不同状态的IC6SX单晶合金在1100℃/130MPa条件下进行持久性能测试,结果表明,经过时效处理后的合金具有最长的持久寿命,高达120h。     

一种镍基单晶高温合金的热处理工艺研究

研究了一种镍基单晶高温合金的热处理工艺。采用差热分析法和金相测试法确定合金的初熔温度在1280℃左右；利用光学金相显微镜观察了合金在不同固溶处理后的微观组织，测试了合金的持久性能。结果表明，合金的最佳热处理工艺为1245℃／2h，AC＋1275℃／4h，AC＋1100℃／2h，AC＋850℃／24h，AC。采用该工艺处...     

热处理工艺对Inconel718合金组织、力学性能及耐蚀性能的影响

对高含H2S/CO2酸性油气田封隔器材料-Inconel718镍基合金进行固溶处理和时效处理,研究不同热处理工艺条件下合金的组织、力学性能、耐蚀性能之间的关系。结果表明:随着固溶温度的升高,δ相不断溶入基体。材料经时效处理后析出第二相γ″相,硬度和强度明显高于固溶处理的样品,1000℃固溶+720℃×8h→50℃/h620℃×8h时效处理的样品硬度和强度达到最大值。高温高压H2S/CO2介质中挂片实验的结果表明,不同热处理的Inconel718合金均具有良好的耐腐蚀性能,经固溶处理的材料耐腐蚀性略优于经固溶+时效处理的材料。高温高压H2S/CO2应力腐蚀实验的结果表明,Inconel718没有发生应力腐蚀开裂迹象。综合考虑耐蚀性能和力学性能,确定Inconel718合金的最佳热处理工艺为:1000℃固溶1h+720℃×8h→50℃/h620℃×8h时效。     

热处理工艺对激光选区熔化AM247LC合金组织与性能的影响规律

目的 研究不同热处理制度对激光选区熔化（SLM）AM247LC合金微观组织和力学性能的影响规律。方法 对激光选区熔化制备的AM247LC合金分别进行900℃/16h的直接时效热处理和1 210℃/30 min+1 050℃/30min+950℃/16h的固溶时效热处理,通过OM、SEM、EBSD、XRD等表征手段研究合金热处理前后的晶粒组织、碳化物及析出相等微观组织的变化,并对打印态及不同热处理态样品的室温拉伸性能进行测试,以表征热处理对其力学性能的影响行为。结果 打印态AM247LC合金中存在大量粗大柱状晶和细小晶粒组织;直接时效热处理（900℃/16 h）后的AM247LC合金晶粒组织与打印态类似,但析出了大量γ’强化相;固溶时效热处理（1 210℃/30 min+1 050℃/30 min+950℃/16 h）后,AM247LC合金发生了再结晶,形成大量退火孪晶,并且析出沿晶界分布非连续的微米级碳化物及大量γ’强化相。合金打印态的屈服强度为846.5 MPa,断裂伸长率可达19.6%;直接时效热处理后,合金屈服强度为1 042.8 MPa,断裂伸长率明显降低,仅为11.2%;固溶...     

不同热处理工艺对TC4-DT钛合金棒材组织和性能的影响

研究了不同热处理工艺对TC4-DT钛合金棒材显微组织和力学性能的影响。结果表明:TC4-DT合金在两相区经过普通退火和再结晶退火后组织发生再结晶,α相尺寸有所增大,具有较好的塑性。经过两相区固溶+时效处理得到双态组织,通过控制固溶时冷却速度及时效温度来调整次生α片层厚度,使得合金强度和断裂韧性得到改善。经单相区固溶水冷得到马氏体组织,随时效温度提高,α片层厚度增加,但析出的次生α相含量减少,导致合金的强度和断裂韧性有所下降。而在单相区固溶空冷+高温时效处理,获得的α片层厚度进一步增大,有助于提高塑性和断裂韧性。采用950℃/1h/WQ+550℃/6h/AC两相区固溶+时效的热处理工艺,可实现合金强度、塑性、韧性的较好匹配,获得优良的综合性能。     

7050铝合金锻件固溶处理工艺优化研究

目的 研究不同固溶温度和固溶保温时间对航空某锻件7050铝合金组织和性能演变规律的影响,优化7050铝合金锻件的固溶热处理工艺参数.方法 通过采用金相组织观察、SEM分析、EBSD测试、导电率测试、室温拉伸性能测试等方法,对比研究合金组织变化如何影响力学性能.结果 随着固溶温度的升高(474～483℃),合金再结晶分数逐渐升高,峰值时效处理后,合金抗拉强度先升高后降低;固溶保温时间(2～5 h)对合金组织与拉伸性能的影响不明显;最优热处理工艺为477℃×4 h固溶处理,而后进行121℃×6 h+177℃×5 h双级时效.热处理后的力学性能:屈服强度为510 MPa,抗拉强度为558 MPa,伸长率为13.6％,电导率为22.7 MS/m.结论 与固溶时间相比,固溶温度对7050铝合金组织和拉伸性能的影响较大,对合理选择航空用7050铝合金锻件的热处理工艺具有指导意义.     

固溶温度对第三代镍基单晶高温合金DD10组织的影响

采用扫描电镜(SEM)和金相显微镜(OM)组织观察以及能谱(EDS)分析等手段研究了固溶处理温度对第三代镍基单晶高温合金DD10显微组织、枝晶偏析和组织稳定性的影响.结果表明:合金经1290℃/6h固溶后共晶基本消除,1330℃/6h固溶时出现少量微孔,1340℃/6h时则出现初熔.合金经1320℃和1330℃固溶处理...     

GH925高温耐蚀合金升温相态转变行为及热处理工艺研究

采用差示扫描量热法(DSC)、扫描电镜(SEM)、电子探针(EMPA)等表征方法,对GH925合金的锻态相转变行为、固溶时效态热处理工艺性能及显微组织进行了研究。研究表明合金从室温25~1 100℃升温区间的相转变序列为:MC相(转变温度为540℃-终止析出温度为1 043℃,下同);γ′相(578~978℃);M23C6-M7C3(679~758℃);σ相(723.5~879℃);η相(807~978℃)。合金锻态组织经(990~1 010℃)×2h固溶+740℃-760℃×8h时效处理,可以获得最佳的综合力学性能。1 000℃×2h固溶+780℃×8h时效热处理,沿晶界有大量的脆硬针片状σ相析出,造成合金冲击韧性的急剧下降。     

热处理对定向凝固合金DZ-80组织和性能的影响

抗燃气腐蚀合金通过定向凝固提高高温强度具有重要的意义。本研究基于不同固溶和时效处理试验发现,固溶温度选择1180～1200℃、时效温度选择1070～1090℃。可获得最佳组织状态,初生γ′溶解充分、二次γ′析出最细小、间距最短、γ-γ′基本消除,可获得最高的持久性能数值。DZ-80合金的中温持久寿命比Rene′80合金提高1倍,高温持久寿命提高1/3。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

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.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

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

Flow calorimeter for enthalpy increment measurements on condensed gases

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

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.……     

Optimum-Simulation von Ernteprozessen

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.     

A study of centrifugal cast high boron high speed steel

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

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     

CNAS Passes APLAC's PTP Review

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.