Studies on the structure and catalytic performance of Cu-Zn-Al catalyst prepared by liquid-phase preparation technology under different heat treatment atmosphere

Cu-Zn-Al slurry catalysts were prepared using a complete liquid-phase preparation technology under different heat treatment atmospheres.The catalysts were characterized using X-ray diffraction,X-ray photoelectron spectroscope,and N2 adsorption-desorption.Their application in the single-step synthesis of dimethyl ether from syngas was also investigated.The results indicate that the type of heat treatment atmosphere has an influence on the Cu species and the Cu0/Cu＋ ratio on the catalyst surface.Moreover,the final Cu/Zn ratio on the catalyst surface is mainly dependent on the composition and reaction environment of the catalyst and less on the type of heat treatment atmosphere.The prepared catalysts can suppress sintering of active sites at high temperatures,and the type of heat treatment atmosphere mainly affects the capability of the catalyst for methanol synthesis.The catalysts perform best using N2 as the heat treatment atmosphere.

Prediction and Minimization of the Heat Treatment Induced Distortion in 8620H Steel Gear:Simulation and Experimental Verification

The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance.It directly affects the dimensional accuracy,the grade of carburized and hardened gears,and the post-quenching manufacturing costs.In this study,three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM software.The results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite,leading to the large runout value at the end face of the gear.Therefore,a novel method was proposed to minimize the heat treatment induced runout value.It was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod structure.Further experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively,which was in good agreement with the simulated results.The novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9%compared to that of the original heat treatment process,which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.

Discussion on the Free Quenching Heat Treatment Process of Automotive Leaf Springs

Free quenching of automotive leaf springs is a new technology that has gradually started to be applied in the industry in China in recent years.Only a few manufacturers are applying it in the industry.Through more than half a year of on-site practice,the changes in the hot forming of spring plates before free quenching have been explored,and finally a heat treatment process that meets the production requirements of our company has been developed,achieving normal production.

Flexible Furnace Concepts for Vacuum Heat Treatment Combined with High-pressure Gas Quenching

IN the past five years the process combination of vacuum hardening, respectively vacuum carburizing with high-pressure gas quenching was successfully introduced to the market, especially in the manufacture of gears. In the meantime furnace concepts for various applications are available to the industry. In the following report three plant varieties are introduced, which differ in process flexibility and throughput. This report also explains criteria for the selection of a furnace in view of the existing application requirements. Besides this a short introduction is given into the vacuum carburizing process and the high-pressure gas quenching technology.

Flow-Optimization to Enhance Gas Quenching Efficiency for Helical Gears Specimen

Numerical simulations based on a conjugate heat transfer solver have been carried out to analyze various gas quenching configurations involving a helical gear streamed by an air flow at atmospheric pressure in a gas quenching chamber. In order to optimize the heat transfer coefficient distribution at key positions on the specimen, configurations involving layers of gears and flow ducts comprising single to multiple gears have been simulated and compared to standard batch configurations in gas quenching. Measurements have been performed covering the local heat transfer for single gears and batch of gears. The homogeneity of the heat transfer coefficient is improved when setting up a minimal distance between the gears (batch density) and when introducing flow ducts increasing the blocking grade around the gears. An offset between layers of the batch as well as flow channels around the gears plays a significant role in increasing the intensity and the homogeneity of the heat transfer in gas quenching process.

Grinding-Hardening of Face Gears Under Minimum Quantity Lubrication with Disc Wheels

To shorten the process of face gears,the grinding-hardening effect experiment of face gears under minimum quantity lubrication(MQL)was carried out.Firstly,the grinding method of face gears was analyzed based on the envelope principle,and the control equation of grinding movement was constructed.Secondly,the distribution ratio equation of heat flux density was established,and the theoretical calculation formula of triangle heat source was derived.Thirdly,since a MATLAB calculation program was compiled,the temperature change law under MQL grinding was analyzed.In the end,the influence of grinding parameters on the grinding-hardening layer depth was analyzed.The results demonstrate that MQL grinding achieves the grinding-hardening effect.

基于数字孪生的热处理智能化技术研究进展

为减少热处理智能化技术数据孤岛的状态,数字孪生的运用被广泛关注。数字孪生技术是智能化制造领域的先进智能技术,也是解决数据孤岛的重要方法之一。本文介绍了数字孪生技术与基于数字孪生的热处理研究现状。以车间数字孪生框架为基础,从物理车间、虚拟车间、车间服务系统、孪生数据4个方面介绍数字孪生的研究现状,分析了各部分中存在的主要问题。针对基于数字孪生为基础的热处理技术,结合传统热处理技术与特殊热处理的智能化研究进展,分析数字孪生技术在热处理中的应用与进展。

Multiphysics FEM Simulation of Contour Induction Hardening Process on Aeronautical Gears

Induction heating has been widely used by the heat treatment industry mainly in the wind-power and automotive sectors,in particular for hardening purposes,in a broad range of applications,its main advantages being the high repeatability and easy automation of the process,both factors leading to improved manufacturing efficiency and reduced CO;emissions.Though,traditional furnace-based case hardening treatments still represent the choice of reference when performance requirements are particularly demanding,either for the critical operating conditions or safety-related issues.The processes of CIH（Contour Induction Hardening）,compared to the traditional carburizing processes,allows to reduce the deformations after heat treatment.The main purpose of these treatments,as well as increases the surface hardness of the piece,is to induce compressive stresses in the superficial layer,improving the fatigue behavior.A multiphysics magneto-thermal simulation can be developed in order to calculate the temperature distribution in the gear,setting the input parameters such as currents,frequencies and treatment times.

泥河湾盆地火山角砾岩原料的热处理实验

泥河湾盆地内发现了众多以精致楔形细石核为特色的细石器遗址。在以往的研究中,研究者对此类石制品组合进行了技术、类型等方面的研究,但其石料来源、石料是否经过热处理等问题仍未得到妥善解决。本文开展了盆地内旧石器时代晚期晚段常用原料火山角砾岩的调查和热处理实验研究。研究表明,泥河湾盆地六棱山基岩中的火山角砾岩,直接使用时,难以满足楔形细石核压制剥片对原料品质的要求;经过600°C的热处理后,其抗力性降低、延展性提高,剥片性能显著提高,可很好地进行楔形细石核的系统压制剥片。基于实验观察,同时借鉴其他学者的研究成果,本文对下卜庄遗址的相关材料进行了初步分析,发现了石料热处理行为的线索。对泥河湾盆地旧石器时代晚期遗址开展系统的石料热处理研究,有望揭示盆地内古人类对石料热处理的复杂行为。

热加工处理技术对拖拉机变速箱齿轮的影响研究

设计了拖拉机变速箱齿轮节曲线方程和齿廓,对其进行了运动学分析,并基于热处理加工技术对拖拉机变速箱齿轮变形影响进行研究,提出了具体的优化措施。SolidWorks仿真结果表明:拖拉机变速箱齿轮设计理论、建模方法和热处理加工工艺都符合要求,验证了整个设计的正确性。

20CrMnTi薄壁齿轮渗碳淬火过程有限元模拟与调控

对实际工况下20CrMnTi薄壁齿轮渗碳淬火过程利用有限元分析软件Deform进行模拟。结果表明,薄壁齿轮渗碳淬火后,渗碳层厚度为1.2 mm,淬火组织主要由马氏体和残余奥氏体组成,表面的残余奥氏体较心部的多4.2%,由于温度场的不均以及组织应力导致其径向产生9%的变形。齿轮表面和心部的残余应力分别为-256.5MPa和141 MPa。实际测得显示薄壁齿轮渗碳层厚度为1.15 mm,淬火后齿轮表面组织由针状马氏体+7%残余奥氏体+颗粒状碳化物组成,心部组织由低碳马氏体+1%残余奥氏体组成,齿轮表面残余应力为(-1078±168.2)MPa,径向最大变形量约7%,与模拟结果对应较好。为此针对薄壁齿轮热处理过程中因热应力与组织应力综合作用下内应力过大造成的变形,使其在不同部位同时冷却或采取径向约束的措施。

食品加工工艺对食品安全的影响研究

食品加工工艺的不断创新推动了食品产业的快速发展,同时给食品安全带来了新的挑战。本文以食品加工工艺对食品安全的影响为切入点,全面剖析了加工工艺的积极作用与潜在风险,同时提出了加工工艺优化与食品安全控制策略,旨在为食品加工企业提供理论依据和实践指导,推动加工技术与食品安全的协同进步,从而为消费者提供更安全、更有营养的食品,促进食品产业的健康可持续发展。

基于机械干态颗粒涂层技术制备cBN@TiN粉体

采用机械干态颗粒涂层技术分别制备了cBN@TiO_(2)(TiO_(2)包覆立方氮化硼)粉体和cBN@(TiO_(2)+C)(TiO_(2)+碳包覆立方氮化硼)粉体,然后在1600℃、N_(2)气氛下进行高温热处理制备cBN@TiN(TiN包覆立方氮化硼)粉体,研究了高温热处理前后粉体的物相组成与微观形貌以及高温反应机理。结果表明:机械干态颗粒涂层技术可以使纳米TiO_(2)和纳米TiO_(2)+C颗粒均匀包裹在cBN颗粒表面。在高温热处理过程中,TiO_(2)与cBN反应生成液相B_(2)O_(3),促进了cBN相变成六方氮化硼(hBN),cBN的高温稳定性差,以cBN@TiO_(2)为原料制备的cBN@TiN粉体颗粒表面形成由TiN相和hBN相组成的片状结构层;当存在碳时,TiO_(2)会优先与碳发生还原反应生成TiN,抑制B_(2)O_(3)的生成,从而降低cBN相变量,此时cBN的高温稳定性好,以cBN@(TiO_(2)+C)为原料制备的cBN@TiN粉体颗粒表面形成主要为TiN相的颗粒结构层。

针对机械热处理工艺在弛豫控制相变技术中的研究

机械热处理工艺在驰豫控制相变技术中的研究旨在通过调控材料的组织结构和相变行为,改善材料的力学性能和性能稳定性。该研究主要包括加热工艺优化、相变动力学研究、材料结构调控、相变组织演变模拟和相变产物性能调控等方面。通过本研究,找出实现材料性能的优化和稳定性的提高措施。本研究对于提高材料性能和开发新型材料具有重要意义,并在多个领域具有广泛的应用前景。

航空齿轮内花键热处理精度控制技术研究

文章针对航空齿轮内花键热处理精度控制展开研究,提出新的技术方法和加工手段,保证内花键的精度能满足未来航空产品的发展需要,提高热处理内花键的加工稳定性和精度,对航空齿轮内花键产品的试制具有重大意义。

热处理对差速器齿轮用SAE4320H钢组织及性能的影响

SAE4320H往往用于耐冲击耐磨损的高端制造业零件,热轧状态或退火状态进行锻造,其热处理相关的研究较少。为探究不同热处理下组织转变和力学性能的变化,将一炼钢通过BOF-LF-VD-CC工艺生产的差速器齿轮用SAE4320H钢采用水淬、油淬、空冷和炉冷的热处理工艺进行冷却并测定力学性能。试验结果表明:淬火对齿轮用SAE4320H钢的屈服强度和抗拉强度有着明显的提升,其中水淬的屈服强度和抗拉强度最高,但塑性最差。925℃正火-880℃淬火-180℃回火后,水淬得到回火马氏体组织,油淬得到回火马氏体+回火贝氏体+少量铁素体组织,空冷得到P+B+F组织,炉冷得到P+F组织。

热处理炉自动化智能控制关键技术研究

随着科学技术的不断发展,我国工业发展能力逐渐提升,能源的开发以及可持续利用取得了较大的进步。热处理工艺是支持钢铁以及机械制造等行业正常运行的基础性环节。通过热处理工艺能够改变金属等工料的组织结构,提升工料的韧性以及耐磨性等。热处理炉的自动化智能控制技术直接关系到工业热处理能力。热处理炉对炉温的控制要求比较严格,在压力加工前的加热温度稍有偏差一般对质量没有太大影响,但是热处理工艺所要求的温度必须满足。随着信息技术的不断应用,工艺升级为热处理炉自动化智能控制提供了可能。以台车式热处理炉为例,分析其构造以及工作原理,探析热处理炉自动化智能控制的意义,并综合探讨了热处理炉自动化智能控制的关键技术,从而实现炉温精准控制的目标。

放射性废物热处理技术

放射性废物的处理一直是核能应用中的重要挑战之一。随着核能技术的发展和核废物数量的增加,寻找有效、安全的废物处理方法变得尤为迫切。在众多处理方法中,热处理技术由于其能够有效减少废物体积、稳定化放射性组分以及可能的资源回收等优点,成为了研究的重点。本文将深入探讨放射性废物热处理技术的各个方面,包括技术选择、预处理方法、具体处理技术以及废物最终处置方案。同时,将考虑到处理过程中的经济性、环境影响及社会接受度等因素。

热处理技术在化工压力容器中的应用

经济社会稳步发展的过程中,许多行业广泛且成功地应用了压力容器,尤其在化工行业中压力容器成为重要的生产要素。将热处理技术应用于压力容器,基本不改变工件的形状及化学成分,而是通过改变工件内部的显微组织或表面化学成分,赋予工件特殊的性能。为推动企业的现代化,各化工企业都应注重其设计与制造,合理采用热处理技术。基于此,本文重点分析了化工压力容器中的热处理技术类型及应用要点,为实际工作提供参考与借鉴。

供热通风与空调工程关键安装技术分析

作为建筑工程的一部分,供热通风空调工程又称暖通空调工程,其安装和施工质量直接影响到人民群众的生产生活。供热通风空调的安装是一项非常重要的工作,不仅能够改善建筑物的内部环境,还能够保证建筑物的安全。因此,施工企业应该特别注意这一方面的质量,并且严格遵守相关的行业标准,以确保安装的完整性和可靠性。供热通风与空调工程的核心特点之一便是其复杂的技术要求,在实施过程中,必须解决各种关键的技术难题,以确保其质量。基于此,该文主要围绕供热通风与空调工程关键安装技术展开分析,并提出具体的技术措施,以供参考。