决定淬火工件表面冷却速度的两个新因素

用标准探棒检测出的油或者水的冷却速度曲线既不能反映探棒表面的冷却情况,也不能用来推测工件表面的冷却过程。因此,应直接观测工件的冷却过程。淬火冷却过程的直接观测和研究发现,除了淬火介质的冷却能力和工件某部位的有效厚度之外,不同工件表面蒸气膜内气体的流动状况和工件表面从蒸气膜向沸腾冷却方式转型的次序,对工件表面的冷却速度和整个工件的冷却均匀性都有很大影响。业已揭示了后两种新因素影响工件冷却速度和冷却均匀性的基本规律,从而可以在淬火冷却过程中对同一工件表面的不同部位的冷却速度分别加以控制,这种控制技术被称为精细淬火冷却技术。     

对自来水作为淬火介质的两大缺点的研究

从自来水淬火时工件容易淬裂、硬度不均且畸变大等现象，列出了自来水作为淬火介质的两大缺点：一是低温冷却速度太快，二是冷却特性对水温变化太敏感。分析了自来水第二大缺点引起淬火硬度不均和畸变的原因。通过与气态介质的对比，指出了液态淬火介质共同的两类缺点：一是任何确定的液态介质，其冷却速度的可调节范围都很有限，以致同一个车间必须配备普通淬火油、中速淬火油和高速淬火油，才能满足不同工件的需要；二是工件从蒸汽膜阶段到沸腾阶段期间，冷却速度突然增大，可能引起较大的淬火畸变。提供了克服液态淬火介质第二类缺点的七类技术方法。     

淬火过程的冷却机理及其影响因素

文章以令人信服的实验结果说明了淬火过程的冷却机理，提示了淬火剂、浴温、浓度与表面润湿时金属的物理性能、冷却速度、热传导系数之间的相互依赖关系。同时也探讨了冷却速度的测量，有表面润湿过程的特征表面润湿对于热传导、时间－温度关系及硬度的影响。为优化淬火工艺提供了重要依据。     

淬火介质(二)

正淬火介质又称淬火剂,淬火介质有固态的(靠热传导)、液态的或气态的,主要是液态的。可分为无物态变化型和有物态变化型两大类:前者多半用于分级淬火和等温淬火,主要靠介质的传导和对流带走工件的热量,冷却能力决定于介质本身的热容,热导、流动性等物理性质,以及工件与介质间的温差。常用的有碱浴、硝盐浴和铅浴。后者按成份又可分为水基型和油基型;按冷却特性可分为非形成薄膜型,淬火过程中工件表面不产生沉积层,和形成薄膜型,淬火时在工件表面迅速形成一层覆膜,冷却     

液态淬火介质的两个共性的缺点及对策

适用范围有限和工件淬火变形大是液态淬火剂的两个带有共性的缺点,提出了克服第一个缺点即扩大液态淬火剂的应用范围的8种技术措施,指出,工件的淬火变形量除淬火介质的冷却速度外,还与其特性温度有关,应选用特性温度稳定的介质淬火。     

沸腾冷却区的宽度及其传达的信息

用摄像记录了液态介质中冷却时试样表面的冷却情况.试验发现,在液态介质中淬火时,试样表面的沸腾冷却是在呈带状的沸腾冷却区扫过的过程中完成的.这类沸腾冷却区通常多很窄,因此工件表面上任何部分经历沸腾冷却的时间都很短,靠沸腾冷却方式降低的温度都不多.淬火冷却中,从工件表面出现第一个超前扩展点开始,到蒸汽膜区完全消失为止的很长一段时间内,三种散热方式共同存在;其中,蒸汽膜冷却方式和与对流冷却方式对工件淬火冷却的贡献都比沸腾冷却的要大.     

水溶性淬火介质的搅拌

MH淬火介质是一种无毒、无臭、不燃烧、无污染的新型水溶性淬火介质[1]，具有冷却速度可调，使用温度范围较宽和价格低廉等一系列优点。本文旨在研究搅拌因素对该介质冷却特性的影响，从而为其在热处理生产中的应用提供重要的参考。1搅拌的作用对水溶性淬火介质来说，搅拌的作用很重要。高聚合物水溶性淬火介质在长期使用过程中，由于与灼热工件的反复作用，会使其中的高聚合物发生分解，从而使淬火介质变质。搅拌可增加淬火工件周围介质的循环，降低温度，从而减缓分解变质，维持介质稳定的冷却特性，所以搅拌可起抗老化的作用。2搅拌速度…     

新型有机聚合物淬火介质及其工业应用

本文通过试验确定了两个典型成份的有机聚合物淬火介质。低浓度有机聚合物淬火介质在650℃～550℃温区有极高的冷却速度,在马氏体相变温区有接近于油的冷却速度。高浓度有机聚合物淬火介质有与油相似的冷却特性,可代替油用于合金钢的淬火。与油比较该淬火介质具有淬火硬度均匀,变形小,淬火时不会燃烧,没有烟雾、无污染,工件可不经过清洗直接进行回火。并进行了实际应用试验。     

淬火介质(九)

（6）淬火的原理 淬火的原理普遍认为：在水、油类淬火介质中冷却过程的冷却特性曲线上分为蒸气膜、沸腾和对流三个阶段,见下图。介质的沸点远比淬火工件温度低,赤热的工件进入淬火介质迅速使周围的淬火液汽化,并形成一层蒸汽膜包围工件,使工件与周围淬火液隔开。     

飞雕环保节能淬火术——“擦油水冷”双液淬火

淬火介质是实施淬火工艺的重要保证,对金属材料热处理后工件的质量有着很大的影响。武汉理工大学有一种节能环保淬火技术-"擦油水冷"双液淬火法,又称"飞雕淬火法"(飞雕技术创新之一),非常值得推广。这种淬火方法适合结构简单的低碳钢、中碳钢、低合金结构钢及不锈钢的淬火和表面防锈处理。     

Importance of Liquid Metal－Solid Wetting in ModernMaterials Science and Technology

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Wetting in Ni/TiC Composite System

The wetting behaviour of titanium carbide by molten nickel was investigated at different oxygen partialpressures by using the sessile drop method.Special attention was paid to the kinetics of wetting.Wettingprocess in the Ni/TiC system is controlled by the dissolution of TiC in the liquid phase.Discussions weremade on the basis of the new experimental results achieved in the present investigation and those given inthe literature for the Ni/TiC system and for some similar metal/carbon systems to elucidate how theinterfacial dissolution reaction influences the wetting process.The reactive wetting process is a complex mat-ter and is very sensitive to the experimental conditions.Implantation of the wetting study in the compositeprocessings was also suggested and the optimum processing is proposed.     

Wetting force and contact angle measurements to evaluate the influence of zinc bath metallurgy on the galvanizability of high-manganese-alloyed steel

The present investigation aimed to evaluate the influence of zinc bath metallurgy on the hotdip galvanizing of a high-manganese-alloyed steel (commercial grade X-IP 1000). Wetting force and contact angle measurements were carried out by the Wilhelmy plate methodology to assess zinc bath compositions. The Wilhelmy plate methodology was particularly suitable for both quantifying liquid zinc wetting and producing coated samples to be characterized. The aluminium content of the zinc bath varied between 0.05 and 1.10 wt % and manganese as well as silicon was additionally added to the bath composition. Best wetting occurred with aluminium contents which are typical for industrial galvanizing baths (0.12-0.22 wt %). But zinc wetting and wetting reactivity decreased with increasing aluminium content > 0.30 wt %. Hence, aluminothermic MnO reduction seems to be ineffective in the present case. Wetting results might be further improved by adding manganese or silicon to the zinc bath due to an improved wetting reaction. However, the formation of additional phases in the coating has to be considered with regard to technical use.     

Thermal Properties and Wetting Behavior of High Temperature Zn-Al-In Solders

Solders for ultrahigh-temperature applications were defined by Vianco as those able to sustain working conditions with temperatures as high as 573 K, with momentary temperature rise up to 623 K. Zn-Al eutectic alloy (12 at.% Al) fits such defined criteria with respect to its melting temperature. It was found that small additions of indium to Zn-Al eutectic lower its melting temperature. The aim of this work is to assess if and to what extent thermal properties and wetting behavior are affected. It was found that addition of In increases electrical resistivity and coefficient of thermal expansion value. Wetting angles on Cu and Al substrates of liquid Zn-Al eutectic-based alloys containing up to 1.5 at.% of In were studied with the sessile drop method, after wetting at 773 K in the presence of flux. A decrease of apparent wetting angle was observed with increasing concentration of In. After wetting tests solidified alloy-substrate couples were cross-sectioned and examined with scanning electron microscopy coupled with electron dispersive X-ray analysis.     

杨氏方程的能量求解法及润湿角计算模型

杨氏方程是通过建立物理模型，利用力学平衡条件所推得，文中从另一角度出发，利用能量最小原理对润湿角与界面张力间的关系进行了推导，所推得的结论与杨氏方程的结论一致。在钎焊过程中，润湿角的大小是评价润湿效果的一项重要指标，但由于界面张力的值较难获得，通过杨氏方程来求解润湿角的值存在诸多困难，而通过试验仪器的方法去测量润湿角的大小，既增加了试验成本，又降低了试验效率。文中建立了一种简便求解润湿角的计算模型，并进行了试验验证，将计算值与实测值进行了比较，二者吻合良好。     

Features of wetting with water of anodic plasma-electrochemical coatings on aluminum and titanium

Wetting with distilled water of coatings formed in orthophosphate-borate aqueous electrolyte is investigated. For an aluminum alloy, the wetting angle of freshly prepared films with water is ∼20°. After annealing in air at temperatures higher than 300°C, the films become hydrophilic and water spreads over their surface. With time of storage in air and after sequential operations of wetting in water-drying in air, the wetting angle increases, reaching the values of ∼70–80°. The composition of the film bulk (X-ray spectral analysis) and surface (X-ray photoelectron spectroscopy) during their wetting and limited wetting with water is presented. The possible causes of the observed phenomena are discussed.     

Optimal conditions for the wetting balance test

Wetting balance tests of copper sheets submerged in tin solder baths were carried out in a completely automatic wetting balance. Wetting curves were examined for three different values of sheet thickness and four different solder bath temperatures. Most of the wetting curves showed a distorted shape relative to that of a standard curve, preventing calculation of important wetting parameters, such as the wetting rate and the wetting force. The wetting tests showed that the distortion increased for a thicker sheet thickness and a lower solder bath temperature, being the result of solder bath solidification around the submerged sheet substrate.     

温度与镀层对Sn-Cu-Ni无铅钎料润湿性能的影响

采用润湿平衡法测定了在不同试验温度下Sn-Cu-Ni无铅钎料在Cu,Au/Ni/Cu,SnBi/Cu三种基板上的润湿时间和润湿力,研究了钎焊温度对Sn-Cu-Ni无铅钎料在不同基板上润湿性能的影响.结果表明,温度升高使Sn-Cu-Ni无铅钎料的表面张力减小,能显著缩短钎料在铜片上的润湿时间,提高润湿力;Ni/Au或SnBi等镀层能显著降低钎料/基板界面张力,因此Sn-Cu-Ni无铅钎料在Au/Ni/Cu或SnBi/Cu基板上的润湿性能优于在Cu基板上的润湿性能.     

锡在Cu6Sn5金属间化合物表面的润湿行为

利用改良座滴法研究了高真空条件下熔融纯Sn在350 ~ 450 ℃下分别与Cu₆Sn₅和T2纯铜的润湿行为. 结果表明,表面镀金的金属间化合物基板在各试验温度下的润湿性均优于纯铜基板;金属基板表面氧化膜对润湿性的影响不容忽视;离子溅射后表面形成的金膜可以作为一种改善润湿性及控制界面IMC厚度的有效方法;润湿性改善的机制为Sn与氧化膜的化学反应,界面析出IMC或者IMC的溶解过程并非限制铺展的主要因素;铺展过程表现出线性铺展规律,可用反应产物控制模型对其进行描述,计算得到Sn/Cu₆Sn₅和Sn/Cu两体系的铺展激活能分别为20.469 kJ/mol和22.270 kJ/mol.     

ZnO-Al_2O_3-B_2O_3-SiO_2系微晶玻璃与可伐合金的润湿性能

研制了一种新型的与可伐熔封的ZnO-Al_2O_3-B_2O_3-SiO_2系微晶玻璃,研究了不同工艺条件下微晶玻璃与可伐合金间的润湿角大小,结果表明,熔封气氛和熔封温度对润湿性能影响很大,熔封时间影响最小.采用最佳的工艺条件,其润湿性能与现有的其它玻璃润湿性能相似.同时发现玻璃与可伐合金间的润湿角保持在10°～30°之间能得到质量良好的熔封产品.在基本不改变传统工艺制度的条件下,可完成锌铝硼硅系微晶玻璃与可伐合金的熔封,即利用排蜡过程同时完成微晶玻璃的形核,熔封后在稍低温度保温或减慢冷却速度可以完成微晶玻璃的结晶过程.锌铝硼硅系微晶玻璃与预氧化可伐合金的封接依靠玻璃中的SiO_2与FeO或Fe_3O4发生界面反应形成牢固的结合.