共查询到20条相似文献,搜索用时 562 毫秒
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稀土在渗硼中渗入机制和作用机理的讨论 总被引:1,自引:0,他引:1
研究了45钢表面硼稀土共渗,讨论了稀土元素的渗入机制、催渗机理及稀土催渗效果出现最佳值的原因。在硼砂型渗硼剂中加入适量的稀土有利于45钢渗硼层质量、厚度及性能的提高,稀土加入量的最佳值为10%。 相似文献
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研究了45钢表面硼稀土共渗,讨论了稀土元素的渗入机制、催渗机理及稀土催渗效果出现最佳值的原因。在硼砂型渗硼剂中加入适量的稀土有利于45钢渗硼层质量、厚度及性能的提高,稀土加入量的最佳值为10%。 相似文献
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尿素对固体渗硼作用的研究 总被引:1,自引:0,他引:1
研究了尿素对固体渗硼的作用。结果表明,固体渗硼时加适量尿素可显著提高渗硼速度,对于20、45钢可提高渗速一倍以上,对于T8、GCr15和Cr12钢也分别提高渗速80%、77%和69%;加尿素渗硼得到的共渗层具有良好的耐蚀和抗高温氧化性能,而显微硬度和耐磨性并不降低;加尿素的固体渗硼实际上是以渗硼为主的硼氮碳共渗。 相似文献
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H13 模具钢低温盐浴碳氮钒共渗工艺 总被引:6,自引:0,他引:6
提出了H13钢的一种新的表面强化工艺———低温盐浴碳氮钒共渗。研究了经560℃左右盐浴碳氮钒共渗后的H13钢试样的显微组织、硬度与相组成。生产试用的结果表明,与气体低温氮碳共渗相比,经上述工艺处理后热挤压模具的平均寿命可提高1倍以上。 相似文献
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为研究氦弧TIG焊焊缝质量,对比分析了2219铝合金氦弧TIG焊与氩弧TIG焊焊缝成形及组织性能.结果表明,在背部熔宽相同的条件下,氦弧TIG焊焊缝正面熔宽、下塌量及热影响区宽度均小于氩弧TIG焊,氦弧TIG焊与氩弧TIG焊焊缝的微观组织及第二相组织基本相似,焊缝区晶粒为等轴晶,热影响区晶粒为粗大的板条状,组织为粗大的α铝基体与金属间化合物Al2Cu及少量的共晶组织,焊缝区的第二相组织明显多于热影响区,无法发挥弥散强化的作用.氦弧TIG焊与氩弧TIG焊焊接接头的断裂方式均为韧性断裂,抗拉强度基本保持一致,氦弧TIG焊焊接接头的断裂总延伸率高于氩弧TIG焊,维氏硬度高于氩弧TIG焊焊缝的硬度. 相似文献
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超声电镀锡铋合金研究 总被引:5,自引:0,他引:5
研究了超声波对锡铋合金电镀的影响.通过赫尔槽试验优选出最佳镀液配方和工艺条件,用SEM法观测了镀层形貌,并测试了镀层和镀液性能.结果表明:超声波的作用扩大了电流密度范围和温度范围;所得镀层表面光亮、结晶更细致、均匀,镀层结合力、抗氧化性和可焊性改善明显,耐蚀性增强;镀液性能稳定,阴极电流效率和沉积速度得到提高.因此,超声波对电镀工艺条件、镀层质量和镀液性能都有明显的改善作用. 相似文献
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Yu. A. Puchkov V. A. Larkin S. H. Nguen O. V. Sedov 《Metal Science and Heat Treatment》2004,46(11-12):521-526
Dies produced from castable and deformable aluminum alloys are studied. The dies are used for molding articles from foaming plastics. Specimens for studying the microstructure are cut from the surface zone of dies. The stress state of the dies is determined by computation. The chemical composition of water and deposits on the surface of dies are studied in order to determine the causes of corrosion cracking. The effect of the composition of the alloy and of water on the composition of corrosion products deposited on die surfaces is studied by means of thermodynamic computation with the help of TERRA software. The materials of dies and alloys suitable for their production are studied and corrosion tests under actual operating conditions are performed. Anodized, epoxy, and epoxy-phenol coatings for the dies are tested. The causes of failure of aluminum dies are analyzed and recommendations for raising their endurance are given. 相似文献
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CBN砂轮陶瓷结合剂的研究进展 总被引:13,自引:4,他引:9
本文对近年来有关CBN砂轮陶瓷结合剂的研究进展作了较详细的综述,介绍了陶瓷结合剂的组成,阐述了硼硅酸盐玻璃结合剂的机理,分析讨论了影响陶瓷结合剂的因素,对目前改进陶瓷结合剂性能,尤其对提高其强度的方法作了归纳和总结,如晶须增韧补强、CBN镀覆、改变助熔剂化学成分等方法。本文还展望了陶瓷结合剂的的研究开发趋势。 相似文献
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本文剖析了通常采用的模块编程法,流程编程法和条件编程法的优缺点,提出控制数据按层次编程的新方法,使控制软件的编制比较简单,程序容量大为减少,软件层次清楚,调试和维护也较为方便,提高了软件的编制质量。 相似文献
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以Ni-WC粉末为主要原料制成涂料涂覆在EPS泡沫塑料模样的表面上,采用V-EPC真空消失模铸造方法浇注45钢液,制备出Ni-WC表面合金化45钢基复合材料.应用光学显微镜、SEM,EDS和XRD观察和分析了复合材料的显微组织.结果表明,复合材料由表面复合层、中间过渡层和内部基体3个区域组成.在表面复合层中,Ni-WC颗粒已全部发生分解,其组织由少童的细小条状的富钨碳化物、大量的粗大网状碳化物和树枝晶基体组成;过渡层在靠近表面复合层一侧有一条全部由极细珠光体组成的窄带,而在靠近基体区域一侧组织由块状的铁素体和珠光体组成,并且在这些晶粒内部和晶界上都可以观察到有碳化物析出;基体区域组织形貌与常规45钢相似,但组织中珠光体含量明显高一些. 相似文献
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Chung-Shin Chang 《International Journal of Machine Tools and Manufacture》1998,38(12):1467-1498
The three-dimensional cutting forces for nose radius tools with a chamfered main cutting edge incorporated with a tool-worn factor are presented in this paper. The variations in shear plane areas occurring in the tool-worn situation are used. The results obtained from the proposed model shows good agreement with the experimental data on both chip formation as well as cutting forces. In the experimental work the throwaway tips are locked onto the pocket of the tool holder. The holders for special tools are designed first. Next, the tool holders are manufactured by using medium carbon-steel bars and the mounting tips are designed based on various specifications. Finally, the nose radius tips mounting in the tool holder are ground to a wear depth, and the worn tool dimensions are measured by using a profile projector. The shear area and the friction area are calculated accordingly. Then the three-dimensional cutting forces will be obtained from those data. 相似文献
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Robert D. Shull 《Journal of Phase Equilibria》1983,4(1):5-15
The procedures by which samples are prepared for phase diagram studies are examined and critically evaluated. The three key elements that require attention (alloy purity, homogeneity, and equilibrium) are separately addressed, and several examples of bad procedure are presented with information on their past and future consequences. The origin of commonly confronted problems are described and special procedures are suggested for their circumvention. Additionally, new methods for the early detection of some sample problems are presented, and the usefulness of rapidly solidified materials (as specimens) in phase diagram studies is illustrated. 相似文献
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细晶粒Ti(C,N)基金属陶瓷制备技术与性能 总被引:3,自引:0,他引:3
对近年来国内外有关细晶粒Ti(C,N)基金属陶瓷制备技术的研究成果进行了分析总结。简要介绍了混料技术、烧结技术对材料晶粒度及组织、性能的影响,概述了新的工艺方法抑制晶粒长大的机理,指出了细晶粒Ti(C,N)基金属陶瓷制备技术的发展方向。 相似文献
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综述了钨及钨合金制备、热加工及应用等方面的发展。详细分析了改善和提高钨及钨合金的塑性和再结晶温度的方法及钨的固溶强化和弥散强化,从而提出了钨合金的设计和制备的发展方向。 相似文献