牙 板 渗 碳 淬 火 工 艺 的 改 进

针对钻井用吊钳牙板使用时易崩碎、不耐磨的特点，分析了原因，改进了牙板渗碳淬火的热处理工艺。实践证明改进后的工艺切实可行。     

大型重载零件高浓度深层渗碳渗层硬度分布的计算机模拟

在对高浓度深层渗碳的特点进行分析的基础上,考虑到碳化物的析出与溶解、温度及碳浓度对扩散行为的影响,气氛环境对相界面碳传递过程的影响,淬火烈度对渗碳层冷却效果的影响,提出了一种新的模拟高浓度深层渗碳渗层硬度分布的方法。     

减速器渗碳齿轮断裂失效分析

对齿轮断裂部位的形貌特征、裂纹走向、齿面加工状况等进行了观察,从断裂区组织与硬度、齿轮材质、渗碳层深度、硬度与组织等方面对断裂的渗碳齿轮进行了检测。分析结果表明,轮齿断裂系疲劳断裂,裂纹起源于齿轮端面与齿面的磨削裂纹。齿轮工作时,损伤最为严重的磨削裂纹在交变工作应力作用下最先扩展,当裂纹扩展到一定程度,轮齿有效承载面积不足以承受工作载荷时,发生断裂。给出了避免与减少磨削裂纹的措施。     

金属材料的碳化腐蚀及防护研究进展

Fe-Cr-Ni合金的碳化导致合金内部形成碳化物,使合金的性能恶化,综述了碳化现象的特征和材料性能的变化,表面处理和氧化膜对碳化的防护作用,并讨论了腐蚀机理和腐蚀动力学。     

浸渍材料试验及性能分析

从提高混凝土强度和密实性出发，采用“ＰＩＣ”法对水泥砂浆试块进行试验和研究。研究表明，浸渍材料可用于要求强度高、抗渗、耐腐蚀等结构部位，或用于已建结构物的加固处理。     

低碳钢激光膏剂渗碳组织及性能研究

采用在０８＃钢试样表面上涂覆渗碳膏剂，用ＣＯ２激光束进行辐照，结果表明该工艺渗层硬度高、渗碳速度快，说明激光膏剂渗碳是一种很有应用前景的新工艺。     

渗碳气体对201奥氏体不锈钢低温离子渗碳效果的影响

用不同的渗碳气体对201奥氏体不锈钢进行了低温离子渗碳(DCPC)处理。实验证明,甲烷和乙炔均可在不锈钢表面形成一层无碳化铬析出的碳的过饱和固溶体(Sc相),使其表面的硬度和耐蚀性均有较大幅度的提高。但用甲烷作为渗碳气体处理的不锈钢表面有一层黑膜,破坏了不锈钢原有的光泽;而用乙炔作为渗碳气体不仅可以获得较为光亮的表面色泽,同时其硬度和耐蚀性也有进一步的提高。     

Influence of carburization followed by shot peening on fatigue property of 20CrMnTi steel

In this study, the influences of carburization (followed by quenching and low-temperature tempering) followed by shot peening on “apparent” fatigue limits of 20CrMnTi steel specimens were studied and quantitatively analyzed according to the microstructure changes, induced residual stress fields, and position of fatigue crack sources, as well as a micro-meso-process theory for fatigue crack initiation previously proposed by the authors (Ref 6–8). The experimental results show that, although the hardness of the surface layer of carburized specimens is much higher than that of the pseudo-carburized specimens, the improvement effect of carburization on the apparent fatigue limits of specimens is uncertain. It should be related to the possible formation of nonmartensitic microstructure in the surface layer of carburized specimen. After the shot peening, the fatigue limit of specimens was improved and rose to a level about 40% higher than that of the pseudo-carburized specimens. Scanning electron microscopy fractographic analyses show that the fatigue sources, which indicate the weakest link of specimens, in pseudo-carburized and ascarburized specimens are all located at the surface, while after shot-peening, they appear in the interior beneath the hardened layer.     

流态化渗碳碳传递系数试验研究及数学模型

以丁烷加空气为流态化渗碳气源,系统试验研究了流态化渗碳温度、气氛碳势、刚玉粒径及表观流态化速度等对碳传递系数的影响。利用单纯形方法回归建立了不同条件下流态化渗碳碳传递系数数学模型和综合影响因素数学模型,试验验证表明,该数学模型具有较高的拟合精度。