Wear and cutting performance of diamond composite material-a comparison with tungsten carbide

A series of wear and rock cutting tests were undertaken to assess the wear and cutting performance of a thermally stable diamond composite (TSDC). The wear tests were conducted on a newly designed wear testing rig in which a rotating aluminium oxide grinding wheel is turned (also known as machined) by the testing tool element.The rock cutting tests were performed on a linear rock-cutting planer. The thrust and cutting forces acting on the tool were measured during these tests. A tungsten carbide element was also studied for comparative purposes. The wear coefficients of both materials were used to evaluate wear performance while cutting performance was assessed by tool wear and the rates of increase in forces with cutting distance.     

新型组合式金刚石圆锯片性能研究

提出一种切割幅面达到其直径2／3的新型组合式金刚石圆锯片基体。应用有限元分析软件ANSYS，针对直径Ф1800mm的新型组合式金刚石圆锯片，分析、计算其固有频率、变形和应力分布情况对工作性能的影响，并与普遍应用的金刚石圆锯片固有频率、振型、应力分布等进行比对分析。结果表明：组合式金刚石圆锯片最大变形0．2mm，表现在切向；最大第一主应力0.13920E＋08Pa，表现在辅助轮与切割外环接触部分及水槽处；固有频率及振型与普通金刚石圆锯片相近，能够满足加工质量要求。     

YG6金刚石涂层刀片衬底真空渗硼预处理新技术研究

本文研究了真空渗硼预处理硬质合金基体的表面组织、形貌、粗糙度，并在处理过的YG6刀片基体上，用强电流直流伸展电弧等离子体CVD法沉积金刚石薄膜涂层。结果表明，真空渗硼预处理不仅可以有效的消除或控制钴在金刚石沉积时的不利影响，而且，还显著粗化硬质合金基体表面。因此，提高了金刚石薄膜的质量和涂层的附着力。     

金刚石薄膜涂层钻头加工高硬度钢的实验研究

为提高金刚石薄膜涂层的韧性，避免金刚石薄膜涂层脆性断裂，以自贡硬质合金厂生产ZK-10型号硬质合金钻头为基体，采用厚度大约为3μmTiC作为过渡层，在表面涂覆4μm～5μm厚度的金刚石薄膜制成金刚石薄膜涂层钻头。用于加工硬度为HRC61的经热处理的GCrl5钢板，分别与未涂层硬质合金钻头、TiC-TiN涂层钻头对比，结果表明，金刚石薄膜涂层钻头由于加工速率高，摩擦发热量少，有效地避免了铁元素在高温下将金刚石转化石墨的作用，结果使用寿命比未涂层硬质合金钻头提高10倍以上，同TiC-TiN涂层钻头相比，初期加工性能明显优越，加工速率成倍数提高．但使用过程中，性能衰减更快，导致总体使用寿命同TiC-TiN涂层钻头相差不大。在表面喷砂处理中，金刚石薄膜涂层大部分易于脱落，剩余部分呈岛状分布，说明金刚石薄膜与基体的结合力分布很不均匀，这可能与金刚石薄膜的形核过程密切相关。     

非金刚石相碳成分对金刚石薄膜晶形的影响

应用Raman光谱和SEM方法研究了在用热丝CVD方法生长金刚石薄膜中,生长膜中非金刚石相碳成分对金刚石晶粒晶形的影响。还讨论了生长条件如碳源浓度、衬底温度等对生长膜中非金刚石相碳成分的影响     

草酸盐共沉淀法制备金刚石金属结合剂

以制备金刚石金属结合剂为目的,本文研究了用共沉淀法制备的含草酸亚铁、草酸铜和草酸镍为所需比例的三组分共沉淀作为金属结合剂前驱体,然后还原制得金属结合剂.研究了草酸盐共沉淀中的各组分的收率,确定了共沉淀的最佳反应条件:溶液浓度(Fe2 )0.38 mol/L,反应温度50℃,反应时间1 h,氢氧化钠和草酸物质的量的比值为1～2:1.通过TPR和MS谱研究了共沉淀的分解还原过程及产物形态,研究发现,两者的加入能降低草酸亚铁的还原温度,共沉淀分解还原后生成合金粉末;对合金粉末进行了机械性能测定,结果表明:合金粉具有较好的硬度,比机械混合的结合剂提高20%以上,抗弯强度略有下降,但二者配合使用有较好的效果.     

金刚石膜氧化行为的TGA分析

采用热重分析法(TGA)对直流等离子体喷射制备的金刚石膜在空气中的氧化行为进行了研究,结果表明;直流等离子体喷射制备的金刚石膜氧化激活能为220KJ/mol,与天然金刚石的氧化激活能相当.用扫描电子显微镜(SEM)和Raman光谱对金刚石膜氧化前后的形貌和成分作了分析.结果表明金刚石膜在空气中氧化优先刻蚀晶界和孔隙,孔隙不断增加,晶界瓦解,金刚石膜成为一个个柱状单晶粉末;金刚石膜氧化前后未出现石墨或其它中间产物.     

金刚石修整滚轮CAD/CAPP集成技术研究

金刚石修整滚轮是目前最为有效的高效、高精砂轮成形修整工具，迎合了磨削技术高精、高速和高效发展趋势，内电镀高精度修整滚轮制造工艺复杂、工序多，影响制造精度因素较多，修整参数选择、滚轮图纸设计和工艺编制是生产中的关键环节。本文从分析金刚石修整滚轮设计制造的特点人手，应用CAD／CAPP集成技术实现了金刚石修整滚轮设计、工艺规程编制和技术文件管理的自动化，提高了滚轮制造工艺水平和对产品质量的控制能力，较好地解决了一些设计和工艺过程相对简单、变化较小的定型产品的CAD／CAPP集成化的问题。     

A new thermomechanical model of cutting applied to turning operations. Part I. Theory

In this paper, an analytical approach is used to model the thermomechanical process of chip formation in a turning operation. In order to study the effects of the cutting edge geometry, it is important to analyse its global and local effects such as the chip flow direction, the cutting forces and the temperature distribution at the rake face. To take into account the real cutting edge geometry, the engaged part in cutting of the rounded nose is decomposed into a set of cutting edge elements. Thus each elementary chip produced by a straight cutting edge element, is obtained from an oblique cutting process. The fact that the local chip flow is imposed by the global chip movement is accounted for by considering appropriate interactions between adjacent chip elements. Consequently, a modified version of the oblique cutting model of Moufki et al. [Int. J. Mech. Sci. 42 (2000) 1205; Int. J. Mach. Tools Manufact. 44 (9) (2004) 971] is developed and applied to each cutting edge element in order to obtain the cutting forces and the temperature distributions along the rake face. The material characteristics such as strain rate sensitivity, strain hardening and thermal softening, the thermomechanical coupling and the inertia effects are taken into account in the modelling. The model can be used to predict the cutting forces, the global chip flow direction, the surface contact between chip and tool and the temperature distribution at the rake face which affects strongly the tool wear. Part II of this work consists in a parametric study where the effects of cutting conditions, cutting edge geometry, and friction at the tool–chip interface are investigated. The tendencies predicted by the model are also compared qualitatively with the experimental trends founded in the literature.     

金刚石表面镀镍工艺研究

研究金刚石表面镀Ni工艺,金刚石经粗化处理后,首先以氯化钯对其表面活化,进行化学镀Ni形成金属表层,然后以滚镀方式在其表面进行电镀加厚,镀Ni层使金刚石强度提高,磨削性能得到改善。讨论了各工艺因素对镀层质量指标的影响。