Research on Austempered Ductile Iron Gear

本研究旨在探讨奥贝球铁（ADI）在齿轮上的强度与切削性.新型奥贝球铁的研制：通过对新型奥贝球铁的组织和力学性能的研究，研制出了具有足够强度和上级加工性能的奥贝球铁齿轮材料，其力学性能为：抗拉强度100 Kgf/mm^2，伸长率10%，布氏硬度300，石墨颗粒数约250个/mm^2。机械加工性试验（1）滚齿试验;后角为15 °、前角为5 °的滚刀和/或通过压缩空气冷却滚刀齿对提高滚刀寿命是有效的。用金属陶瓷精加工滚刀精加工的奥贝球铁齿轮的齿形精度达到JIS 0级，齿面粗糙度Rmax为2- 3 μ m。在使用飞刀的基础试验中，该ADI能够以100米/分钟的切削速度切削。（2）齿圆角的滚压; ...更多信息 详细研究了滚轧齿面圆角的方法和条件。轧制后奥贝球铁齿轮表面硬度升高，对轮齿的弯曲疲劳强度有很大影响.承载能力;（1）抗弯强度;在弯曲疲劳试验中，新ADI的弯曲强度足以满足齿轮材料的要求。经喷丸处理后的奥贝球铁齿轮的抗弯强度接近。渗碳钢齿轮。(2)齿面耐久性;采用双辊式疲劳试验机进行的辊压试验表明，提高奥贝球铁齿轮表面硬度有助于提高齿轮表面的耐久性，而石墨颗粒的数量与奥贝球铁齿轮的表面损伤有关。齿轮试验表明，滚切后的奥贝球铁齿轮具有足够的表面耐久性，用金属陶瓷滚刀精加工奥贝球铁齿轮可提高齿轮的表面耐久性.结论;通过对刀具材料、刀具几何形状和切削条件的优化，使新型奥贝球铁齿轮材料的高效制造成为可能。奥贝球铁在材料强度方面在中硬度齿轮区具有足够的强度。用金属陶瓷精加工滚刀改善齿面粗糙度和用滚压和喷丸处理使齿面圆角加工硬化，表明奥贝球铁齿轮有可能应用于渗碳或感应淬火等高硬度齿轮领域。少

This research aims at investigation of the strength and the machinability of austempered ductile iron (ADI) for its application to gears.1. Development of the new ADI ; By investigating the metallic structures and the mechanical properties of new ADI, the ADI that has enough strength and superior machinability for gear material is developed, that is, the mechanical properties are 100Kgf/mm^2 in tensile strength, 10% in eloggation, 300 in Brinell hardness and the number of graphite grains is approximately 250/mm^2.2. Machinability tests ; (1) Hobbing tests ; The hob with relief angle of 15ﾟ and rake angle of 5ﾟ and/or the cooling of the hob teeth by the compressed air are effective in the improvement of hob life. The ADI gears finished with a cermet finishing hob result in JIS class 0 in tooth profile accuracy and Rmax 2-3mum in tooth surface roughness. In fundamental tests using a fly-tool, this ADI is able to be cut at cutting speed of 100m/min. (2) Rolling of the tooth fillet ; The m … More ethod and the conditions of the rolling of the tooth fillet are investigated in detail. The rise of the surface hardness of the ADI gear rolled is shown, which has a great influence on the bending fatigue strength of gear teeth.3. Load-carrying capacity ; (1) Bending strength ; In bending fatigue tests with a pulsator, the bending strength of the hew ADI is sufficient for the gear material. The bending strength of the ADI gear after shot-seening treatment is nearly equal to. that of the carburized steel gear. (2) Tooth surface durability ; Roller tests using a 2-roller-type fatigue tester clarifieds that the increase of the surface hardness of the ADI gear contributes to improvement of the surface durability, and that the number of graphite grains relates to the surface damage of the ADI gear. Gear tests represents that the ADI gears hobbed have sufficient surface durability, and that the durability increases by finishing the ADI gear with the cermet hob.4. Conclusions ; The new ADI concerned is possible to be manufactured as a gear material efficiently by the optimization of tool materials and tool geometries and the cutting conditions in manufacturing aspects. The ADI has sufficient strength in the region of medium hardness gears in aspects of the material strength. The Improvement of the tooth surface roughness with the cermet finishing hob and the work-hardening of the tooth fillet by the rolling and the shot-seening represent the possibility of application of the ADI gear to the region of high hardness gears such as case-carburized or inductionhardened gears. Less