B690刨床纵向丝杠手把重的解决方法

机床修理中,常遇到机床越修其手轮、手把越重的问题。若更新丝杠丝母,手轮、手把会更重。在B690刨床的修理中,同样遇到这个问题。通过实践,分析了B690纵向丝杠手把重的原因并找到了具体的解决方法。     

难加工材料的低应力磨削

低应力磨削在工件表面能形成低的残余应力,从而提高了零件的疲劳强度和可靠性。本文介绍了难加工材料的低应力磨削技术,推荐了低应力磨削参数。     

采用喷丸硬化和强力刷光的表面复合处理

经喷丸硬化和强力刷光复合处理后,机械零件的疲劳强度与单项处理时相比有更大的提高。在改善疲劳强度方面,强力刷光的作用与喷丸硬化的作用相似。作者们采用 Schenck 型试样进行了平面弯曲疲劳试验,澄清了复合处理的作用。复合处理后,疲劳强度最大提高了79%。同时,也检查了沿深度方向的残余应力分布,另一方面,如果用化学方法去除喷丸硬化表层,去除的深度达应力峰值存在的部位,则疲劳强度进一步提高达98.3%,但是在单独强力刷光时没有明显的提高。     

难加工材料磨削中的砂轮粘附及其抑制措施

分析了磨削中的砂轮粘附情况及其对砂轮磨损的影响 ,提出了抑制砂轮粘附的措施。     

软轴型面成形磨削中的尺寸控制

软轴型面成形磨削中的尺寸控制西安应用电子研究所张武ＣｏｎｔｒｏｌｏｆＤｉｍｅｎｓｉｏｎｉｎｆｌｅｘｉｂｌｅＳｈａｆｔＰｒｏｆｉｌｅＧｒｉｎｄｉｎｇ软轴是某航空电机的关键零件。其上有四段等分的对数螺旋线型面（图１），型面的成形加工（铣，磨等）是软轴加工...     

加工表面完整性对GH4169高温合金疲劳断口形貌的影响

通过扫描电镜观察ＧＨ４１６９高温合金常温与高温低周应力控制疲劳断口的宏观形貌与微观形貌，用断裂力学理论分析了ＧＨ４１６９高温合金疲劳断口的宏观形貌和微观形貌的特征、疲劳断裂的过程以及表面完整性对疲劳断口的宏观形貌和微观形貌的影响规律     

耐低温无石棉绝热层研制

通过添加含卤-锑的阻燃剂、芳纶纤维和增塑剂,研制了一种耐低温无石棉的丁腈绝热层配方 (TI506)。研究了芳纶纤维和增塑剂对绝热层静态烧蚀性能和Tg 的影响,对绝热层材料力学性能、比热容、热 导率等性能进行了测试。结果表明:芳纶纤维浆粕用量为10 ~15 份、芳纶短纤维用量为4 ~6 份时,绝热层烧 蚀性能最佳,线烧蚀率达到45 μm/ s,所选增塑剂DOS 用量为10 份、DBP 或ATBC 用量为20 份时,Tg 可达- 40℃,芳纶纤维制备的丁腈绝热层力学性能及烧蚀性能优良,并满足固体火箭发动机耐-40 ~60℃的环境。     

Grinding behavior and surface appearance of（TiC_p＋ TiB_w）/Ti-6Al-4V titanium matrix composites

（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.