超音波振動付加による超耐熱合金の被削性向上と切削機構解明

为了改善超耐热合金Inconel718的加工性能，利用扭转式超声振动装置对其进行了精车加工。采用CBN刀具和TiAIN涂层硬质合金刀具，在提供生态冷却剂的情况下，对超声振动装置和被加工件的夹持刚度进行了试验研究，结果表明，要实现稳定无颤振的切削加工，必须保证超声振动装置和工件的支撑刚度较高。CBN刀具的振动导致沟槽磨损和后刀面磨损增加，加工表面粗糙度变差。这可能是由于CBN刀具反复粘着和剥落，以及CBN韧性不足所致。(2)CBN刀具中添加植物油的磨损小于压缩空气。(3)CBN刀具中不含U1的新型氟碳制冷剂。与压缩空气相比，振动可以防止更多的工作粘着和端部沟槽磨损。但是，在使用新型氟碳制冷剂时，有时会出现端面断裂的情况。这必须避免。(4)与U1。当切割长度为111m时，液氮供给的粗糙度较小，接近理论值，约为2μm，这可能是由于切割温度较低，导致工件附着力较低所致。关于这一结果，还需要进一步调查。

Finish turning of super heat-resistant alloy, Inconel 718, was tried in order to improve the machinability, assisted by twist-type ultrasonic-vibration equipment. CBN tools and TiAIN coated carbide tools were used with the supply, of ecological coolant.Before the cutting experiment it is made clear that the holding stiffness of ultrasonic vibration equipment and the workpiece must be kept high to perform the stable cutting without chatter vibration.The cutting experiment shows the following;(1) Generally, the application of u1. vibration to the CBN tools results in the growth of groove wear and flank wear and the deterioration of roughness of finished surface. This may be caused by the repetition of workpiece adhesion and peeling, and the lack of toughness of CBN.(2) The supply of vegetable oil to CBN tools gives less toot wear than compressed air.(3) The supply of new fluorocarbon refrigerant to CBN tools without u1. vibration may prevent more work adhesion and end groove wear than compressed air. But, in the cape of new fluorocarbon refrigerant, the breakage of end flank sometimes happen. This must be avoided.(4) With u1. vibration the supply of liquid nitrogen shows small roughness of about 2 μm near the theoretical value after cutting length of 111 m. This result may be attributed to the low adhesion of workpiece resulting from low cutting temperature. Concerning this result, further investigation is needed