大切深外圆车刀刀片紧固螺钉断裂失效分析

Fracture Failure Analysis of Fastening Screws on Turning Blade of Cutting Cylindrical Turning Tools with the Larger Cutting Depth

在石油化工及核电装备的制造中,大型厚壁筒类零件切削加工量很大,车削加工过程中刀具上的紧固螺钉断裂失效严重,导致生产中停机频繁,极大降低了刀具的使用寿命和生产效率。针对此种大切深车刀进行了三维结构建模,结合生产实际并以有限元仿真为研究手段,分析螺钉失效的根本原因,为提出有效提高螺钉寿命的措施提供理论支持。分析结果表明:在大切削深度加工条件下,刀片紧固螺钉失效的主要原因为"切削力与切削热耦合作用下的剪切疲劳失效。"切削热-力耦合作用加速了紧固刀片螺钉的疲劳失效,使用寿命降低较快。

During the manufacture of petrochemical equipment and nuclear power equipment,the cutting amount of the large thick-walled cylinder parts is massive. In the turning process,fracture failure of the tool fastening screws is serious,resulting in frequently shutdown in production,greatly reducing the service life of the tool and production efficiency. Building threedimensional structural model for the turning tools with the larger cutting depth,combined with the actual production,and finite element simulation as a research means,it analyzes the basic reason of the screw failure,to provide theoretical supporting in putting forward effective measurements to improve the life of the screws. The analysis results show that,on the condition of large cutting depth processing,the main reason for the failure of fastening screws on the blade is shear fatigue failure under the effect of coupling the cutting heat with the cutting force. Thermal-mechanical coupled effect accelerates fatigue failure of fastening screws on the blade,and rapid reduction in the life of the screw.