摘要
车辆制动器经维修反复拆装后发现拉杆部件的螺杆发生断裂。通过断口宏微观观察、金相和显微硬度检测等方法,并根据金相检查结果进行热模拟试验,确定了45钢制动器拉杆螺杆的断裂性质,分析了制动器拉杆螺杆断裂失效的原因。研究结果表明:制动器拉杆螺杆的断裂性质为过载断裂,未进行调质处理导致材料强度低、韧性差,加上在服役过程中可能受到异常的弯曲和冲击载荷复合作用,导致螺母与螺杆的交接处发生断裂。建议严格按照螺杆的热处理工艺规程,提升螺杆的强度和韧性。
A screw of the brake drag link of a car was found to have broken after repeated dismounting. The failure cause of the screw was analyzed by macroscopic and microscopic examination of fracture surface, metallographic examination, microhardness testing, and thermal simulation testing. The results show that the failure mode of the crew is over-loading fracture. Without modified treatment, the strength of the material and the toughness was poor. Besides, the screw might have experienced the coeffect of abnormal impact load and flexural load during service. As a result, the screw fractured at the joint of nut and screw. Strict heat treatment processing should be carried out to improve the strength and toughness of the material.
出处
《失效分析与预防》
2015年第1期47-50,共4页
Failure Analysis and Prevention
关键词
制动器拉杆螺杆
45钢
过载断裂
应力集中
调质处理
screw of brake drag link
45 steel
overloading fracture
stress concentration
modified treatment
