关键词: 稳定杆；球头销；电阻焊；镀锌；氢脆

Abstract: The automotive stabilizer is an important component that ensures the smoothness, handling stability, comfort, safety, and accurate driving of the vehicle. Once the ball pin of the stabilizer bar fails, it will lead to the loss of the overall function of the car stabilizer bar, seriously threatening the safety of car driving. An analysis is conducted on the fracture cause of the ball pin in the 40Cr automotive stabilizer bar. To determine the cause of failure, a comprehensive failure analysis is conducted, including macroscopic inspection, chemical composition analysis, metallographic structure analysis, micro Vickers hardness testing, fracture analysis, and hydrogen content detection. In combination with resistance welding and galvanizing processes, it is found that the fracture mode of the ball pin is intergranular brittle fracture. The reason for the fracture is the presence of local non-fusion in the outer layer of the resistance welding fusion zone and the ineffective hydrogen removal treatment after galvanizing, which led to hydrogen absorption in the welding area, resulting in hydrogen embrittlement fracture. By comparing the hydrogen content before and after heat treatment at 200 ℃ for 2 hours, it is proposed to increase the hydrogen elimination heat treatment process and control the resistance welding process parameters, aiming to avoid similar fracture failure and provide reference for the manufacturing of ball pins.

Key words: Stabilizer bar; Ball pin; Resistance welding; Galvanizition; Hydrogen embrittlement