Manufacturing process of corrosion-resistant piston rod of shock absorber for vehicle

Abstract

The invention discloses a manufacturing process of a corrosion-resistant piston rod of a shock absorber for a vehicle, comprising the following steps of: (1) blanking; (2) straightening for the first time; (3) grinding for the first time; (4) quenching; (5) tempering; (6) straightening for the second time; (7) grinding for the second time; (8) finely turning; (9) punching a mounting hole; (10) finely grinding; (11) polishing a resin grinding wheel; (12) supergrinding; (13) checking poriness; (14) automatically plating an upper suspension of a chrome wire workpiece; (15) electrolytic degreasing before the plating: carrying out the electrolytic degreasing on the workpiece as an anode in a lye tank; (16) etching the anode; (17) microcrack hard chrome plating: enabling a plating solution to flow from bottom to top in a plating tank till the plating solution overflows out of the plating tank; (18) cleaning; (19) automatically plating a lower suspension of the chrome wire workpiece; (20) removing hydrogen; and (21) supergrinding after the plating. The invention can effectively enhance the corrosion resistance of the piston rod, ensure the finished product ratio and prevent from generating hydrogen embrittlement, thereby enhancing the safety of the piston rod.

Description

technical field [0001] The invention relates to a manufacturing process for a piston rod of an automobile shock absorber. Background technique [0002] With the development of the automobile industry, higher requirements are put forward for the corrosion resistance of automobile piston rods, so as to adapt to a wide range of climate environments, especially marine environments, and to meet the various performances of automobiles without corrosion of piston rods, resulting in shock absorbers The oil seal is damaged, the oil leakage of the shock absorber fails, the vibration of the car increases, the stability and comfort of the car are affected, and in severe cases, the car is damaged, and even casualties are caused; [0003] At present, in order to improve the corrosion resistance of the piston rod of the shock absorber, its manufacturing process includes the following steps: 1) blanking: select 45# carbon steel; 2) straightening: straightness ≤ 0.1mm; 3) grinding ;4) Qu...

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: 1. After the workpiece is polished by the resin grinding wheel before electroplating, there is a big difference in its porosity or the diameter of the micro-pit on the surface, and the high porosity of the workpiece will lead to the high porosity of the coating in the future, which will reduce the workpiece. 2. The conversion rate of chromium ions in the hard chromium plating process is low, most of the electric energy is used for hydrogen evolution, the coating has fewer cracks, and the corrosion current is more concentrated, which reduces the corrosion resistance of the workpiece. It is difficult to pass the salt spray test; 3) When electrolytic degreasing, the workpiece as the cathode is easy to absorb positively charged hydrogen ions, and in the process of hard chrome plating, as the cathode, the surface of the workpiece will inevitably contact hydrogen atoms. In the process of forming chemical energy, the efficiency of chromium ion deposition on the surface of the workpiece is only about 13.7%.

The remaining about 86.3% is used for hydrogen evolution. In the above two processes, the hydrogen gas formed by the combination of two hydrogen atoms cannot be taken away in time. After a long time, it moves and accumulates to defect parts such as surface cracks and lattice cavities, forming hydrogen pressure. It is easy to produce hydrogen embrittlement, which will seriously affect the mechanical properties of the workpiece, it is difficult to bear heavy loads, and it is easy to break, resulting in car crashes and deaths