Hydraulic Cartridge Relief Valve problem was not solved twice by original manufa

Dolly is from a hydraulic equipment company in Peru. His boss thinks highly of him and plans to promote him to be purchasing manager, but a hydraulic cartridge relief valve stumped him. In the first half of last year, they sold a batch of hydraulic power units. 3 months later, the customer complained that the adjusting screw of the hydraulic cartridge relief valve had serious slippage, and the failure to adjust led to the strike of the equipment. The hydraulic cartridge relief valve manufacturer advised that this hydraulic cartridge relief valve benchmarks HydraForce, and the material is the same as HydraForce. The adjusting screw slipped after 3 months, which was caused by the high frequency of use. It can only be replaced with new ones. But it still slipped after 3 months. The customer was not satisfied, and the boss was also angry. He asked Dolly to replace the manufacturer of the hydraulic cartridge relief valve with a new one and ensure that it was safe for 1 year. Dolly became to be under great pressure.

Dolly noticed AAK hydraulic valve website on Google and left a message: What is the root cause for the regulating screw of the hydraulic cartridge relief valve to slip in 3 months? As soon as I saw this message, I guessed that he had encountered a customer complaint. After communication, I learned that the original manufacturer had replaced the valves twice, the sliding problem was still not solved. This is the first time that I have met such a model, but AAK engineer said confidently that it would not be difficult to solve the problem and guarantee it for 1 year. After 30 days, AAK sent 30 hydraulic cartridge relief valves.

Last week, Dolly sent an order for 960 hydraulic cartridge relief valves, specifically referring to AAK's hydraulic cartridge relief valve adjusting screw. More than 1 year later, there was no slippage, and the customer was satisfied. AAK hydraulic cartridge relief valve has been used at high frequency for 1 year without damage, mainly due to the following 3 aspects:

1. Special material selection: GCr15 high carbon chromium bearing steel is selected as the regulating screw of the hydraulic cartridge relief valve. After special heat treatment, its hardness and wear resistance are increased by 30%. Most hydraulic cartridge valve manufacturers do not pay attention to the regulating screw and select carbon steel.

2. Special heat treatment: the regulating screw is first heated to 810 ℃, isothermal annealed to 720 ℃, then air cooled, then oil quenched at 860 ℃, then carbonitriding at 830 ℃ for 3 hours, oil quenched, cryogenic treated at - 60 ℃ to - 70 ℃, finally tempered at 150 ℃ to 60 ℃, then air cooled, and finally