Abstract: Abstract: The disk opener is the key part of no-tillage planter and belongs to the ultrathin component. The ratio of its diameter and thickness is over 100. It is prone to end up with large deformations during the quenching process. Thus, how to reduce the deformation through optimizing the quenching parameters under the premise of achieving martensite and high hardness property is both a meaningful and challenging subject. In this paper, a new method of water jet impingement was proposed to quench the disc opener. The finite element analysis software DEFORM had been utilized to simulate the water jet impingement quenching process of the disc opener and optimize the quenching parameters. The velocity of the jet current, nozzle diameter and nozzle spacing had been selected as the process parameters of water jet impingement quenching. The control variable method was used to analyze the influence of the quenching parameter. Five levels of each jet array parameter were designed and the influences on the disc opener's hardness and flatness were simulated by DEFORM. The results show that: The nozzle spacing exerts significant influence on hardness and deformation. With the decrease of the nozzle spacing, nozzles above the disc opener become dense. At the same time, the direct heat transfer area expands and the cooling speed enlarges to achieve high hardness. The disc opener can be fully hardened and achieve the highest hardness as nozzle spacing is 4-5 mm. On the other hand, with the increase of the nozzle spacing the cooling uniformity increases first and then decreases. The deformation shows a parabola relationship with nozzle spacing and the maximum deformation reaches 1.80×10-2-3.3×10-2 mm when nozzle spacing values are 5-6 mm; as the jet velocity and nozzle diameter increase, the cooling intensity and cooling speed are improved. The disc opener's hardness and deformation increase obviously with the rise of the jet velocity under various combinations of the nozzle diameter and nozzle spacing. But the increase is not obvious when the jet velocity exceeds 6 m/s; The disc opener's hardness and deformation show a sustainable growth at the value range (nozzle diameter is 4-12 mm) of the nozzle diameter. However, an oversize nozzle diameter can induce excessive water stagnated on the disc opener's surface. During the actual quenching process, increasing the water spray quantity merely cannot acquire a high heat transfer coefficient; it should be integrated with other economic evaluation to select the appropriate nozzle diameter. Finally, a set of devices for water jet impingement quenching has been designed in this research and it has been utilized to conduct the experiment to confirm the simulation results. Hardness and flatness are measured and the experiment results show good consistency with the numerical simulation. It indicates that it is feasible to simulate the water jet impingement quenching of the disc opener. Considering the simulation results and engineering reality, the optimized water jet parameters are: jet velocity is 3-6 m/s，nozzle diameter is 6-8 mm, nozzle spacing is 4-5 mm. Under these parameters, the hardness of the quenched disk opener is 45-49HRC and the flatness is 1.28×10-2-2.49×10-2 mm.