How to ensure the quality stability of heat treatment process in the fourth-level hard tooth surface DFY225 gear reducer

To ensure the quality stability of the heat treatment process in the DFY225 gear reducer, you can start from the following aspects:

• Control material quality : Choose steel with narrow hardenable belts, because the narrower the hardenable belt, the more stable the deformation. At the same time, controlling the A1/N content ratio in the range of 1-2.5 can narrow the hardenable belt and reduce deformation. Pay attention to the frame segregation and strip-like structure of the material to avoid affecting the uneven deformation and uneven carburization of the gear spline holes.

• Optimized preparatory heat treatment : For gear forgings of DFY225 gear reducer, if the normalized hardness is too high, the crystal is mixed, and a large amount of Sorthine or Wei's tissue is present, the inner hole will be deformed and enlarged. Therefore, temperature-controlled normalized fire or isothermal annealing can be used to treat the forgings to obtain appropriate tissue and hardness, laying a good foundation for subsequent heat treatment.

• Precisely set process parameters :

• Heating temperature and time : Accurately set the heating temperature and insulation time according to the characteristics of the gear material and the heat treatment process requirements. The furnace temperature curve can be simulated through computer software, predict the temperature distribution and the thermal reaction of the material, and then conduct actual tests, and adjust the parameters according to the results to ensure that the temperature in the furnace is uniform and the gear heating is sufficient and stable.

• Cooling medium and cooling rate : Choose a suitable cooling medium, such as controlling the hot oil quenching temperature to 100°C±120°C, because hot oil quenching is less deformation than cold oil quenching. At the same time, strictly control the cooling rate to avoid excessive internal stress and deformation of the gears caused by excessive cooling.

• Improve clamping method : Use reasonable clamping method to make the workpiece heat and cooling uniformly and the carburized layer in each part uniformly to reduce thermal stress and structural stress unevenness. For example, disc parts are perpendicular to the oil surface, shaft parts are installed vertically, compensation washer, support washer, superimposed washer, etc., and spline hole parts can be carburized mandrels, etc.

• Strengthen equipment maintenance and calibration : Regularly maintain heat treatment equipment, check whether heating elements, temperature control systems, etc. are working normally, and ensure that the equipment's temperature uniformity, control accuracy and other performance indicators meet the requirements. Determine a reasonable calibration cycle based on the frequency of equipment usage, working environment, etc., and use calibration tools such as high-precision temperature sensors to calibrate the equipment regularly and record the calibration data in detail.

• Strict process monitoring and inspection : Real-time monitoring of key parameters in the heat treatment process, such as temperature, time, cooling rate, etc., and adjust them in time when abnormalities are found. Formulate strict inspection standards and conduct hardness tests, metallographic analysis, dimensional measurement and other inspections on the heat-treated gears to ensure that the gears' hardness, microstructure, distortion and other indicators meet the requirements.

• Establish a quality management system : From raw material procurement, process design, equipment maintenance, personnel training to process monitoring and finished product inspection, establish a complete quality management system to ensure that every link meets quality requirements. At the same time, advanced methods such as statistical process control (SPC) and Six Sigma quality management have been introduced to continuously improve the heat treatment process and improve quality stability.