The depth of carburizing layer on the gear surface is uneven, resulting in discontinuous performance of different parts. The weak area is damaged first, and then the whole gear is damaged, which seriously affects the service life of the gear.
1. Cause analysis
(1) During solid carburizing, the temperature difference in each part of the carburizing box is large, and the uneven carburizing agent causes great differences in carburizing depth. In addition, the size of the carburizing box, furnace loading amount, furnace loading mode, heating rate and charcoal thermal conductivity of the carburizing agent are too low, which will affect the carburizing layer depth.
(2) During gas carburizing, uneven temperature in the furnace, poor circulation of atmosphere in the furnace, failure to remove oil stains from the gear before charging, and carbon black deposition on the gear surface may lead to uneven carburizing layer depth.
2. Preventive measures
(1) Solid carburizing shall be avoided as far as possible for gears produced in batch. When solid carburizing is necessary, the operation process shall be strictly implemented, the charging amount shall be appropriate, and the penetrating agent and charcoal shall be mixed evenly. The carburizing box shall be placed in the middle of the furnace with uniform temperature, and the position of the carburizing box shall be properly changed in the middle of the carburizing process.
(2) During gas carburizing, pay attention to the full circulation of atmosphere in the furnace, uniform furnace temperature, removal of oil stain on the tooth surface, not too much furnace loading, good sealing performance of carburizing furnace, timely replace the leaking muffle tank, and regularly overhaul the carburizing furnace.