我厂5CrMnMo、5CrNiMo钢锻模,燕尾尺寸如图所示,硬度要求HRC34～37。原来燕尾自回火采用观察回火温度的方法,但受操作者技术素质的影响,燕尾硬度不稳定。后经在实践中反复摸索发现,锻模淬入油(20号机械油)冷却4min钟后,将燕尾提出油面,自回火4min钟后,再全部入油冷至180～200℃,出油后经400～500℃ I plant 5CrMnMo, 5CrNiMo steel forging die, dovetail size as shown, hardness requirements HRC34 ~ 37. The original dovetail self-tempering using tempering temperature observation method, but by the technical quality of the operator, dovetail hardness instability. After repeated exploration in practice, forging die quenching oil (20 # mechanical oil) cooling 4min, the dove raised oil surface, self-tempering 4min, then all the oil cooled to 180 ~ 200 ℃, out Oil after 400 ~ 500 ℃