精密复杂的成型模具,特别是压铸模具,为了减少变形,淬火前进行低温退火,以消除机加工应力,温度一般采用650℃,在箱式电阻炉中进行,为防止氧化采用旧木炭或铸铁屑保护,由于木炭和铸铁屑中混有杂质,对模具光洁度有一定的影响。我厂曾发生过消除应力的精密模具,在淬火后模具表面产生严重腐蚀的现象,而造成废品。此后我们利用旧报纸将退火模具包两层,然后再用旧 Precise and complicated forming molds, especially die-casting molds, in order to reduce deformation, low-temperature annealing before quenching to eliminate machining stress, the temperature is generally 650 ℃, in a box resistance furnace, to prevent the oxidation of the old charcoal or cast iron scrap Protection, due to the charcoal and cast iron mixed with impurities, have a certain impact on the mold finish. I plant had occurred to eliminate the stress of precision molds, mold surface after quenching the phenomenon of serious corrosion, resulting in waste. Since then we use the old newspaper will be annealed mold package two, and then use the old