通过在模具使用过程中回火和表面强化等再次热处理工艺,可及时消除应力,减缓龟裂,延长模具寿命。再次热处理的回火工艺为:将压铸模加热至比原回火温度低20～30℃保温3～4h,随炉冷却至400～450℃后出炉空冷;表面强化工艺为:气体软氮化,氮化温度550～570℃,保温4～6h,出炉后油冷或空冷,氮化层深度0.1～0.15mm,表面硬度600～900HV0.1。 Through the use of the mold in the process of tempering and surface re-heat treatment and other processes, the timely elimination of stress, slow down the cracks and extend die life. The tempering process of the second heat treatment is as follows: the die-casting mold is heated to a temperature 20 to 30 DEG C lower than the original tempering temperature for 3 to 4 hours, cooled in an oven to 400 to 450 DEG C and then air-cooled; the surface strengthening process is gas nitrocarburizing, Nitriding temperature 550 ~ 570 ℃, heat 4 ~ 6h, after the oil-cooled or air-cooled, nitride layer depth 0.1 ~ 0.15mm, surface hardness of 600 ~ 900HV0.1.