According to the defect of coarse-grained and forging Fang aluminum alloy forgingwas informed that the aluminum alloy material, alloy die forgings forging processparameters, forging shape, mold temperature, heat treatment process parameters and so on.

2.1 the forging material

Aluminum alloy die forgings with different grades of manufacturing, the products have very big difference in the probability of coarse grain. Aluminium alloy forgingFang remind of Al Zn mg Cu alloy forgings less coarse grain defect, and aluminum - Copper - magnesium, aluminum - magnesium - silicon alloy, relatively more chance of forging appear coarse grain defect.

2.2 the forging process parameters and mold temperature

(1) a reasonable choice of the final forging temperature

The final forging temperature too low forging is very easy to appear coarse,aluminium alloy forging Fang remind especially aluminum - Copper - magnesium,aluminum - magnesium - silicon alloy must strictly control the final forging temperature, such as 2A11 (LY11) alloy blade die forging forging temperature must be higher than 390 DEG C, otherwise easily appear coarse crystal. The forging of different materials on the final forging temperature requirements are also different,but the aluminium alloy forgings all require the final forging temperature not lower than 370 DEG C.

(2) die preheating temperature should not be too low

The mold temperature is too low will accelerate the cavity of metal cooling speed,so that the deformation temperature is too low to make the metal to metal, fills the cavity and may form a coarse grain in the forging surface. Shapes and aluminium alloys and other factors of preheating temperature and forging die, general requirements for control at 300 to 400 DEG C.

(3) the degree of deformation should not be too small.

Aluminium alloy forging Fang said especially the last fire deformation degreeshould not be too small, if the degree of deformation is very small, then the crystal nucleus is less, the incubation period is too long, forging heating again (or heat treatment) after the formation of coarse grain will. If the deformation degree is smallto the critical deformation degree (about 3% ~ 15%) range, the recrystallization grain will grow up rapidly, the forgings will appear coarse grain defect. To strictly control the die forging forging fire times and every fire reduction in production,avoid because of forging fire times too much, a pressing volume is too small andthe forgings in critical state of deformation. In ensuring the metal will eventually fill the die cavity and the low streamline requirements, try to reduce the forging fire times. Simple shape can be easily shaped forgings can be a fire forming, the shapeis complex and not easy to forming of forgings forging fire times to not more than 3 times.

2.3 heat treatment parameter selection

Heat treatment quenching temperature is too high, too long holding time are easy to make the aluminum alloy forgings appear coarse grain. Forging Fang aluminum alloy known especially for Al Mg Si and Al Cu Mg alloy must be strict control of quenching temperature and holding time.