ZM2镁合金铸件的SLS覆膜砂型铸造工艺研究

Casting Process of ZM2Alloy Components with Coated Sand Mold(core)by Selective Laser Sintering

在已开发的140/270目SLS覆膜砂的基础上,选用粒径≤150目的碳粉、硫铁矿和硼酸为阻燃剂,设计制备了含三组元复合阻燃剂的覆膜砂材料。经激光烧结成形,其初强度为0.58MPa,后处理强度为2.34MPa,发气量为9.7mL/g;并在750℃进行了ZM2镁合金浇注,得到了表面金属光泽的镁合金铸件,铸态下的抗拉强度为172 MPa,伸长率为4%,采用含阻燃剂的SLS覆膜砂型(芯)获得了优质镁合金铸件。

Based on the developed 140/270 mesh SLS coated sand, through selecting carbon powder, py- rite and boric acid with particle mesh size≤150 as flame retardant, coated sand materials were designed and prepared with tripropellant composite flame retardant. By the laser sintering forming, green strength is 0.58 MPa, and post-processing strength reaches 2.34 MPa with gas release of 9.7 g/mL. A coated sand mold prepared by the modified coated sand was used for pouring ZM2 magnesium alloy. And the surface qualified magnesium alloy parts were produced successfully wit tensile strength of 172 MPa and elongation of 4%. Finally, by using the SLS coated sand mold （core） with flame retardants, the high-quality magnesium alloy castings were produced.