摘要
以大型环类铝合金铸件为研究对象,通过铸件结构优化设计、合金体系选择与凝固收缩率参数优化,结合FDM/FEM数值仿真工艺,优化完成了环类铸件浇注系统的优化设计;采用分级熔炼与精炼除气工艺,氧化夹渣密度由(12~15)个/cm^2降至(2~3)个/cm^2,平均直径由2.6mm减至0.4mm;选用复合晶粒细化剂后晶粒尺寸由176μm降至68μm,合金的抗拉强度提高8%~10%,伸长率增加约60%;基于多级固溶时效热处理ZL114A合金的抗拉强度、屈服强度与伸长率分别达到了360 MPa、310 MPa与8.2%,ZL205A合金对应力学性能分别为520 MPa、460 MPa与7.4%,断口均为典型韧窝断裂。经深冷处理后,环类铸件内部残余应力峰值可由140~250 MPa降至50~105 MPa,高向与径向加工精度可提高约180%,合金T6态抗拉强度提高约20~30 MPa,伸长率提升2%~3.5%。
The optimized design of gating system for large-scale ring castings was completed by optimizing the structure, selecting the appropriate material and solidification shrinkage process parameters in com- bination with the FDM and FEM numerical simulation. The density of oxidized slagis decreases from （12~15）/cm2 to （2~3）/cm2 , and the average diameter is reduced from 2.6 mm to 0.4 mm after the graded melting and refining process. The average grain size is reduced from 176 μm to 68 μm, and the average tensile strength and elongation are increased about 8% ~10% and 60% by selecting composite grain refinement, respeotively. The average tensile strength, yield strength and elongation of ZI.114A alloy reach 360 MPa, 310 MPa and 8.2%, respectively, based on the multi-stage solid solution and ag- ing process, While the corresponding values of ZL205A are 520 MPa, 460 MPa and 7.4%, and the frac- tures are characterized by typical dimple rupture. The internal residual stress is reduced from 140 MPa~ 250 MPa to 50 MPa^105 MPa, and the machining accuracy of high and radial direction is increased a- bout 180% after the cryogenic treatment. In addition the average tensile strength and elongation are in- creased by 20 MPa^30 MPa and 2%~3.5%, repectiuely, after the T6 treatment.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2017年第7期804-809,共6页
Special Casting & Nonferrous Alloys
关键词
铝合金
环类铸件
结构优化
微观组织
残余应力
Aluminum Alloy, Ring Castings, Structure Optimization, Microstructure, Residual Stress
