LC9模锻件阳极氧化处理表面局部发黑分析

研究LC9模锻件阳极氧化处理表面局部发黑原因,给出阳极氧化处理工艺流程.阳极氧化液成分及工艺参数:ρ(H2SO4)为150 ～ 200 g/L,ρ(Al3+)小于20g/L,温度13～26℃,电流密度0.8 ～ 2.0 A/dm2,电压13 ～26 V,处理时间30 min；热处理工艺:465 ℃固溶处理,水冷,一级时...

Analysis of surface local nigrescence on LC9 mould forging anodic oxidation treatment

To research the reason of LC9 mould forging anodic oxidation treatment surface local nigrescence. Anodic oxidation treatment process flow is given. The composition and process parameters of anodic oxidation solution are as following： mass concentration of sulfuric acid is 150 ~ 200 g/L, mass concentration of Al3 ＋ is less than 20 g/L, temperature is 13 - 26 ℃, current density is 0.8 ~ 2.0 A/dm2, voltage is 13 - 26 V, treatment time is 30 min. Heat treatment process ： 465 ℃ solution treatment, water cooling, first aging temperature 110 ℃, 6 ~ 8 hours, second aging temperature 165 ℃, 8 - 10 hours, air cooling. The nigrescence specimen and normal specimen are analyzed contrastively by adopting element analysis, SEM, microstructure annlysis, the reason of LC9 mould forging anodic oxidation treatment surface local nigrescenee is drawn as following： alloy structure abnormal caused by improper heat treatment, large soluble dispersed precipitated phase and impurity phase, which makes anodic oxidation film appear cavities and slag inclusion, cause oxidation film nigrescence phenomena. The problem can be solved by adopting reheat treatment.