Why the aluminum profile of 6063 was anodized after welding but the color of welding scar was inconsistent with that of the base material?

- May 09, 2019-

Ask: 

Do you know why the aluminum profile of 6063 was anodized after welding but the color of welding scar was inconsistent with that of the base material?

Answer: 

After welding, the metallographic composition of the welding part is different from the main body of aluminum alloy. The material is not even, after anodizing, it is the internal uneven defects appear. How could it be the same color.

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