Replacing rusted steel post with 6 x 6 x 6 pressure treated lumber
Just wanted to says thanks for the advice.  I was able to replace all the steel post successfully and without too much trouble.  I did build 2' deep piers for each post, 8 inches in diameter.   Each pier took two bags of 50lbs concrete. On these I places a 6x6 post base with bolt secured into the concrete.I use a jack to slightly raise the porch floor so I could remove the existing post and install the new ones.  Taking my time I did each post one at a time.







Final result: