Question for guys familiar with 7075 and iron alloys

I’ve never worked with 7075 but do have a lot of experience with different steels and stainless steels and wanting to build a machine that is going to have basically a solid rectangular box 4x5x7 that will be sliding about 8” between steel plates on all side but will never contact the sliding surface as I will have wear plates protecting it. My question is would you be worried about using 7075 vs steel.

I’m building a tubing roller and this rectangular piece is the bending carriage that moves up and down. I’ve actually asked a question about this build before but being that I didn’t even know about 7075 then I ask this. I would use 4140 but can’t find a piece the correct size. Is someone that reads this knows where I can get a piece of 4140 4x5x7 or 4x6x7 or 4x6x6 for a decent price let me know please. I’ve found bigger pieces but would be a pain to machine in my machines and I seen a piece of 7075 for 90 bucks that is almost perfect size that I can machine and it got me thinking. Any help is welcome

I often use rectangular or square steel tubing when I need a kind of big part, but the part does not need to be solid. It saves weight and expense. The wall thickness is proportional to the load on the part. In some cases, I have welded flat plates across the open ends to make a closed box. I always drill the required holes before doing the last weld so the box is vented.

Larry