Rear axel chassis bolts.

After some advice, had a bit of a search but couldn't find anything..
I had one of the rear axel mount areas replaced by a welder, thinking I was being clever I got him to weld in stainless bolts to prevent them rusting and snapping. It wasn't till afterwards I realised I've probably been an idiot. Do these need to be high tensile bolts? Are the stainless bolts too soft and potentially going to make it unsafe? 
Any opinions/advice much appreciated! 

I have no idea what tensile strength the original studs will have been, but I would imagine they'd be stronger than stainless steel. I wouldn't be confident in their ability to handle the sheer force on hard cornering, but that is just my opinion.

My guess repeat guess and its your decision is they would be ok, there are 4 of them and they are of a decent thickness. Its not a heavy car, the rear brakes dont do too much and its never going to pull more than 1g when cornering. I would only suggest use a torque wrench do not over tighten.  Would also suggest do not use stainless nuts, some times the thread can pickup on each other and the bolt will snap before it will undo…

Thank you for the reply's! Pretty much one for and one against 😅

Then you get the casting vote...

Just use plenty of copper Grease on the nuts so they don't get corroded or rust bound.

And don't use stainless steel bolts again for any suspension parts like the bottom bolt on the rear shocks..

I'll have to check on that one! Haven't done anything with it for a while and can't remember what I did 😅…
I need to get the drivers side sorted at some point so might just get them to change the bolts 😬