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OT: Carriage bolt installation in steel?

I'd think hammering a carriage bolt into 0.4" thick steel would not work very well, no matter how high-strength the bolts were.
A lathe tool bit makes a good square punch after you drill a hole in the right place. Heat the steel as necessary.
Easy enough to get grade 5 and Grade 8 carriage bolts. I have used plenty of the gr 5's, I dont like to "waste" them if bolting to wood though...
Mcmaster has them all day long
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Have you got a mig? One quick tack is enough to hold the bolt in place for tightening and a quickzip with a grinder will undo the weld if ever needed.
if there is alot to do, buy a punch and punch them square, 3/8" are slightly larger than a 1/2" square punch, but they make dedicated ones that do carriage bolts.
Would making a countersink hole and using flat head bolts be an option?
Trying to use carriage bolts is just a cluster fuk.
Regular wood deck boards use self
threading 5/16 - 18 bolts that are a flat head and
Torx drive. Maybe just use them, and countersink your
steel plate decking to suit. Then you would be using
screws that are normal to this application.