Bending 304 Stainless Round Bar

[ivorm]

Not sure if this is the right thread for this.

A friend has asked me about bending 3/4" 304 stainless steel round bar. He has a bending machine but the time it would take to get the new dies would be too long. Cold bending by hand is too hard so he wants to heat it to accomplish the bend (3" radius). I think this radius is about the limit for this size bar but I'm wondering if the heat will affect the strength?

The round bar is being formed into a large fishing hook so it would be nice if it's strength wasn't compromised.

Any help would be very much appreciated.

 

[DABwilldo]

A fishing hook from 3/4" stainless rod?! Dare I ask what you're trying to catch? Killer whales? It's not April 1st, so I'll assume this isn't a spoof.

Anyway, 304 is an austenitic stainless steel, so it shouldn't lose any strength from the heating. Bending it could would work harden it, and strengthen it substantially; if it didn't break from the tight radius of the bend...

You do want to avoid holding it for any length of time at high temperatures, or you'll compromise the corrosion resistance of the alloy. You'll get some scaling on the outside regardless, but I doubt this will matter. It'll polish away with a little work.

So, heat rapidly, bend, and water quench to protect the corrosion resistance. Post photo of finished hook and first catch with it, OK? Inquiring minds want to know...

 

[EdStainless]

If you heat it don't go above 800F. Your next option is to take the entire piece above 1900F. You don't want to spend time between those two temperatures.
If you develop any heat tint on the surface it needs to be removed by pickling in acid.

I think that you should just cold bend. It isn't that severe of a bend. Yes the 304 will work harden, but it has very good ductility.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[ivorm]

Sounds great.

Yeah I forgot to mention the hook is for fishing bluefin tuna which can weigh a lot (1496 lbs is the record) and they put up quite a fight.

Thanks guys

 

[racookpe1978]

I've cold bent 3/4 rod on a 3" radius with carbon steel.

No problems there.