Annealing Stainless

[daveo]

Can 304 stainless be annealed like hardened steel so it can be drilled and milled easier? I have looked on the internet but cannot find much info.

[Oldbrock]

The 300 series stainless is austenitic and isn't hardenable. The 400 series is ferretic and can be if there is enough carbon present. When you harden steel you heat it until it in the austenitic state then quench. Peter

[daveo]

But can it be softened?

[rockrat]

Correct me if I'm wrong, but stainless is a bit different than regular old steel.

304 you heat and quench immediately to soften the material. I seem to remember doing this at the old watercooler place when we were trying to form a rolled lip edge without cracking. This took the stainless from hard as Kelsey's nuts to butter soft.

rock~

[daveo]

Thats what im after, im looking to drill and mill on a part without much trouble..... its just a decorative part. Thanks!!!

[Ries]

Yep, heat it to red, and quench it in water, and it will get as soft as its gonna get.
You can spot heat with a torch, in places like work hardened holes in progress, and pour cold water on it- this can help when you toast a drill bit.

[daveo]

Is there a type of stainless that will machine without annealing it?

[fishfrnzy]

FYI, you can anneal 304 stainless but all plate, 99% of bar and angle and probably 95% of the sheet come from the mill in the annealed condition. Welded tubing is rolled will probably be a little harder from the forming as it is made from annealed strip but hte forming will ahrden it some. The only way you can harden it is to cold work harden it ( bend it, let your cutters dwell in a spot etc)

303 ss will machine a little esier as it has sulfur added to it to make the chips break up.

[PaulF]

Yes, it can be annealed. Get the data sheets from the mill.
PaulF

[Circlip]

300 series St St sheet materials we used to purchase were always specified as S and D, Softened and Descaled. For easier to machine bar products, "L" was specified due to the Low carbon content, i.e. 303L,304L.

Regards Ian.

[rockrat]

Welded tubing is rolled will probably be a little harder from the forming as it is made from annealed strip but the forming will harden it some. The only way you can harden it is to cold work harden it ( bend it, let your cutters dwell in a spot etc)

Yup, thats what I remember about my situation. We had some welded tube that was cracking as we formed the lip. We changed to a sheet that we rolled and welded ourselves, then we formed it. Worked much better 'till we received a weird heat of flats. We had to have that batch annealed and we started requesting a cert for the material. Never had the problem again.

rock~

[madman]

304

I been machining a LOT of SS 304 also 316. I order plasma cut chunks with big hole bores already plasma cut out to within a couple hundred thou of finish size. I was trying to shorten my machining times while doing difficult ss material removel (example 6 inch bores through 2 inch thick material) I spent a LOT of time on my 2 horsepower lathe, GNAWING LIKE A BIG RAT through this stuff, I was originially fearfull as hell when my stainless steel supplier said (actually SHE said) Oh we will just Plasma cut it out? I immediately said PLEASE DONT IT WORK HARDENS and she cheerfully replied dont worry Mike we Plasma cut it (the material) while it is Under WATER. Cool i say and was worried Machining it later anyhow, NOW after machining it i havent even used coolant yet? I am surprised how well it machines. I only take very light cuts with my octomill cutter i never take more than .030 thou on two inch wide ss 304 material when squaring up the 8 inch square blocks to size, Anyhow i hope this may be a bit of help to someone for future machining and when ordering ss and having the supplier plasma the huge holes out of the Material to save headaches. Later madmad