stainless sheets 400 series

Date 06-10-2003 11:26

got a line on some 400 series stainless sheets cheap. seller does not know the actual series number. magnetic and stainless, so he figures 400 series. are all the 400 series stainless fairly corrosion resistant. I plan on a big flat pan for finishing maple syrup in. The price is low. keep in mind this is a "government project" for myself, so there won't be any concerns from inspections/codes. I don't want to boil the stuff in a rust bucket though. I realize that it welds poorly and will likely use rivets and silver solder for joining. The main thing it will be exposed to is boiling sap. For a long,long, time.

By Niekie3 (***)

Date 06-10-2003 18:06

Hi bzzzzzzzzzzzzz

Every alloy has its pro's and con's. If you have a ferritic 400 series, then it is relatively easily welded in thin material. In thicker, it suffers seriously from grain growth. If it is martensitic, then you will need to pre-heat etc..

Now for the actual question: Generally 400 series S/Steel is considdered less corrosion resistant than the austenitic S/Steels, from a "general corrosion" point of view. For your application, the 400 series may just be a better material because it has a higher thermal conductivity than the 300 series. Remember that these alloys still have at least 12 or more % Cr, and it is the Cr that really does the corrosion resistant trick.

Another advantage of 400 series is that it does not suffer from Chloride stress corrosion cracking. I don't know much about your application, but if you are going to add salt, then again, you may be better off with 400 series.

Hope this helps

Regards
Niekie Jooste
Fabristruct Solutions

By bzzzzzzzzzz (**)

Date 06-10-2003 20:21

if you're still there and have an answer...Are the 400 series steels cold workable or will it crack wiith a 90 degree bend?

By Niekie3 (***)

Date 06-11-2003 06:09

If it is a ferritic steel, then it will be no problem to bend it. With martensitic, you have the potential that it will crack.

Regards
Niekie Jooste
Fabristruct Solutions

By bzzzzzzzzzz (**)

Date 06-11-2003 11:21

Am I correct that it is ferritic if applied heat has little effect on the stiffness of the steel. (assuming it is a 400 series that is) With martensitic being heat treatable. (and showing softness upon applying heat)

By Niekie3 (***)

Date 06-11-2003 18:04

Hi bzzzzzzzzzzzz

You are correct that ferritic S/Steel is not heat treatable, while martensitic is. It is however not as easy as to say that if it softens with heat that it must be a martensitic s/steel. The reason being that you may have a cold worked ferritic that will "soften" on heating. In addition, you may have a fully annealed martensitic that will not appreciably "soften" with heat.

If you are trying to see what type of material it is, you could either try a hardness test, or cut a small piece off the plate and heat it to around 1000°C and quench it. If it becomes brittle it will be martensitic, if not then it will be ferritic.

Regards
Niekie Jooste
Fabristruct Solutions

By bzzzzzzzzzz (**)

Date 06-11-2003 20:17

amazing stuff, this metallurgy. Thanks for the answers.

By TimGary (****)

Date 06-11-2003 12:51

Hey Bzzzzzzz,
Keep in mind that if you do silver solder this, you'll need to stay away from solder containing Cadmium, or you'll poison your syrup.
It would be kind of like drinking moonshine made in a car radiator.
Tim

By jwright650 (*****)

Date 06-11-2003 13:05

Tim,
Good point!, Hiccup.
John Wriggghhhhhhtttttttttttttttt

By bzzzzzzzzzz (**)

Date 06-11-2003 15:19

oh yeah, or lead for that matter. That's part of the reason I want to stick with stainless. Not to mention it cleans easier. In the old days they used lead solder on galvanized sheets. And I've yet to hear of massive deaths due to poisonings. But I suppose it doesn't hurt to do it up right just the same.