Can Stainless steel be "hardened"
YES. The 300 series stainless steel can be “hardened” BUT only by “work hardening.”
That is by cold working the material, either by cold rolling down to lighter and lighter gauges, or by “drawing” through a die or other size altering operation.
“Annealing” stainless steel will REMOVE the work hardening effect. YES and NO. The 400 series have two different stainless steel structures.
One is called “ferritic” (409, 430, 434. 439) which cannot be hardened by heat treatment.
The other is called “martensitic” (403, 410, 416, 420, & 440 A,B,C) which CAN be hardened by heat treatment.
Can stainless steel be "welded"?
YES. Stainless steel is easily welded, but the welding procedure is different than that used with carbon steel. The “filler” rod or electrode must be stainless steel. (Contact Advance Stainless Steel for more information).
Can stainless steel be machined?
Yes. However the standard grades of stainless steel are usually “gummy” and will not produce a clean chip when machined or turned. To solve this problem, many companies produce “free-machining” grades of stainless where they add a “chip-breaker” to the matrix. Grade 303 is the free-machining equivalent to grade 304.
Can stainless steel be used at very low and very high temperature?
Yes. Stainless steel has excellent properties at both extremes of the temperature scale. Stainless steel can be used down to liquid nitrogen temperatures and up to about 1800° F.
Can stainless steel rust? Why? (I thought stainless did not rust)
Stainless does not “rust” as you think of regular steel rusting with a red oxide on the surface that flakes off. If you see red rust it is probably due to some iron particles that have contaminated the surface of the stainless steel and it is these iron particles that are rusting. Look at the source of the rusting and see if you can remove it from the surface. If the iron is embedded in the surface, you can try a solution of 10% nitric and 2% hydrofluoric acid at room temperature or slightly heated. Wash area well with lots and lots of water after use. Commercially available “pickling paste” can also be used.
Do you need to “preheat” stainless steel before welding?
NO. Austenitic stainless steel (the 300 series) do not need to be preheated before welding.