when i first started, i was curious too about what elements/materials to use and in what conditions to avoid certain others. below i pasted a section from
http://en.wikipedia.org/wiki/Stainless-steel which i found VERY helpful in eliminating most of my confusion about stainless-steel. Stainless steel Grades [list is not exhaustive] - 200 Series=97austenitic chromium-nickel-manganese alloys - 300 Series=97austenitic chromium-nickel alloys - Type 301=97highly ductile, for formed products. Also hardens rapidly during mechanical working. Good weldability. Better wear re= sistance and fatigue strength than 304. - Type 302=97same corrosion resistance as 304, with slightly higher strength due to additional carbon. - Type 303=97easier machining version of 304 via addition of sulfur and phosphorus. Also referred to as 'A1' in accordance with = International Organization for Standardization ISO 3506 [6] . - Type 304=97the most common grade; the classic 18/8 stainless steel. Also referred to as 'A2' in accordance with International Organization for Standardization ISO 3506 [7] . - Type 309=97 better temperature resistance than 304 - Type 316=97the second most common grade ,after 304,; for foodand surgical stainless steeluses; Alloy addition of molybdenum prevents specific forms of corrosion. Also known as 'marine grade' stainless steel due to its increased r= esistance to chloride corrosion compared to type 304. SS316 is often used for= building nuclear reprocessingplants. Most watches that are made of stainless steel are made of this grade. Rolex is an exception in that they use Type 904L. 18/10 stai= nless often corresponds to this grade.[1]Also referred to as 'A4' in accordance with International Organization for Standardization ISO 3506 [8] . - Type 321=97 similar to 304 but lower risk of weld decaydue to addition of titanium. See also 347 wi= th addition of niobium for desensitization during welding. - 400 Series=97ferritic and martensitic chromium alloys - Type 408=97heat-resistant; poor corrosion resistance; 11% chromium, 8% nickel. - Type 409=97cheapest type; used for automobile exhausts ; ferritic ,iron/chromium only,. - Type 410=97martensitic ,high-strength iron/chromium,. Wear resistant, but less corrosion resistant. - Type 416=97 easy to machine due to additional sulfur - Type 420=97'Cutlery Grade' martensitic; similar to the Brearley's original 'rustless steel'. Also known as 'surgical steel= '. Excellent polishability. - Type 430=97decorative, e.g., for automotive trim; ferritic. Good formability, but with reduced temperature and corrosion resist= ance. - Type 440=97a higher grade of cutlery steel, with more carbon in it, which allows for much better edge retention when the steel i= s heat treated properly. It can be hardened to Rockwell 58 hardness, makin= g it one of the hardest stainless steels. Also known as 'razor blade steel'. Available in three grades 440A, 440B, 440C ,more common, and 440F ,= free machinable,. - 500 Series=97heat resisting chromium alloys - 600 Series=97martensitic precipitation hardeningalloys - Type 630=97most common PH stainless, better known as 17-4; 17% chromium, 4% nickel [edit ] Stainless steel finishes [image: 316L stainless steel, with an unpolished, mill finish.] 316L stainless steel, with an unpolished, mill finish. Standard mill finishes can be applied to flat rolled stainless steel directly by the rollers and by mechanical abrasives. Steel is first rolle= d to size and thickness and then annealedto change the properties of the final material. Any oxidation that forms on the surface ,scale, is removed by pickling, and the passivation layer is created on the surface. A final finish can then be applied to achieve t= he desired aesthetic appearance. - No. 0 - Hot Rolled Annealed, thicker plates - No. 1 - Hot rolled, annealed and passivated - No, 2D - cold rolled, annealed, pickled and passivated - No, 2B - same as above with additional pass through polished rollers - No, 2BA - Bright Anealed ,BA, same as above with highly polished rollers - No. 3 - coarse abrasive finish applied mechanically - No. 4 - brushed finish - No. 6 - matte finish - No. 7 - reflective finish - No. 8 - mirror finish
