Stainless Steel alloys

As requested, please find underneath a first look into the very
extended world of Stainless Steel alloys. I am sure that our
metalurgists shall be pleased to give us all a lot more information as
which alloys befit the watch industry (3l3 + 316 with many variations):

STAINLESS STEEL OVERVIEW: ALLOY CLASSIFICATIONS

200 Series Austenitic - Alloys: 201, 202, 203, 204 & 205

Chromium-nickel-manganese alloy with high strength in the annealed .
Non-magnetic, not heat treatable and has excellent formability for
sever forming applications.

Typical use: washing machine tubs, structural applications.

300 Series Austenitic - Alloys: 301, 302, 303, 304, 305, 308, 309,
310, 314, 316, 317, 321, 330, 347, 384

Chromium-nickel alloy than can develop high strength by cold working.
Non-magnetic, not heat treatable and has good formability. Additions of
molybdenum can increase the corrosion resistance.

Typical use: Food equipment, chemical equipment, architectural
applications

400 Series Ferritic - Alloys: 405, 409, 429, 430, 434, 436, 442, 446

Straight chromium alloy, magnetic, but not heat treatable.

Typical use: Automotive trim, cooking utensils

400 Series Martensitic - Alloys: 403, 410, 414, 416, 420, 422, 431,
440

Straight chromium alloy, magnetic, but can be hardened by heat
treatment.

Typical use: Fasteners, pump shafts, turbine blades

Precipitation Hardening - Alloys: 13-8, 15-5, 15-7, 17-4, 17-7

Chromium-nickel, martensitic or austenitic. Develop strength by
precititation hardening reaction due to heat treatment.
Typical use: valves, gears, petro-chemical equipment

Duplex - Alloys: 329, 2205, 2304, 2507, 3RE60

Chromiun-nickel-molybdenum. More resistant to stress corrosion cracking
than austenitic, yet tougher than fully ferritic alloys.

Typical use: pipelines, pressure shafting

More information:

http://en.wikipedia.org/wiki/Stainless_steel
http://en.wikipedia.org/wiki/Maraging_steel
http://en.wikipedia.org/wiki/Eglin_Steel
http://www.ssina.com/publications/design.html

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