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Explore the World of Soft…e: Engineering & Science
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Explore_the_World_of_Software_Engineering_and_Science_HRS_Software_1998.iso
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FAMILY.TXT
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1994-11-01
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6KB
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120 lines
SELECTION OF STAINLESS STEELS
═════════════════════════════
Austenitic Family Cr-Ni-Fe ┌───────────┐
│ 309S │
┌──────────┤ 310S │
┌───────────┐ ╔═════════════════════╗ │ │ 330 │
│ 316L ├────────────╢ 302/304 ╟─┘ └───────────┘
│ 317L │ ║ 50% of Total SS ║ High
└───────────┘ ┌───╢ Production is ╟───┐ Temperature
Corrosion │ ║ Base grades 302/304 ║ │
Resistance │ ╚══════════╤══════════╝ │ ┌───────────┐
│ │ │ │ 201 │
│ │ │ │ 301 │
│ ┌─────┴─────┐ └────────┤ 316 │
┌───────────┐ │ │ 304L │ │ 329 │
│ 303 ├────────┘ │ 347 │ │ 15-5 PH │
│ 303Se │ │ 321 │ │ 17-4 PH │
└───────────┘ └───────────┘ └───────────┘
Better Greater Resistance High
Machinability to Intergranular Strength
Attack
Duplex Stainless Steels
╔═════════════════════╗
║ ║
║ Alloy 2205 ║
║ 329 ║
║ ║
╚═════════════════════╝
Higher Strength and Increased Resistance
to Chloride Stress Corrosion Cracking
Series 400 Stainless Steels
Cr-Fe for lower cost
╔═════════════════════╗
║ ║
║ 409/410 ║
┌──────────────────╢ Base Grades ╟──────────────────┐
│ ║ ║ │
│ ╚═════════╤═══════════╝ │
│ │ │
┌─────┴─────┐ ┌─────┴─────┐ ┌─────┴─────┐
│ 430 │ │ 416 │ │ 420 │
│ 442 │ │ 416S │ │ 440C │
└───────────┘ └───────────┘ └───────────┘
Improved Improved Greater
Scaling Machinability Hardness
Resistance
═══════════════════════════════════════════════════════════════════════════
HIGH TEMPERATURE OXIDATION RESISTANCE
─────────────────────────────────────
Stainless steels are widely used for their oxidation resistance at
elevated temperatures. In air, a protective scale is formed which is
generally quite stable up to about 815C (1500F) to 870C (1600F)
unless substantial cycling of temperature occurs.
Typical applications and maximum service temperatures follow:
Alloy Temperature Applications
409 815C 1500F Automotive mufflers
446 1150C 2100F Industrial furnace components
304 870C 1600F General Purpose
309 980C 1800F Industrial and refinery furnaces
310 1040C 1900F Industrial and process furnaces bolting
321/347 870C 1600F Automotive gaskets
Special Considerations for High Temperature Service
Water vapor and sulfur dioxide, if present, can accelerate oxidation
rates of stainless steels. Hydrogen sulfide and sulfur vapors are more
aggressive to stainless steels than oxygen and substantially reduce the
maximum allowable temperature in air.
Brittle failures under load have occasionally occurred from 475C
(885F) embrittlement in the ferritic grades and from sigma
formation in the 540-815C (1000-1500F) range in 309S and 310S.
═════════════════════════════════════════════════════════════════════════
HIGH STRENGTH ALLOYS
────────────────────
Where strength is a design consideration, the alloys in the first column
are generally preferred over the more widely used alloys in the second
column. Note that the regular carbon grades have somewhat higher
strength than the low carbon grades which are preferred for welded
fabrication.
Applications
304 in lieu of 304L Pump and valve shafting
321 in lieu of 304L Industrial expansion joints
347 in lieu of 304L Aircraft expansion joints
316 in lieu of 316L Heat exchanger tubing
Pump and valve shafting
329 in lieu of 316 Centrifuges
301 in lieu of 304 Wheel covers
201 in lieu of 304 Hose clamps, link belt chains
420 in lieu of 304 Steel mill roll - weld overlay
════════════════════════════════════════════════════════════════════════
MACHINING CONSIDERATIONS
────────────────────────
Stainless alloys are more difficult to machine than carbon steels. Some
of the 18/8 grades of stainless, such as 303 and 303 Se, have sulfur or
selenium additions to the alloy to enhance machinability while still
retaining, although to a reduced degree, corrosion benefits of the
stainless alloy. See the section on "Machining" in this diskette for
more information.