Stainless steels

stainless-steels

34 materials across 1 types

About stainless steels

Stainless steels compared grade by grade: composition, strength, corrosion resistance and use, with the source and test condition behind every number.

Stainless steels are iron alloys with at least 10.5 percent chromium, which forms a thin oxide film that resists rust. The five families differ in structure: austenitic (304, 316), ferritic (430), martensitic (410, 440C), duplex (2205, 2507) and precipitation hardening (17-4 PH).

Strength depends on the condition as much as the grade: annealed, cold worked, hardened and tempered, or aged. Every value on these pages names its condition, and ranges in the table run across the conditions we have a source for.

At a glance

Highest yield strength: Stainless steel 440C reaches 1,896 MPa. Lowest: Stainless steel 316L starts at 170 MPa. (34 of 34 grades have a sourced value.)
Highest tensile strength: AISI 302 stainless steel reaches 2,200 MPa. Lowest: Stainless steel 409 starts at 380 MPa. (34 of 34 grades have a sourced value.)
Highest density: Martensitic stainless steel 13Cr-4Ni (UNS S41500) reaches 8.1 g/cm³. Lowest: Stainless steel 409 starts at 7.6 g/cm³. (33 of 34 grades have a sourced value.)

Ranges run across the conditions each source reports (temper, heat treatment, form), measured at room temperature where the source says so.

Types

Austenitic stainless steels: 15 grades. Austenitic stainless steels (304, 316, 316L): composition, strength and corrosion data with sources.
Duplex stainless steels: 4 grades. Duplex and super duplex stainless steels (2205, 2507): strength, pitting resistance and limits, with sources.
Ferritic stainless steels: 4 grades. Ferritic stainless steels (430): composition, strength and corrosion data with sources.
Martensitic stainless steels: 8 grades. Martensitic stainless steels (410, 440C, S41500): heat treatment, hardness and strength data with sources.
Precipitation-hardening stainless steels: 3 grades. Precipitation-hardening stainless steels (17-4 PH): strength by heat-treatment condition, with sources.

How they compare

The same measurements for every material in the collection. A range means the grade has values under several conditions; "at least" means the source gives a specified minimum. "no data" means no sourced value yet. For ranked tables, open a benchmark.

Material	Yield strength	Tensile strength	Density	Young's modulus	Thermal conductivity	Melting point
Stainless steel 304structural alloy	at least 205 MPa	at least 515 MPa	7.85 to 8.06 g/cm³	200 GPa	14 to 17 W/(m·K)	1,400 to 1,450 °C
Stainless steel 316structural alloy	193 to 213 MPa	480 to 620 MPa	7.87 to 8.07 g/cm³	190 to 205 GPa	13 to 17 W/(m·K)	1,375 to 1,440 °C
Stainless steel 316Lcorrosion-resistant structural alloy	170 to 290 MPa	485 to 558 MPa	7.99 to 8.03 g/cm³	193 to 200 GPa	14.6 to 16.2 W/(m·K)	1,390 to 1,440 °C
Duplex stainless steel 2205structural alloy	at least 450 MPa	655 to 965 MPa	7.8 to 7.82 g/cm³	190 to 200 GPa	14 to 15 W/(m·K)	1,385 to 1,441 °C
Super duplex stainless steel 2507corrosion-resistant structural alloy	at least 530 MPa	750 to 1,000 MPa	7.8 g/cm³	200 GPa	14 W/(m·K)	no data
17-4 PH stainless steelprecipitation-hardening structural alloy	725 to 1,262 MPa	930 to 1,365 MPa	7.75 to 7.86 g/cm³	196 to 201 GPa	17.9 to 22.6 W/(m·K)	1,404 to 1,440 °C
Stainless steel 440Chigh-carbon martensitic stainless steel for bearings and valve parts	1,896 MPa	1,965 MPa	7.61 to 7.7 g/cm³	200 to 210 GPa	22.8 to 24.2 W/(m·K)	1,371 to 1,482 °C
Stainless steel 410structural alloy	205 to 1,089 MPa	448 to 1,331 MPa	7.73 to 7.75 g/cm³	200 GPa	24.9 W/(m·K)	1,482 to 1,532 °C
Stainless steel 430corrosion-resistant trim and sheet alloy	207 to 386 MPa	400 to 630 MPa	7.7 to 7.74 g/cm³	200 GPa	23.9 to 26 W/(m·K)	1,425 to 1,510 °C
Martensitic stainless steel 13Cr-4Ni (UNS S41500)quenched and tempered structural alloy for turbines, pumps and valves	at least 517 MPa	700 to 1,100 MPa	7.61 to 8.1 g/cm³	190 to 215 GPa	25 W/(m·K)	no data
Stainless steel 301structural and spring alloy	205 to 1,103 MPa	515 to 1,276 MPa	7.88 to 8.03 g/cm³	174 to 200 GPa	16.3 to 21.4 W/(m·K)	1,399 to 1,421 °C
Stainless steel 303free-machining structural alloy	172 to 207 MPa	500 to 517 MPa	7.89 to 8.03 g/cm³	193 to 200 GPa	15 W/(m·K)	1,400 to 1,455 °C
Lean duplex stainless steel 2304structural alloy	at least 400 MPa	600 to 820 MPa	7.8 g/cm³	200 GPa	16 W/(m·K)	no data
Stainless steel 409exhaust and muffler stainless steel	170 to 255 MPa	380 to 560 MPa	7.6 to 7.75 g/cm³	208 to 220 GPa	25 to 25.8 W/(m·K)	no data
Stainless steel 444corrosion-resistant ferritic sheet, tube and tank alloy	275 to 350 MPa	415 to 600 MPa	7.7 to 7.75 g/cm³	215 to 220 GPa	23 W/(m·K)	no data
AISI 302 stainless steel18-8 austenitic spring and wire stainless steel with a higher carbon content than 304	195 to 338 MPa	500 to 2,200 MPa	7.9 g/cm³	193 to 200 GPa	16.3 W/(m·K)	1,400 to 1,420 °C
Stainless steel 304Lcorrosion-resistant structural alloy	170 to 241 MPa	485 to 586 MPa	7.9 g/cm³	200 GPa	16.3 to 21.4 W/(m·K)	1,399 to 1,421 °C
AISI 309 stainless steelChromium-nickel austenitic stainless steel for hot oxidising and sulphur-bearing furnace service	207 to 290 MPa	517 to 621 MPa	8.03 g/cm³	200 GPa	15.6 to 18.7 W/(m·K)	1,371 to 1,454 °C
Stainless steel 310Sheat-resistant structural alloy	205 to 290 MPa	500 to 750 MPa	7.8 to 8.03 g/cm³	195 to 196 GPa	13 to 15 W/(m·K)	1,410 °C
AISI 317L stainless steelcorrosion-resistant structural alloy	200 to 260 MPa	500 to 700 MPa	8.03 g/cm³	200 GPa	13.5 to 14 W/(m·K)	1,390 to 1,440 °C
AISI 321 stainless steeltitanium-stabilised austenitic stainless steel for high-temperature and welded service	205 to 320 MPa	515 to 586 MPa	7.92 to 8.09 g/cm³	193 GPa	15 W/(m·K)	1,398 to 1,446 °C
AISI 347 stainless steelNiobium-stabilised austenitic stainless steel for welded, hot service	205 to 250 MPa	515 to 640 MPa	7.96 g/cm³	193 GPa	16.3 W/(m·K)	1,398 to 1,446 °C
AISI 347H stainless steelHigh-carbon niobium-stabilised austenitic stainless steel for hot service	205 to 252 MPa	515 to 643 MPa	7.9 to 7.98 g/cm³	200 GPa	14 W/(m·K)	1,399 to 1,446 °C
Super-austenitic stainless steel 904Lcorrosion-resistant austenitic alloy	220 to 270 MPa	490 to 730 MPa	7.95 to 8 g/cm³	190 to 195 GPa	12 W/(m·K)	1,300 to 1,390 °C
Nitronic 60 stainless steelManganese-nitrogen austenitic stainless steel for galling and wear resistance	345 to 393 MPa	655 to 717 MPa	7.62 gm/cm3	180 GPa	9 Btu/ft hr °F	no data
Lean duplex stainless steel 2101 (UNS S32101)Lean duplex stainless steel for general process service, with high strength and chloride stress corrosion cracking resistance at lower nickel	at least 450 MPa	at least 650 MPa	7.8 g/cm³	200 GPa	16 to 18 W/(m·K)	1,385 to 1,443 °C
Stainless steel 430Ffree-machining bar alloy for automatic screw machines	379 to 500 MPa	552 to 850 MPa	7.7 g/cm³	200 GPa	25 W/(m·K)	1,482 °C
Stainless steel 410Sstructural alloy	207 to 290 MPa	414 to 448 MPa	7.73 g/cm³	200 GPa	26.9 W/(m·K)	1,480 to 1,530 °C
AISI 416 stainless steelfree-machining structural stainless steel	276 to 951 MPa	517 to 1,172 MPa	7.7 to 7.81 g/cm³	190 to 215 GPa	24.9 to 30 W/(m·K)	1,490 °C
Stainless steel 420hardenable martensitic stainless steel for blades, bearings and wear parts	355 to 1,311 MPa	592 to 1,760 MPa	7.7 to 7.75 g/cm³	200 to 215 GPa	24.9 to 30 W/(m·K)	1,454 to 1,510 °C
Stainless steel 431high-strength shaft and valve-stem stainless	600 to 1,034 MPa	800 to 1,379 MPa	7.8 g/cm³	200 to 215 GPa	25 W/(m·K)	no data
Martensitic stainless steelquenched and tempered corrosion-resistant steel for shafts, axles and pump parts	550 to 920 MPa	760 to 1,100 MPa	7.7 g/cm³	200 GPa	15 W/(m·K)	no data
17-7 PH stainless steelhigh-strength semi-austenitic precipitation-hardening stainless steel	310 to 1,896 MPa	827 to 2,034 MPa	7.65 to 7.81 g/cm³	200 GPa	16.9 W/(m·K)	1,404 to 1,440 °C
PH 15-7 Mo stainless steel (15-7 PH)Semi-austenitic precipitation-hardening stainless steel for high-strength springs, rings and aircraft parts	380 to 1,515 MPa	860 to 1,690 MPa	7.67 to 7.8 g/cm³	200 GPa	16.2 W/(m·K)	no data

Material	Main constituents
Stainless steel 304	Fe balance · Cr 18 to 20% · Ni 8 to 11% · C up to 0.08% · Mn up to 2% · Si up to 1% · P up to 0.045%
Stainless steel 316	Fe balance · Cr 16 to 18% · Ni 10 to 14% · Mo 2 to 3% · C up to 0.08% · Mn up to 2% · Si up to 0.75%
Stainless steel 316L	Fe balance · Cr 16 to 18% · Ni 10 to 14% · Mo 2 to 3% · C up to 0.03% · Mn up to 2% · Si up to 0.75%
Duplex stainless steel 2205	Fe balance · Cr 22 to 23% · Ni 4.5 to 6.5% · Mo 3 to 3.5% · N 0.14 to 0.2% · C up to 0.03% · Mn up to 2%
Super duplex stainless steel 2507	Fe balance · Cr 25% · Ni 7% · Mo 4% · N 0.3% · C up to 0.03% · Mn up to 1.2%
17-4 PH stainless steel	Fe balance · Cr 15 to 17.5% · Ni 3 to 5% · Cu 3 to 5% · Nb+Ta 0.15 to 0.45% · C up to 0.07% · Mn up to 1%
Stainless steel 440C	Fe balance · C 0.95 to 1.2% · Cr 16 to 18% · Mo up to 0.75% · Mn up to 1% · Si up to 1% · P up to 0.04%
Stainless steel 410	Fe balance · Cr 11.5 to 13.5% · C 0.08 to 0.15% · Mn up to 1% · Si up to 1% · Ni up to 0.75% · P up to 0.04%
Stainless steel 430	Fe balance · Cr 16 to 18% · C up to 0.12% · Mn up to 1% · Si up to 1% · Ni up to 0.75% · P up to 0.04%
Martensitic stainless steel 13Cr-4Ni (UNS S41500)	Fe balance · Cr 11.5 to 14% · Ni 3.5 to 5.5% · Mo 0.5 to 1% · C up to 0.05% · Mn 0.5 to 1% · Si up to 0.6%
Stainless steel 301	Fe balance · Cr 16 to 18% · Ni 6 to 8% · Mn up to 2% · Si up to 1% · C up to 0.15% · N up to 0.1%
Stainless steel 303	Fe balance · Cr 17 to 19% · Ni 8 to 10% · C up to 0.15% · Mn up to 2% · Si up to 1% · P up to 0.2%
Lean duplex stainless steel 2304	Fe balance · Cr 21.5 to 24.5% · Ni 3 to 5.5% · Mo 0.05 to 0.6% · N 0.05 to 0.2% · Cu 0.05 to 0.6% · C up to 0.03%
Stainless steel 409	Fe balance · Cr 10.5 to 11.8% · Ti up to 0.75% · C up to 0.08% · N up to 0.03% · Mn up to 1% · Si up to 1%
Stainless steel 444	Fe balance · Cr 17.5 to 19.5% · Mo 1.75 to 2.5% · C up to 0.025% · N up to 0.035% · Si up to 1% · Mn up to 1%
Stainless steel 304L	Fe balance · Cr 18 to 20% · Ni 8 to 12% · C up to 0.03% · Mn up to 2% · Si up to 0.75% · P up to 0.045%
Stainless steel 310S	Fe balance · Cr 24 to 26% · Ni 19 to 22% · C up to 0.08% · Mn up to 2% · Si up to 1.5% · P up to 0.045%
AISI 317L stainless steel	Fe balance · Cr 18 to 20% · Ni 11 to 15% · Mo 3 to 4% · Mn up to 2.0% · Si up to 0.75% · C up to 0.03%
Super-austenitic stainless steel 904L	Fe balance · Cr 19.8% · Ni 24.2% · Mo 4.3% · Cu 1.4% · C up to 0.02% · Mn up to 2%
Stainless steel 430F	Fe balance · Cr 16 to 18% · S 0.15 to 0.35% · C up to 0.12% · Mn up to 1.25% · Si up to 1% · P up to 0.06%
Stainless steel 410S	Fe balance · Cr 11.5 to 13.5% · C up to 0.08% · Mn up to 1% · Si up to 1% · Ni up to 0.6% · Ti up to 0.2%
Stainless steel 431	Fe balance · Cr 15 to 17% · Ni 1.5 to 2.5% · C 0.12 to 0.22% · Mn up to 1.5% · Si up to 1% · P up to 0.04%
Martensitic stainless steel	Fe balance · Cr 15 to 17% · Ni 4 to 6% · Mo 0.8 to 1.5% · C up to 0.06% · Si up to 0.7% · Mn up to 1.5%
17-7 PH stainless steel	Fe balance · Cr 16 to 18% · Ni 6.5 to 7.75% · Al 0.75 to 1.5% · C up to 0.09% · Mn, Si, P, S up to 1.00%

Use	Grades
Spacecraft propellant tank	Stainless steel 304
Fasteners and screws	Stainless steel 304
Architectural cladding	Stainless steel 304
Aerospace structures	Stainless steel 316, Stainless steel 316L
Chemical storage, food processing and oil refining equipment	Stainless steel 316
Parts exposed to marine atmospheres	Stainless steel 316L
Ultra-high-vacuum chamber walls (laboratory)	Stainless steel 316L
Chemical process vessels, piping and heat exchangers	Duplex stainless steel 2205
Oil and gas production tubing, flowlines and heat exchangers in sour service	Duplex stainless steel 2205
Marine propellers, shafts, rudders, pumps and valves	Duplex stainless steel 2205
Subsea umbilicals and offshore oil and gas tubing	Super duplex stainless steel 2507
Seawater cooling tubing and desalination pressure vessels	Super duplex stainless steel 2507
Propeller shafts and high-load parts in seawater	Super duplex stainless steel 2507
Aircraft and missile fittings	17-4 PH stainless steel
Bolts and fasteners	17-4 PH stainless steel
Jet engine stator vanes	17-4 PH stainless steel

Material	Best for	Weakest at
Stainless steel 304	Corrosion-resistant housings, fasteners and tanks where ordinary steel would rust	Chloride pitting in acidic solutions, and low strength compared with precipitation-hardened steels
Stainless steel 316	Chloride-bearing and marine-grade service where 304 would pit, in annealed sheet, bar and plate	Crevice and pitting attack in seawater condenser tubes, intergranular attack after heating between 500 and 900 C, and modest strength next to precipitation-hardened grades
Stainless steel 316L	Welded parts in chloride or marine service, and vacuum hardware that is vacuum-fired	Long holds near 650 C form sigma phase, and seawater service needs a pitting resistance equivalent number greater than 40 (Wikipedia)
Duplex stainless steel 2205	Chloride-bearing and sour service where 300-series steels crack, in welded pipe, tube, sheet and plate (ATI, Alleima)	Extended exposure at 343 to 530 C (475 C embrittlement), welds made with straight chromium filler, and sour service above 232 C (ATI, Alleima)
Super duplex stainless steel 2507	Chloride-bearing seawater, subsea and sour oil and gas service that needs high strength and pitting resistance, in solution-annealed tube, bar and forgings	Prolonged exposure above 250 °C, which lowers impact strength, and hydrogen-induced cracking in cathodically protected subsea steel
17-4 PH stainless steel	High-strength fittings, fasteners, shafts and valve parts that need more strength than 304 and moderate corrosion resistance	Stress corrosion cracking and pitting in peak-aged (H900) material, and crevice corrosion in stagnant salt water
Stainless steel 440C	Bearings and valve parts that must be hard and wear-resistant in the hardened and tempered condition (Carpenter, Aalco, Rolled Alloys)	Corrosion resistance in the annealed state or after tempering above about 800 F (427 C), and service above about 400 C (NASA 2018 maximum use temperature)
Stainless steel 410	Hardened and tempered valve, shaft and fastener parts that need strength and a magnetic response	Chloride, marine and strong-acid service, and toughness after tempering at 482 to 538 C
Stainless steel 430	Sinks, appliance trim and architectural cladding, where economy and moderate corrosion resistance matter more than strength (ATI)	Welds and sea water. Welds lose ductility and corrosion resistance, and the datasheet says the grade is not resistant to sea water (Deutsche Edelstahlwerke)
Martensitic stainless steel 13Cr-4Ni (UNS S41500)	Quenched and tempered turbine, pump and valve parts that need good strength and low-temperature toughness, in low-chloride media with polished surfaces	Chloride pitting (DEW: slight attack with a risk of pitting in saturated NaCl at 20 C), the 23 HRC cap for sour gas, and poor weldability (DEW)
Stainless steel 301	Springs, clips and light formed structures where cold-work strength matters more than corrosion resistance	Chloride pitting (critical pitting temperature below 10 C in Outokumpu's test) and carbide precipitation after welding or holding at 427 to 816 C
Stainless steel 303	Heavily machined parts in mild service, such as screws, nuts, bolts, shafts and fittings (Aalco, UPMET)	Chloride and marine service, where Aalco says 303 is not suitable, and welded joints, where Aalco says weldability is poor
Lean duplex stainless steel 2304	Chloride-bearing process piping and heat exchangers, pulp and paper equipment, and strength-limited structures where 304 or 316 would crack or be too weak (Alleima, ATI)	Exposure above about 315 C (600 F), where 475 C embrittlement can follow (ATI); prolonged exposure above 280 C (Alleima); weld metal without an overmatched filler (ATI)
Stainless steel 409	Automotive exhaust systems and heat exchangers, where corrosion protection is needed beyond carbon steel (Combined Metals)	Pitting and intergranular corrosion: Outokumpu prints a critical pitting temperature below 10 °C and N/N for intergranular corrosion, and Aalco limits welded sheet to about 2.5 mm thick
Stainless steel 444	Hot water tanks, heat exchangers and solar tanks in chloride-bearing water, where resistance to chloride stress cracking matters (ATI, Ugitech, Aperam)	Boiling 10 percent sulphuric and sulfamic acids, where ATI's table shows corrosion above 1000 mils per year, and toughness at transition temperatures, welds included (Aperam)
AISI 302 stainless steel	Springs, washers, screens and wire parts that need an 18-8 stainless steel with more carbon than 304 for strength, while keeping ductility (Elgiloy datasheet)	Strength in the annealed state (about 290 MPa typical yield), and ductility after heavy cold work (elongation falls from 48 % at 0 % cold work to 2.2 % at 80 % cold work, fwmetals table)
Stainless steel 304L	Welded parts in corrosive service, where the as-welded condition must resist carbide precipitation	Sea water and chloride service: Carpenter rates 304 and 304L restricted in sea water, and no pitting number for 304L was found
AISI 309 stainless steel	Hot furnace and heat-treatment parts that must resist oxidation to about 1900 to 2000 °F and keep a useful share of their room-temperature strength (Rolled Alloys, NKS, Jacquet)	Carburising atmospheres and hot strength: moderate resistance to carbon absorption (Rolled Alloys), and typical tensile strength falls from 90.0 ksi at 77 °F to 55.0 ksi at 1200 °F (Jacquet)
Stainless steel 310S	Furnace and heat-treatment parts that run hot in oxidising air up to about 1,050 °C, with good creep strength and oxidation resistance	Sulphur-bearing hot gases, which cut the service limit to 950 °C, and long exposure between 650 and 900 °C, which causes sigma-phase embrittlement and chromium-carbide sensitisation
AISI 317L stainless steel	Chloride pitting resistance in process equipment, with a low-carbon grade that limits sensitization in welds	Strength in the annealed state (205 MPa minimum yield) and chloride stress cracking above about 49 °C
AISI 321 stainless steel	Welded parts that run hot in oxidising air, from 427 to 850 degC: titanium holds the grade against carbide precipitation in the 800 to 1500 degF range	Strength when annealed (about 241 MPa typical yield) and cold-work strength only, plus exposure of 900 to 1500 degF for long periods, which lowers general corrosion resistance
AISI 347 stainless steel	Welded hot-service parts that cannot be re-annealed afterwards: niobium stabilisation resists intergranular attack, and the grade is rated to 800 °C in air	Strength when hot: tensile strength falls from 93.3 ksi at 68 °F to 69.5 ksi at 800 °F (Rolled Alloys), and no vacuum, radiation or atomic-oxygen data were found
AISI 347H stainless steel	Welded parts for hot service in air and steam, where creep strength to 1500 degF is needed and niobium stabilisation resists intergranular attack in the as-welded condition	Strength when hot: typical tensile strength falls from 93.3 ksi at 68 degF to 69.5 ksi at 800 degF (Rolled Alloys), and no vacuum, radiation or atomic-oxygen data were found
Super-austenitic stainless steel 904L	Sulfuric and phosphoric acid plant, seawater condensers and heat exchangers, and pulp bleaching, in annealed sheet, plate, strip and tube, where 316L or 317L would corrode	Halide-containing acids and boiling magnesium or lithium chloride, where ATI's U-bend test cracked the alloy, and crevices in chloride water (ATI G-48 onset at 18 °C)
Nitronic 60 stainless steel	Fasteners, pins, bushings and valve trim that must resist galling and wear while staying austenitic and low in magnetic permeability	General corrosion resistance falls between Types 304 and 316, the alloy is hard to machine, the high-strength bar cannot be hot worked or welded without losing strength, and the sources print no space-environment data
Lean duplex stainless steel 2101 (UNS S32101)	Chloride-bearing process equipment where a 300 series grade is too weak or too prone to chloride stress cracking, and nickel cost matters: the grade gives about double the 0.2 % yield of 304 and 316 and no SCC in the boiling CaCl2 U-bend test	Use above about 300 °C: Atlas says held above 300 °C the grade embrittles and only a full solution anneal restores it, and no space-environment data (radiation, outgassing, cryogenic toughness) were found
Stainless steel 430F	Machined parts cut from bar on automatic screw machines, where machinability matters more than corrosion resistance or weldability (Atlas, Deutsche Edelstahlwerke)	Corrosion and welding. The sulphur addition reduces corrosion resistance, especially pitting and crevice attack, and weldability is poor (Deutsche Edelstahlwerke)
Stainless steel 410S	Ferromagnetic, weldable stainless parts for hot or mildly corrosive service, such as distillation trays, tower packing and exhaust components, where the 410 hardening response is not wanted	Chloride and marine service (no 410S test data was found), and room-temperature brittleness in thick sections (Jacquet)
AISI 416 stainless steel	Shafts, axles, gears, valve and pump parts and screw-machine parts that must be cut quickly and then hardened, kept away from chloride exposure	Corrosion resistance. The sulfur addition lowers it below the non-free-machining grade 410, and the Aalco datasheet calls high-sulfur free-machining grades totally unsuitable for marine or chloride exposure
Stainless steel 420	Hardened wear parts, blades and bearing-type components that need high strength and edge retention, from one steel that reaches 48 HRC after tempering at 440 °F	Corrosion resistance and ductility: it resists corrosion less well than austenitic grades, and it loses strength when tempered at 1000 °F (158.5 ksi tensile)
Stainless steel 431	High tensile and torsional strength in shafts, valve stems and pump parts that also need reasonable corrosion resistance (Smith Metal, Smiths High Performance)	Welding and cold forming: welds crack unless preheated, and the grade is not recommended for cold heading or bending (Smiths High Performance, Voestalpine)
Martensitic stainless steel	Quenched and tempered shafts, axles and pump parts that need strength, toughness and good general corrosion resistance, with limited marine exposure (DEW)	Chloride pitting: DEW gives a risk of pitting corrosion in saturated sodium chloride and in sea water at 20 C, and welds need heat treatment afterwards (DEW)
17-7 PH stainless steel	Springs, Belleville washers, eyelets and flat springs that need high strength and stainless corrosion resistance, with formability in the soft state	Stress corrosion cracking in chloride and in nitrogen tetroxide/hydrazine propellant, in every heat-treated condition except CH 900; ductility in CH 900 (2 % elongation)
PH 15-7 Mo stainless steel (15-7 PH)	Springs, retaining rings and seal rings that need high strength with a low-distortion hardening heat treatment (ATI and Ulbrich list these uses)	Stress corrosion cracking in salt water: the 1969 NASA test found the alloy cracked in all conditions except CH 900, and corrosion resistance is below Type 304 (ATI)

About stainless steels

At a glance

Types

How they compare

What these materials are made of

Where they are used

When each grade fits

Materials