ASTM A312 stainless steel

ASTM A312 / A312M, Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes, covering Austenitic stainless steels, and manufactured both welded and seamless type for option.

ASTM A312 stainless steel pipe is widely used for high temperature service and general service, pipe size from 1/8 inch to 30 inch for outside diameter, wall thickness from Schedule 5S to 80S.

Chemical Requirements And Mechanical Properties

ASTM A312 covers Austenitic stainless steels, including TP304, TP304L, TP304H, TP304LN, TP309S, TP309J, TP310S, TP310H, TP316, TP316L, TP316H, TP316TI, TP317, TP317L, TP321, TP321H, TP347, TP347H, these grades have unique composition and properties, common stainless steel grades with chemical composition and properties are specified as following.

Chemical Composition

Grade Carbon Silicon Manganese Chromium Nickel Molybdenum Sulfur Phosphorous
TP304 0,08 1,0 2.00 18.0 – 20.0 8.0 – 11.0 0,03 0,045
TP304L 0,035 1,0 2.00 18.0 – 20.0 8.0 – 13.0 0,03 0,045
TP316 0,08 1,0 2.00 16.0 – 18.0 10.0 – 14.0 2.00 – 3.00 0,03 0,045
TP316L 0,035 1,0 2.00 16.0 – 18.0 10.0 – 15.0 2.00 – 3.00 0,03 0,045
TP321 0,08 1,0 2.00 17.0 – 19.0 9.0 – 12.0 0,03 0,045

Mechanical Properties

Steel Grade Heat Treatment Temperure Min. º F(º C) Tensile Strength Ksi (MPa), Min. Yield Strength Ksi (MPa), Min. Elongation %, Min
TP304 Solution 1900 (1040) 75(515) 30(205) 35
TP304L Solution 1900 (1040) 70(485) 25(170) 35
TP304H Solution 1900 (1040) 75(515) 30(205) 35
TP310S Solution 1900 (1040) 75(515) 30(205) 35
TP316 Solution 1900(1040) 75(515) 30(205) 35
TP316L Solution 1900(1040) 70(485) 25(170) 35
TP316H Solution 1900(1040) 75(515) 30(205) 35
TP316Ti Solution 1900(1040) 75(515) 30(205) 35
TP321 Solution 1900(1040) 75(515) 30(205) 35
TP321H Solution Cold: 2000(1100) Hot: 1925(1050) 75(515) 30(205) 35
TP347 Solution 1900(1040) 75(515) 30(205) 35
TP347H Solution Cold: 2000(1100) Hot: 1925(1050) 75(515) 30(205)
ASTM A312 Pipe Manufacturing

ASTM A312 Seamless Pipe

Pipe should be made from stainless steel billet in hot rolling or cold drawn, no any welding process during manufacturing, seamless pipe has better pressure to withstand, annealing solution and pickling finishing condition, applied for high temperature and corrosion environment.

ASTM A312 Welded Pipe

No additional metal using automatic welding process for welded pipe, made from stainless steel strip or plate, both single welding and double welding for option, smail diameter and arge diameter are available, annealing pickling finish.

Heavily Cold-Worked (HCW) Pipe

Pipe shall be made by applying cold working of not less than 35 % reduction in thickness of both wall and weld to a welded pipe prior to the final anneal. No filler shall be used in making the weld. Prior to cold working, the weld shall be 100 % radiographically inspected.

Heat Treatment

All pipe shall be furnished in the heat-treated condition in accordance with the required heat treating temperature and cooling requirements, pipes shall be individually quenched in water or rapidly cooled by other means (direct quenched).

The pipe shall be free of scale and contaminating exogenous iron particles. Pickling, blasting, or surface finishing is not mandatory when pipe is bright annealed.

ASTM A312 Stainless Steel Pipe Tolerances

Outside Diameter

Outside Diameter, NPS Tolerance, Inch
1/8 To 1-1/2, Incl Over 1/16 Under 1/32
Over 1-1/2 To 4, Incl Over 1/32 Under 1/32
Over 4 To 8, Incl Over 1/16 Under 1/32
Over 8 To 18, Incl Over 3/32 Under 1/32
Over 18 To 26, Incl Over 1/8 Under 1/32
Over 26 To 34, Incl Over 5/32 Under 1/32
Over 34 To 48, Incl Over 3/16 Under 1/32

Wall Thickness

NPS Wall Thickness Tolerance, %
1/8 To 2-1/2 Incl., All T/D Ratios Over 20.2 Under 12.5
Over 3 To 18 Incl., T/D Up To 5% Incl. Over 22.5 Under 12.5
Over 3 To 18, Incl., T/D > 5% Over 15.0 Under 12.5
20 And Large, Welded, All T/D Ratios Over 17.5 Under 12.5
20 And Large, Seamless, T/D Up To 5% Incl. Over 22.5 Under 12.5
>20 And Large, Seamless, T/D > 5% Over 15.0 Under 12.5
ASTM A312 Welded And Seamless Pipe Sizes And Chart

ASTM A312 stainless steel pipe sizes and dimensions should conform to ANSI B36.19, nominal pipe size (NPS) ranges from NPS 1/8 [10.29 mm] to NPS 30 [762 mm], Schedule number for wall thickness from Sch 5s to Sch 80s, value stated respective for specific size, average wall and minimum wall pipe are available upon request.

Note over NPS 12 sizes are actual sizes, not like below NPS 12 size values.

ASTM A312 Equivalent steel grade:
ASTM A312 JIS G3459 DIN 17440 BS NF
TP304 SUS 304 TP X5CrNi 18 9 304S18 A 49-230
TP304H SUS 304 HTP 304S59 A 49-214
TP310 304 LTP X2 CrNi 19 9 304S14 A 49-230
TP316 SUS 304L TP
TP316H 310STP X5 CrNiMo 18 10 316S18 A 35-573
TP316L SUS 316 TP 316S59 A 49-230
TP321 SUS 316 LTP X2 CrNiMo 18 10 316S14 A 49-230
TP347 316 HTP x10 CrNiTi 18 9 321S18 A 49-230
TP347H SUS 316 LTP X5 CrNiNb 18 9 347S18 A 35-573

Nominal wall thickness for ASTM A312(Seamless and straight seame welded steel pipes)

NPS ASTM A312  WT Tolerance, %
+
1/8-2 1 /2 20.0 12.5
3~18, t/D≤ 5% 22.5 12.5
3~18, t/D> 5% 15.0 12.5
≥ 20, welded 17.5 12.5
≥ 20, seamless, t/D≤ 5% 22.5 12.5
≥ 20, seamless, t/D> 5% 15.0 12.5

ASTM A312 Stainless Steel Pipes OD Tolerance

NPS ASTM A312  OD Tolerance
+
inch mm inch mm
1/8~1 1 /2 > 1 1 /2~4 > 4~8 > 8~18 > 18~26 > 26~34 > 34~48 1/64(0.015) 1/32(0.031) 1/16(0.062) 3/32(0.093) 1/8(0.125) 5/32(0.156) 3/16(0.187) 0.4 0.8 1.6 2.4 3.2 4.0 4.8 1/32(0.031) 1/32(0.031) 1/32(0.031) 1/32(0.031) 1/32(0.031) 1/32(0.031) 1/32(0.031) 0.8 0.8 0.8 0.8 0.8 0.8 0.8

This crystal structure makes such steels non-magnetic and less brittle at low temperatures. For higher hardness and strength, carbon is added. When subjected to adequate heat treatment these steels are used as razor blades, cutlery, tools etc.

Significant quantities of manganese have been used in many stainless steel compositions. Manganese preserves an austenitic structure in the steel as does nickel, but at a lower cost.

The AISI defines the following ASTM A312 grades among others:

Also known as "marine grade" stainless steel due to its increased ability to resist saltwater corrosion compared to type 304. SS316 is often used for building nuclear reprocessing plants.


304/304L Stainless Steel

Type 304 has slightly lower strength than 302 due to its lower carbon content.

Chemical Composition - Stainless Steel 304/304L

Element Percentage by Weight Maximum Unless Range is Specified
304 304L 304H
Carbon 0.08 0.030 0.04-0.10
Manganese 2.00 2.00 2.00
Phosphorus 0.045 0.045 0.045
Sulfur 0.030 0.030 0.030
Silicon 0.75 0.75 0.75
Chromium 18.00
20.00
18.00
20.00
18.00
20.00
Nickel 8.0
10.50
8.0
12.00
8.0
10.5
Nitrogen 0.10 0.10 0.10

304 Resistance To Corrosion

Grade 317 317L
UNS Designation S31700 S31703
Carbon (C) Max. 0.08 0.035*
Manganese (Mn) Max. 2.00 2.00
Phosphorous (P) Max. 0.040 0.04
Sulphur (S) Max. 0.03 0.03
Silicon (Si) Max. 1.00 1.00
Chromium (Cr) 18.0–20.0 18.0–20.0
Nickel (Ni) 11.0–14.0 11.0–15.0
Molybdenum (Mo) 3.0–4.0 3.0–4.0
Nitrogen (N)
Iron (Fe) Bal. Bal.
Other Elements

*Maximum carbon content of 0.04% acceptable for drawn tubes

Typical Mechanical Properties-Stainless Steel 304/304L

Grade Tensile Strength Rm N/mm²
Yield Strength Rp 0.2, N/mm² Elongation (%)
304 Annealed 500-700 195 40
304L Annealed 460-680 180 40

The main constituents of 304 stainless steel - other than iron - are Chromium and Nickel.

304 contains 18 - 20% Chromium (Cr). Chromium is the essential chemical in all stainless steel and it is that which forms the thin passive layer that makes the metal "stainless"

304 also contains 8-10.5% Nickel (Ni). This is added to make the Austenitic structure more stable at normal temperatures. 

The nickel also improves high-temperature oxidation resistance makes the steel resistant to stress corrosion cracking.

Where the steel is to be stretched formed a lower percentage (8%) of nickel should be selected. If the steel is to be deep drawn a higher percentage is better (9% or more).

In addition a number of other chemicals may be present but these are expressed as maximum permited levels with the exception of the increased quantity of carbon required in 304H - i.e. a minimum of .04% and a maximum of 0.10%

*Maximum carbon content of 0.04% acceptable for drawn tubes


316/316L Stainless Steel

Type 316/316L Stainless Steel is a molybdenum steel possessing improved resistance to pitting by solutions containing chlorides and other halides.

Chemcial Composition - 316/316L stainless steel tubing and pipe

Grade 316 316L
UNS Designation S31600 S31603
Carbon (C) Max. 0.08 0.030*
Manganese (Mn) Max. 2.00 2.00
Phosphorous (P) Max. 0.045 0.045
Sulphur (S) Max. 0.030 0.030
Silicon (Si) Max. 1.00 1.00
Chromium (Cr) 16.0 – 18.0 16.0 – 18.0
Nickel (Ni) 10.0 – 14.0 10.0 – 14.0
Molybdenum (Mo) 2.0 – 3.0 2.0 – 3.0
Nitrogen (N)
Iron (Fe) Bal. Bal.
Other Elements

Typical Mechanical Properties- Stainless Steel 316/316L

Material Form Tensile Strength (ksi) Yield Strength (ksi)
% Elongation Hardness HB
Alloy 316L 316L Sheet AMS 5507 100 max - 45

-

Alloy 316 316 Sheet AMS 5524 75 min 30 45 207 max

Physical Properties - 316/316L/316H stainless steel in the Annealed Condition at -20°F to +100°F

Alloy UNS Design
-ation
Spec. Tensile Strength
psi MPa ksi
316 S31600 A249, A312 75,000 515 75
316L S31603 A270, A312 70,000 485 70
316H S31609

Yield Strength

Alloy psi MPa ksi Elongation in 2 inches (min.) % Grain Size Req. Max. Hardness Modulus of Elasticity (x106 psi) Mean Coefficient of Thermal Expansion (IN./IN./°F x 10-6) Thermal
Conductivity
(BTU-in/ft2-h-°F)
316 30,000 205 30 35 90 Rb 28.0 9.2 116
316L 25,000 170 25 90 Rb 28.0 9.2 116
316H 7 or coarser
Design Features - 316/316L Stainless Steel
  • Type 316 is more resistant to atmospheric and other mild environments than Type 304.  it is resistant to dilute solutions (i.e. 1-5%) of sulfuric acid up to 120°F.  However, in certain oxidizing acids, Type 316 is less resistant than Type 304.
  • 316 is susceptible to carbide precipitation when exposed in the temperature range of 800° - 1500°F and therefore is susceptible to intergranular corrosion in the as-welded condition.  Annealing after welding will restore corrosion resistance.
  • Type316L has the same composition as Type 316 except the carbon content is held below 0.03%.  Not unexpectedly, its general corrosion resistance and other properties closely correspond to those of Type 316.  However, it does provide immunity to intergranular attack in the as-welded condition or with short periods of exposure in the temperature range of 800° - 1500°F. The use of 316L is recommended when exposure in the carbide precipitation range is unavoidable and where annealing after welding is not practical.  However, prolonged exposure in this range may embrittle the material and make it susceptible to intergranular attack.
  • The maximum temperature for scaling resistance in contnuous services is about 1650°F, and 1500°F for intermittent service.
  • May be susceptible to chloride stress corrosion cracking.
  • Non-hardenable; non-magnetic in the annealed condition, and slightly magnetic when cold worked.
  • Improved corrosion resistance to chlorides.

310S Stainless Steel

310S Stainless Steel has excellent resistance to oxidation under constant temperatures to 2000°F.

Chemical Composition - Stainless Steel 310S

C Cr Mn Mo Ni P S Si
Max    Max Max     Max Max Max
0.08% 24% - 26% 2.0% 0.75% 19% - 22% 0.045% 0.03% 0.75%

Typical Mechanical Properties- Stainless Steel 310S

Alloy Ultimate Tensile Strength (ksi) Yield Strength (ksi)
Elongation % Reduction of Area (%) Hardness HRB
Type 310
Sheet (Sol Trtd)
AMS 5521
75-100 30 40 - 95 max
Type 310 
Bar (Sol Trtd)
AMS 5651
- - - - 187 max

Specifications - Stainless Steel 310S

  • ASTM: A312, A403, A182
  • ASME: SA312, SA403, SA182

317L Stainless Steel

317L is a molybdenum bearing austenitic chromium nickel steel similar to type 316, except the alloy content in 317L is somewhat higher.

Chemical Composition - Stainless Steel 317/317L

Grade 317 317L
UNS Designation S31700 S31703
Carbon (C) Max. 0.08 0.035*
Manganese (Mn) Max. 2.00 2.00
Phosphorous (P) Max. 0.040 0.04
Sulphur (S) Max. 0.03 0.03
Silicon (Si) Max. 1.00 1.00
Chromium (Cr) 18.0–20.0 18.0–20.0
Nickel (Ni) 11.0–14.0 11.0–15.0
Molybdenum (Mo) 3.0–4.0 3.0–4.0
Nitrogen (N)
Iron (Fe) Bal. Bal.
Other Elements

Typical Mechanical Properties- Stainless Steel 317L

Material Ultimate Tensile Strength (Mpa) 0.2 % Yield Strength (Mpa)
% Elongation in 2" Rockwell B Hardness
Alloy 317 515 205 35 95
Alloy 317L 515 205 40 95
Minimum Mechanical Properties by ASTM A240 and ASME SA 240

Specifications - Stainless Steel 317L

  • ASTM: A312, A403, A182
  • ASME: SA312, SA403, SA182

321/321H Stainless Steel

Type 321 is basic type 304 modified by adding titanium in an amount at least 5 times the carbon plus nitrogen contents.

Specifications -321/321H Stainless Steel

  • ASTM:A312, A403, A182
  • ASME: SA312, SA403, SA182

Chemical Composition - 321/321H Stainless steel

Grade 321 321H
UNS Designation S210000 S32109
Carbon (C) Max. 0.08 0.04 – 0.10
Manganese (Mn) Max. 2.00 2.00
Phosphorous (P) Max. 0.040 0.040
Sulphur (S) Max. 0.030 0.030
Silicon (Si) Max. 0.75 0.75
Chromium (Cr) 17.0 – 20.0 17.0 – 20..0
Nickel (Ni) 9.0 – 12.0 9.0 – 12.0
Molybdenum (Mo)
Nitrogen (N) 0.1 Max. 0.1 Max.
Iron (Fe) Bal. Bal.
Other Elements Ti=5(C) to 0.70% Ti=5(C) to 0.60%

*The titanium content shall not be less than 5 times the carbon content and not more than 0.60%.  321H requires the titanium content to be not less than 4 times the carbon content and not more than 0.60%.

Typical Mechanical Properties

Material Tensile Strength Rm, N/mm² Yield Strength Rp 0.2, N/mm²
% Elongation
Alloy 321 Tube
500-730 200 35

410 Stainless Steel

Type 410 is a martensitic stainless steel which is magnetic, resists corrosion in mild environents and has fairly good ductility.

Specifications - Stainless Steel 410

  • ASTM: A268, A815, A182

Chemical Composition - Stainless Steel 410

C Cr Mn Ni P S Si
Max    Max    Max Max Max
0.15% 11.5% - 13.5% 1.0% 0.5% 0.04% 0.03% 0.75%
Typical Applications - Stainless Steel 410
  • Pipelines transporting fluids mixed with solids like coal, sand or gravel.
Tensile Requirements - Stainless Steel 410

Tensile Strength (KSI): 60

Yield Strength (KSI): 30


Duplex 2205 (UNS S31803)

Duplex 2205 (UNS S31803), or Avesta Sheffield 2205 is a ferritic-austenitic stainless steel.

Specifications - Duplex 2205

  • ASTM: A790, A815, A182
  • ASME: SA790, SA815, SA182

Chemical Composition - Duplex 2205 

C Cr Fe Mn Mo N Ni P S Si
Max        Max          Max Max Max
.03% 22%-23% BAL 2.0% 3.0% -3.5% .14% - .2% 4.5%-6.5% .03% .02% 1%

Stainless steels are also classified by their crystalline structure:

  • Austenitic stainless steels comprise over 70% of total stainless steel production. They contain a maximum of 0.15% carbon, a minimum of 16% chromium and sufficient nickel and/or manganese to retain an austenitic structure at all temperatures from the cryogenic region to the melting point of the alloy. A typical composition is 18% chromium and 10% nickel, commonly known as 18/10 stainless is often used in flatware. Similarly 18/0 and 18/8 is also available. ¨Superaustenitic〃 stainless steels, such as alloy AL-6XN and 254SMO, exhibit great resistance to chloride pitting and crevice corrosion due to high Molybdenum contents (>6%) and nitrogen additions and the higher nickel content ensures better resistance to stress-corrosion cracking over the 300 series. The higher alloy content of "Superaustenitic" steels means they are fearsomely expensive and similar performance can usually be achieved using duplex steels at much lower cost.
  • Ferritic stainless steels are highly corrosion resistant, but far lessdurable than austenitic grades and cannot be hardened by heat treatment. They contain between 10.5% and 27% chromium and very little nickel, if any. Most compositions include molybdenum; some, aluminium or titanium. Common ferritic grades include 18Cr-2Mo, 26Cr-1Mo, 29Cr-4Mo, and 29Cr-4Mo-2Ni.
  • Martensitic stainless steels are not as corrosion resistant as the other two classes, but are extremely strong and tough as well as highly machineable, and can be hardened by heat treatment. Martensitic stainless steel contains chromium (12-14%), molybdenum (0.2-1%), no nickel, and about 0.1-1% carbon (giving it more hardness but making the material a bit more brittle). It is quenched and magnetic. It is also known as "series-00" steel.
  • Duplex stainless steels have a mixed microstructure of austenite and ferrite, the aim being to produce a 50:50 mix although in commercial alloys the mix may be 60:40. Duplex steel have improved strength over austenitic stainless steels and also improved resistance to localised corrosion particularly pitting, crevice corrosion and stress corrosion cracking. They are characterised by high chromium and lower nickel contents than austenitic stainless steels.

Austenitic stainless steel

Austenitic stainless steel is the most used stainless material in the world.

Austenitic stainless steel is a specific type of stainless steel alloy. Stainless steels may be classified by their crystalline structure into four main types: austenitic, ferritic, martensitic and duplex. ... Type 316 is the next most common austenitic stainless steel.

Steel No. Standard No. Type Chemical composition Other
C Si S P Mn Cr Ni Mo Other ób ós δ5 HB
00Cr17Ni14Mo2 GB1220 Bar 0.03 1 0.03 0.035 2 16-18 12-15 2-3 480 177 40 187 ψ%:60
00Cr17Ni14Mo2 GB4237 Plate 0.03 1 0.03 0.035 2 16-18 12-15 2-3 480 177 40 187
00Cr17Ni14Mo2 GB/T14976 Pipe 0.03 1 0.03 0.035 2 16-18 12-15 2-3 480 175 35
00Cr19Ni10 GB1220 Bar 0.03 1 0.03 0.035 2 18-20 8-12 480 177 40 187 ψ%:60
00Cr19Ni10 GB4237 Plate 0.03 1 0.03 0.035 2 18-20 8-12 480 177 40 187
00Cr19Ni10 GB/T14976 Pipe 0.03 1 0.03 0.035 2 18-20 8-12 480 175 35
0Cr17Ni12Mo2 GB1220 Bar 0.8 1 0.03 0.035 2 16-18.5 10-14 2-3 520 205 40 187 ψ%:60
0Cr17Ni12Mo2 GB4237 Plate 0.8 1 0.03 0.035 2 16-18 10-14 2-3 520 205 40 187
0Cr17Ni12Mo2 GB/T14976 Pipe 0.8 1 0.03 0.035 2 16-18.5 10-14 2-3 520 205 35
0Cr18Ni9 GB1220 Bar 0.7 1 0.03 0.035 2 17-19 8-11 520 205 40 187 ψ%:60
0Cr18Ni9 GB4237 Plate 0.7 1 0.03 0.035 2 17-19 8-11 520 205 40 187
0Cr18Ni9 GB/T14976 Pipe 0.7 1 0.03 0.035 2 17-19 8-11 520 205 35
0Cr18Ni10Ti GB1220 Bar 0.8 1 0.03 0.035 2 17-19 9-12 Ti:5C 520 205 40 187 ψ%:50
0Cr18Ni10Ti GB4237 Plate 0.8 1 0.03 0.035 2 17-19 9-12 Ti:5C 520 205 40 187
0Cr18Ni10Ti GB/T14976 Pipe 0.8 1 0.03 0.035 2 17-19 9-12 Ti:5C 520 205 35
0Cr18Ni12Mo2Ti GB1220 Bar 0.8 1 0.03 0.035 2 16-19 11-14 1.8-2.5 Ti:5C-0.7 530 205 40 187 ψ%:55
0Cr18Ni12Mo2Ti GB4237 Plate 0.8 1 0.03 0.035 2 16-19 11-14 1.8-2.5 Ti:5C-0.7 530 205 37 187
0Cr18Ni12Mo2Ti GB/T14976 Pipe 0.8 1 0.03 0.035 2 16-19 11-14 1.8-2.5 Ti:5C-0.7 530 205 35
1Cr18Ni9 GB4237 Plate 0.15 1 0.03 0.035 2 17-19 8-10 520 205 40 187
1Cr18Ni9 GB5310 Pipe 0.15 1 0.03 0.035 2 17-19 8-10 Cu:0.2 520 205 35
0Cr25Ni20 GB1220 Bar 0.08 1 0.03 0.035 2 24-26 19-22 520 206 40 187

Formable tubes for versatile use

Austenitic stainless steel is the most used stainless material in the world. The standard grades for everyday business are covered mainly by 304 and 316L/316Ti types of austenitics. 

Austenitic stainless steel sustains its mechanical values, even at higher temperatures. This sustainability of mechanical values makes it possible to obtain 30-minute fire resistance in stainless steel structures, without any additional fire protection.

Advantages of austenitic stainless steel:

  • Excellent formability
  • Excellent corrosion resistance
  • Toughness at low temperatures
  • Good weldability
  • Fire resistance

Available material grades for austenitic stainless steel rectangular tubes:

  • Austenitic metric (1.4301, 1.4307, 1.4404, 1.4571)
  • Austenitic imperial (304, 304L, 316L, 316 Ti)
  • Also special project materials by request

Defining Characteristics

Ferritic steels have a body-centered cubic (BCC) grain structure, but the austenitic range of stainless steels are defined by their face-centered cubic (FCC) crystal structure, which has one atom at each corner of the cube and one in the middle of each face. This grain structure forms when a sufficient quantity of nickel is added to the alloy—8 to 10 percent in a standard 18 percent chromium alloy.

In addition to being non-magnetic, austenitic stainless steels are not heat treatable. They can be cold worked to improve hardness, strength, and stress resistance, however. A solution anneals heated to 1045° C followed by quenching or rapid cooling will restore the alloy's original condition, including removing alloy segregation and re-establishing ductility after cold working.

Nickel-based austenitic steels are classified as 300 series. The most common of these is grade 304, which typically contains 18 percent chromium and 8 percent nickel.

Eight percent is the minimum amount of nickel that can be added to a stainless steel containing 18 percent chromium in order to completely convert all the ferrite to austenite. Molybdenum can also be added to a level of about 2 percent for grade 316 to improve corrosion resistance.

Although nickel is the alloying element most commonly used to produce austenitic steels, nitrogen offers another possibility. Stainless steels with a low nickel and high nitrogen content are classified as 200 series. Because it is a gas, however, only limited amounts of nitrogen can be added before deleterious effects arise, including the formation of nitrides and gas porosity that weaken the alloy.

The addition of manganese, also an austenite former, combined with the inclusion of nitrogen allows for greater amounts of the gas to be added. As a result, these two elements, along with copper—which also has austenite-forming properties—are often used to replace nickel in 200 series stainless steels.

The 200 series—also referred to as chromium-manganese (CrMn) stainless steels—were developed in the 1940s and 1950s when nickel was in short supply and prices were high. It is now considered a cost-effective substitute for 300 series stainless steels that can provide an additional benefit of improved yield strength.

Straight grades of austenitic stainless steels have a maximum carbon content of 0.08 percent. Low carbon grades or "L" grades contain a maximum carbon content of 0.03 percent in order to avoid carbide precipitation.

Austenitic steels are non-magnetic in the annealed condition, although they can become slightly magnetic when cold worked. They have good formability and weldability, as well as excellent toughness, particularly at low or cryogenic temperatures. Austenitic grades also have a low yield stress and relatively high tensile strength.

While austenitic steels are more expensive than ferritic stainless steels, they are generally more durable and corrosion resistant.

Applications

Austenitic stainless steels are used in a wide range of applications, including:

  • Automotive trim
  • Cookware
  • Food and beverage equipment
  • Industrial equipment

Applications by Steel Grade

304 and 304L (standard grade):

  • Tanks
  • Storage vessels and pipes for corrosive liquids
  • Mining, chemical, cryogenic, food and beverage, and pharmaceutical equipment
  • Cutlery
  • Architecture
  • Sinks

309 and 310 (high chrome and nickel grades):

  • Furnace, kiln, and catalytic converter components
  • 318 and 316L (high moly content grades):
  • Chemical storage tanks, pressure vessels, and piping

321 and 316Ti ("stabilized" grades):

  • Afterburners
  • Super heaters
  • Compensators
  • Expansion bellows

200 Series (low nickel grades):

  • Dishwashers and washing machines
  • Cutlery and cookware
  • In-house water tanks
  • Indoor and nonstructural architecture
  • Food and beverage equipment
  • Automobile parts

Material stainless steel grades

Also known as "marine grade" stainless steel due to its increased ability to resist saltwater corrosion compared to type 304. SS316 is often used for building nuclear reprocessing plants.

304/304L Stainless Steel

304 Stainless is a low carbon (0.08% max) version of basic 18-8 also known as 302.

316/316L Stainless Steel

Type 316 is more resistant to atmospheric and other mild environments than Type 304.

310S Stainless Steel

310S Stainless Steel has excellent resistance to oxidation under constant temperatures to 2000°F.

317L Stainless Steel

317L is a molybdenum bearing austenitic chromium nickel steel similar to type 316, except the alloy content in 317L is somewhat higher.

321/321H Stainless Steel

Type 321 is basic type 304 modified by adding titanium in an amount at least 5 times the carbon plus nitrogen contents.

410 Stainless Steel

Type 410 is a martensitic stainless steel which is magnetic, resists corrosion in mild environents and has fairly good ductility.

Duplex 2205 (UNS S31803)

Duplex 2205 (UNS S31803), or Avesta Sheffield 2205 is a ferritic-austenitic stainless steel.

Duplex 2507 (UNS S32750)

Duplex 2507 (UNS S32750) is a super duplex stainless steel with 25% chromium, 4% molybdenum..

DUPLEX UNS S32760

UNS S32760 is described as a super duplex stainless with a microstructure of 50:50 austenite and ferrite.

SA 269

ASTM A269 / A269M Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service

SA 249 Stainless Steel

ASME SA 249 Standard Specification for Welded Austenitic Steel Boiler,
Superheater, Heat-Exchanger, and Condenser Tubes.

904L Stainless steel

904L stainless steel consists of chromium, nickel, molybdenum and copper contents, these elements give type 904L stainless steel excellent properties