Alloy 316/316L (UNS S31600/S31603) is a chromium-nickelmolybdenum austenitic stainless steel developed to provide improved corrosion resistance to Alloy 304/304L in moderately corrosive environments. It is often utilized in process streams containing chlorides or halides. The addition of molybdenum improves general corrosion and chloride pitting resistance. It also provides higher creep, stress-to-rupture and tensile strength at elevated temperatures.It is common practice for 316L to be dual certified as 316 and 316L. The low carbon chemistry of 316L combined with an addition of nitrogen enables 316L to meet the mechanical properties of 316.Alloy 316/316L resists atmospheric corrosion, as well as, moderately oxidizing and reducing environments. It also resists corrosion in polluted marine atmospheres. The alloy has excellent resistance to intergranular corrosion in the as-welded condition. Alloy 316/316L has excellent strength and toughness at cryogenic temperatures.Alloy 316/316L is non-magnetic in the annealed condition, but can become slightly magnetic as a result of cold working or welding. It can be easily welded and processed by standard shop fabrication practices.

 
 

Applications

  • Chemical and Petrochemical Processing — pressure vessels, tanks, heat exchangers, piping systems, flanges, fittings, valves and pumps
    Food and Beverage Processing
    Marine
    Medical
    Petroleum Refining
    Pharmaceutical Processing
    Power Generation — nuclear
    Pulp and Paper
    Textiles
    Water Treatment

Standards

ASTM........A 240
ASME........SA 240
AMS..........5524/5507
QQ-S........766

General Properties

Alloy 316/316L (UNS S31600/S31603) is a chromium-nickelmolybdenum austenitic stainless steel developed to provide improved corrosion resistance to Alloy 304/304L in moderately corrosive environments. It is often utilized in process streams containing chlorides or halides. The addition of molybdenum improves general corrosion and chloride pitting resistance. It also provides higher creep, stress-to-rupture and tensile strength at elevated temperatures.
It is common practice for 316L to be dual certified as 316 and 316L. The low carbon chemistry of 316L combined with an addition of nitrogen enables 316L to meet the mechanical properties of 316.


Alloy 316/316L resists atmospheric corrosion, as well as, moderately oxidizing and reducing environments. It also resists corrosion in polluted marine atmospheres. The alloy has excellent resistance to intergranular corrosion in the as-welded condition. Alloy 316/316L has excellent strength and toughness at cryogenic temperatures.
Alloy 316/316L is non-magnetic in the annealed condition, but can become slightly magnetic as a result of cold working or welding. It can be easily welded and processed by standard shop fabrication practices.

Corrosion Resistance

In most applications Alloy 316/316L has superior corrosion resistance to Alloy 304/304L. Process environments that do not corrode Alloy 304/304L will not attack this grade. One exception, however, is in highly oxidizing acids such as nitric acid where stainless steels containing molybdenum are less resistant. Alloy 316/316L performs well in sulfur containing service such as that encountered in the pulp and paper industry. The alloy can be used in high concentrations at temperatures up to 120°F (38°C).Alloy 316/316L also has good resistance to pitting in phosphoric and acetic acid. It performs well in boiling 20% phosphoric acid. The alloy can also be used in the food and pharmaceutical process industries where it is utilized to handle hot organic and fatty acids in an effort to minimize product contamination.


Alloy 316/316L performs well in fresh water service even with high levels of chlorides. The alloy has excellent resistance to corrosion in marine environments under atmospheric conditions.
The higher molybdenum content of Alloy 316/316L assures it will have superior pitting resistance to Alloy 304/304L in applications involving chloride solutions, particularly in an oxidizing environment.In most instances, the corrosion resistance of Alloys 316 and 316L will be roughly equal in most corrosive environments. However, in environments that are sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones Alloy 316L should be used because of its low carbon content.

 

Composition (Weight Percent)

 

CCT2

CPT3

ALLOY

Cr

Mo

N

PREN1

°F (°C)

°F (°C)

Type 304

18.0

0.06

19.0

<27.5

(<-2.5)

Type 316

16.5

2.1

0.05

24.2

27.5

(-2.5)

59

(15.0)

Type 317

18.5

3.1

0.06

29.7

35.0

(1.7)

66

(18.9)

SSC-6MO

20.5

6.2

0.22

44.5

110

(43.0)

149

(65)

Lowest Temperature (°F) at Which the Corrosion Rate Exceeds 5mpy

CORROSION

ENVIRONMENT

Type

316L

Type

304

2205

(UNS S32205)

2507

0.2% Hydrochloric Acid

>Boiling

>Boiling

>Boiling

>Boiling

1% Hydrochloric Acid

86

86p

185

>Boiling

10% Sulfuric Acid

122

140

167

60% Sulfuric Acid

<54

<59

<57

96% Sulfuric Acid

113

77

86

85% Phosphoric Acid

203

176

194

203

10% Nitric Acid

>Boiling

>Boiling

>Boiling

>Boiling

65% Niitric Acid

212

212

221

230

80% Acetic Acid

>Boiling

212p

>Boiling

>Boiling

50% Formic Acid

104

≤50

194

194

50% Sodium Hydroxide

194

185

194

230

83% Phosphoric Acid +

2% Hydrofluoric Acid

149

113

122

140

60% Nitric Acid +

2% Hydrocloric Acid

>140

>140

>140

>140

50% Acetic Acid +

50% Acetic Anhydride

248

>Boiling

212

230

1% Hydrochloric Acid +

0.3% Ferric Chloride

77p

68p

113ps

203ps

10% Sulfuric Acid +

2000ppm Cl- + N2

77

95

122

10% Sulfuric Acid +

2000ppm Cl- + SO2

<<59p

<59

104

WPA1, High Cl- Content

≤50

<<50

113

203

WPA2, High F- Content

≤50

<<50

140

167

ps = pitting can occur
ps = pitting/crevice corrosion can occur

 

WPA

P2O5

CL-

F-

H2SO4

Fe2O3

Al2O3

SiO2

CaO

MgO

1

54

0.20

0.50

4.0

0.30

0.20

0.10

0.20

0.70

2

54

0.02

2.0

4.0

0.30

0.20

0.10

0.20

0.70

Chemical Analysis

Weight % (all values are maximum unless a range is otherwise indicated)

Element

316

316L

Chromium

16.0 min.-18.0 max.

16.0 min.-18.0 max.

Nickel

10.0 min.-14.0 max.

10.0 min.-14.0 max.

Molybdenum

2.00 min.-3.00 max.

2.00 min.-3.00 max.

Carbon

0.08

0.030

Manganese

2.00

2.00

Phosphorus

0.045

0.045

Sulfer

0.03

0.03

Silicon

0.75

0.75

Nitrogen

0.1

0.1

Iron

Balance

Balance

 

 

Physical Properties

Density

0.285 lbs/in3
7.90 g/cm3

Specific Heat

0.11 BTU/lb-°F (32 – 212°F)
450 J/kg-°K (0 – 100°C)

Modulus of Elasticity

29.0 x 106 psi
200 GPa

 

Thermal Conductivity 212°F (100°C)

10.1 BTU/hr/ft2/ft/°F
14.6 W/m-°K

Melting Range

2450 – 2630°F
1390 – 1440°C

Electrical Resistivity

29.1 Microhm-in at 68°C
74 Microhm-cm at 20°C
Mean Coefficient of Thermal Expansion

Temperature Range

 

°F

°C

in/in °F

cm/cm °C

68-212

20-100

9.2 x 10-6

16.6 x 10-6

68-932

20-500

10.6 x 10-6

18.2 x 10-6

68-1832

20-1000

10.8 x 10-6

19.4 x 10-6

Mechanical Properties

 

ASTM

 

Typical*

Type 316

Type 316L

0.2% Offset Yield Strength, ksi

44

30 min.

25 min.

Ultimate Tensile Strength, ksi

85

75 min.

70 min.

Elongation in 2 inches, %

56

40 min.

40 min.

Reduction in Area, %

69

Hardness, Rockwell B

81

95 max.

95 max.

 

 

Fabrication Data

Alloy 316/316L can be easily welded and processed by standard shop fabrication practices.

Hot Forming

Working temperatures of 1700 – 2200°F (927 – 1204°C) are recommended for most hot working processes. For maximum corrosion resistance, the material should be annealed at 1900°F (1038°C) minimum and water quenched or rapidly cooled by other means after hot working.

Cold Forming

The alloy is quite ductile and forms easily. Cold working operations will increase the strength and hardness of the alloy and might leave it slightly magnetic.

Machining

Alloy 316/316L is subject to work hardening during deformation and is subject to chip breaking. The best machining results are achieved with slower speeds, heavier feeds, excellent lubrication, sharp tooling and powerful rigid equipment.

Operation

Tool

Lubrication

CONDITIONS

 

 

 

Depth-mm

Depth-in

Feed-mm/t

Feed-in/t

Speed-m/min

Speed-ft/min

Turning

High Speed Steel

Cutting Oil

6

.23

0.5

.019

11-16

36.1-52.5

Turning

High Speed Steel

Cutting Oil

3

.11

0.4

.016

18-23

59.1-75.5

Turning

High Speed Steel

Cutting Oil

1

.04

0.2

.008

25-30

82-98.4

Turning

Carbide

Dry or Cutting Oil

6

.23

0.5

.019

70-80

229.7-262.5

Turning

Carbide

Dry or Cutting Oil

3

.11

0.4

.016

85-95

278.9-312.7

Turning

Carbide

Dry or Cutting Oil

1

.04

0.2

.008

100-110

328.1-360.9

 

 

 

Depth of cut-mm

Depth of cut-in

Feed-mm/t

Feed-in/t

Speed-m/min

Speed-ft/min

Cutting

High Speed Steel

Cutting Oil

1.5

.06

0.03-0.05

.0012-.0020

16-21

52.5-68.9

Cutting

High Speed Steel

Cutting Oil

3

.11

0.04-0.06

.0016-.0024

17-22

55.8-72.2

Cutting

High Speed Steel

Cutting Oil

6

.23

0.05-0.07

.0020-.0027

18-23

59-75.45

 

 

 

Drill ø mm

Drill ø in

Feed-mm/t

Feed-in/t

Speed-m/min

Speed-ft/min

Drilling

High Speed Steel

Cutting Oil

1.5

.06

0.02-0.03

.0008-.0012

10-14

32.8-45.9

Drilling

High Speed Steel

Cutting Oil

3

.11

0.05-0.06

.0020-.0024

12-16

39.3-52.5

Drilling

High Speed Steel

Cutting Oil

6

.23

0.08-0.09

.0031-.0035

12-16

39.3-52.5

Drilling

High Speed Steel

Cutting Oil

12

.48

0.09-0.10

.0035-.0039

12-16

39.3-52.5

 

 

 

 

 

Feed-mm/t

Feed-in/t

Speed-m/min

Speed-ft/min

Milling Profiling

High Speed Steel

Cutting Oil

 

 

0.05-0.10

.002-.004

10-20

32.8-65.6

 

 

Welding

Alloy 316/316L can be readily welded by most standard processes. A post
weld heat treatment is not necessary.