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Stainless Steel - Grade 316 (UNS S31600)

Chemical Formula

Fe, <0.03% C, 16-18.5% Cr, 10-14% Ni, 2-3% Mo, <2% Mn, <1% Si, <0.045% P, <0.03% S

Topics Covered

Background

Key Properties

Composition

Mechanical Properties

Physical Properties

Grade Specification Comparison

Possible Alternative Grades

Corrosion Resistance

Heat Resistance

Heat Treatment

Welding

Machining

Dual Certification

Applications

Background

Grade 316 is the standard molybdenum-bearing grade, second in importance to 304 amongst the austenitic stainless steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance to pitting and crevice corrosion in chloride environments. It has excellent forming and welding characteristics. It is readily brake or roll formed into a variety of parts for applications in the industrial, architectural, and transportation fields. Grade 316 also has outstanding welding characteristics. Post-weld annealing is not required when welding thin sections.

Grade 316L, the low carbon version of 316 and is immune from sensitisation (grain boundary carbide precipitation). Thus it is extensively used in heavy gauge welded components (over about 6mm). Grade 316H, with its higher carbon content has application at elevated temperatures, as does stabilised grade 316Ti.

The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.

Key Properties

These properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

Composition

Table 1. Composition ranges for 316 grade of stainless steels.

Grade

 

C

Mn

Si

P

S

Cr

Mo

Ni

N

316

Min

-

-

-

0

-

16.0

2.00

10.0

-

Max

0.08

2.0

0.75

0.045

0.03

18.0

3.00

14.0

0.10

316L

Min

-

-

-

-

-

16.0

2.00

10.0

-

Max

0.03

2.0

0.75

0.045

0.03

18.0

3.00

14.0

0.10

316H

Min

0.04

0.04

0

-

-

16.0

2.00

10.0

-

max

0.10

0.10

0.75

0.045

0.03

18.0

3.00

14.0

-

Mechanical Properties

Table 2. Mechanical properties of 316 grade stainless steels.

Grade

Tensile Str
(MPa) min

Yield Str
0.2% Proof
(MPa) min

Elong
(% in 50mm) min

Hardness

Rockwell B (HR B) max

Brinell (HB) max

316

515

205

40

95

217

316L

485

170

40

95

217

316H

515

205

40

95

217

Note: 316H also has a requirement for a grain size of ASTM no. 7 or coarser.

Physical Properties

Table 3. Typical physical properties for 316 grade stainless steels.

Grade

Density
(kg/m3)

Elastic Modulus
(GPa)

Mean Co-eff of Thermal Expansion (µm/m/°C)

Thermal Conductivity
(W/m.K)

Specific Heat 0-100°C
(J/kg.K)

Elec Resistivity
(nΩ.m)

0-100°C

0-315°C

0-538°C

At 100°C

At 500°C

316/L/H

8000

193

15.9

16.2

17.5

16.3

21.5

500

740

Grade Specification Comparison

Table 4. Grade specifications for 316 grade stainless steels.

Grade

UNS
No

Old British

Euronorm

Swedish
SS

Japanese
JIS

BS

En

No

Name

316

S31600

316S31

58H, 58J

1.4401

X5CrNiMo17-12-2

2347

SUS 316

316L

S31603

316S11

-

1.4404

X2CrNiMo17-12-2

2348

SUS 316L

316H

S31609

316S51

-

-

-

-

-

Note: These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.

Possible Alternative Grades

Table 5. Possible alternative grades to 316 stainless steel.

Grade

Why it might be chosen instead of 316?

316Ti

Better resistance to temperatures of around 600-900°C is needed.

316N

Higher strength than standard 316.

317L

Higher resistance to chlorides than 316L, but with similar resistance to stress corrosion cracking.

904L

Much higher resistance to chlorides at elevated temperatures, with good formability

2205

Much higher resistance to chlorides at elevated temperatures, and higher strength than 316

Corrosion Resistance

Excellent in a range of atmospheric environments and many corrosive media - generally more resistant than 304. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 1000mg/L chlorides at ambient temperatures, reducing to about 500mg/L at 60°C.

316 is usually regarded as the standard “marine grade stainless steel”, but it is not resistant to warm sea water. In many marine environments 316 does exhibit surface corrosion, usually visible as brown staining. This is particularly associated with crevices and rough surface finish.

Heat Resistance

Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 316 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 316L is more resistant to carbide precipitation and can be used in the above temperature range. Grade 316H has higher strength at elevated temperatures and is sometimes used for structural and pressure-containing applications at temperatures above about 500°C.

Heat Treatment

Solution Treatment (Annealing) - Heat to 1010-1120°C and cool rapidly. These grades cannot be hardened by thermal treatment.

Welding

Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 316 with Grade 316 and 316L with Grade 316L rods or electrodes (or their high silicon equivalents). Heavy welded sections in Grade 316 require post-weld annealing for maximum corrosion resistance. This is not required for 316L. Grade 316Ti may also be used as an alternative to 316 for heavy section welding.

Machining

A “Ugima” improved machinability version of grade 316 is available in round and hollow bar products. This machines significantly better than standard 316 or 316L, giving higher machining rates and lower tool wear in many operations.

Dual Certification

It is common for 316 and 316L to be stocked in "Dual Certified" form - mainly in plate and pipe. These items have chemical and mechanical properties complying with both 316 and 316L specifications. Such dual certified product does not meet 316H specification and may be unacceptable for high temperature applications.

Applications

Typical applications include:

  • Food preparation equipment particularly in chloride environments.
  • Laboratory benches & equipment.
  • Coastal architectural panelling, railings & trim.
  • Boat fittings.
  • Chemical containers, including for transport.
  • Heat Exchangers.
  • Woven or welded screens for mining, quarrying & water filtration.
  • Threaded fasteners.
  • Springs.

Source: Atlas Steels Australia

For more information on this source please visit Atlas Steels Australia

Date Added: Sep 13, 2001 | Updated: Jun 25, 2014
Comments
  1. Eddie Owuor Eddie Owuor Kenya says:

    Hi, I find this very informative. Would someone use these kind of specifications for accessories that are used in the house, or is there a set measurement that accommodates household usage, particularly taps and bath accessories.....towel rails ,rings etc?

  2. Kathir Esan Kathir Esan India says:

    Is this suitable for Alum (sulphate of alumina) solution preparation from alum slabs?

  3. Chris Nied Chris Nied United States says:

    Is this composition acceptable for 316 Stainless

    cr 17.72  mn .88  fe 68.77  ni 10.52  mo 2.0  - Used for railing systems  thanks

  4. Harbans Panesar Harbans Panesar India says:

    Is it possible to bend a pipe of 19 diameter & wall thickness 2.5 mm of  ss316 having radius 75 mm. Bending surface should be wrinkle free.

  5. Satoshi Takemoto Satoshi Takemoto Vietnam says:

    Can I use S.S 310 bolt with steel members?

  6. Petr Dostálík Petr Dostálík Czech Republic says:

    What speed of ultrasonic shear waves is stainless steel?
    Please. My email is dostalik@streicher.cz.
    THANKS

  7. Peer Mohamed Peer Mohamed India says:

    For solution annealing of SS316 forged matl of size 100*100 and length of 800mm what is the heating, soaking & quencing time. How do you calc the heating rate and soaking time?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoM.com.
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